Symptom-Based Approach
Amnesia
Clinical Scenario
A 62-year-old man is brought to the emergency department by his wife after suddenly becoming unable to recall events of the past several hours. He repeatedly asks the same questions, is oriented to person and place, but not to time, and has no recollection of how they arrived at the hospital. He has no weakness, speech disturbance, or seizure activity. The episode began abruptly about two hours ago after a stressful family argument. Neurological examination is otherwise normal, and there is no history of head trauma or substance use.
Differential Diagnosis
Transient global amnesia
Transient ischemic attack or hippocampal stroke
Psychogenic (dissociative) amnesia
Toxic/metabolic encephalopathy
Transient epileptic amnesia
Approach to Diagnosis
Evaluation begins by confirming the onset, duration, and nature of memory loss. A focused examination helps differentiate transient global amnesia (TGA) from vascular, epileptic, or metabolic causes. The five most informative physical examination findings are:
Orientation and attention – assess for confusion or impaired awareness suggesting global encephalopathy rather than isolated amnesia.
Memory testing – repeat immediate and delayed recall tasks (e.g., three-word recall) to document anterograde amnesia and recovery pattern.
Cranial nerve and visual field testing – identify subtle posterior circulation deficits or hippocampal involvement.
Motor and coordination testing – check for weakness, ataxia, or asymmetry that would suggest stroke.
Cardiovascular and fundoscopic examination – evaluate for hypertension, arrhythmias, or carotid bruits that may indicate vascular risk.
These bedside findings, combined with MRI (hippocampal DWI lesions) and metabolic screening, guide differentiation between TGA and other etiologies such as seizure, stroke, or toxic-metabolic causes.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
TGA is characterized by sudden-onset anterograde amnesia with preserved identity and language.
Episodes typically resolve within 24 hours and recurrence is rare.
Emotional or physical triggers often precede the event.
MRI with DWI may show transient hippocampal lesions but can be normal early.
Differentiation from seizure, stroke, and toxic or psychogenic causes is essential.
Aphasia
Clinical Scenario
A 68-year-old right-handed person develops sudden difficulty producing words and understanding complex sentences over the course of one hour. Family members notice frequent word substitutions and hesitations during spontaneous speech. There is no head trauma. Past history includes hypertension and hyperlipidemia. No prior seizures are known. On arrival, the patient is alert and follows simple commands but struggles with naming and repeating phrases. Facial symmetry is preserved; there is slight right-arm clumsiness reported by the patient but no objective weakness on brief screening.
Differential Diagnosis
Ischemic stroke in the dominant middle cerebral artery (MCA) territory
Primary progressive aphasia (nonfluent, semantic, or logopenic variants)
Post-ictal (or ictal) aphasia related to focal seizures
Brain tumor involving the dominant perisylvian/language network
Autoimmune or infectious encephalitis affecting language networks
Approach to Diagnosis
Establish whether the language disturbance is acute, subacute, or progressive. Acute onset with vascular risk factors suggests ischemic stroke; gradual progression points to neurodegenerative disease. The five most informative physical examination findings are:
Speech fluency: Assess spontaneous speech for word-finding pauses, effortful output, or jargon.
Comprehension: Test ability to follow simple and complex commands.
Repetition: Have the patient repeat short and long phrases to identify conduction or global aphasia.
Naming: Evaluate confrontation naming (e.g., objects or pictures) to distinguish Broca from anomic aphasia.
Associated neurological signs: Examine for right facial or limb weakness, sensory loss, or visual field defects suggesting dominant MCA stroke.
Supporting tests include glucose, CBC, and coagulation studies in acute presentations, thyroid and B12 for chronic cases, and MRI with DWI or CT angiography to confirm vascular etiology. EEG or CSF studies are considered for seizure, autoimmune, or infectious causes.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Rapidly differentiate aphasia from dysarthria and apraxia of speech by systematically evaluating fluency, comprehension, naming, and repetition.
Acute onset of aphasia, especially with vascular risk factors, is a stroke emergency—initiate urgent neuroimaging and reperfusion assessment.
Always determine the time course: abrupt onset suggests vascular etiology; progressive decline points to neurodegenerative disease; fluctuating symptoms may indicate seizures.
Localizing the specific aphasia type (e.g., Broca, Wernicke, conduction, global) helps infer lesion site and guides management.
Consider non-vascular causes (seizures, tumors, encephalitis, metabolic or toxic etiologies) in atypical presentations or when imaging is unrevealing.
Apraxia
Clinical Scenario
A 72-year-old right-handed male develops difficulty performing daily activities over several weeks. He can describe how to use a comb or a toothbrush but fumble when asked to demonstrate these actions on command. Family notes dressing difficulties (misplacing sleeves), trouble imitating simple gestures, and occasional left–right confusion. There is no new weakness, numbness, or vertigo. On brief screening, speech remains fluent without dysarthria, and motor strength is preserved, but purposive actions break down during tool-use pantomime or multistep gesture sequencing.
Differential Diagnosis
Apraxia (dominant praxis network disorder)
Ideational or ideomotor apraxia subtypes
Callosal disconnection syndrome
Constructional or dressing apraxia
Corticobasal syndrome or Alzheimer spectrum neurodegeneration
Approach to Diagnosis
A focused neurological examination helps distinguish apraxia from motor, sensory, or language deficits. The goal is to confirm impaired praxis and localize the lesion within the dominant parietofrontal network. The five most informative physical examination tests are:
Gesture to command– ask the patient to pantomime tool use (e.g., “show me how you use a comb”). Poor performance on command with preserved imitation suggests ideomotor apraxia.
Gesture imitation – demonstrate a symbolic or tool-related gesture for the patient to copy. Failure of imitation despite comprehension suggests more widespread praxis impairment.
Actual tool use – provide common tools and observe for sequencing errors, misuse, or hesitation; failure of multistep actions suggests ideational apraxia.
Constructional and dressing tasks – have the patient copy simple figures or dress themselves to identify visuospatial and motor planning deficits.
Assessment of intermanual asymmetry – test each hand separately to detect callosal disconnection (e.g., left-hand errors to verbal command with intact right-hand performance).
Additional assessments include language testing to exclude aphasia, visuospatial tasks (line bisection, cancellation) to rule out neglect, and executive testing for sequencing ability. MRI of the brain (DWI/FLAIR) localizes lesions in the inferior parietal lobule, premotor/supplementary motor areas, or corpus callosum. FDG-PET may show network hypometabolism in degenerative disease, and neuropsychological testing quantifies praxis and associated cognitive deficits.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Apraxia is a disorder of learned purposeful movement not explained by weakness, sensory loss, or incoordination.
Differentiate apraxia from aphasia, neglect, and executive dysfunction by testing gesture imitation and tool-use pantomime.
Common subtypes include ideomotor, ideational, limb-kinetic, callosal, and constructional/dressing apraxia.
Diagnostic clues include impaired pantomime on command with preserved imitation, multistep sequencing errors, and visuospatial deficits.
Frequent causes are stroke (dominant MCA or corpus callosum), neurodegenerative diseases (corticobasal syndrome, Alzheimer spectrum), neoplasm, and autoimmune or infectious processes.
Ataxia
Clinical Scenario
A 58-year-old individual presents with a one-year history of progressively worsening unsteadiness while walking and frequent tripping. They report increasing difficulty with fine motor tasks such as buttoning shirts and handwriting. There is no history of dizziness, vertigo, or sensory disturbances. The symptoms have insidiously developed without any acute episodes or identifiable triggers. The patient denies alcohol use or exposure to neurotoxins and has no known family history of neurological disorders. Daily activities have become limited due to concerns about balance and coordination.
Differential Diagnosis
Sensory ataxia secondary to peripheral neuropathy
Vestibular dysfunction
Cerebellar ataxia (degenerative or hereditary)
Normal pressure hydrocephalus
Vitamin deficiency (e.g., B12, E)
Approach to Diagnosis
Evaluation begins with a comprehensive neurological examination to distinguish sensory, vestibular, and cerebellar causes of ataxia.
Five most important physical examination findings include
Proprioception and Romberg Test: Impaired proprioception or a positive Romberg test indicates sensory ataxia.
Nystagmus or Vertigo: Presence of these findings suggests vestibular dysfunction.
Limb Coordination: Dysmetria on finger–nose and heel–knee–shin testing is characteristic of cerebellar ataxia.
Gait Assessment: A wide-based, staggering gait pattern is typical of cerebellar disease.
Speech Evaluation: Dysarthria or scanning speech reflects cerebellar involvement.
Laboratory testing should include evaluation for metabolic and nutritional deficiencies such as vitamin B12 and vitamin E. Brain MRI is essential to identify cerebellar atrophy, demyelination, or structural lesions. If peripheral and vestibular causes are excluded and MRI demonstrates cerebellar degeneration, a diagnosis of cerebellar ataxia is most consistent. Hereditary or degenerative etiologies should be explored with family history and genetic testing. Normal pressure hydrocephalus should be considered if gait disturbance is accompanied by urinary incontinence and cognitive decline, supported by imaging findings.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Ataxia can arise from sensory, vestibular, or cerebellar dysfunction; careful clinical evaluation distinguishes these.
Sensory ataxia is characterized by impaired proprioception and absent reflexes, often due to peripheral neuropathy.
Vestibular ataxia typically presents with vertigo and nystagmus.
Cerebellar ataxia involves incoordination and dysmetria, with preserved sensation and reflexes.
Vitamin deficiencies (B12, E) and normal pressure hydrocephalus are reversible causes and should be investigated.
Athetosis
Clinical Scenario
A 52-year-old person develops subacute, progressive, involuntary writhing movements of the fingers and hands that now interfere with handwriting and utensil use. Family observes intermittent facial grimacing and fluctuations with stress and fatigue. Strength, sensation, and coordination are intact, but movements persist at rest and worsen with posture and action. There is a remote history of mood changes.
Differential Diagnosis
Huntington-spectrum neurodegeneration
Wilson disease
Autoimmune chorea/dyskinesia (e.g., lupus, Sydenham, post–COVID/other)
Structural basal ganglia lesion (lacunar stroke, tumor, demyelination)
Drug-induced dyskinesia (levodopa, antipsychotics), metabolic/toxic
Approach to Diagnosis
Start with a targeted bedside exam to confirm athetosis and localize within the basal ganglia network. Five most informative physical examination tests:
Movement phenomenology: Characterize quality and distribution—slow, sinuous distal writhing favors athetosis; chorea is faster/irregular; dystonia shows sustained patterned postures. Confirm persistence at rest and worsening with posture/action.
Activation/suppressibility maneuvers: Test distractibility, entrainment, and voluntary suppression to identify functional overlay or psychogenic features.
Extrapyramidal signs: Assess rigidity, bradykinesia, postural instability, and look for coexisting chorea or dystonia to support basal ganglia involvement and mixed phenotypes.
Oculomotor and orofacial exam: Check for saccadic intrusions, impaired pursuits, and orobuccal dyskinesias—clues to Huntington spectrum disorders.
Systemic/neurologic clues: Slit lamp for Kayser Fleischer rings; distal sensory exam and reflexes for peripheral neuropathy; patterned dystonic postures features suggesting Wilson disease or neuroacanthocytosis.
In addition to the physical examination, basic laboratory studies (CMP, thyroid, B12, copper studies) and brain MRI are essential to identify metabolic or structural causes. MRI often reveals basal ganglia signal change or atrophy, and additional imaging such as FDG-PET or DAT scans may assist in distinguishing degenerative or dopaminergic etiologies.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Athetosis presents as slow, writhing distal limb movements persisting at rest and worsening with action.
Differentiate from chorea (faster, irregular), dystonia (sustained postures), tremor, and myoclonus by movement quality and pattern.
Common causes include Huntington disease, Wilson disease, neuroacanthocytosis, autoimmune, metabolic, structural, and drug-induced etiologies.
Family history and subacute onset suggest hereditary or autoimmune causes; abrupt focal onset favors structural lesions.
Kayser–Fleischer rings and peripheral neuropathy are key clues for Wilson disease and neuroacanthocytosis.
Bradykinesia
Clinical Scenario
A 68-year-old man presents with gradually worsening slowness of movement over the past year. He notices increasing difficulty initiating movements, taking longer to complete daily activities, and smaller handwriting. Family members report reduced facial expression and decreased arm swing while walking. There is no history of recent stroke, new medications, or toxin exposure. Neurological examination is otherwise unremarkable aside from movement slowness.
Differential Diagnosis
Idiopathic Parkinson’s disease
Atypical parkinsonism (MSA, PSP, CBD, DLB)
Vascular parkinsonism
Drug-induced parkinsonism
Normal pressure hydrocephalus
Approach to Diagnosis
Evaluation of bradykinesia centers on targeted physical examination to characterize movement slowness, symmetry, associated features, and functional impact. Five most important physical examination assessments:
Finger tapping and hand opening/closing: Assess speed, amplitude, and decrement with repetition — core bedside tests for bradykinesia.
Tone and rigidity testing: Examine for cogwheel or lead-pipe rigidity in wrists and elbows to differentiate Parkinsonian from spastic tone.
Postural and gait evaluation: Observe arm swing, stride length, and turning; reduced arm swing and shuffling gait suggest parkinsonism.
Facial expression and voice: Look for hypomimia and hypophonia, which commonly accompany idiopathic Parkinson’s disease.
Eye movements and postural stability: Vertical gaze limitation points to PSP, while early falls and poor postural reflexes suggest atypical parkinsonism.
In addition, basic labs (CBC, CMP, thyroid, ceruloplasmin) and brain MRI help rule out vascular or metabolic causes, while DAT-SPECT or PET imaging aids in confirming dopaminergic deficit and differentiating idiopathic from atypical parkinsonism.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Differentiating idiopathic Parkinson’s disease from atypical causes is critical for prognosis and management.
Asymmetric onset, presence of tremor, and good levodopa responsiveness strongly suggest idiopathic Parkinson’s disease.
Early falls, vertical gaze palsy, and autonomic failure are important clues pointing towards atypical parkinsonism.
Vascular parkinsonism often presents with a lower-body predominance and a stepwise clinical course.
DAT-SPECT imaging and careful clinical follow-up are valuable in cases where diagnosis is uncertain.
Chorea
Clinical Scenario
A 45-year-old man presents with a 2-year history of involuntary, irregular, dance-like movements involving his limbs and face. His wife reports progressive difficulty with memory, concentration, and mood swings, including irritability and depression. There is a family history of similar movements and early dementia in his father. Neurological examination reveals choreiform movements, mild rigidity, and impaired executive function. Genetic testing confirms an expanded CAG repeat in the HTT gene, consistent with Huntington’s disease.
Differential Diagnosis
Huntington’s disease (genetic)
Sydenham’s chorea (post-streptococcal autoimmune)
Drug-induced chorea (e.g., levodopa, antiepileptics)
Wilson’s disease (copper metabolism disorder)
Lupus erythematosus with neuropsychiatric involvement
Approach to Diagnosis
The diagnostic approach to chorea begins with a detailed history emphasizing onset, tempo, family history, and neuropsychiatric features. Physical examination is central to identifying the underlying etiology. Five most important physical examination includes:
Observation of involuntary movements: Note distribution, amplitude, and character—irregular, unpredictable, flowing movements are classic for chorea.
Motor tone and strength assessment: Evaluate for accompanying rigidity or dystonia, which may indicate basal ganglia involvement or mixed movement disorders.
Eye movement examination: Look for saccadic intrusions or slow pursuit abnormalities, particularly suggestive of Huntington’s disease.
Cognitive and psychiatric screening: Brief bedside evaluation for executive dysfunction, irritability, or mood changes helps distinguish neurodegenerative from secondary causes.
Gait and balance testing: Assess for instability, fidgety gait, or choreiform truncal movements, which help gauge functional impact and disease severity.
Supporting investigations include serum ceruloplasmin and copper levels for Wilson’s disease, antistreptolysin O titers for Sydenham’s chorea, and autoimmune panels when systemic disease is suspected. MRI may show caudate nucleus atrophy in Huntington’s disease, and definitive confirmation requires HTT gene testing.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
| Family history of chorea and dementia | Choreiform, non-rhythmic movements | Serum ceruloplasmin | MRI brain for basal ganglia changes | Huntington disease |
| Subacute onset after infection or autoimmune trigger | Associated psychiatric or cognitive changes | Autoimmune markers | CSF analysis if encephalitis suspected | Autoimmune chorea |
| History of pregnancy | Limb chorea resolving postpartum | Hormonal profile | MRI brain | Chorea gravidarum |
| History of neuroleptic use | Tardive movements, orofacial involvement | Drug levels if relevant | Imaging if secondary cause suspected | Drug-induced chorea |
| Childhood onset with systemic involvement | Kayser–Fleischer rings | Liver function, copper, ceruloplasmin | MRI basal ganglia | Wilson disease |
Key Clinical Points
Chorea is a hallmark of several neurologic and systemic disorders; onset pattern, family history, and associated features guide diagnosis.
Huntington’s disease should be considered in adult-onset cases with cognitive and psychiatric features.
Always exclude reversible causes like drug-induced chorea, Wilson’s disease, and autoimmune etiologies.
MRI and targeted laboratory testing help differentiate causes, but genetic testing is definitive for Huntington’s.
Management is supportive and multidisciplinary, including pharmacologic symptom control and psychological support.
Confusion / Altered Mental Status
Clinical Scenario
A 72-year-old man is brought to the emergency department by his family for acute confusion and disorientation over the past 12 hours. He is unable to state the date or recognize family members, frequently repeats questions, and appears inattentive. Past medical history is notable for hypertension and type 2 diabetes. He is afebrile, vital signs are stable, and neurological examination shows no focal deficits. Laboratory tests reveal mild hyponatremia.
Differential Diagnosis
Delirium – acute, fluctuating course, impaired attention, reversible.
Dementia – chronic, progressive cognitive decline without fluctuation.
Metabolic encephalopathy – due to systemic derangements (e.g., hepatic, renal, electrolyte).
Toxic encephalopathy – due to medications, alcohol, or poisons.
Structural brain lesions – stroke, subdural hematoma, tumor causing acute cognitive change.
Approach to Diagnosis
Confusion/ AMS is almost always secondary to non neurological causes and likely from metabolic or infectious processes. A focused history should clarify onset, course, and associated factors such as infection, trauma, or toxins. The five key physical examinations include:
Level of consciousness and arousal
Attention and orientation
Pupillary size and reactivity
Presence of meningeal or focal neurological signs
Signs of systemic illness (fever, dehydration, jaundice)
Laboratory studies should include CBC, electrolytes, renal and liver function, thyroid panel, glucose, and toxicology screen. Neuroimaging (CT/MRI) is indicated when structural pathology is suspected, while lumbar puncture is performed for possible CNS infection. EEG assists in detecting nonconvulsive status epilepticus or diffuse encephalopathy when the diagnosis remains uncertain.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Rapid differentiation between delirium, dementia, metabolic, toxic, and structural causes is critical for management.
Always rule out reversible causes (e.g., hypoglycemia, infection, electrolyte imbalance) early in the evaluation.
A thorough medication review is essential as polypharmacy is a common culprit.
EEG is useful for diagnosing nonconvulsive status epilepticus or diffuse encephalopathy when etiology is unclear.
More often that not, confusion is multifactorial, especially in elderly patients with comorbidities.
Diplopia
Clinical Scenario
A 62-year-old man presents with sudden onset of double vision that worsens when he looks to the right. He denies headache, trauma, or vision loss. His past medical history includes hypertension and diabetes mellitus. On examination, his right eye fails to abduct past the midline, while other ocular movements are intact. Pupils are equal and reactive, and there are no sensory or motor deficits elsewhere.
Differential Diagnosis
CN VI palsy
CN III palsy
Myasthenia gravis
Thyroid eye disease
Internuclear ophthalmoplegia
Approach to Diagnosis
Evaluation of diplopia begins with distinguishing monocular from binocular causes. A focused history should document onset, duration, variability, and associated neurological or systemic symptoms. The five most important physical examinations in diplopia include:
Assessment of ocular motility in all directions of gaze to identify paresis or restriction.CN VI palsy – horizontal diplopia, worse on lateral gaze.CN III palsy – ptosis, "down and out" eye, possible pupillary involvement.
Evaluation of pupil size and reactivity to detect compressive or parasympathetic involvement.Myasthenia gravis – fluctuating diplopia, fatigability, variable involvement.restrictive ophthalmopathy, proptosis.Internuclear ophthalmoplegia – failure of adduction with nystagmus of abducting eye.
Eyelid inspection for ptosis or fatigability suggesting myasthenia gravis.
Alignment testing (cover–uncover and alternate cover tests) to detect subtle deviations.
Observation for associated neurological signs such as facial weakness, sensory deficits, or ataxia indicating brainstem pathology.
Supporting investigations include thyroid function tests, acetylcholine receptor antibodies, and inflammatory markers if systemic disease is suspected. MRI or CT of the brain and orbits is warranted to evaluate for structural, demyelinating, or orbital causes.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Always distinguish monocular from binocular diplopia—monocular causes are rarely neurological and often ocular (e.g., lens or corneal pathology).
Binocular diplopia that varies with gaze direction suggests extraocular muscle or cranial nerve involvement; associated neurological symptoms may indicate brainstem or systemic disease.
Isolated, pupil-sparing cranial nerve palsies in patients with vascular risk factors is usually due to microvascular ischemia of the nerve. It can be observed, but urgent imaging is warranted if there is pupil involvement, pain, or additional deficits.
Myasthenia gravis and thyroid eye disease are common mimics; consider variability, fatigability, and systemic features.
Beware of "occult" trauma, orbital pathology, or giant cell arteritis (in older adults) when symptoms are atypical or accompanied by pain.
Dizziness
Clinical Scenario
A 55-year-old woman develops brief spinning when rolling over in bed or looking up. Episodes last <1 minute with nausea but no hearing loss, headache, or focal neurological symptoms. Between attacks she is normal, but Dix-Hallpike provokes vertigo with torsional upbeat nystagmus.
Differential Diagnosis
- Benign paroxysmal positional vertigo (BPPV)
- Vestibular neuritis/labyrinthitis
- Posterior circulation stroke (AICA/PICA)
- Meniere disease
- Vestibular migraine
Approach to Diagnosis
Clarify whether symptoms are vertigo, presyncope, or imbalance; note timing (acute vs episodic), triggers (position, standing), hearing changes, migraine history, and vascular risk factors. The five most important examinations include:
- HINTS exam (head impulse, nystagmus, test of skew) in acute vestibular syndrome to separate peripheral from central causes.
- Dix-Hallpike maneuver to elicit positional vertigo/nystagmus typical of BPPV.
- Orthostatic vitals to uncover autonomic failure, hypovolemia, or medication-related hypotension.
- Gait and stance (Romberg, tandem) to detect cerebellar or sensory ataxia.
- Focused neuro exam for limb ataxia, dysarthria, diplopia, weakness, or sensory loss that suggests stroke.
Baseline labs (glucose, electrolytes) can exclude metabolic triggers. Audiometry is indicated if hearing loss accompanies vertigo. MRI brain with diffusion and vascular imaging is warranted when central signs or red flags are present.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
- First separate true vertigo from presyncope or imbalance; then use timing, triggers, and targeted exam to localize.
- HINTS (by trained examiners) can outperform early MRI in acute vestibular syndrome for detecting stroke.
- Positional vertigo with classic torsional upbeat nystagmus strongly suggests BPPV; treat with canalith repositioning maneuvers.
- Red flags (new focal deficits, severe gait ataxia, direction-changing nystagmus, headache, neck pain, vascular risk) warrant emergent MRI with vascular imaging.
- Hearing changes point toward inner ear pathology (Meniere, labyrinthitis, AICA stroke); normal hearing favors vestibular neuritis or central causes.
Dysarthria
Case Scenario
A 65-year-old man with a history of hypertension presents with slurred speech for two days. His wife reports that he is otherwise alert and understands speech normally. There is no history of confusion, word-finding difficulty, or limb weakness. On examination, his speech is slow and effortful, with preserved comprehension and naming. Cranial nerve exam reveals right-sided tongue deviation.
Differential Diagnosis
Stroke involving corticobulbar pathways
Motor neuron disease (e.g., ALS)
Cerebellar ataxia
Myasthenia gravis or neuromuscular junction disorders
Brainstem tumor or demyelinating disease (e.g., MS)
Approach to Diagnosis
Begin with a detailed history to determine onset, tempo, and associated neurological symptoms. Sudden onset suggests a vascular event, while gradual progression indicates a degenerative or neoplastic process. The five most important physical examinations in dysarthria include:
Speech quality and articulation — classify spastic, flaccid, ataxic, hypokinetic/hyperkinetic, or mixed features.
Cranial nerve examination (V, VII, IX, X, XII) — assess facial symmetry, palatal movement, and tongue strength/deviation.
Gag reflex and palatal elevation — identify bulbar involvement and risk of aspiration.
Fatigability testing — look for fluctuation with repeated counting or sustained phonation to assess neuromuscular junction disorders.
Screen for associated limb or cerebellar signs — check dysmetria, ataxic gait, or UMN signs that refine localization.
Laboratory evaluation and imaging are guided by clinical findings: MRI of the brain and brainstem for structural causes, and EMG/nerve conduction studies when neuromuscular disease is suspected.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Dysarthria is a motor speech disorder due to impaired muscle control of the speech apparatus.
Comprehension and language content are intact, differentiating it from aphasia.
It can result from supranuclear, nuclear, or peripheral lesions involving corticobulbar tracts, brainstem nuclei, or cranial nerves.
It may be associated with other brainstem signs or motor deficits depending on the lesion site.
Careful speech analysis (rate, rhythm, articulation) can help localize the lesion.
Dyskinesia
Clinical Scenario
A 58-year-old woman with schizophrenia treated with a dopamine receptor–blocking agent (DRBA) for many years presents with involuntary, repetitive orobuccolingual movements. Her family notes chewing motions, tongue protrusions, and lip smacking that worsen with stress and diminish during sleep. She denies rigidity or bradykinesia. On examination, there are choreoathetoid movements of the face and distal upper limbs with intermittent trunk swaying. Strength, reflexes, and sensation are normal.
Differential Diagnosis
Tardive dyskinesia (drug-induced)
Drug-induced parkinsonism
Huntington disease (chorea)
Dystonia (including tardive dystonia)
Akathisia
Approach to Diagnosis
Begin with a detailed treatment history, focusing on duration and cumulative exposure to dopamine receptor–blocking agents and the timing of symptom onset after prolonged therapy or dose changes. The five most important physical examinations in this patient include:
Assessment of involuntary movement type and distribution — chorea, athetosis, or stereotypy, particularly in the orobuccolingual region.
Evaluation for rigidity and bradykinesia to exclude drug-induced parkinsonism.
Inspection for dystonic posturing or sustained contractions suggestive of tardive dystonia.
Observation of movement variability, suppressibility, and disappearance during sleep to confirm dyskinesia.
Assessment for associated neurologic deficits or psychiatric symptoms indicating broader basal ganglia involvement.
Laboratory studies may help exclude metabolic, autoimmune, or genetic mimics when indicated. Severity should be quantified using standardized tools such as the AIMS scale. Neuroimaging is typically normal and reserved for atypical presentations or diagnostic uncertainty.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Tardive dyskinesia is a chronic, often irreversible complication of long-term dopamine receptor blockade, distinguished by delayed onset and persistent orobuccolingual movements.
Symptoms may fluctuate with attention, stress, or voluntary suppression and typically decrease during sleep.
VMAT2 inhibitors (valbenazine, deutetrabenazine) are first-line treatments, with dose reduction or switching to lower-risk agents as adjunctive strategies.
Regular screening with AIMS and early recognition are essential for mitigating severity and improving quality of life.
Distinguishing TD from acute dystonia, akathisia, parkinsonism, and primary chorea is crucial for management.
Dysphagia
Clinical Scenario
A 68-year-old woman presents with progressive difficulty swallowing over the past 3 months. Initially, she struggled with solid foods, but now also with liquids. She frequently coughs during meals and reports unintentional weight loss. Neurological examination reveals mild dysarthria and tongue fasciculations. There is no limb weakness.
Differential Diagnosis
Bulbar-onset amyotrophic lateral sclerosis (ALS)
Brainstem stroke involving nucleus ambiguus
Myasthenia gravis
Oculopharyngeal muscular dystrophy
Structural esophageal disease (e.g., achalasia, carcinoma)
Approach to Diagnosis
Evaluation begins by clarifying whether the dysphagia is oropharyngeal or esophageal—difficulty initiating swallowing indicates oropharyngeal dysfunction, whereas a sensation of food sticking suggests esophageal involvement. History should assess onset, progression, nasal regurgitation, coughing during meals, weight loss, or limb weakness.
The five most important physical examination findings include:
Cranial nerve assessment (IX, X, XII) — evaluate palatal and tongue weakness.
Palatal elevation and gag reflex — test for bulbar involvement.
Tongue inspection — look for atrophy or fasciculations suggestive of motor neuron disease.
Swallowing and speech fatigability — assess for neuromuscular junction disorders.
Bedside swallow evaluation — detect aspiration risk.
Laboratory studies may include autoimmune markers, acetylcholine receptor antibodies, or CK levels. MRI is indicated for brainstem or structural lesions, while EMG and electrophysiologic studies help identify neuromuscular causes. A modified barium swallow or videofluoroscopy remains the gold standard for localizing swallowing dysfunction.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Early identification of aspiration risk is critical to prevent pneumonia and malnutrition.
Progressive dysphagia with tongue fasciculations strongly suggests bulbar-onset ALS.
Fluctuating swallowing difficulty worsening with fatigue is characteristic of myasthenia gravis.
Sudden onset dysphagia with cranial nerve deficits may indicate brainstem stroke.
Videofluoroscopic swallow study is the gold standard for functional assessment and localization of swallowing dysfunction.
Dystonia
Clinical Scenario
A 45-year-old woman presents with involuntary twisting movements and abnormal posturing of her right hand that have gradually worsened over the past year. She reports that symptoms are more pronounced during writing and improve somewhat with rest. There is no family history of neurological disorders. Neurological examination reveals sustained muscle contractions causing repetitive movements and abnormal postures predominantly affecting the right upper limb. There are no signs of weakness or sensory loss. Cognitive functions are intact, and brain MRI is unremarkable.
Differential Diagnosis
Laboratory evaluation should include serum ceruloplasmin and copper studies if Wilson’s disease is suspected. Brain MRI is essential to rule out structural lesions such as stroke or tumor. Genetic testing is considered in early-onset or familial cases, and EMG may confirm characteristic co-contraction patterns.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Dystonia is characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements and postures.
It can be focal, segmental, multifocal, or generalized in distribution.
Symptoms may be task-specific and often worsen with voluntary movement.
Diagnosis is clinical, supported by history and examination; imaging is used to exclude secondary causes.
Common causes include idiopathic, genetic mutations, drug-induced, and structural brain lesions.
Facial Pain
Clinical Scenario
A 64-year-old woman presents with recurrent, severe, electric shock-like pain on the right side of her face, predominantly involving the cheek and jaw. The episodes last for seconds but occur multiple times per day, often triggered by light touch, talking, chewing, or brushing her teeth. There is no facial numbness, weakness, or visual changes. Neurological examination is normal between episodes. The patient reports significant anxiety about daily activities due to fear of triggering pain.
Differential Diagnosis
Classical trigeminal neuralgia
Secondary trigeminal neuralgia (e.g., due to multiple sclerosis or tumor)
Post-herpetic neuralgia
Temporomandibular joint disorder or dental pathology
Cluster headache or SUNCT syndrome
Approach to Diagnosis
The evaluation of facial pain begins with a detailed history, emphasizing pain quality, duration, triggers, and distribution. Electric shock-like, paroxysmal pain triggered by light stimuli suggests trigeminal neuralgia, whereas constant, burning pain points to post-herpetic or secondary neuralgias.
Key Physical Examination include:
Facial Sensation: Assess all three trigeminal divisions (V1–V3) for sensory loss or allodynia.
Corneal Reflex: Test to evaluate ophthalmic division and brainstem integrity.
Temporomandibular Joints and Masticatory Muscles: Inspect and palpate for tenderness or crepitus.
Motor Function: Evaluate masseter and pterygoid strength to detect motor branch involvement.
Other Cranial Nerves: Examine VII and VIII for deficits suggesting secondary pathology in the cerebellopontine angle.
MRI with a trigeminal nerve protocol is essential to exclude structural causes such as vascular compression, demyelination, or tumor. Laboratory studies, including inflammatory and autoimmune panels, are reserved for atypical or systemic presentations.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Trigeminal neuralgia is characterized by brief, paroxysmal, lancinating facial pain in the distribution of one or more trigeminal nerve branches.
Pain is typically unilateral and triggered by innocuous stimuli (allodynia).
Neurological examination is usually normal; sensory deficits suggest a secondary cause.
MRI is essential to exclude secondary causes such as tumors or multiple sclerosis.
First-line therapy includes carbamazepine or oxcarbazepine; surgical options are available for refractory cases.
Facial Palsy
Clinical Scenario
A 45-year-old previously healthy man presents with sudden onset of left-sided facial weakness. He is unable to close his left eye, smile symmetrically, or raise his eyebrow on the affected side. He denies trauma, rash, or recent illness but reports mild pain around the ear before onset. Examination reveals a complete lower motor neuron facial palsy affecting the upper and lower face without any other neurological deficits.
Differential Diagnosis
Bell’s palsy (idiopathic LMN facial palsy)
Ischemic or hemorrhagic stroke (UMN facial palsy)
Ramsay Hunt syndrome (herpes zoster oticus)
Lyme disease (especially with bilateral involvement)
Parotid or cerebellopontine angle tumor
Approach to Diagnosis
The evaluation of facial palsy begins with determining whether the weakness pattern is upper or lower motor neuron. Involvement of the forehead indicates a lower motor neuron (LMN) lesion, as seen in Bell’s palsy or infectious/inflammatory causes, whereas forehead sparing suggests an upper motor neuron (UMN) lesion such as stroke.
Key Physical Examination includes:
Forehead Movement: Assess to differentiate UMN from LMN involvement.
Eye Closure and Bell’s Phenomenon: Evaluate strength and corneal protection.
Nasolabial Fold and Smile Symmetry: Observe for asymmetry or flattening.
Taste and Lacrimation: Test taste on the anterior two-thirds of the tongue and check lacrimation to assess facial nerve branch involvement.
Associated Findings: Examine for vesicular rash, parotid swelling, or other cranial nerve deficits suggesting secondary causes.
If atypical or progressive features are present, MRI with contrast should be performed to exclude structural lesions. Additional investigations may include Lyme serology, CSF analysis, or audiometry in select cases based on clinical suspicion.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Facial palsy can be classified as upper motor neuron (UMN) or lower motor neuron (LMN).
UMN lesions (e.g., stroke) spare the forehead due to bilateral innervation.
LMN lesions (e.g., Bell’s palsy) affect both the upper and lower face.
Bell’s palsy is an idiopathic LMN palsy and is a diagnosis of exclusion.
MRI or further testing is indicated if atypical features or progressive symptoms are present.
Fasciculation
Clinical Scenario
A 35-year-old software engineer presents with a 6-month history of intermittent twitching in his calves and forearms. The twitches are visible under the skin and occur spontaneously, especially after exercise or stress. He denies weakness, muscle wasting, sensory symptoms, or weight loss. Neurological examination is normal. Blood tests, including electrolytes, thyroid function, and creatine kinase, are within normal limits. Electromyography shows benign fasciculation potentials without denervation.
Differential Diagnosis
Benign Fasciculation Syndrome – isolated fasciculations, no weakness or atrophy.
Amyotrophic Lateral Sclerosis (ALS) – fasciculations with progressive weakness and UMN/LMN signs.
Peripheral Nerve Hyperexcitability (e.g., neuromyotonia) – twitching with stiffness and cramping.
Electrolyte Imbalances (e.g., hypocalcemia, hypomagnesemia) – twitching with other neuromuscular symptoms.
Drug- or Toxin-induced Fasciculations – stimulants, lithium, organophosphates.
Approach to Diagnosis
Evaluation of fasciculations begins with a detailed history focusing on onset, distribution, and associated symptoms such as weakness, atrophy, or cramps. Key Physical Examination includes:
Muscle Bulk and Tone: Assess to detect atrophy or spasticity.
Visible Fasciculations: Inspect at rest and after gentle percussion.
Muscle Strength: Test proximal and distal groups to identify lower motor neuron weakness.
Deep Tendon Reflexes: Evaluate to differentiate upper versus lower motor neuron involvement.
Sensory Function and Coordination: Assess to exclude peripheral or mixed disorders.
Laboratory evaluation should include electrolytes, calcium, magnesium, thyroid function, and creatine kinase (CK) levels to rule out metabolic or endocrine causes. Electromyography (EMG) confirms the presence of fasciculations and detects chronic denervation patterns suggestive of motor neuron disease. Additional investigations such as nerve conduction studies or imaging are considered when secondary or central causes are suspected.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Fasciculations are spontaneous, involuntary muscle fiber contractions visible under the skin, often described as "muscle twitching."
They may be benign or indicative of motor neuron disease, requiring careful clinical correlation.
Absence of weakness, atrophy, or hyperreflexia strongly suggests a benign etiology.
Common benign triggers include stress, fatigue, caffeine, and post-exercise states.
EMG and clinical follow-up are crucial for excluding evolving neuromuscular disease.
Foot Drop
Case Scenario
A 45-year-old man presents with a one-week history of difficulty lifting his right foot while walking, causing him to trip on uneven surfaces. He recalls no trauma but reports habitually crossing his legs at work. On examination, there is weakness of ankle dorsiflexion and eversion on the right, with sensory loss over the dorsum of the foot and lateral shin. Ankle inversion strength and the knee jerk reflex are preserved.
Differential Diagnosis
Common peroneal (fibular) neuropathy at the fibular head
L5 radiculopathy (disc herniation or foraminal stenosis)
Sciatic neuropathy (peroneal division)
Motor neuron disease (e.g., ALS with lower motor neuron onset)
Central causes (stroke, spinal cord lesion)
Approach to Diagnosis
Begin with a targeted history to determine onset (sudden vs insidious), antecedent trauma or compression, associated back or leg pain, and systemic symptoms. The five most important physical examinations in foot drop include:
Ankle dorsiflexion and eversion strength — weakness of both localizes to the common peroneal nerve or L5 root; isolated dorsiflexion weakness may indicate a deep peroneal branch lesion.
Ankle inversion strength (tibialis posterior) — preserved inversion with weak dorsiflexion favors peroneal neuropathy over L5 radiculopathy, since tibialis posterior is innervated by the tibial nerve and L5 root.
Sensory examination of the dorsal foot and lateral leg — loss over the dorsum of the foot and lateral calf supports a peroneal distribution, while extension to the medial foot or posterolateral thigh suggests L5 root or sciatic involvement.
Tinel sign at the fibular head — percussion-induced tingling confirms peroneal nerve entrapment at the most common compression site.
Straight leg raise and lumbar examination — a positive test with radicular pain suggests L5 radiculopathy; the presence of crossed straight leg raise increases specificity for disc herniation.
Electrodiagnostic studies (NCS/EMG) are essential to confirm the site and severity of the lesion. MRI of the lumbar spine is obtained when radiculopathy is suspected, and MRI or ultrasound of the knee region when peroneal neuropathy is considered.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Foot drop is a clinical sign, not a diagnosis; it requires systematic evaluation to identify the underlying cause.
The most common cause is compression of the common peroneal nerve at the fibular head from habitual leg crossing, prolonged squatting, or tight casts.
Preserved ankle inversion is the single most useful bedside finding to distinguish peroneal neuropathy from L5 radiculopathy.
Electrodiagnostic studies (nerve conduction and EMG) are the gold standard for localizing and quantifying the nerve injury.
Prognosis depends on the mechanism: compressive neuropraxia often recovers fully, while axonal injury or progressive disease (e.g., ALS) carries a less favorable outlook.
Gait Ataxia
Clinical Scenario
A 74-year-old man presents with progressively worsening unsteady gait over the past six months. He describes his walking as "magnetic," feeling as if his feet are stuck to the floor. His family also reports increasing forgetfulness and occasional urinary urgency. There is no history of recent falls, head trauma, or alcohol use. On examination, his gait is broad-based and shuffling, with difficulty initiating steps. Cognitive testing shows mild impairment in short-term memory, and there is evidence of urinary incontinence.
Differential Diagnosis
Parkinson’s disease
Cerebellar ataxia (degenerative or vascular)
Subcortical vascular dementia
Progressive supranuclear palsy (PSP)
B12 deficiency-related myelopathy
Approach to Diagnosis
Evaluation of suspected normal pressure hydrocephalus (NPH) begins with a thorough history emphasizing the classic triad of gait disturbance, cognitive impairment, and urinary incontinence.
Key Physical Examination includes:
Gait Pattern: Assess for the characteristic broad-based, magnetic gait with difficulty initiating steps.
Cognitive Function: Evaluate attention, recall, and executive function using bedside testing.
Frontal Release Signs: Examine for grasp or snout reflexes.
Tone and Postural Reflexes: Assess to distinguish from extrapyramidal syndromes.
Cerebellar or Sensory Ataxia: Inspect to rule out alternative causes.
Neuroimaging with MRI or CT typically reveals ventriculomegaly disproportionate to cortical atrophy. Additional investigations include laboratory tests to exclude metabolic or nutritional causes and CSF analysis to rule out infection or inflammation. A high-volume lumbar puncture (CSF tap test) demonstrating transient gait improvement supports the diagnosis and predicts shunt responsiveness. Multidisciplinary evaluation is essential to exclude mimics and guide management.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Normal pressure hydrocephalus (NPH) is characterized by the triad of gait disturbance, cognitive decline, and urinary incontinence.
Gait impairment ("magnetic gait") is usually the earliest and most prominent feature.
CSF pressure is normal, but ventriculomegaly is present due to impaired CSF absorption.
MRI and clinical assessment guide diagnosis; CSF tap test can predict shunt responsiveness.
Ventriculoperitoneal shunting may improve symptoms, especially gait dysfunction.
Headache
Clinical Scenario
A 42-year-old woman presents with a 6-month history of recurrent headaches described as a dull, pressure-like pain encircling her forehead and occipital region. The headaches typically occur in the late afternoon after long workdays and improve with rest or sleep. They are not associated with nausea, vomiting, photophobia, phonophobia, or visual aura. She denies focal neurological symptoms. The patient reports increased work-related stress and poor sleep but has no significant past medical history. Neurological examination is normal.
Differential Diagnosis
Migraine without aura
Cervicogenic headache
Medication-overuse headache
Secondary headache due to mass lesion or increased ICP
Temporal arteritis (in older patients)
Approach to Diagnosis
The evaluation of a patient with recurrent headache begins with a comprehensive history focusing on onset, character, frequency, duration, and associated symptoms. The absence of red flags such as sudden onset (“thunderclap”), neurological deficits, systemic signs (fever, weight loss), or altered consciousness strongly suggests a benign etiology.
Key Physical Examination includes:
Inspection: Look for signs of trauma, infection, or temporal tenderness.
Fundoscopic Examination: Evaluate for papilledema or optic disc changes.
Cranial Nerve Evaluation: Assess for focal deficits or asymmetry.
Cervical and Scalp Assessment: Palpate for muscle tenderness or tension. Check for occipital neuralgia.
Gait and Coordination Testing: Examine for cerebellar or motor abnormalities.
Laboratory studies are rarely required unless systemic causes are suspected. Neuroimaging (MRI or CT) is indicated only if atypical features are present. Tension-type headache is a clinical diagnosis based on typical symptom patterns—bilateral, pressing or tightening quality, mild-to-moderate intensity, and lack of aggravation by routine activity. The absence of migrainous features and a normal examination support the diagnosis.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Tension-type headache (TTH) is the most common primary headache, characterized by bilateral, non-pulsating, pressure-like pain.
Typically associated with muscle tension, stress, or fatigue and not accompanied by aura, photophobia, or significant nausea.
Absence of red flag features (e.g., sudden onset, focal deficits, systemic signs) supports a benign primary headache diagnosis.
Diagnosis is clinical; neuroimaging is reserved for atypical features or secondary headache suspicion.
Management includes lifestyle modification, stress reduction, analgesics, and preventive therapy in chronic cases.
Hemiballismus
Clinical Scenario
A 68-year-old man with poorly controlled type 2 diabetes mellitus presents with sudden onset of violent, flinging movements of his right arm and leg. The movements are continuous at rest and worsen with voluntary activity. He remains conscious and oriented.
Differential Diagnosis
Chorea – lower amplitude, distal, flowing movements.
Dystonia – sustained or twisting postures.
Myoclonus – shock-like, rapid jerks.
Tremor – rhythmic, oscillatory movements.
Athetosis – slow, writhing, continuous movements, often distal and associated with basal ganglia pathology.
Approach to Diagnosis
Evaluation of hemiballismus begins with a comprehensive history focusing on the onset, speed, and context of the abnormal movements, including vascular risk factors, recent metabolic disturbances, or infections. A detailed neurological examination is essential to define the nature and distribution of movements and to identify associated neurological or systemic abnormalities. Key clinical features to assess include:
Characterization of movements: Large-amplitude, flinging or rotary involuntary movements predominantly affecting one side of the body, especially proximal limbs.
Muscle tone: Typically normal or mildly decreased between movement episodes.
Strength and reflexes: Usually preserved, helping differentiate from hemiparesis.
Sensory and cranial nerve examination: Typically normal, confirming the focal nature of the movement disorder.
Presence of associated signs: Absence of parkinsonism, chorea, dystonia, or encephalopathy supports the diagnosis of isolated hemiballismus.
Brain MRI is the imaging modality of choice, particularly to evaluate the contralateral subthalamic nucleus for ischemic or hemorrhagic lesions. Laboratory studies should include serum glucose and metabolic panels, as non-ketotic hyperglycemia is a common reversible cause. In subacute or progressive cases, inflammatory markers, cerebrospinal fluid (CSF) analysis, and autoimmune or neoplastic screening may be warranted. An integrated approach combining clinical, imaging, and laboratory data is essential for accurate diagnosis and treatment planning.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Hemiballismus is characterized by large-amplitude, proximal, flinging limb movements, typically unilateral.
Classically caused by a lesion in the contralateral subthalamic nucleus, often due to a lacunar stroke.
Movements resolve during sleep and may subside over weeks to months.
Metabolic causes (e.g., non-ketotic hyperglycemia) and secondary etiologies should be considered.
Chronic cases may evolve into choreiform movements over time as neuroplastic changes occur.
Hypertonia / Spasticity
Clinical Scenario
A 55-year-old man presents with gradually worsening stiffness and reduced mobility in his right leg over the past year. He reports that walking has become more effortful, and he occasionally experiences muscle spasms. There is no history of trauma or significant sensory loss. Neurological examination reveals increased tone in the right leg, exaggerated reflexes, and a positive Babinski sign.
Differential Diagnosis
Stroke (chronic UMN lesion)
Multiple sclerosis
Spinal cord compression or myelopathy
Cerebral palsy
Hereditary spastic paraplegia
Approach to Diagnosis
The evaluation of hypertonia begins with a detailed history to assess onset, progression, and associated neurological symptoms. On examination, five key assessments are essential:
Muscle tone assessment – to detect spasticity and velocity-dependent resistance.
Deep tendon reflex testing – to evaluate hyperreflexia.
Clonus testing – at the ankle or wrist to assess sustained rhythmic contractions.
Plantar response (Babinski sign) – to confirm upper motor neuron involvement.
Gait analysis – to identify spastic patterns such as circumduction or scissoring.
MRI of the brain and spinal cord remains crucial to detect demyelination, infarcts, or compressive lesions. Additional laboratory and CSF studies may be required to exclude inflammatory or metabolic etiologies. Correlating clinical findings with imaging ensures accurate diagnosis and localization of the lesion.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Points
Hypertonia refers to increased muscle tone, commonly caused by upper motor neuron (UMN) lesions.
Spasticity is a velocity-dependent increase in muscle tone, often seen in conditions such as stroke, multiple sclerosis, and spinal cord injury.
It is frequently accompanied by hyperreflexia, clonus, and pathological reflexes (e.g., Babinski sign).
Differentiation from rigidity (seen in Parkinsonism) and dystonia is essential for accurate diagnosis.
Diagnosis relies on clinical assessment and neuroimaging to identify underlying CNS pathology.
Myoclonus
Clinical Scenario
A 58-year-old man presents with sudden, brief, involuntary jerks of his upper limbs and trunk that have progressively worsened over six months. The movements are spontaneous, sometimes stimulus-sensitive, and occasionally triggered by attempting fine motor tasks. He denies any loss of consciousness but notes occasional startle responses and generalized twitching during sleep. His medical history includes hypertension and mild cognitive changes over the past year. There is no family history of movement disorders. Neurological examination reveals multifocal jerks involving proximal muscles without associated weakness or sensory deficits.
Differential Diagnosis
Cortical myoclonus secondary to neurodegenerative disease (e.g., Creutzfeldt-Jakob disease)
Post-hypoxic or metabolic myoclonus (e.g., Lance–Adams syndrome)
Epileptic myoclonus
Paraneoplastic or autoimmune myoclonus
Drug-induced or toxic myoclonus
Approach to Diagnosis
Evaluating myoclonus begins with careful clinical characterization of the jerks, including their distribution (focal, multifocal, or generalized), triggers (spontaneous or stimulus-sensitive), and timing (rest or action). Associated neurological features such as cognitive decline, seizures, or ataxia help narrow the differential diagnosis.
A thorough history is essential to identify reversible causes such as recent hypoxic events, metabolic disturbances, or drug exposures. Rapidly progressive dementia or behavioral changes raise suspicion for neurodegenerative or prion diseases, while systemic symptoms may suggest autoimmune or paraneoplastic origins. Physical examination emphasizes five key assessments:
Observation of jerk pattern and distribution – to distinguish focal, multifocal, or generalized myoclonus.
Cortical reflex testing – to detect stimulus-sensitive or reflex myoclonus.
Cranial nerve examination – for brainstem involvement or facial myoclonus.
Cerebellar assessment – to evaluate for ataxia or coordination deficits.
Motor and sensory examination – to identify associated weakness, rigidity, or sensory abnormalities.
Laboratory tests and imaging—such as metabolic panels, autoimmune screens, EEG, and brain MRI—further refine the diagnosis. In select cases, CSF analysis and specialized antibody testing are warranted to identify specific etiologies.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Myoclonus is characterized by sudden, brief, involuntary jerks that can be spontaneous or stimulus-sensitive.
Detailed history and neurological examination are critical to differentiate underlying causes.
EEG and brain MRI are essential tools to identify cortical or structural abnormalities.
Consider metabolic, toxic, autoimmune, infectious, and neurodegenerative etiologies.
Accurate diagnosis guides prognosis and targeted therapeutic interventions.
Numbness
Clinical Scenario
A 48-year-old man presents with progressive numbness and tingling in his feet over the past six months, gradually ascending to mid-calf. He denies weakness but notes occasional imbalance and burning sensations. Past history includes poorly controlled diabetes. Neurological examination reveals reduced vibration and position sense in a stocking distribution and diminished ankle reflexes.
Differential Diagnosis
Diabetic peripheral neuropathy
Cervical or thoracic spinal cord lesion (myelopathy)
Multiple sclerosis
Mononeuritis multiplex (vasculitic neuropathy)
Thalamic stroke
Approach to Diagnosis
A structured approach focuses on the pattern and distribution of sensory loss, temporal profile, associated motor/autonomic findings, and systemic features. Physical examination should include the following five key assessments:
Sensory examination – to determine modality-specific loss (light touch, vibration, pinprick, proprioception) and its distribution.
Reflex testing – to identify hypo- or areflexia suggesting peripheral neuropathy, or hyperreflexia indicating a central lesion.
Motor strength assessment – to detect associated weakness or muscle wasting.
Gait and coordination testing – to evaluate sensory ataxia or imbalance.
Autonomic examination – including orthostatic blood pressure and sweating abnormalities.
Nerve conduction studies and electromyography (EMG) help confirm peripheral neuropathies, while MRI identifies central causes. Laboratory workup targets metabolic, autoimmune, and infectious etiologies.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Numbness is a common neurological symptom resulting from sensory pathway involvement at any level — peripheral nerve, plexus, spinal cord, brainstem, thalamus, or cortex.
The pattern (dermatomal, stocking-glove, hemisensory, patchy) provides clues to the lesion location.
Peripheral neuropathies are often length-dependent and symmetric, whereas central lesions usually follow a sensory level or involve one side.
Metabolic, inflammatory, infectious, and structural causes should be systematically considered.
Electrophysiology and imaging are key tools for localizing and characterizing the pathology.
Nystagmus
Clinical Scenario
A 42-year-old woman presents with acute onset of spinning vertigo, nausea, and gait unsteadiness for 24 hours. She notes horizontal, left-beating double vision when looking left, which improves when she fixes her gaze on a target. There is no new headache, diplopia, dysarthria, or limb weakness. Examination shows unidirectional, horizontal nystagmus that increases with left gaze and decreases with visual fixation; a positive head impulse test to the right; no skew deviation; and intact limb coordination.
Differential Diagnosis
Vestibular neuritis/labyrinthitis (peripheral)
Benign paroxysmal positional vertigo (BPPV)
Cerebellar or brainstem stroke (central)
Multiple sclerosis (central demyelination)
Drug-induced or toxic nystagmus (e.g., anticonvulsants, alcohol)
Approach to Diagnosis
Begin by characterizing the nystagmus: direction (horizontal, vertical, torsional), effect of gaze and visual fixation, and triggers (spontaneous vs positional). The five most important physical examinations in this patient include:
Head Impulse Test – to assess vestibulo-ocular reflex; an abnormal response suggests a peripheral lesion.
Nystagmus Assessment – observe for direction, suppression with fixation, and gaze dependency to distinguish peripheral from central causes.
Test of Skew – vertical ocular misalignment indicates a central lesion.
Cerebellar Examination – evaluate for ataxia, dysmetria, or dysdiadochokinesia suggestive of brainstem or cerebellar pathology.
Positional Testing (Dix–Hallpike Maneuver) – to identify benign paroxysmal positional vertigo (BPPV) or positional nystagmus.
Laboratory testing targets metabolic or toxic contributors when suspected. Imaging is guided by concern for central pathology: diffusion-weighted MRI may be required to exclude posterior circulation stroke if red flags are present. Vestibular testing (video head impulse, calorics) and positional maneuvers help confirm peripheral disorders.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Nystagmus is an involuntary rhythmic oscillation of the eyes resulting from imbalance in ocular motor or vestibular pathways.
Peripheral (vestibular) nystagmus is typically unidirectional, suppresses with fixation, and is often accompanied by vertigo.
Central nystagmus may be direction-changing, vertical, or purely torsional, and does not suppress with fixation; associated focal neurological signs raise concern for stroke or demyelination.
The bedside HINTS exam (Head-Impulse, Nystagmus, Test-of-Skew) helps differentiate peripheral from central causes in acute vestibular syndrome.
Medications (e.g., anticonvulsants, sedatives), alcohol, and metabolic derangements can cause gaze-evoked or downbeat nystagmus.
Pain
Clinical Scenario
A 45-year-old man presents with 3 weeks of sharp, shooting low back pain radiating down the posterolateral left leg to the lateral foot. He reports paresthesias in the same distribution and difficulty dorsiflexing the left ankle. Pain worsens with coughing and sitting, and improves when lying down. There is no fever, weight loss, or bowel/bladder dysfunction. On examination, straight-leg raise is positive on the left; there is decreased pinprick over the lateral foot, mild weakness of ankle dorsiflexion, and a reduced left Achilles reflex.
Differential Diagnosis
Lumbar or cervical radiculopathy (disc herniation, foraminal stenosis)
Peripheral neuropathy (length-dependent, stocking–glove)
Myopathy (proximal weakness without sensory loss)
Spinal canal stenosis (neurogenic claudication)
Referred pain (hip/SI pathology, visceral)
Approach to Diagnosis
Begin with onset, radiation, aggravating/relieving factors, red flags (cancer, infection, trauma, weight loss, night pain, bowel/bladder symptoms), and prior episodes. The five most important physical examinations for this patient include:
Sensory mapping – identify dermatomal distribution of sensory loss (e.g., L5 lateral leg/foot).
Motor testing – assess myotomal weakness (e.g., ankle dorsiflexion for L5, plantar flexion for S1).
Deep tendon reflexes – evaluate for depressed reflexes (e.g., Achilles for S1, patellar for L4).
Provocative maneuvers – perform straight-leg raise and crossed SLR (lumbar) or Spurling’s test (cervical) to localize root irritation.
Gait and posture assessment – observe for antalgic gait, foot drop, or compensatory trunk lean indicating functional impact.
Initial management is conservative unless red flags are present. MRI is indicated for progressive deficit, refractory pain, or red flags; EMG/NCS is useful when imaging and examination findings are discordant.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Radiculopathy causes dermatomal pain radiating from the spine into the limb, often with paresthesias and myotomal weakness.
Mechanical provocation (Valsalva, flexion) and a positive straight-leg raise (L4–S1) or Spurling (cervical) support nerve root irritation.
Examination localizes the root via sensory loss (dermatome), weakness (myotome), and depressed reflexes.
MRI of the spine is the imaging modality of choice when red flags are present or symptoms persist despite conservative care.
EMG/NCS can confirm root involvement and differentiate radiculopathy from plexopathy or peripheral neuropathy.
Ptosis
Clinical Scenario
A 28-year-old woman presents with intermittent drooping of her right eyelid, worsening toward the end of the day. She reports occasional double vision, particularly in the evenings, but denies pain or visual loss. There is no history of trauma, infection, or systemic illness. On examination, ptosis increases with sustained upward gaze and improves after brief rest.
Differential Diagnosis
Myasthenia gravis
Horner syndrome
Third nerve palsy
Chronic progressive external ophthalmoplegia (CPEO)
Lambert-Eaton myasthenic syndrome (LEMS)
Approach to Diagnosis
The evaluation of myasthenia gravis begins with recognition of characteristic fatigable weakness and diurnal fluctuation. The five most important physical examinations in this patient include:
Sustained Upgaze Test – observe for worsening ptosis with prolonged upward gaze, which indicates fatigability.
Cogan’s Lid Twitch Sign – look for a brief upward overshoot of the eyelid when returning from downgaze, suggestive of MG.
Ice-Pack Test – apply an ice pack over the ptotic lid for 2–3 minutes; improvement supports the diagnosis.
Extraocular Movement Examination – identify fatigable ophthalmoparesis without pupillary involvement.
Bulbar Muscle Assessment – evaluate speech, swallowing, and facial strength for fatigable weakness.
Serological testing for acetylcholine receptor (AChR) or muscle-specific kinase (MuSK) antibodies and electrophysiological studies (repetitive nerve stimulation or single-fiber EMG) confirm the diagnosis. Imaging for thymoma should be performed in all cases. Differentiating MG from Horner syndrome, third nerve palsy, and mitochondrial myopathies is essential for accurate management.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
|---|---|---|---|---|
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Key Clinical Points
Ptosis with fatigability and diurnal variation is highly suggestive of myasthenia gravis.
Normal pupillary reflexes help differentiate MG from third nerve palsy and Horner syndrome.
Ice-pack test is a simple bedside tool to transiently improve ptosis in MG.
Early diagnosis and immunotherapy can prevent progression and improve quality of life.
Always evaluate for thymoma with imaging in confirmed MG cases.
Seizure
Clinical Scenario
A 45-year-old man with no prior seizure history presents after a witnessed generalized tonic–clonic seizure. Family report a brief prodrome of odd smell and confusion, followed by loss of consciousness and rhythmic jerking lasting 90 seconds with post-ictal lethargy. He notes several weeks of new headaches and subtle left-hand clumsiness. Neurological examination reveals mild left pronator drift. Brain MRI shows an enhancing right frontal mass with surrounding edema, concerning for a primary brain tumor.
Differential Diagnosis
Brain tumor (primary or metastatic)
Ischemic or hemorrhagic stroke (early cortical involvement)
Infectious encephalitis (e.g., HSV)
Toxic–metabolic derangements (electrolytes, glucose, uremia, hepatic)
Idiopathic epilepsy (less common for true new-onset in mid-life)
Approach to Diagnosis
Evaluation begins with stabilization and rapid bedside glucose. History should characterize semiology (focal aware/impaired, generalized), triggers, head trauma, intoxicants, malignancy history, immunosuppression, and medication changes. The five most important physical examinations for this patient include:
Level of consciousness and orientation – to distinguish postictal confusion from ongoing seizure or encephalopathy.
Cranial nerve examination – to identify focal deficits suggesting structural lesions such as tumor or stroke.
Motor and sensory assessment – to detect focal weakness (e.g., Todd’s paresis) or asymmetry indicating cortical involvement.
Fundoscopic examination – to look for papilledema, supporting increased intracranial pressure or mass effect.
Meningeal and systemic examination – to detect signs of infection or metabolic encephalopathy (fever, neck stiffness, jaundice).
Initial studies include CBC, electrolytes, calcium, magnesium, renal and liver function, and toxicology as indicated. MRI brain with contrast is preferred to detect mass, stroke, or encephalitis; CT head is useful urgently to exclude hemorrhage or large mass with mass effect. EEG supports the diagnosis (focal epileptiform discharges) and excludes nonconvulsive status. Consider lumbar puncture if infection or inflammation is suspected. Early neurosurgical or oncology consultation is indicated when imaging suggests tumor.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
New-onset seizures in adults require prompt evaluation for structural causes (e.g., tumors, stroke, hemorrhage).
Red flags include progressive headaches, focal deficits, personality or cognitive change, and subacute course.
MRI with epilepsy protocol and early EEG help define lesion burden and epileptogenicity.
Stabilize first (airway, breathing, circulation, glucose), then pursue targeted diagnostics.
Treat acute seizures and address the underlying cause; tumor-directed therapy often reduces recurrence.
Syncope
Clinical Scenario
A 24-year-old woman experiences a brief loss of consciousness while standing in a crowded, warm room. She reports preceding nausea, warmth, lightheadedness, blurred vision, and diaphoresis. A bystander notes pallor and that she slumped to the floor without tonic–clonic movements, tongue bite, or incontinence. She regained consciousness within seconds and was fully oriented with lingering fatigue. There is no cardiac history or family history of sudden death. Examination in clinic is normal.
Differential Diagnosis
Vasovagal (reflex) syncope
Orthostatic hypotension (volume depletion, autonomic failure, medications)
Cardiac arrhythmia (brady/tachyarrhythmias, long QT)
Structural cardiac or cardiopulmonary causes (aortic stenosis, HCM, PE)
Seizure or other non-syncopal causes of transient loss of consciousness
Approach to Diagnosis
A systematic evaluation of syncope begins with detailed event characterization—posture, triggers, prodrome, duration of loss of consciousness, injury, and recovery. The five most important physical examinations for this patient include:
Orthostatic Vital Signs – Measure blood pressure and heart rate in supine, sitting, and standing positions to identify orthostatic hypotension.
Cardiac Examination – Assess for murmurs (aortic stenosis, hypertrophic cardiomyopathy), irregular rhythms, or gallops suggesting structural or arrhythmic causes.
Balance testing – Check for vestibular imbalance with a sharpened Romberg testging to assess for vestibular, cerebellar and posterior column sensory issues.
Neurological Examination – Evaluate cranial nerves, motor strength, coordination, and reflexes to exclude focal deficits or seizure mimics.
General Examination – Look for signs of dehydration, anemia, or trauma secondary to the syncopal event.
All patients should undergo a 12-lead ECG. Further studies—such as ambulatory rhythm monitoring, echocardiography, or tilt-table testing—are guided by clinical suspicion. Laboratory tests are obtained when indicated, and neuroimaging is reserved for those with focal neurological findings.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Syncope is a transient, self-limited loss of consciousness due to global cerebral hypoperfusion with rapid, spontaneous recovery.
Vasovagal (reflex) syncope is the most common cause; typical features include identifiable triggers (heat, emotion, pain), prodrome, and quick recovery without focal deficits.
Cardiac arrhythmias and structural heart disease are high-risk causes that must be excluded with ECG and targeted testing.
Orthostatic hypotension causes syncope shortly after standing, often in older adults or with volume depletion/medications.
Careful history, orthostatic vitals, and ECG guide further testing (tilt-table, ambulatory monitoring, echocardiography) and risk stratification.
Tremor
Clinical Scenario
A 68-year-old man presents with a 10-year history of tremor in both hands, which worsens when drinking from a cup or writing. The tremor improves after consuming a small amount of alcohol. There is no bradykinesia, rigidity, or gait disturbance. His father had a similar tremor.
Differential Diagnosis
Parkinson’s disease
Dystonic tremor
Enhanced physiologic tremor
Cerebellar tremor
Drug- or toxin-induced tremor
Approach to Diagnosis
Tremor evaluation is essential to identify the underlying etiology. The five most important physical examinations include:
Tremor characterization – Assess amplitude, frequency, and activation condition (postural, kinetic, or intention tremor).
Tone and rigidity assessment – Evaluate for absence of cogwheel rigidity or bradykinesia to exclude Parkinson’s disease.
Coordination testing – Perform finger-to-nose and heel-to-shin tests to rule out cerebellar tremor.
Gait and posture evaluation – Observe for normal tandem gait and absence of ataxia or balance impairment.
Head, voice, and jaw tremor inspection – Identify involvement beyond the limbs to support the diagnosis of essential tremor.
Family history, gradual progression, and alcohol responsiveness further support the diagnosis. Many medications can cause tremors.Neuroimaging is usually normal but may be obtained to exclude structural causes. Laboratory testing should be directed toward suspected secondary etiologies such as thyroid dysfunction, medication effects, or metabolic derangements.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Essential tremor (ET) is the most common movement disorder, characterized by a bilateral, symmetric action tremor.
It predominantly affects the upper limbs but may involve the head, voice, or jaw.
Tremor is typically absent at rest and worsens with posture or goal-directed movement.
ET often has a positive family history and may improve transiently with small amounts of alcohol.
Diagnosis is clinical, based on exclusion of secondary causes and absence of Parkinsonian features.
Vertigo
Clinical Scenario
A 62-year-old woman presents with recurrent episodes of spinning sensation lasting less than a minute, typically triggered by rolling over in bed or looking upward. The episodes are associated with nausea but no hearing loss, tinnitus, or focal neurological deficits. There is no history of recent infection, trauma, or migraine. Between episodes, she is asymptomatic. Neurological examination is normal except for reproduction of vertigo and characteristic nystagmus during the Dix–Hallpike maneuver.
Differential Diagnosis
Benign Paroxysmal Positional Vertigo (BPPV)
Vestibular neuritis or labyrinthitis
Ménière’s disease
Cerebellar or brainstem stroke
Acoustic neuroma (vestibular schwannoma)
Approach to Diagnosis
Evaluation begins with a detailed history characterizing the vertigo’s onset, duration, triggers, and associated symptoms (e.g., hearing loss, headache, neurological deficits). Positional vertigo triggered by specific head movements and lasting seconds strongly suggests BPPV, whereas prolonged episodes or spontaneous onset may indicate vestibular neuritis or central causes.
The five most important physical examinations include:
Dix–Hallpike maneuver – Elicits transient rotatory nystagmus with latency and fatigability in posterior canal BPPV.
Head impulse test – Assesses vestibulo-ocular reflex; an abnormal corrective saccade suggests a peripheral vestibular lesion.
Nystagmus characterization – Evaluate direction (horizontal, vertical, torsional), persistence, and gaze dependence to distinguish peripheral from central vertigo.
Gait and Romberg testing – Check for imbalance or postural instability; severe truncal ataxia favors a central lesion.
Cranial nerve and cerebellar examination – Identify associated diplopia, dysarthria, or limb ataxia indicating brainstem or cerebellar involvement.
Laboratory testing is rarely required unless systemic causes are suspected. Imaging (e.g., MRI) is indicated if central vertigo or structural lesions are considered. Audiometry may be useful if hearing loss is present. Early identification and canalith repositioning maneuvers remain the cornerstone of BPPV management.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Clinical Points
Vertigo is a false sensation of movement, often described as spinning, and results from vestibular system dysfunction.
Benign Paroxysmal Positional Vertigo (BPPV) is the most common peripheral vestibular cause, triggered by specific head movements.
Distinguishing peripheral from central causes is critical — peripheral vertigo typically presents with brief, position-triggered episodes and horizontal-rotatory nystagmus.
The Dix–Hallpike test is diagnostic for posterior canal BPPV.
Canalith repositioning maneuvers (e.g., Epley) are highly effective treatments.
Muscle Weakness
Clinical Scenario
A 34-year-old previously healthy man presents with progressive weakness in his legs over the past five days. It started with difficulty climbing stairs and has now spread to his arms, causing trouble lifting objects. He denies sensory loss, visual changes, or bowel/bladder symptoms. Two weeks prior, he had a mild gastrointestinal illness with diarrhea. On examination, there is symmetric flaccid weakness in both lower limbs (MRC grade 3/5) and upper limbs (4/5), generalized areflexia, and preserved sensation. Cranial nerves are intact. Vital signs are stable, but there is mild tachycardia.
Differential Diagnosis
AIDP (Acute Inflammatory Demyelinating Polyradiculoneuropathy) – the most common form of Guillain–Barré Syndrome (GBS)
Acute motor axonal neuropathy (AMAN) or acute motor-sensory axonal neuropathy (AMSAN)
Acute transverse myelitis
Hypokalemic paralysis
Myasthenia gravis or botulism (if cranial involvement)
Approach to Diagnosis
Evaluation of acute muscle weakness begins with assessing the pattern (symmetry, distribution, proximal vs. distal) and associated features (reflexes, sensory changes, cranial involvement). Rapid progression over days to weeks with areflexia strongly suggests a peripheral neuropathy such as Guillain–Barré Syndrome (GBS).
The five most important physical examination findings include:
Deep tendon reflexes – Generalized areflexia or hyporeflexia is a hallmark feature of GBS.
Muscle strength assessment – Symmetric, ascending flaccid weakness involving lower then upper limbs.
Cranial nerve examination – Facial and bulbar weakness may occur, indicating more severe disease.
Sensory testing – Typically normal or mildly reduced; marked sensory loss suggests an alternative diagnosis.
Autonomic evaluation – Check for tachycardia, blood pressure variability, or urinary retention as signs of autonomic dysfunction.
A detailed history should explore preceding infections, vaccinations, or toxin exposures. Laboratory testing helps exclude metabolic or electrolyte causes. CSF analysis typically shows elevated protein with normal white cell count (albuminocytologic dissociation). Nerve conduction studies reveal demyelinating or axonal features. MRI may be performed to exclude central causes such as transverse myelitis.
Diagnostic Matrix
| History | Examination | Laboratory | Diagnostics | Diagnosis |
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Key Points
Guillain–Barré Syndrome (GBS) is an acute, immune-mediated polyradiculoneuropathy often triggered by infection.
Classically presents with rapidly progressive, symmetric ascending weakness and areflexia.
Sensory symptoms are minimal or absent; autonomic dysfunction and respiratory compromise may occur.
Diagnosis is clinical, supported by CSF (albuminocytologic dissociation) and nerve conduction studies.
Early treatment with IVIG or plasmapheresis improves outcomes; corticosteroids are ineffective.