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USMLE Step 2 (Fach) / Neurology (Lektion)
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- Postdural puncture headache Risk factors:- Female- Young (20-40 years old)- Low BMI Clinical features:- After lumbar puncture or neuraxial anesthesia- Positional (worse when upright, improves when supine)- Neck stiffness- Photophobia, diplopia- Hearing loss, tinnitus- Pain can last up to 15 days Management:- Typically self-limited- Epidural blood patch: Indicated in severe refractory post-lumbar puncture headache
- Clinical features of RA cervical myelopathy Symptoms:- Neck pain radiating to occipital region- Slowly progressive spastic quadriparesis- Painless sensory deficits in hands or feet- Respiratory dysfunction (e.g., from vertebral artery compression) Signs:- Protruding anterior arch of atlas- Scoliosis with loss of cervical lordosis- Upper motor neuron signs (e.g., spastic paresis, hyperreflexia, Babinski sign)- Hoffman sign
- Seizure vs. Syncope Preceding symptoms:- Seizure: Aura (e.g., smell, visual disturbance) or none- Syncope: Prodrome (e.g., nausea, diaphroesis) or none Patient position- Seizure: Any position- Syncope: Often standing (vasovagal), but can occur in any position (cardiogenic) Tongue biting:- Seizure: Common, often lateral- Syncope: Rare, frontal if present Convulsive movements:- Seizure: Common, typically start before or simultaneous with LOC- Syncope: Less common but can occur after LOC Urinary incontinence:- Seizure: Common- Syncope: Less common but can occur after LOC Post-episode recovery:- Seizure: Variable (minutes to hours or days), residual confusion is common- Syncope: Rapid (1-2 minutes), no residual deficit
- Perilymphatic fistula Rare, but debilitating, complication of head injury or barotrauma. Clinical features:- Progressive sensorineural hearing loss caused by damage to cochlear hair cells from loss of endolymph- Episodic vertigo with nystagmus triggered by pressure changes in the inner ear (e.g., Valsalva maneuver, elevation changes [e.g., riding in elevator] due to acutely increased endolymph leakage) Diagnostics:- Loud clap (i.e., pressure change due to sound conduction through the ossicles) near the patient's ear causes nystagmus (Tullio phenomenon) Teratment:- Limit activities that increase inner ear pressure- ENT referral
- Spinal epidural hematoma Epidemiology:- ♂ > ♀ (4:1)- Bimodal distribution (peaks during childhood and between age 40–50 years) Etiology: Spontaneous or traumatic (e.g., following lumbar puncture, pulling epidural catheter) bleeding Risk factors:- Thrombocytopenia- Bleeding diathesis- Anticoagulation- Vascular malformations- Acute spinal cord compression Clinical features: Back pain, lower extremity weakness and numbness, hyporeflexia Diagnostics: - MRI with and without gadolinium: to demonstrate hematoma and underlying pathology Treatment:- Surgical decompression to avoid permanent neurologic dysfunction (laminectomy and evacuation of blood)
- Progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome) Clinical features:- Postural instability (leading to frequent falls)- Frontal lobe abnormalities (e.g., apathy, disinhibition, impaired reasoning)- Vertical gaze palsy, especially downward gaze, to complete external ophthalmoparesis - Rigor- Bradykinesia- Dysarthria, dysphagia- Dementia Diagnosis:- MRI: “hummingbird sign” showing atrophy of midbrain structures with a relatively intact pons region
- Parkinson-plus syndromes Parkinson-plus syndromes have a number of features that differentiate them from Parkinson disease (PD): - Poor response to levodopa- Early involvement of the autonomic nervous system (orthostatic hypotension, impotence, incontinence, anhidrosis)- Early onset of postural instability with frequent falls - Dementia- Visual hallucinations (usually a sign of Lewy-body disease)- Signs of cerebellar involvement- Pathological reflexes present (e.g., Babinski sign); enhanced proprioceptive reflexes- Eating and swallowing disorders; pronounced dysarthria- Apraxia Multiple system atrophy (MSA)- Lewy bodies- Autonomic dysfunction with urogenital problems Progressive supranuclear palsy (PSP)- Vertical gaze palsy- Frontal lobe disturbances Corticobasal degeneration (CBD)- Asymmetric motor symptoms- Alien limb phenomenon Dementia with Lewy bodies (DLB)- Lewy bodies- Visual hallucinations
- Corticobasal degeneration Clinical features:- Dementia (at any stage)- Asymmetric motor abnormalities, often initially affecting only one limb- Alien limb phenomenon: The patient perceives the affected limb as not belonging to him or her. Diagnosis: asymmetric focal cortical atrophy and bilateral atrophy of the basal ganglia on MRI
- Classification & features of hearing loss Sensorineural:- Cause: Disorder involving inner ear, cochlea, or auditory nerve- Presbyacusis- Ménière disease- Barotrauma- Acoustic neuroma- Cerebrovascular ischemia Conductive:- Cause: Any cause that limits sounds from gaining access to the inner ear- Otitis externa or media- Cholesteatoma- Trauma- Cerumen- Tympanic membrane perforation
- Head thrust test Positive: Inability to maintain visual fixation during forced, rapid head movement Evaluates the vestibuloocular reflex, which is affected by peripheral but not central vestibulopathies.
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- Autonomic neuropathy Urogenital system:- Erectile dysfunction (most common)- Bladder dysfunction: urinary retention, incomplete bladder emptying, bladder distention, overflow incontinence, poor urinary stream Cardiovascular system- Silent myocardial infarction- Decreased heart variability or fixed rhythm- Orthostatic hypotension- Persistent sinus tachycardia- Ventricular arrhythmia Gastrointestinal system:- Gastroparesis (→ delayed gastric emptying, risk of postprandial hypoglycemia): nausea, abdominal bloating, loss of appetite, early satiety- Diarrhea, constipation, incontinence- Treatment involves prokinetic agents (e.g., metoclopramide (1st-line), erythromycin, cisapride). Other manifestations:- Sweat gland dysfunction associated with heat intolerance- Pupillary dysfunction- Risk of hypoglycemia due to absence of hormonal counterregulation (secretion of cortisol, glucagon, and catecholamines)
- Vestibular schwannoma (acoustic neuroma) Epidemiology:- Median age: 50- Usually unilateral (bilateral associated with NF type 2) Clinical features:- Sensorineural hearing loss & imbalance (CN VIII Schwann cell tumor)± Facial numbness &/or paralysis (CN V & VII compression) Diagnostics:- Audiogram- MRI with contrast of internal auditory canal Management:- Observation (e.g., small tumors, minimal symptoms, older or infirm patients)- Surgery- Radiation therapy
- Degenerative disc disease Epidemiology:- Age: most common at 30–50 years- ♂ > ♀- About 5% of back pain is a consequence of disc herniation- L5-S1 (most common site) Clinical features:- Acute onset of severe back pain→ Stabbing or resembling electric shock (most commonly of the lower back, called lumbago)→ Radiates to the legs (sciatic pain) or the arms- Paresthesia of affected dermatome- Muscle weakness and atrophy- Loss of deep tendon reflexes in the indicator muscles- Pain increases with pressure (e.g., from coughing or sneezing)- Short walks and changing position reduces the pain C6 radiculopathy: From upper lateral elbow over radial forearm up to thumb → Biceps and wrist extensorsC7 radiculopathy: Fingers II–IV → Triceps and wrist flexorsC8 radiculopathy: Fingers IV-V → Finger flexorsL3 radiculopathy: Anterior lateral area of the thigh → Hip flexionL4 radiculopathy: Extending from distal lateral thigh area over patella up to inner side of lower leg → Knee extension, tibialis anterior muscle (foot dorsiflexion) → difficulty heel walkingL5 radiculopathy: Dorsolateral thigh, lateral side of the knee, anterolateral lower leg, dorsum of foot, big toe→ Extensor hallucis longus muscle (first toe dorsiflexion) → difficulty heel walking (foot drop)S1 radiculopathy: Lateral foot → Peroneus longus and brevis muscle (foot eversion) and gastrocnemius muscle (foot plantarflexion) → difficulty toe walking
- Adrenoleukodystrophy Inheritance: X-linked disorder Epidemiology: rare- Most often manifests in young males (early childhood) Pathophysiology: mutation of the ABCD1 gene, which encodes a peroxisomal ATP-binding cassette (ABC) transporter protein- Impaired transport of very long chain fatty acids (VLCFA) into peroxisomes- Impaired β-oxidation of VLCFA results in accumulation of VLCFA in the adrenal glands, testes, and white matter- Neuron demyelination and destruction of renal and Leydig cells. Clinical features:- Cognitive impairment- Progressive vision, hearing, and motor deterioration- Dementia- Adrenal insufficiency- Coma, death Treatment: supportive (diet and "Lorenzo's oil")
- Advanced sleep-wake phase disorder Circadian rhythm disorder characterized by the inability to stay awake in the evening (usually after /:00 PM) and by early morning insomnia
- Sensorimotor polyneuropathy Most common neuropathy in patients with diabetes Small fiber injury: Predominance of positive symptoms (e.g., pain, paresthesias, allodynia) Large fiber injury: Predominance of negative symptoms (e.g., numbness, loss of proprioception and vibration sense, diminished ankle reflexes)
- Akathisia Extrapyramidal symptom Etiology:- Antipsychotics - Antiemetics (e.g., prochlorperazine, promethazine, metoclopramide) Clinical features:- Inner restlessness- Internal sense of unease- Need to walk or pace