USMLE Step 3 (Subject) / Neurology (Lesson)

First Aid Step 3

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• Myasthenia gravis Epidemiology:- Sex: ♀ > ♂ (3:2)- Age of onset: Possible at any age, but often→ ♀: 20-40 years→ ♂: 60-80 years Etiology:- Autoimmune: autoreactive antibodies directed against postsynaptic acetylcholine receptors or receptor-associated proteins→ Association with other autoimmune diseases: especially Hashimoto thyroiditis, rheumatoid arthritis, sarcoidosis, systemic lupus erythematosus- Associated with→ Thymoma (the most common primary tumor in the anterior mediastinum) in 10-15% of patients→ Thymic hyperplasia in 65% of patients- In rare cases, can also be caused by graft-versus-host reaction after allogeneic stem cell transplantation (especially in children)   Clinical features:- Symptoms worsen with increased muscle use throughout the day and improve with rest.- Sometimes associated with exacerbating factors, including: → Medications: muscle relaxants, beta blockers, benzodiazepines, aminoglycosides, low-potency antipsychotics, tricyclic antidepressants, d-penicillamine→ Stress→ Infection→ Pregnancy- Eye muscle weakness: most common initial symptom→ Ptosis, Diplopia, Blurred vision- Bulbar muscle weakness: Slurred speech, difficulty chewing and/or swallowing- Proximal limb weakness→ Rising from a chair, Climbing stairs, Brushing hair- Weakness of respiratory muscles Diagnostics:- Suspected cases of MG are generally confirmed via EMG and AChR antibodies and should receive a chest CT to rule out thymoma.- AChR antibody test (most specific test)- Other associated antibodies: anti-MuSK- Electromyography (EMG): a decremental response following repetitive nerve stimulation- Chest CT: always indicated in newly diagnosed MG patients to rule out thymoma- Edrophonium test (Tensilon test): Symptoms improve rapidly after administration of a short-acting acetylcholinesterase inhibitor   Treatment:- First line: cholinesterase inhibitors  → Drug of choice: pyridostigmine- Supplemental immunosuppressants: if symptoms persist despite anticholinesterase treatment→ Glucocorticoids→ Alternatives: azathioprine, cyclosporine, mycophenolate mofetil- Rapid immunomodulating therapies: in cases of myasthenic crisis→ Plasmapheresis→ IV immune globulin- Thymectomy: can be beneficial even if a thymoma is not present→ Not for patients with MuSK antibody-associated MG without a thymoma
• Lambert-Eaton myasthenic syndrome (LEMS) LEMS is a rare autoimmune disease that reduces neuromuscular transmission and leads to muscle weakness. Pathophysiology: Autoantibodies are directed against presynaptic voltage-gated calcium channels → impaired acetylcholine release in the NMJ. Association: small-cell lung carcinoma (in ⅔ of LEMS cases) Clinical features:- Proximal muscle weakness- Reduced or absent reflexes- Autonomic symptoms: → Dry mouth→ Constipation→ Orthostatic dysregulation Diagnostics:- Active muscle contraction or repeated muscle tapping increases reflex activity.- Lambert's sign: Muscle strength improves after muscle use.  - EMG: Repetitive nerve stimulation results in incremental responses.- Confirmatory test: serologic detection of antibodies directed against voltage-gated calcium channels
• Ischemic stroke Epidemiology: ∼ 85% of all strokes Etiology:- Embolism- Thrombus- Small vessel occlusion (lipohyalinosis)- Systemic hypoperfusion Risk factors:- Age > 65 years- Hypertension- Diabetes mellitus- Atrial fibrillation- Carotid artery stenosis Clinical features: Sudden onset of focal neurologic deficits Diagnosis:- Noncontrast head CT to rule out hemorrhage- MRI- CTA/MRA: If the patient is a candidate for thrombectomy or to better identify the affected blood vessel Treatment:- tPA (if within < 4.5 hours of onset of symptoms)- Intra-arterial thrombolysis- Thrombectomy- Aspirin or clopidogrel for secondary prevention
• Intracerebral hemorrhage Epidemiology: ∼ 10% of all strokes Etiology:- Ruptured cerebral artery or microaneurysm- Trauma- Reperfusion injury after ischemic stroke Risk factors:- Age > 65 years- Hypertension- Vasculitis- Malignancy- Ischemic stroke Clinical features:- Headache, confusion, nausea- Sudden onset of focal neurologic deficits Diagnostics:- Noncontrast head CT- MRI- CTA/MRA Treatment:- Reversal of coagulopathy- Blood pressure management- Surgical intervention if there are signs of herniation or increased ICP
• Subarachnoid hemorrhage Epidemiology: ∼ 5% of all strokes Etiology:- Ruptured berry aneurysm- Arteriovenous malformation- Trauma Risk factors:- Hypertension- Tobacco use- Family history Clinical features:- Rapid onset of severe headache- Meningeal signs- Sudden onset of focal neurologic deficits Diagnostics:- Noncontrast head CT- CTA- Lumbar puncture   Treatment:- Reversal of coagulopathy- Blood pressure management- Prevention of vasospasm- Surgical clipping
• Stroke symptoms – Middle cerebral artery (MCA) - Contralateral sensory loss- Contralateral weakness in the arms, lower half of the face, and lower limbs- Gaze deviates toward the side of infarction- Contralateral homonymous hemianopia without macular sparing  - Aphasia if in dominant hemisphere (usually left MCA territory)→ Broca aphasia (lesion to inferior frontal gyrus, which is supplied by the superior division of MCA)→ Wernicke aphasia (lesion to superior temporal gyrus, which is supplied by the inferior division of MCA)→ Conduction aphasia (lesion to supramarginal gyrus, which is supplied by the inferior division of MCA)- Hemineglect if in nondominant hemisphere (usually right MCA territory)
• Stroke symptoms – Anterior cerebral artery (ACA) - Contralateral weakness in the lower limbs > upper limbs- Contralateral sensory loss in the lower limbs > upper limbs- Abulia (A milder form of akinetic mutism that is characterized by disinterest and a slowed mental state)- Urinary incontinence- Dysarthria (A condition of impaired articulation resulting from motor dysfunction of the tongue, lips, or vocal cords. Typical pathologic speech patterns include slurring, mumbling, staccato pronunciation, and changes in speed and pitch.)- Transcortical motor aphasia (A type of aphasia characterized by a lack of fluency with intact comprehension and repetition)- Limb apraxia (The inability to perform coordinated, purposeful, and/or learned movements when asked even though the request is understood (e.g., combing one's hair, putting on shoes and socks).)
• Stroke symptoms – Posterior cerebral artery (PCA) - Contralateral homonymous hemianopia with macular sparing- Contralateral sensory loss due to lateral thalamic involvement: light touch, pinprick, and positional sense may be reduced.- Memory deficits- Vertigo, nausea Localized findings:- Left PCA territory: alexia without agraphia, anomic aphasia, visual agnosia- Right PCA territory: prosopagnosia (The inability to recognize familiar faces) Thalamic syndromes:- Decreased arousal- Variable sensory loss- Aphasia- Visual field losses- Apathy, agitation, personality changes
• Stroke symptoms – Posterior inferior cerebellar artery Lateral medullary syndrome (Wallenberg syndrome) - Can also be seen with vertebral artery infarction- Dysphagia, hoarseness, hiccups, decreased gag reflex: specific to posterior inferior cerebellar artery lesions (vs. vertebral artery)- Nystagmus, vertigo  - Body: contralateral decrease in pain and temperature sensations- Face: ipsilateral decrease in pain and temperature sensations- Ipsilateral limb ataxia and dysmetria- Autonomic dysfunction: ipsilateral Horner syndrome
• Stroke symptoms – Anterior inferior cerebellar artery Lateral pontine syndrome (Marie-Foix syndrome): due to basilar artery and/or anterior inferior cerebellar artery infarction- Corticospinal tract: contralateral weakness- Lateral spinothalamic tract: contralateral loss of pain and temperature sensation- Cerebellar tracts: ipsilateral limb and gait ataxia- Cranial nerve nuclei involvement is possible.→ Facial nerve nuclei: ipsilateral facial muscle weakness→ Vestibulocochlear nerve nuclei: vertigo, nystagmus, and ipsilateral hearing loss→ Trigeminal nerve nuclei (motor and sensory): ipsilateral weakness of mastication muscles, ipsilateral loss of facial sensation to pain and temperature- Sympathetic tract: ipsilateral Horner syndrome
• Stroke symptoms – Basilar artery - Consciousness is usually preserved.- Vertebrobasilar insufficiency → Vertigo, drop attacks, tinnitus, hiccups, dysarthria, dysphagia→ Ipsilateral cranial nerve deficits→ Diplopia→ Gait ataxia→ Paresthesias- Pontine syndromes → Ventral pontine syndrome→ Lateral pontine syndrome→ Inferior medial pontine syndrome→ Locked-in syndrome (bilateral basilar artery occlusion)- Cerebellar syndromes
• Lacunar stroke type Pure motor stoke:- Posterior limb of the internal capsule (most common)  - May also involve the corona radiata, basal pons, medial medulla- Often caused by occlusion of the lenticulostriate artery→ Contralateral hemiparesis of the face, arm, and leg (circumduction gait)→ In some cases, dysarthria→ No sensory impairment→ Most common type of lacunar stroke (> 50%) Pure sensory stroke:- Thalamus (most common)- May also involve the posterior limb of the internal capsule, pontine tegmentum, corona radiata→ Contralateral numbness and paresthesia of the face, arm, and leg Hemiballismus:- Caudate nucleus, putamen, thalamus, globus pallidus, corona radiata, subthalamic nucleus→ Contralateral, involuntary, large flinging movements of the arm or leg
• Stroke treatment Stabilization and monitoring:- Maintain euvolemia with fluid replacement as needed.  - Maintain a sufficient oxygen supply and consider intubation if the patient shows signs of increased intracranial pressure (e.g., altered mental state).- Maintain euglycemia (e.g., blood glucose levels within 140-180 mg/dL).- Maintain normothermia (e.g., antipyretics).- Cardiac monitoring (for at least 24 hours)- Maintain a normal acid-base status.- Monitor for signs of elevated intracranial pressure (see elevated intracranial pressure and brain herniation).- Evaluate for dysphagia. Blood pressure management:- Always treat hypotension (e.g., with fluid replacement, vasopressors).→ Ischemic stroke: permissive hypertension  → Only treat severe hypertension (> 220 systolic pressure and/or 120 mm Hg diastolic pressure)- Hemorrhagic stroke: Reduce systolic blood pressure to approx. 140-160 mm HgNitrates should be avoided because they can increase intracranial pressure.
• Seizure disorders (Epilepsy) Situational factors that can trigger epileptic seizures in epilepsy patients:- Excessive physical exertion- Sleep deprivation- Strobe light flashing- Loud music Provoked seizures:- Metabolic and electrolyte disturbances: hypoglycemia and hyperglycemia, hyponatremia and hypernatremia, hypocalcemia, uremia, thyroid storm, hyperthermia, water intoxication- Mass: brain tumors and metastases, hippocampal sclerosis- Alcohol withdrawal (most common trigger in adults)- Noncompliance with anticonvulsant treatment- Medication withdrawal  - Acute intoxication: cocaine, ecstasy, carbon monoxide poisoning, metal poisoning- Pharmacotherapy: amitriptyline, penicillin, maprotiline, lithium, lidocaine, antipsychotics, theophylline- Infections: encephalitis, brain abscess, meningitis, septic shock- Ischemia: stroke, perinatal injuries  - Trauma: traumatic brain injury- Increased ICP and cerebral edema: eclampsia, hypertensive encephalopathy, cerebrovascular malformation- Fever in infants and children (see febrile seizures) Clinical features:- Ictal phase:→ Sudden onset→ Rapid progression of symptoms→ Duration usually 1-3 minutes  - Postictal phase:→ Varying degree of confusion, impaired alertness→ Residual neurologic symptoms (e.g., Todd's paralysis)→ Duration usually minutes or hours Diagnostics:1. Confirm a seizure- Patient history (from patient or witnesses): e.g., evidence of an aura, observation of typical symptoms (e.g., twitching), identification of provocative factors (e.g., sleep deprivation or unreliable intake of antiseizure medication)- EEG  → During the seizure (ictal): Epileptiform discharges (e.g., spikes, sharp waves, spike waves, and hypsarrhythmia) are usually detected.  If no epileptiform discharges are detected, diagnosis of pseudoseizures should be considered.→ Between seizures (interictal): Often normal findings (even after provocation via sleep deprivation, hyperventilation, or visual stimuli). Possibly showing epileptiform activity (bursts of abnormal discharges featuring spikes and/or sharp waves)2. Exclude an underlying condition- ECG: In every patient with loss of consciousness during an ictal event, cardiogenic causes (e.g., cardiac arrhythmias resulting in cerebral hypoxia) should be ruled out. - CT/MRI (with and without contrast): structural lesions (e.g., brain tumors) should be ruled out after a first seizure.  - Laboratory tests: Blood glucose, electrolytes, Prolactin, Antiepileptic drug levels, Toxicology screen, CBC, ESR, Rapid plasma reagin, Creatine kinase, Renal and liver function tests- Lumbar puncture: cerebrospinal fluid analysis (e.g., if CNS infection is suspected) Treatment:- First seizure: Long-term medical therapy is usually not required, unless there are abnormalities seen on EEG or MRI - Criteria for the choice of antiepileptic drugs:1. Type of epilepsy (as per clinical evaluation or instrumental findings)2. Patient age3. Comorbidities and contraindications- Focal seizures  → First‑line treatment: lamotrigine, levetiracetam, phenytoin, carbamazepine, oxcarbazepine, phenobarbital (children)- Primary generalized seizures→ Tonic-clonic: First‑line treatment: lamotrigine, valproate, phenobarbital (children)→ Typical absence: First‑line treatment: ethosuximide, valproate→ Atypical absence, myoclonic, atonic: First‑line treatment: valproate, lamotrigine, topiramate
• Status epilepticus Criteria:≥ 5 min of continuous seizuresOR ≥ 2 seizures with consciousness not being fully regained in the interictal period Treatment1. Initial assessment and supportive treatment:  - Place patient in recovery position to prevent injury.- Quick neurological examination (to determine type and cause of status epilepticus) and general medical evaluation (particularly airway, breathing, and circulation)- Establish secure IV access (two, if possible), collection of blood for routine blood tests (particularly electrolytes and glucose levels), toxicology screen, antiepileptic drug levels, and arterial blood gas (ABG) analysis  - Supportive therapy as necessary (e.g., oxygen, glucose, thiamine, naloxone)- Monitoring of vital signs: especially oxygen saturation (via pulse oximetry), blood pressure, cardiac action, and breathing- If patient does not regain consciousness after seizures stop or nonconvulsive status epilepticus is suspected → continuous EEG monitoring- If acute brain injury (e.g., intracerebral hemorrhage) is suspected → obtain a cranial CT- If CNS infection is suspected → conduct a lumbar puncture  2. Pharmacological interruption of seizures: initial treatment  - First line: IV lorazepam; second line: IV diazepam or midazolam → if IV access is not possible or drugs are administered by someone who is not a medical professional → select another application form (e.g., rectal diazepam, buccal or intranasal lorazepam/midazolam)- If the patient does not respond within 1 minute → administer additional lorazepam (or a second-line benzodiazepine)- If the patient does not respond within another 10-20 minutes → saturation with fosphenytoin via separate access (alternatively: phenobarbital, levetiracetam, or valproate)- If seizure activity does not stop despite application of a benzodiazepine and a nonbenzodiazepine antiseizure drug → refractory status epilepticus- No later than 45-60 min after onset: continuous administration of anesthetics with intubation and ICU monitoring; e.g., thiopental, propofol, or midazolam3. Nonbenzodiazepine therapy (to prevent recurrence): fosphenytoin or valproate
• Breath-holding spell Epidemiology: Occurs in children (6 months-6 years) Strong association with iron deficiency anemia Clinical features:- Episodes of prolonged expiratory apnea- Followed by loss of consciousness (syncope)- Transient paroxysms of cyanosis or pallor- Possibly generalized stiffness and jerky movements of the limbs (anoxic seizure)  - Triggers: distress, strong emotions (e.g., anger, frustration) due to tantrums or injury Diagnosis: based on typical presentation of BHS (no confirmatory test exists)- Further work-up is generally not necessary. Only if atypical presentation of BHS: EEG to differentiate from epileptic seizures- ECG to rule out cardiac causes of syncope- Laboratory analysis: CBC, serum ferritin (rule out iron deficiency anemia) Treatment: reassurance 
• Spinal cord compression Occurs when the spinal cord is compressed by a lesion such as a tumor, fracture, or ruptured disk Etiology:- Acute onset (within minutes to hours): vertebral fracture, acute disc herniation, hematoma- Insidious onset: abscess, primary tumor, metastasis (days to weeks); degenerative spine changes, e.g., spondylosis (months to years) Clinical features:- Common features: back pain, radicular pain (follows dermatomal distribution of affected nerve), and neurological deficits below the level of the lesion (first sensory abnormalities, followed by motor and/or bladder/bowel dysfunction)- Incomplete spinal cord syndromes: cauda equina syndrome and conus medullaris syndrome  - Patients may develop symptoms of isolated cauda equina syndrome, isolated conus medullaris syndrome, or a combination of the two.- Considered a medical emergency!   Treatment:1. IV glucocorticoids: reduce pain, swelling, and inflammation → immediate decompression; bridge time until surgery can be performed  - Opioids for further pain control if necessary2. Surgical management: definitive treatment- Decompression surgery- Stabilization surgery  3. Radiation therapy: indicated if tumor is inoperable and following surgery; controls local tumor growth and significantly reduces pain
• Conus medullaris syndrome Etiology: Damage to the spinal cord segments S3-S5 (conus medullaris), which are situated at the level of L1 vertebra- Spinal tumors- Trauma (e.g., vertebral fracture, spondylolisthesis) Onset: Sudden bilateral onset Pain:- Lower back pain- Less severe radicular pain Motor symptoms:- Symmetric, hyperreflexic distal paresis of lower limbs, possibly fasciculations- Achilles reflex may be absent   Sensory symptoms:- Symmetric, bilateral perianal numbness (saddle anesthesia)- Sensory dissociation Urogenital and rectal symptoms:- Early onset of bladder and fecal incontinence  - Erectile dysfunction
• Cauda equina syndrome Etiology:- Damage to or compression of the cauda equina with nerve fibers of L3-S5 (below L2)  - Large posteromedial disc herniation, trauma, or tumors Onset: Gradual unilateral onset Pain: Severe radicular pain Motor symptoms:- Asymmetric, areflexic, flaccid paresis of the legs  - Muscle atrophy Sensory symptoms:- Saddle anesthesia (may be asymmetric)- Asymmetric, unilateral numbness and/or paresthesia in lower limb dermatomes Urogenital and rectal symptoms:- Late onset of urinary retention- Change in bowel habits- Decreased rectal tone or bulbocavernosus reflex- Erectile dysfunction
• Guillain-Barré syndrome (GBS) Acute postinfectious polyneuropathy Epidemiology:- Incidence: 1-4 cases per 100,000- Sex: ♂ > ♀ (1.5:1)- Adults are affected more frequently than children. Etiology:- About ⅔ of GBS patients experience symptoms of an upper respiratory or gastrointestinal tract infection 1-4 weeks prior to onset of GBS.- Pathogens associated with GBS: Campylobacter jejuni, Cytomegalovirus, Epstein-Barr virus, HIV, influenza, and Mycoplasma pneumoniae Clinical features:- Initial symptoms: back and limb pain, esp. paresthesias affecting distal extremities- Advanced symptoms→ Ascending paralysis: Bilateral flaccid paralysis spreads from the lower to the upper limbs in a “stocking‑glove” distribution. → Cranial nerve involvement: frequently bilateral facial nerve involvement (facial diplegia)→ Landry paralysis: involvement of the respiratory muscles- Reduced or absent muscle reflexes- Peripheral, symmetric paresthesias in the hands and feet- Neuropathic pain develops in about ⅔ of patients- Cardiovascular autonomic dysfunction (arrhythmia), voiding dysfunction, and/or intestinal dysfunction Diagnostics:- Cerebrospinal fluid: Albuminocytologic dissociation: elevated protein levels and normal cell counts in cerebrospinal fluid (CSF); CSF cell counts higher than 50 cells per μl CSF indicate that GBS is unlikely!  - Serological screening: → To identify potential pathogens (e.g., Campylobacter jejuni)→ Detection of antibodies directed against gangliosides (e.g., anti‑GM1 antibodies)- Electroneurography: reduced nerve conduction velocity (NCV) due to demyelination: increased F‑wave latency Treatment:- Monitor cardiac and respiratory function: in some cases, intensive care unit (ICU) treatment and intubation may be indicated- Prevent decubitus and/or thrombosis (esp. pulmonary embolism)- High dose of intravenous immunoglobulins  - Plasmapheresis→ In adults: equivalent outcome as IV immunoglobulins→ In children: only recommended in children with rapidly progressing or severe disease  
• Multiple sclerosis (MS) Most common sites of demyelination in MS:- Periventricular areas- Brainstem- Cerebellum- Spinal cord Clinical features:- Optic neuritis (most often the earliest manifestation): impaired vision and color blindness  - Internuclear ophthalmoplegia (INO) as a result of a lesion in the medial longitudinal fasciculus (MLF)  → Ipsilateral medial rectus weakness but an intact convergence reflex→ Disconjugate, lateral gaze nystagmus in the contralateral eye- Demyelination of spinal cord tracts→ Lhermitte's sign: a shooting electric sensation that travels down the spine when the patient flexes his/her neck  → Absent abdominal reflex (An early and important sign which is seen in 70% of cases)→ Pyramidal tract lesion: upper motor neuron weakness characterized by spasticity, hyperreflexia, and a positive Babinski's sign (see upper vs lower motor neuron lesions)→ Involvement of the dorsal spinal column: loss of vibration and fine touch sensations, numbness, paresthesias, sensory ataxia- Cerebellar involvement → Charcot's neurological triad  → Scanning speech (A type of speech characterized by slow speech with recurring pauses between syllables and undue emphasis on various syllables)→ Nystagmus→ Intention tremors- Cranial nerve palsies  - Autonomic dysfunction: bowel and bladder disorders, impaired sexual activity  - Change in mental state: memory deficits, impaired concentration, and/or depression  - Uhthoff's phenomenon: a reversible exacerbation of neurological symptoms following physical exertion, a warm bath, or fever   Diagnostics:- Plain MRI (brain and spine): investigation of choice→ Multiple sclerotic plaques (most commonly seen in periventricular white matter) with finger-like radial extensions (Dawson's fingers)  - Lumbar puncture for CSF examination→ Lymphocytic pleocytosis→ Oligoclonal bands (↑ production of IgG subfractions)   Treatment of acute exacerbations:- First line: high-dose glucocorticoid therapy for 3-5 days (methylprednisolone 500-1000 mg/d IV or PO)- Second line: plasmapheresis Disease-modifying MS therapy (prevention of exacerbations):- Interferon beta- Glatiramer acetate (copolymer-1)- Mitoxantrone- Fingolimod- Alemtuzumab- Natalizumab
• Peripheral vs Central Vertigo Peripheral: - Pathology: Lesion of the vestibular apparatus of the inner ear or CN VIII- Clinical features:→ Intermittent, positional vertigo→ May be associated with tinnitus, hearing loss, and postural unsteadiness→ Nystagmus is rotary, unidirectional, and fatigable→ Fixation of gaze does stops vertigo Central:- Pathology: Lesion of the brainstem vestibular nuclei or their connections- Clinical features:→ Vertigo is not positional→ May have accompanying cranial nerve injuries (e.g., facial droop, dysarthria, absent corneal reflexes)→ Nystagmus changes direction with gaze; vertigal nystagmus is highly specific for central vertigo→ Visual fixation does not stop vertigo
• Duchenne muscular dystrophy (DMD) Epidemiology: Onset before age 5 years old Clinical features:- Paresis and atrophy starting in the proximal lower limbs (pelvic girdle), later spreading to the upper body and distal areas- Weak reflexes- Waddling gait (bilateral Trendelenburg's sign)- Gower maneuver: To stand up, the patient supports himself on his thighs and uses the hands to essentially "walk" up the body until reaching a standing position. It is a classic sign in DMD but also occurs in e.g., Becker muscular dystrophy, dermatomyositis.  - Calf pseudohypertrophy- Inability to walk by approx. 12 years of age- Cardiac and respiratory muscle involvement→ Dilated cardiomyopathy: common cause of death→ Cardiac arrhythmias→ Respiratory insufficiency→ Cognitive impairment Diagnostics:- Blood tests: ↑↑ creatine kinase in serum of almost all affected individuals (also, in > 50% of female carriers), ↑ serum aldolase- Genetic analysis (confirmatory test): detect dystrophin gene mutation- Muscle biopsy Treatment: - Glucocorticoids (e.g., prednisone)
• Parkinson disease Epidemiology:- Sex: ♀ ≅ ♂  - Prevalence: increases with age- Age of onset: ∼ 60 years Risk factors:- Familial history (various genes) → in approximately 10-15% of cases- Environmental factors (e.g., exposure to manganese and other substances)- Diet/metabolism (e.g., low levels of vitamin D, high iron intake, obesity)- Structural damage (e.g., history of traumatic brain injury) Etiology:- Parkinson disease: PD is commonly considered idiopathic- Secondary parkinsonism (pseudoparkinsonism)→ Medication (drug-induced parkinsonism): typical antipsychotics (e.g., haloperidol), some antiemetics (e.g., metoclopramide), some calcium channel blockers (e.g., flunarizine, amiodarone), valproate, and lithium→ MPTP: Illegal drug, metabolized to MPP+, damages substantia nigra→ Metabolic disorders: e.g., Wilson disease→ Toxins: e.g., manganese, carbon monoxide, carbon disulfide→ Cerebrovascular disease (vascular parkinsonism): e.g., subcortical arteriosclerotic encephalopathy→ CNS infections: Viruses: e.g., herpes simplex virus, human immunodeficiency virus, Bacteria: e.g., Treponema pallidum, Protozoa: e.g., Toxoplasma gondii, Prion agents: e.g., Creutzfeldt-Jakob disease Pathophysiology:- Progressive dopaminergic neuron degeneration in the substantia nigra (part of the basal ganglia) and the locus coeruleus - Serotonin and noradrenaline depletion (in the Raphe nuclei): likely cause of depressive symptoms- Acetylcholine surplus (in the nucleus basalis of Meynert): likely cause of dyskinesia Clinical features:- Clinical course > 10 years; unilateral onset with persistently asymmetrical course (i.e. unilaterally pronounced symptoms) but may progress to the contralateral side- Bradykinesia/akinesia- Bradydiadochokinesia  - Resting tremor (4-6 Hz)→ Pill-rolling tremor that subsides with voluntary movements, but increases with stress→ Typical in hands; may involve the legs, jaw, lips, and tongue- Rigidity→ Froment maneuver: The patient is asked to perform repetitive movements in the contralateral extremity (e.g., opening and closing of the left fist if the right side is examined) → Subclinical rigidity becomes more pronounced and may be detected.→ Special form: cogwheel rigidity  - Postural instability  → Pull test  - Parkinsonian gait: shuffling gait with quickened and shortened steps  - Unhabituated glabellar reflex  - Signs of dystonia: E.g., after raising the patient's head and suddenly releasing it, it sinks back down very slowly.- Pyramidal signs (but normal tendon reflexes)- Good response to levodopa Diagnostics:- Levodopa challenge test Treatment:- Patients under the age of 65 with no significant comorbidities→ First-line treatment: Non-ergot dopamine agonists (e.g., pramipexole, ropinirole, apomorphine): as monotherapy or in combination with levodopa/carbidopa  → MAO-B inhibitors (e.g., selegiline): may be used as a monotherapy or in combination with dopamine agonists or levodopa/carbidopa→ COMT inhibitors (e.g., entacapone): in combination with levodopa/carbidopa- Patients over the age of 65 or multimorbid patients of any age→ First-line treatment: levodopa + decarboxylase inhibitor (carbidopa)
• Huntington's disease Epidemiology:- Sex: ♂ = ♀- Peak incidence: ∼ 40 years of age Etiology:- Increased number of CAG repeats in the huntingtin gene on chromosome 4 (most likely due to DNA polymerasemalfunction) → expression of an altered huntingtin protein  - Autosomal dominant- Anticipation: increase in the number of CAG repeats in subsequent generations Pathophysiology: Molecular and cellular changes lead to neuronal loss and gliosis in the striatum (particularly in the caudate nucleus) and, subsequently, the thalamus and the cortex Clinical features:- Initial stages→ Chorea (involuntary, irregular, nonrepetitive, arrhythmic movements of the limbs, neck, head, and/or face)→ Oculomotor disorders (e.g., reduced velocity in optokinetic nystagmus, hypometric saccades)→ Hyperreflexia→ Sensory deficits→ Autonomic symptoms (hyperhidrosis, urinary incontinence)- Advanced stages→ Hypokinetic motor symptoms (dystonia, rigidity, bradykinesia)  → Akinetic mutism (inability to move or speak)→ Motor impersistence (inability to sustain simple voluntary acts, e.g., tongue protrusion)→ Dysarthria and dysphagia→ Dementia (particularly executive dysfunction)→ Depression (possibly including suicidal tendencies)→ Apathy→ Anxiety→ Aggression and psychosis  → Cachexia (due to dysphagia and high energy consumption) Diagnostics:- Patient history- Genetic testing, e.g. polymerase chain reaction  - Imaging is rarely used Treatment:- Hyperkinetic/choreatic movements→ Monoamine‑depleting drugs (e.g., tetrabenazine)→ Atypical neuroleptics (e.g., clozapine)→ NMDA-receptor antagonists (e.g., amantadine)- Psychosis: atypical neuroleptics (e.g., clozapine)- Depression: SSRIs (e.g., citalopram)
• Amyotrophic lateral sclerosis (ALS) Epidemiology:- Incidence: 2-3 cases/100,000 population per year- Sex: ♂ > ♀  - Mean age of onset is 65 years- Can be sporadic (90%) or familial (10%) Pathophysiology: Classically affects the entire motor neuron system at two or more levels (both upper and lower motor neurondegeneration). Can be caused by mutations of superoxide dismutase 1. Clinical features:- Early symptoms→ Symptoms are highly variable and potentially non-specific (e.g., subtle vocal changes or difficulties grasping objects)→ Asymmetric limb weakness, often beginning with weakness in the hands and feet  → Bulbar symptoms such as dysarthria and dysphagia (20% of cases at disease onset)→ Fasciculations, cramps, and muscle stiffness- Late symptoms→ Cognitive impairment (approx. 15% of ALS patients meet the criteria for frontotemporal dementia)→ Autonomic symptoms (e.g., constipation) and sensory loss are possible but rare→ Respiratory failure due to paralysis of respiratory muscles→ Dysphagia due to bulbar weakness   Diagnostics:- Physical examination (including testing reflexes, Babinski's sign, etc.)- Electromyography→ Denervation: indicated, e.g., by fibrillations, positive sharp waves, and large amplitudes→ Fasciculations- Nerve conduction studies: usually normal- MRI and laboratory tests to exclude other potential diagnoses- Increased creatine kinase Treatment:- Riluzole (glutamate antagonist): prolongs survival of patients with ALS- Edaravone (free radical scavenger): has been shown to slow functional decline in some patients with ALS  
• Wernicke encephalopathy and Korsakoff syndrome Etiology:- Wernicke encephalopathy and Korsakoff syndrome are caused by a severe deficiency of thiamine (vitamin B1).- Thiamine deficiency can be due to:→ Chronic heavy alcohol use (most common) → inadequate intake, absorption, and hepatic storage of thiamine→ Thiamine-deficient diets: Anorexia nervosa, starvation, Malabsorption→ Increased demand (hypermetabolic states): Pregnancy and lactation, Hyperthyroidism, Systemic diseases, Malignancy→ Increased loss: Diarrhea, Hyperemesis, Dialysis Wernicke encephalopathy (acute, reversible)- Should be suspected in any patient with a history of chronic heavy alcohol use who presents with one/more symptoms of the classic triad of Wernicke encephalopathy  1. Confusion (most common)  2. Oculomotor dysfunction  - Gaze-induced horizontal/vertical nystagmus (most common)- Diplopia  - Conjugate gaze palsy3. Gait ataxia: wide-based, small steps   Korsakoff syndrome (chronic, irreversible):- Korsakoff syndrome is a late development in patients with persistent vitamin B1 deficiency. It is most often seen in thiamine deficiency due to chronic heavy alcohol use.- Confabulation: Patients produce fabricated memories to fill in lapses of memory.- Anterograde and retrograde amnesia (anterograde > retrograde)  - Personality changes (in frontal lobe lesions): apathy, indifference, decrease in executive function- Disorientation to time, place, and person- Hallucinations Diagnostics: Usually clinical- Laboratory tests: ↓ Serum thiamine levels, ↓ Erythrocyte transketolase activity (thiamine dependent), ↑ Serum lactate and pyruvate- Evidence of alcohol-related liver dysfunction in patients with chronic heavy alcohol use  - Brain MRI: T2-weighted hyperintense lesions in the mammillary bodies, midbrain tectal plate, dorsomedial nuclei of the thalamus, cerebellum, and around the aqueduct and the third ventricle Treatment:- Wernicke encephalopathy  → Immediate IV administration of high-dose vitamin B1/thiamine upon suspicion of Wernicke encephalopathy until symptoms recede, followed by a lower dose  → Long-term oral replacement of vitamins B1, B6, B12, and folic acid (vitamin B complex)  → Abstinence from alcohol- Korsakoff syndrome→ Oral thiamine supplementation to prevent further progression to irreversible complications→ Abstinence from alcohol→ Psychiatric and psychological therapy→ Memory strengthening exercises and aids→ The use of signs and arrows at home can help with orientation.
• Dorsal midbrain syndrome (Parinaud syndrome) Caused by damage to the dorsal midbrain Etiology: stroke, pinealoma, hydrocephalus Clinical features: - Vertical gaze palsy- Lid retraction- Pupillary light-near dissociation- Convergence-retraction nystagmus
• Idiopathic intracranial hypertension Epidemiology:- Predominantly affects obese women aged 15-45 years Risk factors:- Obesity- Certain medications, including: Growth hormone, Tetracyclines, Excessive vitamin A or derivatives Clinical features:- Diffuse headaches- Transient vision loss  - Photopsia (seeing flashes of light)- Diplopia- Retrobulbar pain- Pulsatile tinnitus- Cranial nerve disorders (especially CN VI)- Back pain Diagnostics:- Opthalmoscopy: bilateral papilledema  - Visual field test may show peripheral loss of vision- MRI: To rule out other causes of increased ICP→ Unremarkable brain parenchyma→ Possible abnormalities of the sclera and/or optic nerve (e.g., scleral flattening)→ Empty sella  - Lumbar puncture: Elevated opening pressure >20-25 cm H2O (with patient lying on the side, legs extended) Treatment:- Discontinue any offending agents- Weight loss- Medical therapy (first line): Acetazolamide→ Add furosemide if acetazolamide alone is not sufficient- Surgery: if conservative measures fail
• Juvenile myoclonic epilepsy (Janz syndrome) Age at disease onset: 12-20 years Clinical features: Triad of seizures1. Bilateral symmetrical myoclonic jerks, primarily after awakening, without impaired consciousness2. Generalized tonic-clonic seizures3. Absence seizures with impaired consciousness  - Triggers: sleep deprivation, alcohol consumption, flickering lights Ictal EEG: Irregular 3-5 Hz polyspikes and slow-waves with frontocentral predominance Treatment:- Responds well to antiseizure drug therapy (e.g., valproic acid); seizures become less frequent in adulthood- Life-long treatment usually required (high risk of recurrence)- Increased risk of psychiatric comorbidities
• Valproate Indication:- First-line long-term treatment for tonic-clonic generalized seizures- Partial (focal) seizures- Absence seizures- Myoclonic seizures- Bipolar disorder Pathophysiology:- Inhibits GABA transaminase→ ↑ GABA → decreased neuronal excitability- Inactivates Na+ channels Side effects:- Gastrointestinal upset (e.g., abdominal discomfort)- Hepatotoxicity (rare)  - Teratogenicity- Tremor- Sedation- Ataxia- Alopecia- Pancreatitis- Skin rash- Agranulocytosis- Weight gain
• Concussion Clinical features:- Transient neurologic disturbance (eg, dizziness, disorientation, amnesia) after mild TBI- No structural intracranial injury Management:- Remove from same-day physical play- Neurologic evaluation- Rest for ≥ 24 hr- Gradual return to normal activity if symptoms do not worsen→ Physical: light aerobic exercise → noncontact sports → contact sports→ Neurocognitive: limited screen time, school accommodations (eg, frequent breaks, shortened days)
• Abusive head trauma (shaken baby syndrome) Definition: head trauma through strong rotational and shearing force Epidemiology: high mortality and a significant cause of death   Etiology: violent shaking of a child Pathophysiology: rotational and shearing forces → shearing off of bridging veins → diffuse axonal damage Clinical findings:- Inconsistent or implausible history from care takers- From the outside, injuries are hardly evident or entirely absent- Retinal hemorrhages- Irritability or lethargy- Seizures- Vomiting- Tense fontanelle- Long-term: sight, hearing, and speech impairment; massive neurological deficits- Associated injuries: Rib fractures, Visceral injuries   Diagnostics:- Non-contrast CT: Subdural and/or subarachnoid hemorrhage  → Reversal sign: diffuse blurring of the grey-white matter interface→ Diffuse punctate hemorrhages: variable localization, but most often interhemispheric  → Multiple subdural hematomas of varying ages may be seen- Skeletal survey- MRI: if CT findings are abnormal, or in asymptomatic children with noncranial injuries  
• Postconcussion syndrome A symptom complex that can occur after minor traumatic brain injury. Clinical features:- Headaches- Dizziness- Fatigue- Sleep disturbance- Irritability- Impaired memory- Impaired concentration- Can last for weeks to months after the inciting trauma.
• Narcolepsy Epidemiology:- Bimodal distribution: first peak at 15 years; another smaller peak around age 35 Etiology:- Narcolepsy type 1: Loss of hypothalamic neurons, which produce orexin A and orexin B (i.e., hypocretin-1 and hypocretin-2) → severe orexin deficiency  - Narcolepsy type 2: Idiopathic- Secondary narcolepsy:→ Cerebral damage (e.g., tumor, stroke, inflammation, vascular malformation)→ Genetic syndromes (e.g., Niemann-Pick disease type C and Prader-Willi syndrome) Clinical features:- Excessive daytime sleepiness (EDS): Affected individuals experience an irresistible urge to sleep and sudden, short sleep attacks (< 30 minutes), which may occur in inappropriate situations (e.g., while driving a car).- Abnormal REM sleep→ Cataplexy (60-70% of cases): sudden muscle weakness in a fully conscious person, triggered by strong emotions (affected individuals may experience buckling of the knees upon laughing.)→ Sleep paralysis (∼ 50% of cases): Complete paralysis occurs for 1-2 minutes after waking or before falling asleep; external stimuli (e.g., stirring or addressing the affected individual) can relieve paralysis.  - Hypnagogic hallucinations (∼ 50% of cases): vivid, often frightening visual or auditory hallucinations that occur as the patient falls asleep- Hypnopompic hallucinations: experienced while waking up (less common than hypnagogic hallucinations)- Automatic behavior: During narcoleptic episodes, patients often perform routine repetitive tasks automatically without conscious awareness of their environment.  - Other: depression, obesity, impotence or low sex drive, headaches, decreased functional performance Diagnostic criteria:- Irresistible urge to sleep or daytime sleep lapses ≥ 3 times/week for at least 3 months- At least one of the following:→ Cataplexy plus specific findings on a multiple sleep latency test and polysomnography→ Abnormal CSF orexin A levels Diagnostics:- Polysomnography: PSG findings are characterized by EEG beta waves that appear abnormally early after falling asleep (shortened REM sleep latency).- Multiple sleep latency test (MSLT):→ Falls asleep with a mean latency of ≤ 8 minutes→ Shows sleep-onset REM periods (SOREMPs) within 15 minutes after sleep onset in at least 2 out of the 5 opportunities provided  - Decreased CSF orexin A levels: supports diagnosis if ≤ 110 pg/mL or < ⅓ of mean values in healthy persons   Treatment:- Excessive daytime sleepiness: Drug of choice: modafinil (nonamphetamine CNS stimulant)- Cataplexy, sleep paralysis, and sleep hallucinations:→ SSRIs (e.g, citalopram) or SNRIs (e.g., venlafaxine)  → Nighttime sodium oxybate (highly effective for severe cataplexy)  
• Contraindications to fibrinolysis with tPA - Presence of active internal bleeding- Bleeding diathesis (e.g., platelets < 100,000/µL)- Hypodensity in > 33% of an arterial territory on CT scan- Presence of intracranial hemorrhage on CT scan- Intracranial surgery in the last 3 months- Blood pressure > 185/110 mm Hg
• Symptomatic management of common MS findings Depression: Antidepressants (e.g., SSRIs, SNRIs) Spasticity:- Physical therapy & stretching- Massage- Baclofen Fatigue:- Sleep hygiene, regular exercise- Amantadine- Stimulants (e.g., methylphenidate, modafinil) Neuropathic pain: Gabapentin or duloxetine Urge urinary incontinence:- Timed voiding- Fluid restriction (< 2 L/day)- Anticholinergic medication (e.g., oxybutynin, tolterodine)
• Indications for CT scan after minor head trauma High-risk patients:- Age > 65- Coagulopathy- Drug or alcohol intoxication- High-risk injury mechanism: → Pedestrian struck by vehicle→ Ejection from vehicle→ Fall from height High-risk symptoms:- Retrograde amnesia (> 30 min before injury)- Vomiting 2+ times- Seizure- Severe headache High-risk signs:- Glasgow Coma Scale < 14- Suspicion of depressed skull fracture- Signs of basilar skull fracture→ Battle sign (mastoid ecchymoses)→ Raccoon eyes (orbital ecchymoses)→ Cerebrospinal fluid rhinorrhea or otorrhea→ Hemotympanum- Altered mental status or loss of consciousness- Neurological deficit
• Diagnostic features of dementia with Lewy bodies Central (required):- Progressive cognitive decline, dementia Core:- Fluctuating cognition- Visual hallucinations (detailed, recurrent)- Spontaneous parkinsonism features- REM sleep behavior disorder (eg, dream enactment) Suggestive:- Severe antipsychotic sensitivity- SPECT or PET showing low dopamine transporter uptake in basal ganglia Supportive:- Repeated falls- Syncope or near-syncope- Severe autonomic dysfunction- Delusions- Depression or anxiety Conflicting (make DLB less likely):- Neuroimaging showing cerebrovascular disease- Parkinsonism appearing first with dementia later
• Dementia with Lewy bodies Epidemiology:- ♂ > ♀ (up to 4:1)- Second most common form of neurodegenerative dementia (10-20% of dementia cases)   Clinical presentation: The sequence of symptoms is more variable than in most other types of dementia.- Dementia- Extrapyramidal motor symptoms- Visual hallucinations and paranoid episodes- Episodic impairment of vigilance- Frequent falls- Rapid eye movement sleep behavior disorder (RBD)- Increased sensitivity to neuroleptic medication and metabolic perturbation Treatment:- No causal therapy available- Supportive therapy, behavioral therapy, physical therapy- Parkinsonian symptoms: generally analogous to treatment of Parkinson disease- Dementia symptoms: generally analogous to treatment of major neurocognitive disorder Prognosis: Median survival is approx. 10 years.
• Cluster headache Epidemiology:- Sex: ♂ > ♀ (3:1)- Peak incidence: 20-40 years Risk factor: tobacco use  Possible triggers: alcohol, histamine, seasonal fluctuations Clinical features:- Agonizing pain- Strictly unilateral, periorbital, and/or temporal- Short, recurring attacks that usually occur in a cyclical pattern (“clusters”)  - May become chronic (less common), with interruptions of less than one month between cluster bouts- Attacks often wake patients up during sleep.- Conjunctival injections and/or lacrimation- Rhinorrhea and nasal congestion- Partial Horner syndrome: ptosis and miosis, but no anhidrosis  - Restlessness and agitation   Treatment:- Acute→ Oxygen therapy with FiO2 100%→ First-line: triptans (e.g., sumatriptan) or zolmitriptan  → Pain relievers (i.e. NSAIDs) are generally not recommended because their onset of action is too slow.- Prevention  → First-line treatment: verapamil  → Steroids (e.g., prednisone) are very effective at ending a cluster cycle and may be used to bridge the time until verapamil becomes effective.→ Second-line treatment: lithium, topiramate, ergot derivatives
• Dystonia Etiology:- Idiopathic (familial or sporadic) - Hereditary (evidence of inherited genetic mutation)- Drugs: dopamine antagonists→ High-potency typical antipsychotics (e.g., haloperidol) are more likely than atypical antipsychotics to induce acute dystonia. → Metoclopramide- Neurologic disorders: Huntington disease- Metabolic: Wilson disease- Hypoxic or structural cerebral injury  - Infections: encephalitis, HIV- Psychogenic: conversion disorder Treatment:- Focal dystonia: Periodic botulinum toxin injections- Generalized dystonia:→ First-line: levodopa/carbidopa  → Second-line: Anticholinergics (benztropine, trihexyphenidyl) or antihistamines (diphenhydramine)  → Deep brain stimulation  - Supportive measures: physiotherapy, ergotherapy
• Cerebral venous thrombosis Epidemiology:- Sex: ♀ > ♂, 3:1  - Age of onset: ≤ 40 years Etiology:- Oral contraceptives, pregnancy, and postpartum period  - Hypercoagulable states- Minor head trauma- Neurosurgical procedures (e.g., lumbar puncture)- Additional associated systemic conditions: Inflammatory bowel disease, collagen vascular diseases, vasculitis, nephrotic syndrome- Infectious: Otogenic (e.g., after acute otitis media), rhinogenic (e.g., after sinusitis), through facial infections, meningitis Clinical features:- Headache (acute, subacute, or chronic)  - Nausea, vomiting- Vision impairment, bilateral papilledema on ophthalmoscopy- Cranial nerve symptoms (e.g., diplopia, tinnitus, unilateral deafness, facial palsy) - Focal epileptic seizures  - Impaired consciousness and awareness- Hemispheric symptoms  - In cases of cavernous sinus thrombosis: patients may develop cavernous sinus syndrome  Since the thrombus develops gradually, clinical symptoms appear progressively and may initially fluctuate in magnitude. Diagnostics:- D-dimers: > 500 μg/L- CT/MRI (with or without venography): tests of choice to confirm the diagnosis Treatment:- Acute phase: heparinization  - In individual cases: local thrombolysis (E.g., comatose patients or if the patient's condition deteriorates after heparin is given)- Surgical therapy → Progressive neurologic worsening (despite adequate anticoagulation) → Acute rise in intracranial pressure→ Impending herniation→ Surgical options: Blood clot removal, vessel recanalization, shunt placement  
• Evaluation for fibrinolytic therapy Inclusion and exclusion characteristics of patients with ischemic stroke who could be treated with rtPA within 3 hours from symptom onset Inclusion criteria:- Diagnosis of ischemic stroke causing measurable neurologic deficit- Onset of symptoms < 3 hours before beginning treatment- Age ≥ 18 years Exclusion criteria:- Significant head trauma or prior stroke in previous 3 months- Symptoms suggest subarachnoid hemorrhage- Arterial puncture at noncompressible site in previous 7 days- History of previous intracranial hemorrhage→ Intracranial neoplasm, AV malformation, or aneurysm→ Recent intracranial or intraspinal surgery- Elevated blood pressure (systolic > 185 mmHg or diastolic > 110 mmHg)- Active internal bleeding- Acute bleeding diathesis, including but not limited to:→ Platelet count < 100 000/mm3→ Heparin received within 48 hours, resulting in aPTT greater than the upper limit of normal→ Current use of anticoagulant with INR > 1.7 or PT > 15 seconds→ Current use of direct thrombin inhibitors or direct factor Xa inhibitors with elevated sensitive laboratory tests (such as aPTT, INR, platelet count, and ECT; TT; or appropriate factor Xa activity assays)- Blood glucose concentration < 50 mg/dL (2.7 mmol/L)- CT demonstrates multilobar infarction (hypodensity > 1/3 cerebral hemisphere)
• HINTS Head Impulse, Nystagmus, and Test of Skew examination Findings concerning for a central cause of vertigo:- Absence of catch-up saccades on the head impulse test- Bidirectional nystagmus - Vertical skew 
• Non-REM sleep arousal disorders Recurrent incomplete awakenings from non-REM sleep with 1 of the following:- Sleepwalking: Blank, staring face, relatively unresponsive to attempts to waken- Sleep terrors: Abrupt arousals from sleep (panicked scream, terror, autonomic arousal, unresponsive to comfort)Little or no dream recallAmnesia for episodes Prognosis and treatment:- Mostly self-limiting- Administer low-dose benzodiazepine at bedtime if episodes are frequent, persistent & distressing Differential diagnosis:- Nightmare disorder (occurs during REM, detailed dream recall)- REM sleep-related behavior disorder (occurs during REM, "acts out dreams"- Sleep-related seizures- Nocturnal panic attacks
• Sleep terror disorder Definition: a NREM-related parasomnia that occurs during the N3 sleep stage (slow-wave sleep), characterized by episodes of sleep terror Epidemiology: Discrete episodes of sleep terrors are relatively common in children (∼ 20% of children and ∼ 2% of adults), but the disorder is rare. Etiology: unknown; presumed to be genetic (family history) Risk factors:- Stress or fatigue- Fever- Sleep deprivation - Obstructive sleep apnea- Nocturnal seizures- Drugs (e.g., lithium) Clinical features:- Screaming or crying suddenly upon awakening, usually in the first part of the night (rarely during daytime naps) - Intense fear and agitation- Tachypnea, diaphoresis, tachycardia during episodes- Difficulty arousing patients during episodes- Patients usually return to sleep after the episode.- Typically no recollection of the arousal episode (unlike with nightmare disorder) Treatment:- Education and reassurance (disorder usually self-limited)- Removal of dangerous objects from bedroom to reduce risk of self-injury- In refractory cases, benzodiazepines

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