ABIM Neurocritical cheat sheet

IV alteplase 0.9 mg/kg (max 90 mg): 10% bolus over 1 minute, remainder over 60 minutes; eligible within 4.5 hours of last known well.

Tenecteplase 0.25 mg/kg single IV bolus (max 25 mg) is an alternative to alteplase in eligible acute ischemic stroke, including thrombectomy candidates.

Blood pressure must be <185/110 mmHg before thrombolysis and <180/105 mmHg for 24 hours afterward.

Mechanical thrombectomy is indicated for anterior large-vessel occlusion within 6 hours of onset, and 6-24 hours with DAWN or DEFUSE-3 mismatch criteria.

ICH: target systolic BP 130-150 mmHg; reverse warfarin with 4F-PCC plus vitamin K 5-10 mg IV, dabigatran with idarucizumab 5 g, and factor Xa inhibitors with andexanet alfa or 4F-PCC.

Aneurysmal SAH: nimodipine 60 mg PO or NG every 4 hours for 21 days, and secure the aneurysm by clipping or coiling.

Cerebral venous thrombosis: give therapeutic LMWH or unfractionated heparin even with hemorrhagic venous infarction, then oral anticoagulation for 3-12 months.

ICH score: GCS 3-4, age >=80 years, volume >=30 mL, infratentorial origin, and intraventricular hemorrhage each score 1 point, for a total of 0-6.

Cerebellar hemorrhage >3 cm or with brainstem compression or hydrocephalus warrants surgical evacuation.

GCS <=8: intubate; avoid SpO2 <90% and systolic BP <100 mmHg (or <110 mmHg if age 50-69 years).

After severe TBI, target ICP <22 mmHg and cerebral perfusion pressure 60-70 mmHg.

Hyperosmolar therapy: mannitol 0.25-1 g/kg IV or 3% saline 250 mL bolus; target serum sodium 145-155 mmol/L.

Prophylactic phenytoin or levetiracetam for 7 days reduces early posttraumatic seizures but does not prevent late seizures.

Prophylactic hyperventilation is not recommended; brief hyperventilation to PaCO2 30-35 mmHg is reserved for impending herniation.

Corticosteroids are contraindicated in traumatic brain injury because they increase mortality.

Acute spinal cord injury: maintain MAP 85-90 mmHg for 5-7 days; high-dose methylprednisolone is not routinely recommended.

The ASIA Impairment Scale grades spinal cord injury from A (complete) to E (normal).

Decompressive craniectomy is an option for refractory intracranial hypertension after severe TBI.

Convulsive status epilepticus: lorazepam 0.1 mg/kg IV (max 4 mg), repeated once; IM midazolam 10 mg if no IV access.

Second-line therapy: levetiracetam 60 mg/kg (max 4.5 g), fosphenytoin 20 mg PE/kg, or valproate 40 mg/kg IV.

Refractory status epilepticus: continuous midazolam, propofol, or pentobarbital titrated to EEG burst suppression.

After convulsive status epilepticus is controlled, continue EEG monitoring for at least 24 hours because nonconvulsive seizures are common.

Postanoxic coma: generalized suppression, burst suppression, or status myoclonus persisting >=72 hours after cardiac arrest predicts poor outcome.

Burst suppression consists of 1-3 bursts per second separated by periods of EEG suppression and is the target for pharmacologic coma.

Absence status epilepticus shows 2-3 Hz generalized spike-and-wave discharges and responds to IV valproate or benzodiazepines.

Lateralized periodic discharges at >=2 Hz with clinical correlation may warrant a trial of antiseizure medication.

Guillain-Barre syndrome: IVIG 0.4 g/kg/day for 5 days or plasma exchange (5 exchanges); corticosteroids are ineffective.

Intubate Guillain-Barre patients for FVC <15-20 mL/kg, negative inspiratory force weaker than -30 cmH2O, or a >30% decline in vital capacity.

Guillain-Barre dysautonomia causes labile blood pressure and arrhythmias; avoid succinylcholine because of hyperkalemia risk.

Myasthenic crisis: treat with IVIG or plasma exchange; avoid aminoglycosides, fluoroquinolones, magnesium, and beta-blockers.

Miller Fisher variant: ophthalmoplegia, ataxia, and areflexia with anti-GQ1b antibodies.

Critical illness polyneuropathy: associated with sepsis and multiorgan failure, with reduced sensory and motor nerve action potentials.

Critical illness myopathy: prolonged ventilator weaning with normal or mildly elevated CK and reduced compound muscle action potentials.

Monitor respiratory function serially with FVC, negative inspiratory force, and maximum expiratory pressure; tracheostomy if prolonged ventilation is expected.

Suspected bacterial meningitis: dexamethasone 10 mg IV before or with the first antibiotic dose, continued for 4 days.

Empiric therapy: ceftriaxone 2 g every 12 hours plus vancomycin, with ampicillin added for Listeria risk (age >50 or immunocompromised).

HSV encephalitis: IV acyclovir 10 mg/kg every 8 hours for 14-21 days; CSF PCR and temporal lobe involvement support the diagnosis.

Tuberculous meningitis: adjunctive dexamethasone improves survival; treat with prolonged multidrug therapy.

Anti-NMDAR encephalitis: IVIG or plasma exchange first-line, rituximab or cyclophosphamide second-line, and screen for ovarian teratoma.

Neuromyelitis optica spectrum attacks: IV methylprednisolone 1 g/day for 5 days, plasma exchange if refractory, and eculizumab for relapse prevention.

Cerebral malaria: IV artesunate is preferred over quinine for severe disease.

Cryptococcal meningitis in HIV: amphotericin B plus flucytosine induction, with serial therapeutic lumbar punctures for elevated intracranial pressure.

Coma: eyes closed, no command following, no verbal output, and no purposeful movement; GCS <=8.

Brain death prerequisites: known irreversible cause, core temperature >=36 degrees C, systolic BP >=100 mmHg, and exclusion of confounders.

Apnea test is positive when PaCO2 rises >=20 mmHg above baseline and reaches >=60 mmHg without respiratory effort.

Ancillary tests (cerebral angiography, EEG, HMPAO SPECT) are used when the apnea test cannot be completed.

Absent brainstem reflexes in brain death: pupillary, corneal, oculocephalic, oculovestibular, gag, and cough.

Spinal reflexes such as the Lazarus sign may persist in brain death and do not preclude the diagnosis.

Vegetative state: sleep-wake cycles without awareness; minimally conscious state: reproducible but inconsistent evidence of awareness.

Locked-in syndrome: ventral pontine lesion with preserved consciousness, quadriplegia, and vertical eye movements.

After cardiac arrest, absent pupillary and corneal reflexes at 72 hours predict poor neurologic outcome.

Use isotonic crystalloid such as 0.9% saline in neurologic patients; avoid hypotonic fluids that worsen cerebral edema.

Correct chronic hyponatremia by no more than 8-10 mmol/L per 24 hours; use 3% saline for seizures or coma.

Septic shock: 30 mL/kg IV crystalloid within 3 hours and broad-spectrum antibiotics within 1 hour.

ARDS: low tidal volume 6 mL/kg predicted body weight and plateau pressure <=30 cmH2O; avoid permissive hypercapnia with intracranial hypertension.

Glycemic target in critically ill neurologic patients is 140-180 mg/dL.

Fever >38 degrees C is associated with worse neurologic outcome and should be treated with antipyretics and cooling.

Restrictive transfusion threshold: hemoglobin <7 g/dL unless there is active ischemia.

Start enteral nutrition within 24-48 hours and avoid overfeeding.

Use LMWH or unfractionated heparin for DVT prophylaxis when hemorrhage risk is acceptable.

Normal ICP is 10-15 mmHg; treat sustained ICP >22 mmHg.

Cerebral perfusion pressure = mean arterial pressure minus intracranial pressure; target 60-70 mmHg.

Level the external ventricular drain at the foramen of Monro (tragus) and zero the transducer there.

Transcranial Doppler: mean MCA velocity >120 cm/s suggests vasospasm, and a Lindegaard ratio >3 supports the diagnosis.

Brain tissue oxygen <15 mmHg indicates ischemia; a common treatment threshold is >20 mmHg.

Jugular venous oxygen saturation <50% suggests hypoperfusion and >75% suggests hyperemia or infarction.

Lundberg A waves (plateau waves) of 50-100 mmHg lasting 5-20 minutes indicate critically reduced intracranial compliance.

Optic nerve sheath diameter >5 mm on ultrasound suggests elevated intracranial pressure.

Pupillometry and near-infrared spectroscopy are noninvasive adjuncts and not standalone diagnostic tests.

Analgosedation with propofol or dexmedetomidine is preferred for short-term sedation, with daily interruption when safe.

Propofol infusion syndrome occurs with doses >4-5 mg/kg/h and causes metabolic acidosis, rhabdomyolysis, hyperkalemia, and cardiac failure.

Prolonged benzodiazepine infusions cause accumulation, delayed awakening, and delirium.

Give IV thiamine 500 mg before glucose in at-risk patients to prevent Wernicke encephalopathy.

Hepatic encephalopathy: treat with lactulose and rifaximin and avoid sedating drugs.

Serotonin syndrome: clonus, hyperreflexia, and autonomic instability; stop serotonergic drugs and consider cyproheptadine.

Neuroleptic malignant syndrome: rigidity, hyperthermia, and elevated CK; treat with dantrolene or bromocriptine and supportive care.

Phenytoin and carbamazepine are CYP inducers with multiple drug interactions.

Toxic-metabolic encephalopathy shows diffuse EEG slowing, with triphasic waves in hepatic or uremic encephalopathy.

External ventricular drain complications include hemorrhage and infection; use sterile technique and antibiotic-impregnated catheters.

Consider tracheostomy after 7-14 days of ventilation when prolonged weaning is expected.

Family meetings use shared decision-making and document goals of care in the medical record.

Surrogate decision makers apply substituted judgment (what the patient would have wanted) or best interests when preferences are unknown.

Palliative care consultation is appropriate for refractory symptoms, family conflict, or prolonged ICU stay.

Organ donation occurs after brain death or after circulatory death, with a no-touch period of usually 2-5 minutes.

Document the time of death after completing the apnea test and brainstem reflex examination.

Ethics consultation is indicated when interventions are considered futile or goals of care conflict.

The SPIKES framework structures delivery of bad news: setting, perception, invitation, knowledge, empathy, and summary.