SCRN cheat sheet

Anterior circulation arises from the internal carotid artery (MCA, ACA); posterior circulation arises from the vertebral arteries (PICA, basilar, AICA, PCA); the anterior and posterior communicating arteries connect the two systems.

MCA occlusion: contralateral face and arm weakness greater than leg weakness, gaze deviation toward the lesion, aphasia with dominant-hemisphere lesions, and neglect with nondominant-hemisphere lesions.

ACA occlusion: contralateral leg weakness greater than arm weakness, abulia, urinary incontinence, and grasp reflex.

PCA occlusion: contralateral homonymous hemianopia, visual agnosia, and thalamic pain syndrome.

Basilar artery occlusion: quadriparesis, cranial nerve deficits, fluctuating consciousness, and locked-in syndrome; mortality is very high without reperfusion.

Lacunar infarcts involve penetrating arteries (lenticulostriate, thalamoperforating) and cause pure motor, pure sensory, sensorimotor, or ataxic hemiparesis without cortical signs.

Watershed (border-zone) infarcts result from hypoperfusion at MCA/ACA or MCA/PCA junctions and typically produce proximal limb weakness.

Cerebral blood flow thresholds: core infarct below 10 mL/100 g/min (irreversible), penumbra 10-20 mL/100 g/min (viable, target of reperfusion), normal approximately 50 mL/100 g/min.

Cerebral autoregulation maintains flow near 50 mL/100 g/min between mean arterial pressures of about 60 and 150 mm Hg; the curve shifts rightward in chronic hypertension and is impaired in acute stroke.

NIHSS: 15 items, total score 0-42; severity bands are 1-4 minor, 5-15 moderate, 16-20 moderate-severe, and 21-42 severe.

Noncontrast CT is the first imaging study; its primary purpose is to exclude intracranial hemorrhage before a thrombolytic is given.

Early CT ischemia signs include hyperdense MCA sign, loss of the insular ribbon, obscured lentiform nucleus, and sulcal effacement; sensitivity in the first hours is low.

ASPECTS is a 10-point CT score of the MCA territory; a score of 6 or more generally supports thrombectomy, while 5 or less indicates a large core.

CTA (often with CT perfusion or CTA source images) identifies large vessel occlusion and characterizes collateral flow.

MRI diffusion-weighted imaging detects ischemia within minutes and is more sensitive than CT for small and posterior circulation infarcts; FLAIR positivity suggests onset beyond 4.5 hours.

Time last known well, not time of symptom discovery, anchors reperfusion windows; wake-up and unwitnessed strokes require imaging-based selection.

Point-of-care glucose is mandatory because hypoglycemia is a common and fully reversible stroke mimic; INR, platelets, and renal function are checked before thrombolysis.

BE-FAST (Balance, Eyes, Face, Arm, Speech, Time) is the public recognition tool; posterior circulation deficits such as vertigo, diplopia, dysphagia, and ataxia are frequently underscored by the NIHSS.

IV alteplase 0.9 mg/kg (maximum 90 mg): 10% as a 1-minute bolus, remainder infused over 60 minutes, within 0-4.5 hours of last known well; tenecteplase 0.25 mg/kg as a single bolus is an accepted alternative.

Thrombolysis exclusions include blood pressure above 185/110 mm Hg unresponsive to treatment, glucose below 50 mg/dL, INR above 1.7, platelets below 100,000, recent major surgery, and prior intracranial hemorrhage.

Blood pressure must be below 185/110 mm Hg before thrombolysis and below 180/105 mm Hg for 24 hours afterward; without thrombolysis, permissive hypertension up to 220/120 mm Hg is allowed.

Mechanical thrombectomy: ICA or MCA-M1 occlusion, NIHSS 6 or more, ASPECTS 6 or more, within 6 hours; up to 24 hours with favorable perfusion imaging (DAWN/DEFUSE-3 criteria).

Process targets: door-to-needle 60 minutes or less, door-to-groin 90 minutes or less, and door-to-recanalization 120 minutes or less.

After hemorrhage is excluded, aspirin 325 mg is started within 24-48 hours; after thrombolysis, antiplatelet and anticoagulant drugs are withheld for 24 hours with follow-up imaging first.

Intracerebral hemorrhage with systolic 150-220 mm Hg: lower systolic smoothly to about 140 mm Hg and reverse anticoagulation immediately (vitamin K plus PCC for warfarin; andexanet alfa or PCC for factor Xa inhibitors).

Supportive bundle: keep SpO2 above 94%, treat fever, target glucose 140-180 mg/dL, and complete a dysphagia screen before any oral intake.

Malignant MCA edema with declining consciousness: decompressive hemicraniectomy within 48 hours reduces mortality in patients younger than 60 years.

Mobilize within 24-48 hours once medically stable; very early high-dose mobilization (AVERT protocol) did not improve and may worsen 3-month outcomes.

Dysphagia affects roughly half of stroke patients; screen swallowing before oral intake, medications, or food to reduce aspiration pneumonia.

Aphasia is treated with speech-language therapy; melodic intonation therapy is used for severe nonfluent aphasia; most recovery occurs in the first 3-6 months.

Spasticity develops over weeks to months, is graded with the modified Ashworth scale, and is managed with positioning, stretching, therapy, and focal botulinum toxin.

Constraint-induced movement therapy requires some active wrist and finger extension; repetitive task-specific practice is the core driver of motor recovery.

DVT prophylaxis: intermittent pneumatic compression for immobile patients, and prophylactic low-molecular-weight heparin once hemorrhage is excluded.

The 90-day modified Rankin Scale score of 0-2 defines functional independence; the NIHSS and Barthel index are also used to track recovery.

Depression, anxiety, and fatigue are common after stroke; screen with the PHQ-9 and treat because they reduce rehabilitation participation.

Bladder management favors avoidance of indwelling catheters, with intermittent catheterization for retention; incontinence often improves with rehabilitation.

Noncardioembolic stroke: aspirin 50-325 mg, clopidogrel 75 mg, or aspirin plus clopidogrel for 21-90 days after minor stroke or high-risk TIA, then a single antiplatelet agent.

Atrial fibrillation: anticoagulate with a direct oral anticoagulant (preferred) or warfarin; warfarin is required for mechanical valves and moderate-to-severe mitral stenosis.

Timing of anticoagulation after AF-related stroke is typically 4-14 days depending on infarct size and hemorrhage risk; heparin bridging is not recommended.

Symptomatic carotid stenosis of 70-99%: carotid endarterectomy within 2 weeks of the index event; 50-69% is considered individually; below 50% no revascularization.

High-intensity statin therapy for all atherosclerotic ischemic stroke or TIA, with an LDL cholesterol target below 70 mg/dL.

Blood pressure target after stroke is below 130/80 mm Hg, provided it is tolerated by the patient.

Diabetes: target HbA1c around 7%, with SGLT2 inhibitors or GLP-1 receptor agonists preferred when atherosclerotic cardiovascular disease coexists.

Lifestyle: smoking cessation, no more than 2 alcoholic drinks per day, 150 minutes per week of moderate exercise, Mediterranean-type diet, and weight reduction.

Patent foramen ovale closure is considered for cryptogenic stroke in patients younger than 60 years with high-risk PFO features such as a large shunt or atrial septal aneurysm.

Thrombolysis in an incapacitated patient without an available surrogate proceeds under the emergency medical exception, with presumed consent documented in the record.

Decision-making capacity requires understanding, appreciation, reasoning, and expression of a choice; when absent, the health care proxy or surrogate decides.

Discharge planning begins at admission; the team evaluates function, home safety, caregiver capacity, and equipment needs, and holds family meetings.

Inpatient rehabilitation facility criteria: tolerance of 3 hours of therapy daily, need for at least 2 therapy disciplines, and realistic functional goals.

Post-stroke depression affects roughly one third of survivors and is associated with worse functional outcomes and higher mortality.

Caregiver burden includes depression, financial strain, and lost employment; caregiver training, respite care, and support groups improve outcomes.

Driving is generally not resumed before 4 weeks; it requires visual, cognitive, and motor assessment, and some jurisdictions mandate clinician reporting.

Palliative care focuses on symptom control and goals of care; it is appropriate alongside restorative treatment and in severe stroke with poor prognosis.

Organized stroke unit care reduces death and disability compared with care on a general ward.