10.1 Ischemic & Hemorrhagic Stroke

Two Mechanisms, Opposite Treatments

Stroke is an acute neurologic deficit caused by disrupted cerebral blood flow. About 87% of strokes are ischemic (arterial occlusion from a thrombus or embolus) and roughly 13% are hemorrhagic, split between intracerebral hemorrhage (ICH, ~10%) and subarachnoid hemorrhage (SAH, ~3%). The CCRN tests your ability to separate these two on the emergent noncontrast head CT, because the treatments are diametrically opposed: an ischemic stroke may receive a clot-dissolving drug, while giving that same drug into a bleed is catastrophic. Time is brain — roughly 1.9 million neurons die each minute of large-vessel ischemia, which is why door-to-needle and door-to-groin times drive stroke systems of care.

Ischemic Stroke: Thrombolysis

IV thrombolysis with alteplase (tissue plasminogen activator, tPA) is indicated within 4.5 hours of symptom onset (measured from last-known-well time, not arrival); tenecteplase (0.25 mg/kg) is an increasingly used single-bolus alternative. Alteplase is dosed at 0.9 mg/kg (maximum 90 mg): 10% given as a bolus, the remainder infused over 60 minutes. Before administration, blood pressure must be below 185/110 mmHg — use IV labetalol or nicardipine to get there. After alteplase, keep BP below 180/105 for 24 hours and withhold anticoagulants and antiplatelets for 24 hours while watching for the feared complication: symptomatic intracranial hemorrhage (sudden headache, vomiting, acute neuro decline, BP spike).

Absolute contraindications include any hemorrhage on CT, active internal bleeding, recent intracranial/spinal surgery or head trauma within 3 months, platelet count <100,000, INR >1.7, glucose <50 mg/dL, and BP that cannot be lowered below 185/110. The 3-4.5-hour extended window adds relative exclusions (age >80, oral anticoagulant use, prior stroke plus diabetes, NIHSS >25).

NIHSS and Mechanical Thrombectomy

The National Institutes of Health Stroke Scale (NIHSS) scores deficits from 0 to 42 — higher is worse, and a score of 6 or more raises suspicion of a large-vessel occlusion (LVO). Mechanical thrombectomy (endovascular clot retrieval) is the treatment for LVO of the internal carotid or proximal middle cerebral artery. The standard window is within 6 hours, extended to 24 hours in selected patients with a favorable perfusion-imaging mismatch (DAWN and DEFUSE-3 criteria). Thrombectomy and tPA are complementary; an eligible patient often receives both.

Blood Pressure: Permissive Hypertension

When a patient is not a thrombolysis candidate, permissive hypertension protects the ischemic penumbra. Antihypertensives are generally withheld unless BP exceeds ~220/120 mmHg (or there is another indication such as aortic dissection or acute MI). Lowering pressure aggressively can extend the infarct — a classic CCRN trap.

Rapid Recognition and Localization

Bedside screening uses BE-FAST — Balance, Eyes (sudden visual loss), Face droop, Arm drift, Speech change, Time — to trigger a stroke alert. Localizing the deficit predicts the vessel: dominant (usually left) hemisphere strokes produce aphasia with right-sided weakness, nondominant strokes cause neglect and left-sided weakness, and posterior-circulation strokes cause vertigo, diplopia, dysarthria, and ataxia. A hyperdense middle cerebral artery sign on CT hints at a proximal clot. The nurse documents the exact last-known-well time, checks fingerstick glucose (hypoglycemia is a common stroke mimic), draws coagulation labs, and keeps the patient NPO until a swallow screen is passed. During and after alteplase, perform neuro checks and vital signs every 15 minutes for 2 hours, then every 30 minutes — a sudden headache, nausea, acute hypertension, or declining exam suggests symptomatic hemorrhage, so you stop the infusion and obtain an emergent CT.

Hemorrhagic Stroke

ICH management centers on blood-pressure control and reversing coagulopathy. Target a systolic BP around 140 mmHg (acceptable ~130-150) with a titratable agent such as nicardipine, and reverse anticoagulation urgently — 4-factor PCC plus vitamin K for warfarin, andexanet or idarucizumab for DOACs, protamine for heparin. Watch for hematoma expansion, hydrocephalus, and rising intracranial pressure.

Subarachnoid Hemorrhage

Aneurysmal SAH classically presents as a sudden thunderclap or worst headache of my life, often with meningismus and photophobia. Severity is graded by the Hunt-Hess scale:

Before the aneurysm is secured (clipped or coiled), keep SBP <160 mmHg to reduce rebleeding, the deadliest early complication (highest risk in the first 24 hours). Three complications drive nursing surveillance: rebleeding; cerebral vasospasm / delayed cerebral ischemia (DCI), which peaks days 4-14 and is countered with oral nimodipine 60 mg every 4 hours for 21 days (it reduces DCI harm rather than abolishing angiographic vasospasm; once the aneurysm is secured, symptomatic vasospasm is treated with euvolemia and induced hypertension); and hyponatremia from cerebral salt wasting (hypovolemic) or SIADH (euvolemic) — avoid hypotonic fluids. Maintain the airway (GCS 8 or less means intubate), perform frequent NIHSS/neuro checks, keep glucose 140-180, ensure normothermia, and screen for dysphagia before any oral intake.