4.1 Neurological Disorders Overview

Why Neurological Emergencies Dominate the Domain

The Neurological Disorders domain on the Board of Certification for Emergency Nursing (BCEN) Certified Emergency Nurse (CEN) exam tests rapid recognition and intervention for conditions where minutes determine outcome. The highest-yield concept is acute stroke, where "time is brain" is literal: an untreated large-vessel ischemic stroke kills roughly 1.9 million neurons per minute. The CEN expects you to differentiate stroke types, apply validated scales, screen for thrombolytic eligibility, and manage blood pressure within precise thresholds.

Stroke splits into two mechanisms. Ischemic stroke (about 87% of strokes) results from a thrombus or embolus occluding a cerebral artery. Hemorrhagic stroke (about 13%) results from a ruptured vessel bleeding into brain tissue (intracerebral hemorrhage) or the subarachnoid space. The distinction is not academic: thrombolytics that dissolve a clot would be catastrophic in a bleed. That is why a non-contrast head computed tomography (CT) is the first study ordered — it reliably detects acute blood, and a positive scan is an absolute contraindication to alteplase.

Scales and the Door-to-Needle Clock

Prehospital and triage screens such as Cincinnati Prehospital Stroke Scale (face droop, arm drift, speech) and BE-FAST (Balance, Eyes, Face, Arm, Speech, Time) flag a possible stroke. In the emergency department the NIH Stroke Scale (NIHSS) quantifies severity across 11 items for a total of 0 to 42; higher equals worse. A score above 6 typically signals a large-vessel occlusion appropriate for thrombectomy.

The target is a door-to-CT time under 25 minutes and a door-to-needle time under 60 minutes. Establish last-known-well (not the time symptoms were discovered) because every window is measured from it.

Thrombolytics, Thrombectomy, and TIA

5 hours** of last-known-well. 7, and blood glucose below 50 mg/dL until corrected. Blood pressure must be controlled below 185/110 mmHg before the bolus, usually with IV labetalol or nicardipine, and kept below 180/105 mmHg for 24 hours afterward. Monitor closely for the most feared complication — symptomatic intracranial hemorrhage — signaled by sudden headache, worsening deficit, nausea, or acute hypertension.

Mechanical thrombectomy physically retrieves the clot via endovascular catheter. Based on the DAWN and DEFUSE-3 trials, it extends care to up to 24 hours for anterior-circulation large-vessel occlusion (intracranial internal carotid or proximal middle cerebral M1) when perfusion imaging shows a small core and salvageable penumbra (clinical-core or perfusion mismatch).

A transient ischemic attack (TIA) produces stroke-like deficits that resolve, classically within an hour, with no infarct on imaging. It is a warning, not a benign event: stroke risk is highest in the first 48 hours and is stratified with the ABCD2 score (Age, Blood pressure, Clinical features, Duration, Diabetes).

Localizing the Deficit and Setting Priorities

A quick mental map of cerebral territory helps you anticipate findings and avoid missing strokes. The middle cerebral artery (MCA) is the most commonly occluded vessel and produces contralateral face and arm weakness, sensory loss, and aphasia when the dominant (usually left) hemisphere is involved, or neglect when the non-dominant side is hit. The anterior cerebral artery favors the leg, and the posterior circulation produces brainstem and cerebellar signs that look nothing like a classic stroke. Recognizing that right-sided weakness implies a left hemispheric lesion is routinely tested.

While the imaging and reperfusion decision proceeds, basic emergency priorities still govern care. Maintain a patent airway in a patient who cannot protect it, keep oxygen saturation at or above 94% (supplemental oxygen is given only for hypoxia, not routinely), and keep the patient NPO until a swallow screen passes, because stroke-related dysphagia drives aspiration pneumonia.

Treat fever and hyperglycemia, both of which worsen ischemic injury, and do not aggressively lower blood pressure in an ischemic stroke patient who is not a thrombolytic candidate — permissive hypertension up to about 220/120 mmHg preserves perfusion of the penumbra. These priorities recur across every stroke scenario the CEN presents.

Hemorrhagic Stroke and Stroke Mimics

When the CT shows blood, the pathway changes entirely. Intracerebral hemorrhage (ICH) — bleeding into the brain parenchyma — is most often driven by chronic uncontrolled hypertension and presents with a severe headache, rapidly depressed consciousness, vomiting, and very high blood pressure.

Management is the opposite of ischemic stroke in one crucial way: blood pressure is lowered, typically toward a systolic of about 140 mmHg with titratable agents such as nicardipine, and any anticoagulation is urgently reversed (vitamin K and four-factor prothrombin complex concentrate for warfarin; specific reversal agents for direct oral anticoagulants). Neurosurgery is consulted for possible evacuation or external ventricular drainage.

Finally, build a short list of stroke mimics so you do not over- or under-treat. Hypoglycemia is the great imitator and is excluded by the bedside glucose. Seizure with a postictal Todd's paralysis can leave transient focal weakness. Complicated migraine, Bell's palsy, and conversion disorder can also masquerade as stroke. The CEN tests your judgment in distinguishing these from a true infarct, because giving a thrombolytic to a mimic exposes the patient to bleeding risk with no benefit. The safeguard is the standardized work-up: glucose, focused exam, NIHSS, and non-contrast CT.