Neurological Emergencies in Emergency Medicine
Learning Objectives
By the end of this page, you should be able to:
- Differentiate ischemic from hemorrhagic stroke and state the tPA eligibility window and its major contraindications.
- Sequence the stepwise drug management of status epilepticus by time elapsed.
- Apply a structured mnemonic (AEIOU-TIPS) to work up a patient with altered mental status.
- Recognize the classic presentation of subarachnoid hemorrhage and its correct imaging/LP algorithm.
- Distinguish neurological emergencies that are commonly confused on exams (e.g., ischemic vs. hemorrhagic stroke, seizure vs. syncope, delirium vs. dementia).
- Identify red-flag findings that change management within minutes, not hours.
Quick Answer
Neurological emergencies are time-critical brain and spinal cord conditions where "time is tissue" — every minute of delay costs neurons. The big three tested repeatedly are acute ischemic stroke (treat with tPA within 4.5 hours, thrombectomy up to 24 hours for select large-vessel occlusions), status epilepticus (seizure activity lasting more than 5 minutes, treated with a strict drug-and-time algorithm starting with benzodiazepines), and altered mental status (worked up systematically, never assumed to be purely psychiatric until reversible causes are excluded). They matter because rapid, protocol-driven recognition — not fancy testing — is what actually saves neurons and lives.
Acute Stroke: Ischemic vs. Hemorrhagic
Stroke happens when brain tissue is deprived of blood flow, and it comes in two flavors that are treated in opposite ways — which is exactly why exams love testing the distinction.
- Ischemic stroke (~85% of cases): a clot blocks a cerebral vessel. Treatment aims to restore flow — thrombolysis or thrombectomy.
- Hemorrhagic stroke (~15% of cases): a vessel ruptures and bleeds into the brain. Treatment aims to stop bleeding and control pressure — giving tPA here would be catastrophic.
That is why the single most important first step in any suspected stroke is a non-contrast CT head — its only job at this stage is to rule out bleed before you can even think about thrombolytics.
Presentation (think FAST): sudden facial droop, arm/leg weakness (usually one-sided), slurred or absent speech, and time of onset. Also watch for monocular vision loss, ataxia, and severe sudden headache (raises suspicion for hemorrhage).
tPA (Alteplase) Eligibility
- Window: within 4.5 hours of clearly known symptom onset (the classic teaching is 3 hours, extended to 4.5 hours for eligible patients based on trial data — know both numbers, as exams test either cutoff).
- Key absolute contraindications: any evidence of intracranial hemorrhage on CT, recent major surgery or head trauma, active internal bleeding, BP persistently >185/110 despite treatment, platelets <100,000, or use of anticoagulants with elevated INR/aPTT.
- Mechanical thrombectomy: reserved for large-vessel occlusions, can be offered up to 24 hours from onset in carefully selected patients based on perfusion imaging — this is a newer, high-yield addition many older textbooks omit.
Status Epilepticus
Definition: a single seizure lasting more than 5 minutes, or recurrent seizures without return to baseline consciousness in between. The 5-minute cutoff matters because that's roughly when seizures stop self-terminating and start causing neuronal injury — waiting for the "textbook" 30-minute definition to treat is a dangerous, outdated habit.
Management is a timed algorithm, and exam questions frequently test which drug belongs at which stage:
| Time | Step |
|---|---|
| 0–5 min | ABCs, oxygen, glucose check (treat hypoglycemia immediately — it's a rapidly reversible mimic) |
| 5–20 min | First-line: IV lorazepam or IM midazolam (benzodiazepines) |
| 20–40 min | Second-line: IV fosphenytoin, valproate, or levetiracetam |
| 40+ min (refractory) | Third-line: general anesthesia (propofol, midazolam infusion, or barbiturates) with intubation and continuous EEG |
Why benzodiazepines first? They rapidly enhance GABA-mediated inhibition, the fastest way to terminate abnormal cortical firing. Repeated seizures also cause GABA receptor internalization over time, which is why delayed treatment becomes progressively harder to reverse — a nice mechanistic reason examiners like to probe.
Altered Mental Status: The Systematic Workup
A confused or unresponsive patient is not automatically "psych" or "just old and demented" — this is one of the most dangerous assumptions in emergency medicine, because reversible metabolic and toxic causes are common and time-sensitive. Use the mnemonic AEIOU-TIPS to keep the differential systematic:
- A – Alcohol / Abuse (drugs)
- E – Epilepsy / Electrolytes / Encephalopathy
- I – Insulin (hypo/hyperglycemia)
- O – Overdose / Oxygen (hypoxia)
- U – Uremia (renal failure)
- T – Trauma / Temperature (hypo/hyperthermia)
- I – Infection (meningitis, sepsis, UTI in elderly)
- P – Psychiatric / Poisoning
- S – Stroke / Space-occupying lesion / Subarachnoid hemorrhage
First three bedside tests, always: fingerstick glucose, pulse oximetry, and a focused neuro exam. Glucose and oxygen are cheap, fast, and instantly reversible — missing them is an unforgivable exam trap. If the patient doesn't wake up with glucose correction and there's any suspicion of opioid or benzodiazepine toxicity, naloxone and flumazenil are diagnostic-therapeutic trials (flumazenil is used cautiously due to seizure risk in chronic benzodiazepine users).
Subarachnoid Hemorrhage (SAH)
Classic presentation: sudden, severe "thunderclap" headache — patients often say it's "the worst headache of my life." Associated features: neck stiffness, photophobia, vomiting, and sometimes a brief loss of consciousness (from the abrupt pressure spike).
Diagnostic algorithm: non-contrast CT head first (highly sensitive within 6 hours of onset). If CT is negative but suspicion remains high, proceed to lumbar puncture, looking for xanthochromia (yellow discoloration from breakdown of red cells) — this distinguishes a true SAH from a traumatic tap, since xanthochromia takes hours to develop and a traumatic tap won't show it.
Treatment: identify and secure the aneurysm early — endovascular coiling or surgical clipping — plus nimodipine to reduce vasospasm-related secondary ischemia, and strict blood pressure control.
Key Terms
| Term | Definition |
|---|---|
| tPA (alteplase) | Tissue plasminogen activator; a thrombolytic drug that dissolves clots in ischemic stroke within the eligible time window |
| NIHSS | National Institutes of Health Stroke Scale; a standardized score used to quantify stroke severity and guide treatment decisions |
| Thrombectomy | Mechanical removal of a clot from a large cerebral vessel, an option beyond the tPA window in selected patients |
| Status epilepticus | A seizure lasting more than 5 minutes, or repeated seizures without recovery of consciousness between them |
| Xanthochromia | Yellow discoloration of cerebrospinal fluid caused by breakdown of red blood cells; confirms true subarachnoid hemorrhage over a traumatic LP |
| AEIOU-TIPS | Mnemonic for the differential diagnosis of altered mental status |
| Glasgow Coma Scale (GCS) | A 3–15 point scale assessing eye, verbal, and motor response, used to grade level of consciousness |
| Nimodipine | A calcium channel blocker given after SAH specifically to reduce cerebral vasospasm and secondary ischemic injury |
Common Mistakes
Misconception 1: "Status epilepticus is only diagnosed after 30 minutes of seizing." Why it's wrong: this outdated definition delays treatment during the window when benzodiazepines work best and neuronal injury is still preventable. Correct: treat any seizure lasting more than 5 minutes as status epilepticus and start the timed drug algorithm immediately.
Misconception 2: "If the CT head is negative, you can rule out subarachnoid hemorrhage." Why it's wrong: CT sensitivity for SAH drops significantly after the first 6 hours from symptom onset, so a negative scan days later can miss a real bleed. Correct: if clinical suspicion remains high despite a negative CT, proceed to lumbar puncture and look for xanthochromia before dismissing SAH.
Misconception 3: "Every ischemic stroke patient should get tPA as fast as possible, regardless of blood pressure or coagulation status." Why it's wrong: giving tPA to a patient with uncontrolled hypertension, recent surgery, or abnormal coagulation dramatically raises the risk of fatal intracranial bleeding. Correct: confirm the time window and screen every absolute contraindication (BP, platelets, INR, recent bleeding/surgery, hemorrhage on CT) before administering thrombolytics.
Comparison and Connections
| Feature | Ischemic Stroke | Hemorrhagic Stroke | Status Epilepticus | Subarachnoid Hemorrhage |
|---|---|---|---|---|
| Underlying cause | Vessel occlusion (clot) | Vessel rupture (bleed) | Uncontrolled seizure activity | Ruptured aneurysm/AVM |
| Key first test | Non-contrast CT (to exclude bleed) | Non-contrast CT | Bedside glucose + EEG if refractory | Non-contrast CT, then LP if negative |
| Definitive treatment | tPA / thrombectomy | BP control, possible surgery | Benzodiazepine → antiepileptic → anesthesia | Coiling/clipping + nimodipine |
| Classic red flag | Sudden focal deficit (FAST) | Sudden focal deficit + severe headache | Seizure >5 minutes | "Thunderclap" worst headache of life |
Practice Questions
Recall 1: What is the maximum time window for administering IV tPA in acute ischemic stroke? Answer guidance: Within 4.5 hours of clearly established last-known-well time.
Recall 2: Name the three drug tiers used in the status epilepticus treatment algorithm. Answer guidance: Benzodiazepines (lorazepam/midazolam) → antiepileptics (fosphenytoin/valproate/levetiracetam) → general anesthesia (propofol/barbiturates) for refractory cases.
Understanding 1: Why must a CT scan be performed before giving tPA, rather than starting treatment based on clinical exam alone? Answer guidance: Ischemic and hemorrhagic stroke present similarly but require opposite treatment; giving a clot-dissolving drug to a patient who is actually bleeding would worsen the hemorrhage and could be fatal.
Understanding 2: Explain why hypoglycemia must be checked before other causes of altered mental status are pursued. Answer guidance: Hypoglycemia is rapid, cheap to test, immediately reversible with dextrose, and can mimic stroke, seizure, or coma — missing it causes preventable harm while more elaborate workups are pursued.
Application 1: A 68-year-old presents with left arm weakness that started 3 hours ago. CT head is negative for hemorrhage, BP is 150/90, platelets and coagulation studies are normal. What is the next step? Answer guidance: She is within the 4.5-hour window with no absolute contraindications, so administer IV tPA after confirming no other exclusion criteria.
Application 2: A patient seizes continuously for 8 minutes in the ED. IV lorazepam is given but the seizure continues 10 minutes later. What is the next step? Answer guidance: Move to second-line therapy — IV fosphenytoin, valproate, or levetiracetam — since benzodiazepine monotherapy has failed and this now qualifies as refractory status epilepticus.
Analysis 1: Compare why a "worst headache of life" prompts a different diagnostic pathway than a typical migraine, even though both can present with severe head pain and vomiting. Answer guidance: The thunderclap, sudden-maximal-intensity quality suggests subarachnoid hemorrhage, warranting emergent CT and possibly LP; a migraine typically has a gradual build, prior similar episodes, and lacks findings like neck stiffness or LOC.
Analysis 2: A patient with known chronic benzodiazepine dependence presents unresponsive with pinpoint pupils and shallow breathing. Discuss why flumazenil is used cautiously here. Answer guidance: Flumazenil can precipitate acute benzodiazepine withdrawal seizures in dependent patients, so it is reserved for carefully selected cases; naloxone is safer to trial first if opioid co-ingestion is suspected, and supportive airway management takes priority regardless.
FAQ
Q1: Is the tPA window 3 hours or 4.5 hours? Both numbers matter for exams. The original trial-proven window is 3 hours; it was later extended to 4.5 hours for patients meeting additional eligibility criteria (age, diabetes/prior stroke history, NIHSS severity). Know which population each cutoff applies to.
Q2: Why is glucose checked before assuming a stroke or seizure diagnosis? Because severe hypoglycemia can perfectly mimic focal neurological deficits or seizure-like activity, and it's instantly correctable with IV dextrose — skipping this step risks treating the wrong problem entirely.
Q3: What's the difference between status epilepticus and a normal seizure that just looks scary? Duration and recovery: a typical seizure self-terminates within a couple of minutes and consciousness returns. Status epilepticus means either the seizure passes the 5-minute mark or a second seizure starts before the patient recovers baseline mental status.
Q4: Why do we do a CT before a lumbar puncture when SAH is suspected? CT is fast, non-invasive, and highly sensitive early after a bleed. LP is reserved as the follow-up test when CT is negative but suspicion remains, because LP carries its own risks (post-LP headache, and theoretical herniation risk if there's raised intracranial pressure from a mass).
Q5: Can thrombectomy be done outside the tPA window? Yes — this is a key modern update. Mechanical thrombectomy can be offered up to 24 hours after onset in select patients with large-vessel occlusion and favorable perfusion imaging, even if they are outside or ineligible for the tPA window.
Quick Revision
- Ischemic stroke = clot (85%); hemorrhagic stroke = bleed (15%) — treatments are opposite.
- Always get non-contrast CT before considering tPA — its job is to exclude bleed.
- tPA window: 3 hours standard, extended to 4.5 hours for eligible patients.
- Thrombectomy can extend treatment up to 24 hours for large-vessel occlusions with good perfusion imaging.
- Absolute tPA contraindications: hemorrhage on CT, recent surgery/trauma, active bleeding, BP >185/110 uncontrolled, platelets <100,000.
- Status epilepticus = seizure >5 minutes or recurrent seizures without recovery.
- Drug order for status epilepticus: benzodiazepine → antiepileptic (fosphenytoin/valproate/levetiracetam) → anesthesia.
- Altered mental status workup mnemonic: AEIOU-TIPS.
- Always check glucose and oxygen saturation first in any altered mental status patient — cheap, fast, reversible.
- SAH presents as "thunderclap" worst headache of life; workup is CT first, then LP for xanthochromia if CT is negative.
- Xanthochromia distinguishes true SAH from a traumatic LP tap.
- Nimodipine is given after SAH specifically to prevent vasospasm-related secondary ischemia, not to lower blood pressure broadly.
Related Topics
Prerequisites: Basic neuroanatomy of cerebral blood supply, general approach to the unconscious patient, and fundamentals of the Glasgow Coma Scale.
Related Topics: Cardiovascular emergencies (arrhythmia-related embolic stroke), toxicology (drug-induced altered mental status and seizures), and pediatric neurological emergencies (febrile seizures differ substantially in management).
Next Topics: Trauma-related head injury management, ICU-level neurocritical care, and rehabilitation/secondary prevention after stroke.