Category: Acute Internal Medicine / Neuro-Emergency / SDEC & Same Day Emergency Care
Reading Time: 8 minutes
Introduction: The Hyperacute Triage Dilemma
When an acutely unwell patient presents to the emergency department or Same Day Emergency Care (SDEC) unit with sudden-onset focal neurological deficits, the clinical mandate is absolute: time is brain. In hyperacute ischemic stroke, up to 1.9 million neurons are lost every minute treatment is delayed.
However, frontline medical teams face a significant diagnostic hurdle: up to 20% to 30% of hyperacute stroke admissions are ultimately diagnosed as stroke mimics—organic or functional conditions that closely imitate focal cerebral ischemia. Inappropriately withholding intravenous thrombolysis (IVT) or mechanical thrombectomy (MT) in a true stroke leads to permanent disability. Conversely, administering thrombolytic agents to a stroke mimic, such as an intracranial mass, severe hypoglycemia, or hemiplegic migraine, carries unnecessary bleeding risks.
Building on our front-door cognitive screening frameworks in Acute Delirium vs. Dementia on the Intake and frailty triage in Frailty at the Front Door: Comprehensive Geriatric Assessment (CGA) and SDEC Risk Triage, navigating neuro-emergencies requires rapid, systematic differentiation.
1. Stroke vs. Mimics: Dissecting Clinical Signatures
While ischemic stroke is characterized by the sudden onset of negative neurological symptoms (loss of motor, sensory, or visual function corresponding to a single vascular territory), mimics frequently exhibit positive neurological symptoms (pins and needles, visual scintillations, involuntary movements) or non-vascular distributions.
Clinical Feature Matrix
| Clinical Parameter | Acute Ischemic Stroke | Common Stroke Mimics |
| Onset Profile | Explosive, maximal at onset | Gradual, progressive, or fluctuating |
| Neurological Character | Negative symptoms: weakness, numbness, hemianopia, aphasia | Positive symptoms: scintillating scotoma, paresthesia, jerking |
| Common Etiologies | Embolic, atherothrombotic, small vessel occlusion | Hypoglycemia, Todd’s paresis, migraine with aura, sepsis |
| Systemic Features | Normal inflammatory markers, clear vascular risk factors | Fever, extreme metabolic derangement, severe stress |
| Pathway Action | Immediate non-contrast CT and CT Angiography | Targeted metabolic, EEG, or MRI evaluation |
2. Front-Door Screening: FAST, ROSIER, and the NIHSS
At front-door triage, rely on validated clinical instruments to quantify neurological deficits and guide emergency imaging decisions:
FAST (Face, Arm, Speech, Time): Rapid pre-hospital screen to identify acute facial, motor, or speech deficits.
ROSIER Score (Recognition of Stroke in the Emergency Room): Ranges from -2 to +5 points. A score greater than 0 strongly suggests acute stroke.
NIHSS Scale (National Institutes of Health Stroke Scale): Ranges from 0 to 42 points. Standardized bedside tool to quantify stroke severity and track neurological deterioration.
The ROSIER Scoring Breakdown
Asymmetric Facial Weakness: +1 point
Asymmetric Arm Weakness: +1 point
Asymmetric Leg Weakness: +1 point
Speech Disturbance: +1 point
Visual Field Deficit: +1 point
Loss of Consciousness or Syncope: -1 point
Seizure Activity at Onset: -1 point
Immediate Metabolic Rule-Out
Always check capillary blood glucose immediately upon arrival. Severe hypoglycemia (below 3.0 mmol/L) can perfectly mimic hemiplegia and aphasia. Reversing hypoglycemia resolves symptoms instantly, avoiding unnecessary stroke team activations and unwarranted neuroimaging.
When syncopal collapse accompanies acute neurological signs, cross-reference red flag screening via Sudden Cardiac Death in the Young: Red Flag Syncope and Channelopathy Screening and Postural Orthostatic Tachycardia Syndrome (PoTS) on the Acute Intake.
3. Hyperacute Reperfusion Windows and Decision Making
Once hypoglycemia is excluded and acute stroke is suspected, execute immediate non-contrast head CT and CT Angiography (CTA) to exclude intracranial hemorrhage and identify Large Vessel Occlusion (LVO).
Reperfusion Intervention Targets
| Treatment Modality | Time Window | Key Eligibility & Action Targets |
| Intravenous Thrombolysis | Within 4.5 hours of symptom onset | Administer Alteplase (0.9 mg/kg) or Tenecteplase (0.25 mg/kg) IV if non-contrast CT excludes hemorrhage. |
| Mechanical Thrombectomy | Within 6 to 24 hours of symptom onset | Perform endovascular thrombectomy for anterior circulation LVO identified on CTA, utilizing CT Perfusion or MRI mismatch for extended windows. |
Key Thrombolysis Contraindications
Active internal bleeding or severe bleeding diathesis (platelets below $100 \times 10^9/\text{L}$, INR above 1.7).
Recent major surgery, trauma, or severe head injury within the past 14 days.
Persistent severe hypertension above 185/110 mmHg despite acute antihypertensive treatment with IV Labetalol or Nicardipine.
If acute stroke presents alongside severe hypertension or organ damage, coordinate blood pressure management with emergency nephrology protocols in The Acute Cardio-Renal Syndrome Matrix: Balancing Decongestion and Renal Perfusion.
4. Identifying and Managing Functional and Organic Stroke Mimics
When neuroimaging excludes acute ischemia and intracranial hemorrhage, evaluate for common underlying mimics:
Todd’s Paresis: Transient focal neurological weakness following a focal or unwitnessed seizure.
Sepsis and UTIs: Decompensation and re-emergence of old stroke deficits caused by systemic infection or fever.
Migraine with Aura: Hemiplegic migraine presenting with marching sensory or motor aura preceding headache.
Functional Neurological Disorder (FND): Inconsistent motor or sensory deficits accompanied by positive physical examination signs, such as Hoover’s sign of leg paresis.
If systemic sepsis or infection drives the re-emergence of old stroke deficits, execute the modern sepsis protocol outlined in Severe Sepsis and Septic Shock in 2026: Restrictive Resuscitation and the NICE NG253 Mandate.
Furthermore, when evaluating functional or anxiety-driven neurological presentations, apply the empathetic communication strategies detailed in The Organic-or-Psychogenic Dilemma: Managing Severe Health Anxiety and Somatization.
5. Summary Actions for Front-Door Intake
Stroke Triage Emergency Checklist
Check Glucose: Rule out hypoglycemia immediately at initial triage.
Establish Last Known Well: Confirm exact Last Known Well time with relatives or witnesses.
Calculate ROSIER Score: Calculate the ROSIER score and trigger the hyperacute stroke team if the score is greater than 0.
Urgent Neuroimaging: Target a door-to-CT time of less than 20 minutes and a door-to-needle time of less than 45 minutes.
Blood Pressure Control: Maintain blood pressure below 185/110 mmHg prior to administering thrombolysis.
Safety Escalation: A sudden drop in consciousness, severe new “thunderclap” headache, or rapid neurological deterioration following thrombolysis suggests secondary hemorrhagic transformation or rising intracranial pressure. Escalate care immediately under the safety framework in Beyond NEWS2: Martha’s Rule, the PIER Framework, and Escalating the Deteriorating Inpatient.
For complex multi-organ decompensation or shock states, integrate bedside hemodynamic windows from Point-of-Care Ultrasound (POCUS) on the Acute Take and Massive PE vs. Cardiac Tamponade: Bedside Management of Obstructive Shock.
