What is the initial assessment and treatment approach for patients presenting with acute stroke symptoms using the National Institutes of Health Stroke Scale (NIHSS)?

Initial Assessment and Treatment Approach for Acute Stroke Using NIHSS

All patients presenting to an emergency department with suspected acute stroke must have an immediate clinical evaluation using the National Institutes of Health Stroke Scale (NIHSS) to determine focal neurological deficits, assess stroke severity, and establish eligibility for thrombolytic therapy and endovascular treatment. 1

Initial Rapid Assessment

1. Airway, Breathing, Circulation (ABC) Assessment 1

   • Ensure patent airway and adequate oxygenation
   • Assess vital signs: heart rate, rhythm, blood pressure, temperature, oxygen saturation

2. Neurological Examination with NIHSS 1, 2

   • NIHSS components:
     • Level of consciousness (0-3 points)
     • Orientation questions (0-2 points)
     • Response to commands (0-2 points)
     • Gaze (0-2 points)
     • Visual fields (0-3 points)
     • Facial movement (0-3 points)
     • Motor function - arms (0-4 points each)
     • Motor function - legs (0-4 points each)
     • Limb ataxia (0-2 points)
     • Sensory (0-2 points)
     • Language (0-3 points)
     • Articulation (0-2 points)
     • Extinction/inattention (0-2 points)
     • Total score ranges from 0-42

3. Stroke Severity Classification Based on NIHSS 2

   • Small stroke: NIHSS <5
   • Moderate stroke: NIHSS 5-15
   • Large/severe stroke: NIHSS >16

Immediate Diagnostic Workup

1. Urgent Blood Work 1

   • Electrolytes, random glucose
   • Complete blood count
   • Coagulation status (INR, aPTT)
   • Creatinine, eGFR
   • Troponin
   • Note: Do not delay imaging or treatment decisions while awaiting results

2. Immediate Brain Imaging 1

   • Non-contrast CT or MRI to differentiate ischemic from hemorrhagic stroke
   • Consider CT angiography for patients with disabling symptoms
   • Note: "Neurons over nephrons" principle - don't delay CTA for renal function results in most patients

3. Additional Assessments 1

   • ECG (can be deferred until after acute treatment decision)
   • Chest X-ray (only if evidence of acute heart/pulmonary disease)
   • Swallowing screen (within 24 hours, but should not delay acute treatment)

Treatment Decision Algorithm Based on NIHSS

1. For Ischemic Stroke

   • NIHSS 5-22: Consider thrombolytic therapy 2
   • NIHSS >22: Consider additional endovascular therapies 2
   • NIHSS ≥6-7: Predictive of large vessel occlusion (sensitivity 68-81%, specificity 77-79%) 2
   • Caution with posterior circulation strokes: Lower NIHSS scores (≥2) may still indicate severe stroke requiring intervention 3, 4

2. Blood Pressure Management 1

   • For thrombolytic candidates: Reduce BP if >185/110 mmHg
   • For non-thrombolytic candidates: Only treat if >220/120 mmHg
   • Note: Aggressive BP lowering may decrease perfusion pressure and worsen ischemia

3. Seizure Management 1

   • Treat new onset seizures with short-acting medications (e.g., lorazepam IV) if not self-limited
   • Single self-limiting seizures don't require long-term anticonvulsants
   • Monitor for recurrent seizure activity

Prognostic Value of NIHSS

• NIHSS <6: Good recovery likely 2
• NIHSS <10: 60-70% favorable outcomes at 1 year 2
• NIHSS >16: High probability of death or severe disability 2, 5
• NIHSS >20: Only 4-16% favorable outcomes at 1 year 2

Important Caveats and Pitfalls

1. Posterior Circulation Strokes

   • NIHSS underestimates severity of posterior circulation strokes 3, 4
   • Optimal NIHSS cutoff for outcome prediction is 4 for posterior circulation vs. 8 for anterior circulation 3
   • 15% of patients with "minor" posterior circulation strokes (NIHSS ≤4) still have poor outcomes 3

2. Very Low NIHSS Scores (0-1)

   • Thrombolysis in patients with NIHSS 0-1 may be associated with early neurological deterioration and lower rates of excellent outcomes 6
   • Carefully weigh risks and benefits in these patients

3. Monitoring for Deterioration

   • Regular reassessment with NIHSS is crucial to detect early neurological deterioration
   • Percent change in NIHSS from baseline to 3 months is a useful outcome measure 7
   • In moderate stroke (NIHSS 7-15), improvement of at least 55% predicts functional independence at 3 months 7

By systematically applying this assessment and treatment approach using the NIHSS, clinicians can optimize outcomes for patients with acute stroke symptoms.