Is thrombolysis with tissue plasminogen activator (tPA) indicated for a patient with a National Institutes of Health Stroke Scale (NIHSS) score of 2?

Thrombolysis for NIHSS 2 Stroke

For patients with NIHSS score of 2, thrombolysis with tPA should be administered if the deficits are functionally disabling (affecting independence, driving, work, or activities of daily living), but should be withheld if deficits are non-disabling, in which case dual antiplatelet therapy is preferred. 1

Decision Algorithm for NIHSS 2

Step 1: Assess Functional Impact

• Disabling deficits include: isolated hemianopia affecting driving, language impairment preventing communication, distal hand weakness affecting fine motor tasks, or gait disturbance affecting independence 1, 2
• Non-disabling deficits include: mild sensory changes, minimal facial weakness without functional impact, or symptoms not affecting daily activities 1

Step 2: Treatment Based on Disability Assessment

If Disabling (proceed with thrombolysis):

• Administer tPA 0.9 mg/kg (maximum 90 mg), with 10% as IV bolus over 1 minute, remaining 90% over 60 minutes 3
• Within 0-3 hours: Strong recommendation (Grade 1A) 3
• Within 3-4.5 hours: Conditional recommendation (Grade 2C) 3
• Expected benefit: 3-fold increased odds of excellent outcome 1

If Non-Disabling (alternative therapy):

• Initiate dual antiplatelet therapy with aspirin plus clopidogrel for 21 days within 12-24 hours of onset 1
• This approach is preferred for NIHSS ≤3 with non-disabling deficits 1

Safety Profile in Low NIHSS Patients

The bleeding risk is acceptably low in mild strokes:

• Historical NINDS data showed only 3% symptomatic intracranial hemorrhage (sICH) risk in patients with NIHSS <10 1
• In patients with NIHSS ≤4, sICH occurred in only 1% (1 patient out of 107 treated) 2
• Overall sICH rate with proper dosing is 4-6% 3

Critical Pitfalls to Avoid

Do not exclude based solely on NIHSS score:

• The NIHSS does not capture all functionally significant deficits 2
• Language impairment (present in two-thirds of low NIHSS patients), distal hand paresis (one-third), and gait disorders are commonly disabling despite low scores 2
• All patients with NIHSS ≤4 who were considered for treatment had functional impairment (mRS ≥2) 2

Do not withhold treatment for "rapidly improving" symptoms:

• Avoid thrombolysis only if symptoms are truly resolving AND the patient no longer has disabling deficits at the time of treatment decision 1
• Despite treatment, 26% of patients with NIHSS ≤4 had unfavorable outcomes (mRS >1) at 3 months, and 52% had persisting symptoms 2

Pre-Treatment Requirements

Blood pressure control is mandatory:

• SBP must be <185 mmHg and DBP <110 mmHg before initiating tPA 4
• Severe uncontrolled hypertension (SBP >180 or DBP >110 unresponsive to therapy) is an absolute contraindication 4

Post-treatment monitoring:

• Maintain SBP ≤180 mmHg and DBP ≤105 mmHg for 24 hours after tPA 4
• Monitor BP every 15 minutes for 2 hours, every 30 minutes for hours 2-8, then hourly 4

When Uncertainty Exists

Consult stroke specialist urgently:

• When unclear whether deficits are disabling, obtain immediate stroke neurology consultation within the institution or via telestroke 3
• Do not delay imaging, but MRI should not delay treatment decisions in NIHSS 3-5 range with clearly disabling deficits 1