Stroke Evaluation Algorithm (Ischemic vs Hemorrhagic tPA Decision Window)

# Stroke Evaluation Algorithm (Ischemic vs Hemorrhagic tPA Decision Window)

## Clinical Pearl
If you remember ONE thing, it is that a Non-Contrast Head CT MUST be done before giving tPA to rule out a hemorrhagic stroke. Giving tPA to a patient with a brain bleed is fatal. Additionally, always check a point-of-care blood glucose, as hypoglycemia can perfectly mimic acute stroke symptoms.

## Memory Targets
- Blood pressure must be < 185/110 before administering tPA.
- Hypoglycemia must be ruled out as it mimics stroke.
- The standard extended tPA window is 4.5 hours.
- No aspirin or anticoagulants for 24 hours after tPA administration.
- Mechanical thrombectomy can be performed up to 24 hours after symptom onset for large vessel occlusions.

## Process Steps
undefined. Patient presents with acute focal neurologic deficits; time of last known normal is established.
undefined. Non-Contrast Head CT is immediately performed to evaluate the brain parenchyma.
undefined. CT rules out Hemorrhagic Stroke (no acute blood) and confirms Ischemic Stroke (or no visible changes yet).
undefined. The 4.5 Hour Time Window is verified to ensure the patient is eligible for thrombolytics.
undefined. Alteplase (tPA) is administered intravenously to dissolve the clot.
undefined. If large vessel occlusion is present or the time window is missed, Mechanical Thrombectomy is performed (up to 24 hours).

## Phonetic & Etymology Clues
Alteplase: Aluminum Teapot (Al-tea) + Plastic plates (plase) = A specialized solvent poured from an Aluminum Teapot melting Plastic plates,Thrombectomy: Trombone (Thromb) + Extractor claw (ectomy) = A mechanical extraction claw shaped like a giant trombone,Ischemic: Ice (Isch) + Chemical (emic) = A mechanism frozen solid in an Ice Chemical block,Hemorrhagic: Hem (sewing hem) + Raging (orrhagic) = A raging, violently leaking red fluid bursting through a stitched hem

## Entity Summary
- **Non-Contrast Head CT**: The initial, mandatory diagnostic imaging test used to rapidly rule out intracranial hemorrhage before administering thrombolytics. → Hemorrhagic Stroke, Ischemic Stroke
- **Hemorrhagic Stroke**: A rupture of a blood vessel in the brain causing bleeding, which is an absolute contraindication for thrombolytic therapy. → Non-Contrast Head CT, Alteplase (tPA)
- **Ischemic Stroke**: An occlusion of a cerebral blood vessel causing tissue hypoxia, which is the target condition for thrombolytic therapy if within the time window. → Non-Contrast Head CT, Alteplase (tPA), Mechanical Thrombectomy
- **Alteplase (tPA)**: A tissue plasminogen activator that catalyzes the conversion of plasminogen to plasmin, breaking down the fibrin clot. → Ischemic Stroke, 4.5 Hour Time Window
- **4.5 Hour Time Window**: The strict temporal threshold from symptom onset during which Alteplase can be safely administered; beyond this, the risk of hemorrhagic transformation outweighs the benefits. → Alteplase (tPA), Ischemic Stroke
- **Mechanical Thrombectomy**: An endovascular procedure to physically extract a clot from a large vessel occlusion, viable up to 24 hours after symptom onset. → Ischemic Stroke, 4.5 Hour Time Window

If you remember ONE thing, it is that a Non-Contrast Head CT MUST be done before giving tPA to rule out a hemorrhagic stroke. Giving tPA to a patient with a brain bleed is fatal. Additionally, always check a point-of-care blood glucose, as hypoglycemia can perfectly mimic acute stroke symptoms.