What is the best course of treatment for a patient with an acute ischemic infarct to the left temporal lobe in the setting of metabolic encephalopathy?

Management of Acute Ischemic Stroke with Concurrent Metabolic Encephalopathy

The primary treatment priority is rapid restoration of cerebral blood flow through IV thrombolysis (rtPA) within 3-4.5 hours or endovascular thrombectomy within 6-24 hours if eligible, while simultaneously identifying and correcting the underlying metabolic derangement causing the encephalopathy. 1

Immediate Reperfusion Therapy

Thrombolytic Treatment Window

• Administer IV rtPA (0.9 mg/kg, maximum 90 mg) if treatment can be initiated within 3 hours of symptom onset (10% bolus over 1 minute, remaining 90% over 60 minutes) 2
• Consider IV rtPA between 3-4.5 hours of onset, though evidence is weaker in this extended window 2
• Do not administer IV rtPA beyond 4.5 hours from symptom onset 2

Endovascular Intervention

• Pursue mechanical thrombectomy for proximal large-vessel occlusions in the anterior circulation within 24 hours of symptom onset, preferably within 6 hours 2, 1
• If IV rtPA is contraindicated (e.g., therapeutic anticoagulation), mechanical thrombectomy becomes first-line treatment 2

Metabolic Encephalopathy Management

Identify and Correct Underlying Causes

The metabolic encephalopathy requires urgent parallel investigation and treatment, as these conditions are potentially reversible 3, 4:

• Immediately check blood glucose, arterial blood gases, serum electrolytes, ammonia, lactate, and liver function tests 4
• Correct hypoglycemia urgently if blood glucose <60 mg/dL with 25 mL of 50% dextrose IV push 2
• Evaluate for diabetic ketoacidosis, which can cause severe metabolic encephalopathy with temporal lobe abnormalities 5
• Assess for drug intoxication, systemic metabolic disease, or oxygen deprivation as contributing factors 3

Fluid Management

• Use only isotonic solutions (0.9% normal saline) for hydration 2
• Avoid hypotonic solutions like 5% dextrose or 0.45% saline, as these distribute into intracellular spaces and worsen cerebral edema 2

Blood Pressure Management

Pre-Thrombolysis

• If systolic BP >185 mmHg or diastolic >110 mmHg, administer labetalol 10-20 mg IV over 1-2 minutes (may repeat once) or nicardipine drip 5 mg/h titrated up by 2.5 mg/h every 5-15 minutes (maximum 15 mg/h) 2
• Do not administer rtPA if BP cannot be reduced and maintained below these thresholds 2

Post-Thrombolysis Monitoring

• Check BP every 15 minutes for 2 hours, then every 30 minutes for 6 hours, then hourly for 16 hours 2
• For systolic 180-230 mmHg or diastolic 105-120 mmHg post-rtPA, give labetalol 10 mg IV over 1-2 minutes, may repeat every 10-20 minutes (maximum 300 mg) 2
• Avoid nitroprusside if possible, as it causes cerebral venodilation and increases intracranial pressure 2

Cerebral Edema Management

Positioning and Basic Measures

• Elevate head of bed 20-30 degrees with neck in neutral position to facilitate venous drainage 2
• Maintain normothermia and provide adequate pain control 2
• Ensure good head-body alignment to prevent increased intrathoracic pressure 2

Pharmacologic Treatment

• Administer mannitol 0.25-0.50 g/kg IV over 20 minutes every 6 hours if cerebral edema develops, though evidence for routine use in ischemic stroke is limited 2
• Consider furosemide 40 mg IV as adjunctive therapy, but avoid long-term use 2

Surgical Decompression

• For large middle cerebral artery territory infarcts with life-threatening edema, hemicraniectomy performed within 48 hours reduces mortality and improves outcomes 2
• Large cerebellar infarctions causing brainstem compression require urgent surgical decompression 2

Antiplatelet Therapy

• Initiate aspirin 160-325 mg within 48 hours of stroke onset 2, 1
• Delay aspirin for 24 hours if rtPA was administered 2

Monitoring and Supportive Care

Neurological Assessment

• Perform frequent neurological assessments to detect changes in brain perfusion, particularly if hyperventilation is used for ICP management 2
• Monitor for seizures, which can occur with large cortical strokes and require immediate treatment 2

Cardiac Monitoring

• Continuous cardiac monitoring to detect arrhythmias 1

Avoid Neuroprotective Agents

• Do not use citicoline, sovateltide, or other putative neuroprotective agents, as they have not demonstrated efficacy in improving stroke outcomes 6, 7

Critical Pitfalls to Avoid

• Never use hypotonic IV fluids, as they worsen cerebral edema in both stroke and metabolic encephalopathy 2
• Do not aggressively lower blood pressure with venodilating agents like nitroprusside, as this increases ICP 2
• Do not delay rtPA administration for line placement beyond a few minutes—insert necessary lines rapidly 2
• The metabolic encephalopathy does not contraindicate thrombolysis if the patient otherwise meets eligibility criteria and the stroke symptoms are clearly distinguishable from the encephalopathy 2