What is the best course of action for a patient with a history of right Middle Cerebral Artery (MCA) infarct and new onset episodic twitching?

Evaluation and Management of New Onset Twitching in a Patient with Prior Right MCA Infarct

Immediate Diagnostic Workup

This patient requires urgent neuroimaging to exclude new stroke, hemorrhagic transformation, or seizure-related complications, followed by EEG monitoring to characterize the episodic twitching. 1

Neuroimaging Priority

• MRI with diffusion-weighted imaging (DWI) is superior to CT for detecting new ischemic events and should be obtained urgently to rule out new infarction, hemorrhagic transformation, or mass effect from delayed cerebral edema 1
• MRI gradient-echo sequences are essential to detect microhemorrhages and hemorrhagic transformation that CT may miss, particularly important given the chronic infarct history 1
• CT head without contrast is acceptable if MRI is unavailable or contraindicated, though it has lower sensitivity for acute ischemia and subacute hemorrhage 1

Vascular Assessment

• CTA head and neck should be performed to evaluate for new vascular occlusion or stenosis progression that could explain new symptoms 1
• This is particularly important given the history of right MCA infarct, as recurrent embolic events or progressive atherosclerotic disease may be present 2

Seizure Evaluation

The episodic, movement-triggered, non-rhythmic twitching pattern strongly suggests focal motor seizures rather than myoclonus or other movement disorders.

EEG Monitoring

• Obtain EEG as soon as possible to capture ictal activity and confirm seizure diagnosis 1
• Consider continuous EEG monitoring if episodes are frequent, as brief focal seizures may not be clinically obvious and could indicate ongoing epileptogenic activity 1
• Enhanced seizure monitoring is particularly warranted in patients with otherwise unexplained symptoms following stroke 1

Seizure Management Approach

• If seizures are confirmed and recurrent (more than one episode), initiate antiepileptic drug therapy immediately 1
• A single self-limiting seizure occurring within 24 hours of stroke onset should not be treated with long-term anticonvulsants, but this patient's stroke occurred in March 2025 (remote), making this a late-onset post-stroke seizure requiring treatment 1
• Prophylactic anticonvulsants are NOT recommended and may harm neurological recovery 1

Antiepileptic Drug Selection

• For focal seizures following stroke, initiate therapy at 10-15 mg/kg/day, increasing by 5-10 mg/kg/week to achieve seizure control 3
• Target therapeutic valproate serum concentrations of 50-100 mcg/mL for most patients 3
• Monitor for thrombocytopenia, which increases significantly at trough valproate levels above 110 mcg/mL in females and 135 mcg/mL in males 3
• Alternative agents effective for focal seizures include carbamazepine, phenytoin, lamotrigine, and levetiracetam, though valproate has broad-spectrum efficacy 4

Assessment for Stroke Complications

Delayed Cerebral Edema

• Monitor for signs of increased intracranial pressure, as edema can develop days after the initial infarct 5
• Brain swelling is responsible for approximately one-third of deterioration cases in MCA territory infarctions, with risk estimated at 10-20% 5
• Clinical predictors include severe neurologic deficits, nausea/vomiting, and involvement of large MCA territory 5

Hemorrhagic Transformation

• Assess for hemorrhagic transformation on MRI gradient-echo sequences, as this complication increases with large infarct size and can present with new neurological symptoms 5
• The presence of small numbers of microhemorrhages (<5) does not contraindicate treatment but requires monitoring 1

Metabolic and Systemic Evaluation

• Repeat comprehensive metabolic panel including electrolytes, glucose, calcium, and magnesium to exclude metabolic triggers for seizures, despite normal values 3 weeks ago 1
• Check complete blood count and liver function if initiating antiepileptic therapy 3
• Evaluate for infection (pneumonia, urinary tract infection) that could lower seizure threshold 1

Secondary Stroke Prevention Review

Given new symptoms in a patient with prior MCA infarct, reassess secondary prevention strategies:

• Confirm patient is on appropriate antiplatelet therapy (aspirin 75-325 mg daily or alternative) 6
• Evaluate for atrial fibrillation with 12-lead ECG and consider prolonged cardiac monitoring, as paroxysmal atrial fibrillation may have been missed initially 2
• Assess blood pressure control with target systolic BP <120 mmHg 2
• Perform carotid duplex ultrasound to evaluate for progressive stenosis if not recently done 2

Critical Pitfalls to Avoid

• Do not dismiss episodic twitching as benign myoclonus without EEG confirmation - focal motor seizures are common after cortical strokes and require treatment 1, 4
• Do not start prophylactic anticonvulsants before confirming seizures, as this may impair neurological recovery 1
• Do not delay neuroimaging - new symptoms in a stroke patient warrant urgent evaluation for recurrent stroke or complications 1
• Do not assume stable electrolytes from 3 weeks ago - acute metabolic derangements can develop rapidly and trigger seizures 1

Monitoring and Follow-up

• Serial neurological assessments every 4 hours initially to detect clinical deterioration 1
• If seizures are confirmed and treated, monitor antiepileptic drug levels and adjust dosing based on clinical response and serum concentrations 3
• Repeat neuroimaging if clinical deterioration occurs to assess for cerebral edema, hemorrhagic transformation, or new infarction 1, 5
• Referral to neurology for ongoing seizure management and stroke care 1