Cortical Hemiballism: A Case of Hemiballismus Associated with Parietal Lobe Infarct

CONTEXT: Hemiballismus is characterized by involuntary, irregular, large amplitude, and violent flinging movements of limbs. Stroke (middle and posterior cerebral artery) remains the most common etiology with 2/3 being lacunar. Lesions outside the substantia niagra (STN) can cause hemiballism, and only a minority by STN lesions, unlike the classical belief. Compared to those arising from STN, cortical hemiballismus is usually less severe with a good prognosis. CASE REPORT: A 61-year-old man presented with sudden onset involuntary flinging movements of his right upper extremity accompanied by numbness and tingling. Past medical history was significant for stroke 2 years back with no residual deficits. Vitals signs were blood pressure of 165/84 mm Hg, and heart rate - 82 beats/min. Irregular, arrhythmic, jerky flinging movement, and decreased sensation to light touch in right upper extremity was noted. Magnetic resonance imaging of the brain revealed acute posterior left parietal lobe infarction. He was treated with aspirin and atorvastatin. Thrombolytic therapy was offered but declined. The movements resolved spontaneously over the next 2 days. No further episodes occurred at 3-month follow-up. CONCLUSION: Lesions affecting various areas outside the STN can cause hemiballism and usually carries a good prognosis with spontaneous resolution. Acute thrombolytic therapy may be considered on an individual basis. Treatment with antipsychotics can be useful for severe and recurring symptoms.