When a side-locked headache becomes a stroke code: indomethacin-responsive hemicrania continua with transient hemiplegia.

Hemicrania continua is a primary headache disorder characterized by strictly unilateral pain, cranial autonomic features, and absolute responsiveness to indomethacin. Presentation as an acute stroke mimic with transient focal neurologic deficits is rare. We report a 40-year-old woman with a 4-year history of strictly right-sided headaches who presented with acute right-sided sensory marching and motor weakness, accompanied by ipsilateral facial flushing, sweating, and miosis. Emergent multimodal neuroimaging was negative; intravenous tenecteplase was administered for suspected ischemic stroke. Subsequent brain magnetic resonance imaging revealed no acute infarction. After the postthrombolysis safety window, an oral indomethacin trial led to complete headache resolution and rapid clearing of deficits. This case illustrates that hemicrania continua can manifest with hemiplegic features due to overlapping cortical spreading depression biology and highlights the diagnostic utility of an inpatient indomethacin trial.