Menstruation-triggered paroxysmal hemicrania

A woman in her late 30s presented with a 7-year history of recurrent strictly left-sided headaches occurring exclusively during menstruation. Attacks began from 2 days before menstruation to the first day of bleeding and recurred for 7–10 days each cycle. Pain was severe, orbital–temporal, lasted 5–20 min and occurred five to eight times daily. Associated features included restlessness, agitation and conjunctival injection, lacrimation and rhinorrhoea. She had no nausea, photophobia, phonophobia, aura or interictal pain. Laboratory investigations and neuroimaging were normal. Multiple preventive and symptomatic treatments had been ineffective. The clinical phenotype suggested paroxysmal hemicrania (PH), and an indomethacin trial was given. Indomethacin 25 mg three times per day resulted in complete remission within 24 hours, with repeated benefit in subsequent cycles. This case highlights that not all menstruation-associated headaches are migraine and that PH should be considered in women with short-lasting unilateral cyclical headaches.