Do paroxysmal hemicrania and hemicrania continua represent different headaches? A retrospective study.

Hemicrania continua and paroxysmal hemicrania are considered different headaches belonging to a group of trigeminal autonomic cephalalgias. However, they share many clinical features. Both headaches also show complete response to indomethacin, which is a mandatory criterion for their diagnosis. Are they really different headaches? To answer this question, we compared the pain characteristics and autonomic features between two headaches. We also determined whether paroxysmal hemicrania transforms into hemicrania continua or vice versa in their natural history.The patients with hemicrania continua and paroxysmal hemicrania were compared for severity, location, character, and mean effective indomethacin dose. The number of autonomic features and their severity was also compared. The natural history of headache was looked into to see the evolution of hemicrania continua and paroxysmal hemicrania from episodic and chronic pains, respectively.We included 35 patients with hemicrania continua and 27 patients with paroxysmal hemicrania from July 2015 to March 2017. The mean age of patients with paroxysmal hemicrania was 34.42 years, and hemicrania continua was 37 years. Both groups were similar for majority of pain characteristics and number/severity of autonomic features. However, paroxysmal hemicrania had higher pain severity. Five patients transformed from paroxysmal hemicrania to hemicrania continua, and 3 patients transformed from hemicrania continua to paroxysmal hemicrania.Paroxysmal hemicrania and hemicrania continua were similar on majority of pain characteristics and autonomic features. The paroxysmal hemicrania and hemicrania continua are not exclusive headaches and can transform into each other.