Secondary hemicrania continua: Case reports and a literature review.

Hemicrania continua (HC) is an indomethacin responsive primary headache disorder. Secondary or symptomatic HC is associated with another neurological or non-neurological disease. We report three patients with secondary HC. We also review the literature to identify the clinical predictors of an underlying disease entity. Intracranial structural lesion, head and neck vessel pathology, and carcinoma lung should be suspected in every patient. The factors that may suggest a secondary pathology are: elderly age, male sex, smoking habit, constitutional symptoms, symptoms related to respiratory system, frequent and short-lived exacerbation, nocturnal exacerbation, HC evolving from remitting form, recent neck and/or head trauma, miosis, elevated ESR, and fading effect of indomethacin. We recommend MRI brain in all the patients presenting with HC or HC like headache. Angiography and CT chest are two other investigations that may be supplemented in patients with high risk for head/neck vessel pathology and carcinoma lung.