Paroxysmal hemicrania: a retrospective study of a consecutive series of 22 patients and a critical analysis of the diagnostic criteria

BACKGROUND: Paroxysmal hemicrania (PH) is a probably underreported primary headache disorder. It is characterized by repeated attacks of severe, strictly unilateral pain lasting 2 to 30 minutes localized to orbital, supraorbital, and temporal areas accompanied by ipsilateral autonomic features. The hallmark of PH is the absolute cessation of the headache with indomethacin. However, these all features may not be present in all cases and a few cases may remain unclassified according to the 2nd Edition of The International classification of Headache Disorders (ICHD-II) criteria for PH. METHODS: Twenty-two patients were included in this retrospective observation. RESULTS: We describe 17 patients, observed over six years, who fulfilled the ICHD-II criteria for PH. In parallel, we identified five more patients in whom one of the features of the diagnostic criteria for PH was missing. Two patients did not show any evidence of cranial autonomic feature during the attacks of headache. Another two patients did not fulfill the criteria for PH as the maximum attack frequency was less than five. One patient had an incomplete response to indomethacin. CONCLUSION: A subset of patients may not have all the defined features of PH and there is a need for refinement of the existing diagnostic criteria.