Hemicrania continua.

In recent years, hemicrania continua has become a well-recognized primary headache disorder known for its chronicity and resulting disability in a subset of patients with headache. The core clinical features have been well described: unilateral, side-locked headaches that are continuous (although interrupted by frequent severe exacerbations), associated with autonomic symptoms and a response to indomethacin. However, areas of relative controversy remain in its classification and diagnosis. Several relatively large case series have better delineated the associated features of this disorder, including atypical presentations. Recently, neuroimaging research has provided new insights into the underlying pathways involved in the disorder, in particular activation of the contralateral posterior hypothalamus and the ipsilateral dorsal rostral pons. Despite its well-known response to indomethacin, many patients still endure long delays in the appropriate diagnosis and treatment. There remains a need for new treatments given the morbidity associated with long-term indomethacin use.