Activation of the brainstem but not of the hypothalamus in hemicrania continua without autonomic symptoms

A 64-year-old woman presented with a 6-month history of right-sided continuous headache, without autonomic symptoms and complete response to indomethacin. Clinical examination and structural brain imaging were normal. A diagnosis of hemicrania continua (HC) was made. We sought to determine the brain structures active during the pain in a patient who met all of the diagnostic criteria for HC with the exception of autonomic symptoms. A brain positron emission tomography study was performed during pain, and completely pain-free after indomethacin administration. Comparing the pain with pain-free states, the region of the dorsal pons was significantly activated. There was no activation in the hypothalamus, as previously reported in HC with autonomic symptoms. Although definitive conclusions can not be drawn from a single observation, the lack of autonomic symptoms along with the absence of hypothalamic activation suggests that the clinical presentation may predict the pattern of brain activation in primary headache syndromes.