Posterior hypothalamic and brainstem activation in hemicrania continua.
OBJECTIVE
To determine the brain structures involved in mediating the pain of hemicrania continua using positron emission tomography.


BACKGROUND
Hemicrania continua is a strictly unilateral, continuous headache of moderate intensity, with superimposed exacerbations of severe intensity that are accompanied by trigeminal autonomic features and migrainous symptoms. The syndrome is exquisitely responsive to indomethacin. Its clinical phenotype overlaps with that of the trigeminal autonomic headaches and migraine in which the hypothalamus and the brainstem, respectively, have been postulated to play central pathophysiologic roles. We hypothesized, based on the clinical phenotype, that hemicrania continua may involve activations in the hypothalamus, or dorsal rostral pons, or both.


METHODS
Seven patients with hemicrania continua were studied in two sessions each. In one session, the patients were scanned during baseline pain and when rendered completely pain free after being administered indomethacin 100 mg intramuscularly. In the other session, the patients were scanned during baseline pain and when still in pain after being administered placebo intramuscularly. Seven age- and sex-matched nonheadache subjects acted as the control group. The scan images were processed and analyzed using SPM99.


RESULTS
There was a significant activation of the contralateral posterior hypothalamus and ipsilateral dorsal rostral pons in association with the headache of hemicrania continua. In addition, there was activation of the ipsilateral ventrolateral midbrain, which extended over the red nucleus and the substantia nigra, and bilateral pontomedullary junction. No intracranial vessel dilatation was obvious.


CONCLUSIONS
This study demonstrated activations of various subcortical structures, in particular the posterior hypothalamus and the dorsal rostral pons. If posterior hypothalamic and brainstem activation are considered as markers of trigeminal autonomic headaches and migrainous syndromes, respectively, then the activation pattern demonstrated in hemicrania continua mirrors the clinical phenotype, with its overlap with trigeminal autonomic headaches and migraine.
Institute of Neurology, Headache Group, London, United Kingdom.
Manjit S
MS
Matharu
Anna S
AS
Cohen
David J
DJ
McGonigle
Nick
N
Ward
Richard S
RS
Frackowiak
Peter J
PJ
Goadsby
D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D002560:Cerebrovascular Circulation; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007031:Hypothalamus / Q000473:pathology / Q000503:physiopathology*; D007213:Indomethacin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000188:drug therapy / Q000503:physiopathology*; D011149:Pons / Q000473:pathology / Q000503:physiopathology*; D049268:Positron-Emission Tomography; D012012:Red Nucleus / Q000473:pathology / Q000503:physiopathology; D013378:Substantia Nigra / Q000473:pathology / Q000503:physiopathology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D007213:Indomethacin