Migraine headache intensity and intracranial pressure.

2003;43:96-98), Doepp et al reported that 68% of patients with migraine experienced increased headache intensity when a Queckenstedt maneuver was performed with the patients supine. They concluded thdt the increased headache intensity was caused by in-tracranial venous distension. This conclusion may be incorrect. Schumacher and Wolff reported that by increasing intracranial pressure and thereby reducing intracra-nial vascular distension, they were able to reduce the intensity of the pain in histamine-induced headache'l Increasing intracranial pressure did not, however, reduce pain intensity in patients with migraine. They concluded that the pain of migraine was not due to distension of intracranial vessels. Doepp et al make the assumption that in the upright position cerebral blood drainage occurs "via the intraspinal and extraspinal venous system." Principal outflow through the internal jugular veins can indeed be substituted completely by the large vertebral plexus through communications at the cranial base.2 One would have to ask why this happens when the patient is upright, but not when the patient is supine. There should be adequate drainage even when the jugular veins are occluded. South Africa REFERENCES 1. Schumacher GA, Wolff HG. Experimental studies on headache: a contrast of histamine headache with the headache of migraine and that associated with hyper-tension. B. Contrast of vascular mechanisms in pre-headache and in headache phenomena of migraine' Ar ch N eur o I P s y chiatry. 19 47;;45:799'274-2. Andeweg J. The anatomy of collateral venous flow from the brain and its value in aetiologeal interpretation of intracranial pathology. Neuroradiology' 1996:38.62I'628. study from Schumacher and Wolff published in 1947, wherein an increase ofintracranial pressure (ICP) provoked by connecting the subarachnoid space with a high column of fluid was produced in 7 patients during a migraine attack.l The authors assumed that the increase in ICP reduced vascular distension of the basal cerebral arteries. No decrease of headache intensity was observed. Dr. Shevel proposes that these findings argue against the hypothesis that cerebral ve-nous distension is involved in the increase of migraine headache. Even so, several animal studies have shown that an increase in cerebrospinal fluid (CSF) pressure does not cause compression of intracranial arterial or venous vessels; elevation of CSF pressure leads to a marked dilatation of pial arteries and a minor dilata-tion of pial veins.z'3 In another study, the caliber of pial veins remained unchanged during ICP changes due to mannitol infusion in cats with normal and elevated ICP.4 Bridging veins …