INTRACRANIAL ARTERIOVENOUS MALFORMATIONS AND HEADACHE O. Waltimo, M.D. E. Hokkanen, M.D. R. Pirskanen, M.D. Submitted 12/30/1974 Revision accepted 2/27/1975 SYNOPSIS Twenty-nine males and 19 females with intracranial arteriovenous malformation were questioned about migraine and headache. Fifteen (31.2%) had a long history of migraine, 23 (48%) suffered from other headaches, and 10 (20.8%) were headache free. The frequency of headache was similar to that in the general population, but the frequency of migraine was higher. Migraine was more common with small malformations when the malformation had bled or when it was occipital. Unilateral headache was nearly always on the side of the malformation. Thermography was asymmetric in 56%, the warm side coincided with that of malformation in 3/4 of these patients. INTRACRANIAL HEMORRHAGE and epilepsy are the most important complications of intracranial arteriovenous malformations (AVM). Headache is also a cardinal symptom.1-5 Migrainous headache has been noted in 13 - 20% of patients with AVM,1-4 but in a comprehensive review of radiologically studied patients6 a positive history of migraine was found in only 12 (5%) of a total of 220 patients with AVM. On the other hand, 202 (5.4%) of 3736 patients with normal angiograms had a history of migraine. This varying incidence of migraine in patients with AVMs has led us to analyze the frequency of headache and migraine in our patients with AVM. We also examined the relationship of headaches to other characteristics of AVM. PATIENTS AND METHODS Twenty-nine males and 19 females with intracranial AVM were hospitalized in the Department of Neurology, University of Helsinki from 1966 to 1972. They were personally examined and questioned about headaches. AVM were demonstrated by carotid angiography. Twenty-nine malformations were left-sided and 16 on the right. Three meningeal AVMs were diffuse in location. There were 13 frontal, 15 parietal, 7 temporal, 6 occipital, 3 central and one AVM was in the posterior fossa. The volume of malformations was calculated from angiographic films using the ellipsoid approximation technique.7 The median volume was 7.0 cm3 (range 0.1 to 79.8 cm3). There were three groups of patients; migraineurs, patients with other headaches and patients without headache. Migraine was present if the headaches were intermittent and had at least 3 of the following features: 1. they were unilateral, 2. an aura was present, 3. autonomic imbalance (nausea, vomiting, chills, dyspnoea, diarrhea, etc.), 4. pulsating, throbbing pain, 5. positive family history of migraine or 6. beneficial effect of ergotamine tartrate on acute attacks of headache. The other headache patients had tension headaches. Five patients who had some migrainous features did not fulfill other criteria for migraine. They were included in the tension headache group. Migraineurs were further subdivided into classic and common migraine. Thermography was performed with an AGA Thermovision apparatus. RESULTS Fifteen (31.2%) patients had migraine, and 23 (48%) suffered from other headaches, 10 (20.8%) patients were headache free (Table 1). There were more women in the migraine group than in other patient groups (p