Significance of the Characteristics of Precedent Headache and Nuchal Pain associated with Non-traumatic Dissecting Cerebral Aneurysms in the Posterior Fossa : An Investigation of 57-Consecutive Cases at Our Institution

Abstract

Spontaneous dissecting aneurysms are recognized to be uncommon We assessed the clinical manifestation of dissecting cerebral aneurysms in the posterior fossa, and especially investigated the difference between the precedent headache and nuchal pain associated with subarachnoid hemorrhage (SAH) and that associated with infarction. Medical records and neuroimaging scans of 57 consecutive patients over 8 years with dissecting aneurysms in the posterior circulation were investigated. The incidence of sideration as an initial symptom (symptom that necessitated the visit to our hospital) and the incidence and characteristics of headache and nuchal pain were reviewed. Among 57 consecutive patients, twelve patients (21%) presented with SAH, 19 (33%) with infarction, and 23 patients (40%) presented with only headache and nuchal pain. In comparison with the values reported in the literature, the number of mildly symptomatic patients diagnosed with dissecting aneurysms without SAH or infarction has increased. This increase can be attributed to an increased awareness about dissecting aneurysms and the improvements in diagnostic technology. Precedent headache and nuchal pain occurred in 65% patients with SAH or infarction. Six of the 12 patients (50%) with SAH experienced precedent headache and nuchal pain, and 5 patients (83%) had sudden-onset pain. Fourteen of the 19 patients (74%) with infarction experienced precedent headache and nuchal pain, whereas 4 patients (29%) had sudden-onset pain that gradually progressed to headache and nuchal pain in most cases. Patients who had only headache and nuchal pain were younger than those with SAH or infarct. Further, patients with precedent headache and nuchal pain were younger than those without precedent headache and nuhcal pain. I assumed that the difference in the incidence of precedent headache and nuchal pain in patients with SAH and infarct can be accounted for by 2 factors: the localization pattern of the substance P fiber in the intracranial arterial wall and the direction of the growing pseudolumen. A number of patients were undiagnosed when they visited the clinic with precedent headache and nuchal pain only, and these patients showed clinical exacerbation later. Persistent unilateral headache and nuchal pain without sudden-onset is possibly caused by a dissecting aneurysm. Early diagnosis of dissecting aneurysms in patients presenting with precedent headache and nuchal pain is important for preventing adverse effects such as SAH or infarct.