A case presenting as fatal subarachnoid hemorrhage due to segmental arterial mediolysis associated with Crohn's disease.

Abstract Background Segmental arterial mediolysis (SAM) is a rare arterial pathology and can cause rupture or dissection of the intracranial arterial wall. The etiology is unveiled, but vasospastic stimuli such as migraine are considered as a possible cause of SAM. We present the first case of subarachnoid hemorrhage (SAH) due to SAM associated with Crohn's disease and migraine, and discuss the possible contribution of Crohn's disease to the development of SAM besides migraine. Case description A 33-year-old man with Crohn's disease, which had been treated with adalimumab, repeatedly underwent 3-tesla magnetic resonance (MR) imaging and angiography for severe headache due to migraine and the subsequent development of fatigue in the left arm and both legs. At 7 months after the last MR imaging studies showing no abnormalities, he had a sudden onset of severe SAH, which was caused by rupture or dissection of the terminal portion in the right internal carotid artery. As his brain-stem reflexes were absent, the patient was conservatively treated and died 6 days after the ictus. By postmortem histopathological examination, SAM was diagnosed as the cause of SAH. Vasa vasorum was also observed around the rupture point. Conclusions Our case suggests that: 1) the formation of vasa vasorum may be an antecedent pathology for vessel rupture of the fragile arterial wall affected by SAM, and 2) vasospastic nature of both Crohn's disease and migraine may contribute to the development of intracranial SAM.