Hemorrhagic cerebrovascular event associated with intracranial aneurysmal dilatation in Moyamoya disease

Introduction: Moyamoya disease is a rare cerebrovascular disease characterized by progressive stenosis or occlusion of the terminal internal carotid artery (ICA) and proximal cerebral arteries, with the development of an abnormal collateral vessel network. In childhood it presents mainly with ischemic events, whereas in adults it may also present with hemorrhagic cerebrovascular events. Chronic hemodynamic stress and pathological collateral circulation increase the load on the vessel wall and may predispose to the development of intracranial aneurysms or the enlargement of existing aneurysmal structures. We report aneurysmal changes in Moyamoya disease in an adult patient who presented with subarachnoid and intraventricular hemorrhage.Case: The patient’s clinical features were evaluated retrospectively together with cranial CT, CT angiography, and digital subtraction angiography (DSA) findings. A 53-year-old woman with no chronic illness presented with headache. Her neurological examination was normal; she was oriented and cooperative, and her Glasgow Coma Scale (GCS) score was 15. Cranial nerve examination, eye movements, motor examination, deep tendon reflexes, and pathological reflexes were normal. There was no limb weakness, sensory deficit, or cerebellar sign. Cranial CT showed hemorrhagic densities in the cerebral hemispheres, basal cisterns, and ventricular system, interpreted as subarachnoid and intraventricular hemorrhage. CT angiography raised suspicion of aneurysmal dilatation of the distal basilar artery, and the DSA performed for this showed aneurysmal dilatation in the P1 segment of the left posterior cerebral artery (PCA). The left middle cerebral artery (MCA) territory was supplied via the left PCA, while the right MCA territory filled retrogradely. The left ICA was occluded at the cavernous segment and the right ICA at its proximal segment. Together with the well-developed collateral circulation, these findings were consistent with Moyamoya disease (Figure 1–5).Discussion/Conclusion: Although Moyamoya disease is rare in adults, it may be associated with hemorrhagic cerebrovascular events. The abnormal collateral vessel network and increased hemodynamic stress seen in the disease can cause structural changes in the vessel wall and raise the risk of aneurysm formation. This case shows that in adults presenting with subarachnoid and intraventricular hemorrhage, not only primary aneurysmal pathologies but also underlying vascular diseases should be investigated. DSA is critical for confirming the diagnosis of Moyamoya disease, evaluating the collateral circulation in detail, and revealing accompanying aneurysmal lesions.Keywords: