Case Presentation: We present a rare case of MoyamoyaDisease (MMD) in a 44-year-old Caucasian female with a medical history of severe recurrent headaches. She presented with an excruciating headache and was found to have right-sided facial droop, and dysarthria. Initial imaging demonstrated an intraparenchymal and intraventricular hemorrhage, along with chronic occlusions of the middle cerebral arteries (MCA), anterior cerebral arteries (ACA), and posterior cerebral arteries (PCA) with extensive fine collateral vascularization. Angiogram showed bilateral internal carotid artery stenosis and confirmed the absence of the proximal ACA, MCA and PCA. Instead of having a Circle of Willis, our patient had an intricate grid of collaterals that gave the angiogram a hazy, cloudy appearance. This was most compatible with a rare diagnosis of MMD.

Discussion: MMD is a progressive occlusive vascular disease, which causes diminished cerebral perfusion due to bilateral stenosis of the intracranial carotid arteries and its branches. As a compensatory mechanism, a labyrinth of the intricate collateral arteries is formed. This classically gives it angiographic appearance of “puff of smoke”, which translates to the term Moyamoyain Japanese. Clinical presentation varies with the degree of arterial involvement and patients can range from being asymptomatic to having severe neurologic symptoms including recurrent strokes, TIAs, paralysis, or seizures. Our patient suffered with severe chronic headaches for years, likely due to dilation of the collateral vessels stimulating the dural nociceptors. Her headaches were never thoroughly evaluated in the past, which potentially lead to her disease progressing and presenting as a debilitating stroke. She did have significant neurological recovery with intensive rehab. She eventually underwent a reconst ructive procedure called encephaloduromyosynangiosis for indirect revascularization. This has shown to increase the collateral flow to the brain in turn reducing the risk of future strokes.

Conclusions: MMD is commonly seen in Asiatic countries, and has a near 2:1 female to male ratio. It is autosomal dominant with incomplete penetrance. An older review reported that in Washington State and California in 1987-1998, record show 298 patients with MMD. The incidence was 4.6 times higher in Asian Americans than in Caucasians. A more recent American Nationwide Inpatient Sample database from 2005 to 2008 found the incidence of MMD was increasing in the West. There were 7473 total patients diagnosed with MMD, with most patients being Whites. This growing frequency of MMD indicates that there may be more underlying, undiscovered cases. If common symptoms like severe headaches get thoroughly worked up, a potential diagnosis of MMD can be made early. This way, early medical and surgical intervention can take place to reduce the risk of devastating outcomes like strokes.