Moyamoya disease is a medical condition in which there are blocked arteries at the base of the brain. This a rare condition that gets worse over time, and was first diagnosed in Japan during the 1960s, explains the National Institute of Neurological Disorders and Stroke (NINDS). The carotid arteries tend to narrow in this disease, causing a decrease in oxygen to the brain.
This can lead to blood clots and a subsequent stroke, states Boston's Children's Hospital. Moyamoya is more common in children, but adults can also have this disorder. Children can experience either a series of transient ischemic attacks or a stroke that can present symptoms like body weakness on one side of the body. Similarly, some other symptoms that may develop are problems with speech, vision and cognitive functions, states NINDS. When this disorder is present in adults, it can cause a debilitating hemorrhagic stroke.
Although the exact cause for this disorder is not entirely known, scientists think that it can be linked to heredity and the environment, reports the Barrow Neurological Institute. Surgery to remove the obstruction in the affected arteries is the treatment option for this condition.
The term "moyamoya" is a Japanese word that refers to the appearance of the small blood vessels formed to compensate for the blockage in the affected artery. On an angiogram, these tiny vessels look like a "puff of smoke", the Japanese translation of the word moyamoya.