Symptoms in an affected child or adult may include disturbed consciousness, speech deficits, sensory and cognitive impairment, involuntary movements, or vision problems
The condition is characterized by stenosis (narrowing) or occlusion (blockage) of one or both ICA with subsequent formation of an abnormal network of blood vessels adjacent to the ICA.
Moyamoya disease is a rare disorder of blood vessels in the brain known as internal carotid arteries (ICA).
There is no cure for moyamoya disease. Early treatment is important to avoid mental and physical impairment. Treatment options include medications and surgical revascularization
The cause of moyamoya disease is unknown. Possible explanations for the disorder include injuries to the brain, infection, multifactorial inheritance, genetic factors, or other causes
medical professionals involved in the care of patients with moyamoya disease generally include specialists in neurology, neurosurgery, neuroradiology, and anesthesiology.
Moyamoya disease tends to be more progressive in children than in adults. In those patients who don't stabilize clinically, significant disability or death may occur.
Moyamoya disease is a cerebrovascular disorder. It is a rare condition in which the walls of the "internal" carotid arteries - which supply blood to important areas of the brain - become thickened.
The purpose of revascularization surgery in moyamoya disease is to augment or redirect blood flow in the brain. Surgical revascularization has been reported to improve cerebral blood flow
It is a disease of the arteries of the brain.... That requires surgery..... It is extremely rare.....
studies used to establish the diagnosis of moyamoya disease include cerebral angiography , magnetic resonance imaging (MRI) , magnetic resonance angiography (MRA), and computed tomography (CT ) scan
According to a report in 1998, more than 6000 cases had been described. The disease occurs in about one in a million people per year. Estimates of disease incidence in Japan are as much as ten times greater
Interventions such as physical, occupational, and speech therapy may be recommended for management of problems such as hemiparesis, speech problems, and sensory deficits
Cerebral hemorrhage occurs as a result of breakdown of the coexisting blood vessels that formed earlier in life due to stenosis or occlusion of the ICA
I had a quick look on the Wikipedia page (see link) and apparently it's not fatal. However - many patients suffer strokes leading to paralysis and other associated problems.