What is Moya Moya Syndrome?|
The term "moya moya" is of Japanese origin meaning "puff of smoke". This comes from the appearance of the brain blood vessels affected by moya moya syndrome during an angiogram (a special picture of the brain where an x-ray is taken after a special injection is given that allows your doctor to see the blood vessels). Moya-moya is a rare disorder of uncertain cause that leads to irreversible blockage of the main blood vessels to the brain as they enter into the skull1.
Signs and symptoms
In young children transient ischemic attack (mini-stroke) is the commonest initial symptom. Some children may experience seizures or involuntary movements and even exhibit signs of mental retardation. In young patients, moyamoya disease is usually associated with headaches, speech difficulties, and episodes of paralysis involving the feet, legs or upper extremities, hemorrhage and anemia3.
In adults, presenting features are those of intracranial hemorrhage (bleeding within the skull). Disturbances of consciousness or subarachnoid hemorrhage is prominent. The arachnoid is a connective tissue sheath that covers the brain.
The patient may have fainting episodes (black outs). In addition, the patient may also suffer visual abnormalities may occur alone or in combination - loss of sight in one eye(hemianopia), blurry vision (diplopia), poor vision if both eyes (bilaterally diminished visual acuity), and the inability to recognize objects. Papilledema, or localised swelling of the tissues affected may indicate subarachnoid or cerebral hemorrhage.
The "moya moya" disease is often found among Japanese2. The onset is the highest in the ages around 5 years and next in the 4th decade. The cause of the syndrome is unknown.
The process of narrowing of the brain arteries seems to be a reaction of the brain's blood vessels to a wide variety of external stimulus, injuries, or genetic defects. In a series of patients, the syndrome was associated with Asian birth (nine children), neurofibromatosis - the congenital condition that causes tumors to grow on nerves (12 children), Down Syndrome (a chromosome defect - 9 children), following cranial x-ray or chemotherapy treatments (10 children). There is also seems to be an association with a previous history of surgery for congenital heart disease, suggesting that there may be a genetic defect in the blood vessel wall in these patients. But more than half of the children seen with this disease have no known cause for their moyamoya syndrome5.
The disease often progresses despite any known medical management unless treated with surgery. The repeated strokes can lead to severe problems with functions related to the area of the brain affected and may even cause death. It is important to recognize these lesions and treat them early on.
How is it diagnosed?
Once a diagnosis is suspected by CT or MRI, the next step is usually an angiogram to confirm the diagnosis and to see the what the blood vessels involved look like. Often nuclear medicine studies such as SPECT (single photon emission computerized tomography) are used to show the decreased blood and oxygen supply to areas of the brain affected with the Moya-moya disease.
How is it treated?
Certain medications can be very helpful in the treatment of the symptoms caused by moyamoya syndrome. The basis for some of the strokes in this condition is sludging of blood within the narrowed arteries at the base of the brain, the formation of tiny blood clots at these areas, and the subsequent breaking off of these clots into downstream blood vessels -- which blocks them off temporarily or permanently.
Medicines which prevent this micro-clot formation, such as aspirin, are essential in moyamoya syndrome, and some doctors5 believe that all moyamoya patients<