Moyamoya, Japanese for “puff of smoke,” describes the tangle of tiny blood vessels that characterize this disease. It is a progressive disease where the arteries at the base of the brain become blocked, and to compensate for the blockage, tiny blood vessels grow in a wispy, tangled mass.
This disease usually affects children, but can also occur in adults, often presenting as a stroke or hemorrhage (bleeding). If left untreated, moyamoya disease can cause multiple strokes that lead to neurological decline, severe brain damage and death.
Symptoms of Moyamoya Disease
Children with moyamoya disease may experience an array of symptoms:
- Transient ischemic attacks (TIAs or mini strokes)
- Developmental delays
- Speech problems
- Uncontrollable movements, or an inability to move arms, legs or feet
- Anemia (low iron in the blood)
Adults with moyamoya disease may display a different set of symptoms than children:
- Fainting or “blacking out”
- Poor or blurry vision, vision loss in one eye or inability to recognize objects
Diagnosis of Moyamoya Disease
If moyamoya disease is suspected, it is important to diagnose it as quickly as possible to prevent complications, such as stroke and disability. The neurosurgeons at Houston Methodist may suggest one or more imaging scans and tests to diagnose moyamoya disease.
- Magnetic resonance imaging (MRI) can detect blocked blood vessels.
- Computerized tomography (CT) scans can also detect blocked blood vessels.
- Angiogram can confirm the diagnosis and show the structure of the affected blood vessels.
- Single-photon emission computerized tomography (SPECT) is a nuclear medicine technique that shows blood flow in the brain.
Treatment Options for Moyamoya Disease
Surgery is the only treatment for moyamoya disease. Neurosurgeons at Houston Methodist perform several types of revascularization surgeries that open narrow blood vessels, bypass blocked arteries and restore blood flow to the brain.
Direct revascularization (STA-MCA bypass)
This surgery connects a branch of the scalp artery, the superficial temporal artery (STA), to a branch of the brain artery, the middle cerebral artery (MCA) on the outer surface of the brain. This improves the brain’s blood supply right away. This microsurgical procedure is also called an extracranial to intracranial bypass graft (EC-IC bypass).
Children under age five may not be good candidates for this procedure because their arteries are often too small to bypass.
EDAS is a surgery that supplies new blood flow to the brain indirectly. In this procedure, a branch of the superficial temporal artery (a large blood vessel in the neck) is laid on the surface of the brain. This artery will usually grow new arteries into the brain to provide more blood flow in about six to eight weeks.
This procedure may be done when a direct graft is not possible. Children are often better candidates than adults.
EMS is another indirect bypass surgery. In this procedure, the neurosurgeon frees a muscle from the patient’s temple area, directs it through a hole in the skull, and places the muscle onto the surface of the brain. A new blood supply to the brain will develop in about six to eight weeks.
EDAMS combines both EDAS and EMS procedures.
Omental-cranial transposition (transplantation)
The omentum, the lining that surrounds the abdominal organs, has a rich blood supply. This procedure places the omentum onto the surface of the brain to generate new vessels to supply blood to the brain.
Multiple burr holes
In this indirect revascularization procedure, several small holes (burr holes) are drilled into the skull. This allows blood vessels from the scalp to grow into the brain to provide a new blood supply.
Medications for Moyamoya Disease
Currently, no drugs are available to treat moyamoya disease, but some medications can treat side effects or prevent complications.
- Aspirin or other anticoagulants help prevent blood clots from forming, which can help prevent strokes.
- Calcium channel blockers help lower blood pressure and reduce headaches.
Recovery and Rehabilitation
Recovery depends on many factors, such as how far moyamoya disease has progressed before treatment, the patient’s overall health status and how quickly revascularization (establishment of a new blood supply) takes place.
Generally, patients are in the hospital three to five days and can often resume regular activities within two to six weeks. Even though symptoms may improve right away after treatment, it can take 6 to 12 months for new vessels to develop completely.
Our physicians at Houston Methodist specialize in managing moyamoya disease at: