What Is Moyamoya Disease?

What is moyamoya disease?

Moyamoya disease is a cerebrovascular disease.

It is characterized by abnormal vascular network of skull base and chronic stenosis or occlusion of:

  • bilateral internal carotid artery end,
  • anterior cerebral artery, and
  • middle cerebral artery.

Since this abnormal vascular network of skull base is shaped like “smoke” on the cerebral angiography image, it is called “moyamoya disease”.

Moyamoya disease can be divided into four types.

Transient ischemic attack (TIA) type

TIA type accounts for about 70% of moyamoya diseases.
This type of disease has repeated episodes. Patients have symptoms such as convulsions and weakness. Most of them suffer from hemiplegia, alternating left and right hemiplegia, or bilateral hemiplegia.

Infarct type

Acute stroke leads to persistent paralysis, aphasia, visual impairment and mental retardation.

Epilepsy type

Frequent or partial seizures of epilepsy may lead to moyamoya disease.

Hemorrhage type

Subarachnoid hemorrhage or parenchymal hemorrhage may lead to moyamoya disease. The incidence of this type in adult patients is greater than that in children.

The last three types are collectively referred to as “non-TIA type“.

Key words: moyamoya disease; TIA type; non-TIA type.

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