Moyamoya disease is an arterial disorder. Precisely, it is a disorder of angiogenesis, that is, the formation of blood vessels. It affects the internal carotid arteries in the path of entry to the skull.
Anatomically, the carotid arteries are born as two vessels close to the heart. They go up the neck, where each one is divided into two: internal carotid arteries and external carotid arteries.
From the neck, each pair of vessels enters the skull carrying the blood pumped by the heart to the brain. It is understood that A pathology of these vessels is potentially lethal.
In moyamoya disease the internal carotid arteries narrow, decreasing blood flow to the brain. As the human body has among its priorities to ensure a good cerebral blood supply, a network of small blood vessels develops to bypass the obstruction.
Those new glasses, neovessels, fulfill the function of generating an accessory way of rise for blood from the heart. The small collateral vessels located at the base of the skull, when viewed through complementary diagnostic methods, emulate cigarette smoke in the air.
'Moya-moya'In Japanese means' cloud of smoke'. Hence the etymology of the name of the disease. It is also the word that describes the smoke that comes out of the volcanoes. Through angiographic images, the scientists Susuki and Takaku gave name to this disease in 1969.
Distribution of moyamoya disease
Moyamoya disease has an age distribution in two peaks. Generally, the symptoms are present in children and middle-aged adults. The first age group most affected are infants between five and ten years of age. The second group are people between thirty and fifty years old.
Southeast Asian children are the most affected by moyamoya disease.
Although there have been cases around the world, with low frequency, it can be said that the most affected area is Southeast Asia. The countries of Japan, China and Korea concentrate the largest number of global cases. In Japan, for example, the prevalence is one in thirty-two thousand inhabitants.
Also in Southeast Asia there have been series of studies that found that every two thousand Japanese adults without symptoms of the pathology, there is one that has brain images compatible with moyamoya disease.
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As of today, the etiology of the disease is not clear. It is suspected that the origin is genetic and that arterial obstruction would have a hereditary component.
Anyway, you can name five risk factors that increase the predisposition to suffer it:
- Family background: when a family member has had moyamoya disease, the likelihood of another direct family member having it also increases up to forty times.
- Asian descent: the association may occur due to genetic issues. People who are born or come from Southeast Asia are much more likely to carry the disorder than the rest of the world.
- Female sex: the disease is more frequent among women than among men.
- Under fifteen years old: Pediatric age, as we explained earlier, is one of the most affected age groups.
- Other diseases: some cases of moyamoya were described combined with certain pathologies, such as Down syndrome, for example.
Symptoms of moyamoya disease
The clinical debut form is stroke. Either because the arterial obstruction does not let enough blood flow to the brain, or because the accessory vessels are weak and break before an effort. Both ischemia and hemorrhage are the almost lethal result.
Stroke can give prior warning. In children, recurrent seizures usually occur that respond to a lack of sufficient brain irrigation. In adults, there may be transient ischemias that are expressed with hemiparesis or hemiplegia.
Moyamoya disease shares symptoms with strokes.
The following are symptoms of bad brain irrigation:
- Visual alterations
- Difficulties in speech
- Involuntary movements
In the pediatric age, a usual trigger is crying. Children hyperventilate when they cry intensely. Hyperventilation requires a change in the flow of blood to the brain that is regulated through the constriction and dilation of blood vessels and can cause a break.
To continue reading: The most common cerebrovascular diseases
Diagnosis and treatment
The only way to diagnose Moyamoya disease is with brain imaging. Angiography and angioresonance are the rigorous studies to detect the pathology. In the images obtained, the decrease in arterial light in the internal carotids will be evident.
The treatment is presented under two options:
- One option is pharmacological. The drugs do not reverse the evolution, but they help to reduce the risk of stroke. Anticoagulants, vasodilators and platelet antiaggregants have been used.
- The second option is surgical treatment. The indication of an intervention is for those patients who have already suffered a cerebrovascular event and who, with or without sequelae, are prone to repeat it.