Moyamoya disease is a rare, progressive cerebrovascular disorder characterized by narrowed brain arteries and fragile collateral vessels, leading to stroke and other neurological symptoms.

Moyamoya disease is a rare and progressive condition affecting the blood vessels in the brain. It is characterized by the narrowing or blockage of the terminal internal carotid arteries, which are major blood vessels supplying the brain. In response to this blockage, the body attempts to compensate by developing a network of tiny, fragile collateral blood vessels at the base of the brain. These delicate vessels, which resemble a puff of smoke on angiography, are what give the disease its name, "moyamoya" being a Japanese term for this appearance [3, 7].

While primarily known for affecting intracranial arteries, moyamoya disease can also cause changes in extracranial vessels, including those supplying the heart [2]. The exact cause of moyamoya disease is often unknown, though genetic and autoimmune factors are being investigated [8].

Recognizing Moyamoya Symptoms

The symptoms of moyamoya disease can vary widely, often depending on whether the brain is experiencing a lack of blood flow (ischemia) or bleeding (hemorrhage). Common presentations include:

Stroke: Patients may experience recurrent ischemic strokes, which occur when blood flow to part of the brain is interrupted. This can manifest as abrupt weakness in the face or limbs [3]. Hemorrhagic strokes, caused by the rupture of the fragile moyamoya vessels, are also a significant concern [4].
Headaches: Headaches are a very common symptom, reported in up to 75% of patients with moyamoya angiopathy. These headaches can mimic migraines, tension-type headaches, or even cluster headaches. The exact cause of these headaches is complex, likely involving impaired blood flow regulation in the brain, microvascular ischemia, and the development of the collateral vessels themselves [7].
Cardiac Issues: A notable aspect of moyamoya disease is its association with coronary artery disease (CAD), with a high prevalence reported in affected individuals [1, 2]. This can lead to serious cardiac events, such as ST-elevation myocardial infarction (a type of heart attack), even in young adults [2]. The mechanism differs from typical atherosclerosis; it involves fibrous thickening of the inner lining of coronary arteries, which can predispose to spasms and blood clot formation [2].

Diagnosing Moyamoya Disease

Diagnosing moyamoya disease typically involves a combination of imaging techniques to visualize the brain's blood vessels and assess blood flow:

Magnetic Resonance Imaging (MRI) and Magnetic Resonance Angiography (MRA): These non-invasive scans can suggest the presence of narrowed arteries and the development of collateral vessels [3].
Digital Subtraction Angiography (DSA): Considered the gold standard, DSA provides detailed images of the blood vessels, confirming the characteristic tapering of the distal internal carotid arteries, involvement of other major arteries (like M1 segments), and the prominent collateral revascularization unique to moyamoya disease [3].
CT Perfusion (CTP): This imaging technique can assess blood flow to different parts of the brain, identifying areas with delayed perfusion or compromised hemodynamics [3].
Optical Coherence Tomography (OCT): For patients presenting with cardiac symptoms, OCT can be used to evaluate the characteristics of plaques or thickening within the coronary arteries, helping to differentiate moyamoya-related changes from traditional atherosclerosis [1, 2].

Associated Conditions and Risk Factors

While the cause of moyamoya disease is often unknown, certain conditions and genetic factors have been linked to its development:

Hypertension: Poorly controlled high blood pressure can be a contributing factor or exacerbate symptoms [3].
Graves' Disease: There is a higher prevalence of moyamoya disease among patients with Graves' disease, a common autoimmune thyroid disorder. One study found a prevalence of 45.36 per 100,000 patients with Graves' disease. In these cases, moyamoya disease is often diagnosed within a year of Graves' disease onset, and there is a notable female predominance (1:12 male to female ratio) [5].
Genetic Factors: Research suggests a genetic predisposition, particularly in Japanese populations, where the HLA-DRB1*04:10 allele has been identified as a risk allele for moyamoya disease. This allele is also associated with autoimmune thyroid disease, further highlighting a potential link between moyamoya and autoimmune conditions [8].

Treatment Approaches for Moyamoya Disease

Treatment for moyamoya disease aims to prevent strokes, manage symptoms, and improve blood flow to the brain. The approach depends on the individual's symptoms and disease progression.

Medical Management: Standard treatments for stroke prevention, such as antiplatelet therapy, statins, and blood pressure control, are often initiated [3]. However, for coronary artery disease associated with moyamoya, standard drug treatments like high-dose statins and antiplatelet drugs may be insufficient to stabilize inflammatory plaques [1]. For cardiac events like myocardial infarction, percutaneous intervention may be necessary to restore coronary blood flow [2]. There is currently no standardized treatment specifically for headaches related to moyamoya disease [7].
Surgical Revascularization: Surgical intervention is a key treatment option, particularly for preventing recurrent strokes. Procedures like indirect revascularization aim to promote the growth of new blood vessels to bypass the narrowed arteries and improve cerebral blood flow [6]. For adult patients who have experienced hemorrhagic moyamoya disease, surgical treatment has been shown to be superior to conservative management in preventing recurrent strokes, including both hemorrhagic and ischemic events [4]. Planning for bypass surgery often utilizes CT perfusion and digital subtraction angiography to guide the procedure [3].

Living with Moyamoya Disease

Moyamoya disease is a complex condition that requires ongoing medical care and monitoring. While there is no cure, effective treatments can significantly reduce the risk of stroke and manage symptoms. Patients with moyamoya disease should work closely with their healthcare team to develop a personalized treatment plan, which may involve a combination of medical management and surgical intervention. Continued research is vital to better understand the disease's mechanisms and develop more targeted therapies.

Sources

This article summarises published research for a general audience. It is not medical advice — talk to a qualified clinician about your own situation. Need help finding one? Browse doctors.