When a patient presents with loss of sensation, poor motor coordination, speech deficits, balance problems or impaired cognitive function, physicians are likely to consider stroke as the cause of symptoms. Yet if the patient does not fit the typical stroke profile—especially if she or he is of younger age than usual with stroke—other causes need to be considered, including Moyamoya disease, a progressive cerebrovascular disorder.
In patients with Moyamoya disease, the arteries at the base of the brain occlude and tiny blood vessels form a tangle of new vessels to adapt to the increasing blockage. On a conventional cerebral angiogram, this tangle of blood vessels resembles a puff of smoke, which is what the word “moyamoya” means in Japanese.
The disease was first identified in Japan and had been thought of as occurring chiefly in Asians. That assumption has changed in recent years, with Moyamoya disease in the United States being identified among Caucasians, African Americans and Hispanics as well as Asians. Some patients have a genetic predisposition for the condition; it also may develop from certain infections as well as from uncontrolled hypertension, hypercholesterolemia or thyroid disease.
Moyamoya disease is easy to miss through standard diagnostics. Adults with the condition may have experienced a hemorrhagic stroke (intraventricular, subarachnoid or intracerebral), so doctors might attribute the problem to an arterial blockage in the head and not investigate further. If the blockage is not identified correctly as being caused by Moyamoya disease—and treated appropriately—the reduced blood flow continues and intensifies. Patients then may suffer recurrent seizures and strokes that reduce quality of life and can result in death.
At Abington Memorial Hospital, the Moyamoya Disease Task Force is a specialized team encompassing all neurological disciplines to maximize beneficial patient outcomes. Our team includes experts in neurosurgery, neurointerventional and neurocritical care, neurology and neurodiagnostic radiology. Abington is one of only a few centers nationwide providing such coordinated care for Moyamoya disease.
Our team conducts a differential work-up for each patient, including screening by a physician, diagnostic imaging (MRI/MRA, magnetic resonance image/angiogram, or CTA, computed tomography angiogram), a cerebral angiogram and blood tests. If those studies suggest a narrowing of the blood vessels in the brain, a thorough work-up and neuropsychological screening clarify whether the patient has Moyamoya disease. Patients with the condition receive a perfusion CT with Diamox to determine which side of the brain needs surgical treatment and how urgently that treatment might be needed.
From diagnostic exams to recovery, our team follows an efficient and timely treatment process that is vital for the best care of Moyamoya disease. Patients who present while symptoms are evolving have a better prognosis than those with static symptoms, including a completed stroke. We use non-surgical methods when appropriate, such as for patients who may be only experiencing headache.
When symptoms and testing show that surgery is necessary, our experienced Moyamoya disease task force team—part of Abington’s Neurosciences Institute—performs a special bypass operation to increase blood supply to the brain. This surgery, known as EDAS (encephalo-duro-arterio-synangiosis), uses sophisticated new devices and equipment that enable us to indirectly revascularize the brain’s surface. We accomplish this by dissecting a section of scalp artery and suturing it to the surface of the brain through a temporary opening in the skull. EDAS has been shown to be relatively low-risk compared with other techniques used for Moyamoya disease.
Post-operatively, patients are admitted to the ICU for 24 to 48 hours, receiving needed scans during that time. They then have follow-up examinations and testing at one month, three months, six months and one year after surgery. Close monitoring through repeated studies is important: it can take three to six months for collateral circulation development to occur and new blood vessels to grow, so patients are at risk of suffering additional strokes or other symptoms during recovery. They continue to be followed annually for five years.
For patients who are screened correctly, treatment for Moyamoya disease can bring improvements in cognition, memory, cortical region function and a decrease in neurological symptoms. At Abington’s Neurosciences Institute, our Moyamoya disease team draws on its expertise to achieve long-term benefits for our patients.
Qaisar A. Shah, MD, is Director of Neurointerventional and Neurocritical Care in the Neurosciences Institute of Abington Memorial Hospital (www.amh.org).