Reversible cerebral vasoconstriction syndrome (RCVS)
Another rare cause of stroke is RCVS, which typically presents as thunderclap headaches with or without neurologic symptoms. MRI may be normal, but symmetric border zone infarctions and small subarachnoid hemorrhages are possible. Catheter, CT, or MR angiography show segmental arterial vasoconstriction. “You always have to exclude cerebral aneurysm,” Dr. Berlit said. “There is reversibility of RCVS within 3 months.” RCVS is often associated with a long list of drugs, including phenylpropanolamine, Methergine (methylergonovine), bromocriptine, lisuride, SSRIs, triptans, isometheptene, tacrolimus, cyclophosphamide, erythropoietin, intravenous immunoglobulins, erythrocyte concentrates, nasal sprays, cocaine, ecstasy, amphetamines, cannabis, and LSD. “After stopping responsible medications, treatment involves a course of nimodipine,” he said.
Moyamoya disease (MMD)
Dr. Berlit closed his presentation by discussing MMD, a rare occlusive cerebrovascular disorder characterized by progressive stenosis or occlusion of the intracranial portion of the internal carotid artery and proximal cerebral arteries with an extensive network of fine collaterals. “This is an idiopathic vasculopathy with remarkable regional and racial differences worldwide; it’s most frequently found in Asians, especially in Japan and Korea,” he said. “In Europe, there is about one-tenth the incidence, compared with that of Japan. In Asian MMD, about 15% of cases follow an autosomal dominant inheritance. The collaterals in MMD present histologically as a thin media, a fragmented elastic laminae, and the formation of microaneurysms. There is no inflammation.”
MMD diagnostic criteria include stenosis or occlusion of the terminal portion of the internal carotid artery and at the proximal portion of the anterior and middle cerebral arteries. Abnormal vascular networks are present in the basal ganglia and angiographic findings present bilaterally. Cases with unilateral angiographic findings are considered probable. Clinicians should exclude the following conditions: arteriosclerosis, autoimmune disease, brain neoplasm, history of cranial irradiation, Down syndrome, head trauma, neurofibromatosis, and meningitis. “If the angiographic pattern is resembled by one of these conditions, this is called moyamoya syndrome,” Dr. Berlit noted. “MMD is a progressive disorder. Within a few months you can see occlusion of the middle cerebral artery and the anterior cerebral artery, so you have to treat these patients.”
In patients who are white, MMD presents with lower rates of hemorrhage, but in Asians, microbleeds occur in up to 44% of patients and hemorrhages in up to 65% patients. “Both subarachnoidal and intracerebral hemorrhages occur, especially in connection with pregnancy and delivery,” he said. “The risk of both cerebral ischemia and hemorrhagic complications increases with stages of MMD.”
Direct or indirect intracranial bypass surgery is recommended in stages 3 or more, and has been shown to significantly reduce the 5-year stroke risk. To date, Dr. Berlit and his associates have treated 86 hemispheres in 56 patients. The average age of the patients was 42 years, 70% were female, and the average follow-up was 39 months. All intracranial bypasses were open on follow-up, and a decrease of the typical moyamoya vessels was observed in 81% of patients.
Dr. Berlit reported having no financial disclosures.