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Moyamoya disease is a disease in which certain arteries in the brain are constricted. Blood flow is blocked by constriction and blood clots (). [2]A collateral circulation develops around the blocked vessels to compensate for the blockage, but the collateral vessels are small, weak, and prone to bleeding, aneurysm and thrombosis.
Symptoms are thought to arise from transient abnormalities in the blood vessels of the brain. [1] In some cases, it may be associated with childbirth, vasoactive or illicit drug use, or complications of pregnancy. [1] If it occurs after delivery it may be referred to as postpartum cerebral angiopathy.
Emboli break off from the plaque and travel through the circulation to blood vessels in the brain. As the vessels get smaller, an embolus can lodge in the vessel wall and restrict the blood flow to parts of the brain. This ischemia can either be temporary, yielding a transient ischemic attack (TIA), or permanent resulting in a thromboembolic ...
In many cases there is evidence of constriction of the blood vessels (if angiography is performed), suggesting a possible overlap with reversible cerebral vasoconstriction syndrome (RCVS). Diffusion MRI may be used to identify areas of cytotoxic edema caused by poor blood flow (ischemia) but it is not clear if this prognostically relevant.
Cerebral blood flow (CBF) is the blood supply to the brain in a given period of time. [8] In an adult, CBF is typically 750 millilitres per minute or 15.8 ± 5.7% of the cardiac output. [9] This equates to an average perfusion of 50 to 54 millilitres of blood per 100 grams of brain tissue per minute. [10] [11] [12]
The most definitive diagnostic modality is a biopsy of the affected blood vessel however brain biopsy has a low yield, with up to 30-50% of biopsies being normal in suspected cases. [5] This is due to some cases having an irregular distribution of vessel involvement (making biopsy technically difficult) or larger vessels being unable to be ...
The medication is designed to constrict blood vessels, explains Jamie Alan, Ph.D., an associate professor of pharmacology and toxicology at Michigan State University. “In congestion, this will ...
The drugs of this class act as agonists for serotonin 5-HT 1B and 5-HT 1D receptors at blood vessels and nerve endings in the brain. The first clinically available triptan was sumatriptan, which has been marketed since 1991. Triptans have largely replaced ergotamines, an older class of medications used to relieve migraine and cluster headaches. [3]