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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.
The narrowing of blood vessels leads to an increase in peripheral resistance, thereby elevating blood pressure. While vasoconstriction is a normal and essential regulatory mechanism for maintaining blood pressure and redistributing blood flow during various physiological processes, its dysregulation can contribute to pathological conditions.
The impairment of cerebral blood flow that underlies hypertensive encephalopathy is still controversial. Normally, cerebral blood flow is maintained by an autoregulation mechanism that dilates arterioles in response to blood pressure decreases and constricts arterioles in response to blood pressure increases.
Zamboni theorized that malformed blood vessels cause increased deposition of iron in the brain, which in turn triggers autoimmunity and degeneration of the nerve's myelin sheath. [19] [22] While the initial article on CCSVI claimed that abnormal venous function parameters were not seen in healthy people, others have noted that this is not the ...
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.
If the appearances are not typical, other causes for the symptoms and the imaging abnormalities need to considered before PRES can be diagnosed conclusively. [4] 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).
This condition is thought to result from severe hypocapnia that induces blood vessels in the brain to constrict, leading to brain ischemia. [3] Other symptoms caused by CNH are electrolyte dysequilibrium and mood changes that primarily include anxiety due to the hyperventilation. [1] [4]
Acute hypocapnia causes hypocapnic alkalosis, which causes cerebral vasoconstriction leading to cerebral hypoxia, and this can cause transient dizziness, fainting, and anxiety. [3] A low partial pressure of carbon dioxide in the blood also causes alkalosis (because CO 2 is acidic in solution), leading to lowered plasma calcium ions ...