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Cataplexy due to brainstem lesions is uncommon particularly when seen in isolation. The lesions include tumors of the brain or brainstem and arterio-venous malformations. Some of the tumors include astrocytoma, glioblastoma, glioma, and subependymoma. These lesions can be visualized with brain imaging, however in their early stages they can be ...
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]
Catalepsy is a symptom of certain nervous disorders or conditions such as Parkinson's disease and epilepsy.It is also a characteristic symptom of cocaine withdrawal, as well as one of the features of catatonia.
The brain requires approximately 3.3 ml of oxygen per 100 g of brain tissue per minute. Initially the body responds to lowered blood oxygen by redirecting blood to the brain and increasing cerebral blood flow. Blood flow may increase up to twice the normal flow but no more.
Brain ischemia has been linked to a variety of diseases or abnormalities. Individuals with sickle cell anemia, compressed blood vessels, ventricular tachycardia, plaque buildup in the arteries, blood clots, extremely low blood pressure as a result of heart attack, and congenital heart defects have a higher predisposition to brain ischemia in comparison to the average population.
There are several theories as to why these blood vessels may become inappropriately permeable and allow the surrounding brain tissue to become swollen. The "vasogenic" theory posits that elevated blood pressure overcomes the normal capability of blood vessels in the brain to maintain a normal cerebral blood flow.
Diagnosis of primary CNS vasculitis may be made with brain imaging and biopsy of the affected blood vessel. 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]
Extracellular brain edema, or vasogenic edema, is caused by an increase in the permeability of the blood–brain barrier. [18] The blood–brain barrier consists of astrocytes and pericytes joined with adhesion proteins producing tight junctions. [1] Return of blood flow to these cells after an ischemic stroke can cause excitotoxicity and ...