This contributes to the weakened immune response seen in those infected with EBOV.Endothelial cells may be infected within three days after exposure to the virus. The breakdown of endothelial cells leading to blood vessel injury can be attributed to EBOV glycoproteins. This damage occurs due to the synthesis of Ebola virus glycoprotein (GP), which reduces the availability of specific integrins responsible for cell adhesion to the intercellular structure and causes liver damage, leading to improper clotting. The widespread bleeding that occurs in affected people causes swelling and shock due to loss of blood volume. The dysfunctional bleeding and clotting commonly seen in EVD has been attributed to increased activation of the extrinsic pathway of the coagulation cascade due to excessive tissue factor production by macrophages and monocytes.After infection, a secreted glycoprotein, small soluble glycoprotein (sGP or GP) is synthesised. EBOV replication overwhelms protein synthesis of infected cells and the host immune defences. The GP forms a trimeric complex, which tethers the virus to the endothelial cells. The sGP forms a dimeric protein that interferes with the signalling of neutrophils, another type of white blood cell. This enables the virus to evade the immune system by inhibiting early steps of neutrophil activation. Immune system evasion
Filoviral infection also interferes with proper functioning of the innate immune system.
One small, possibly biased study found that the condition was eventually diagnosed in 45% of outpatients with sudden headache, and 46% of outpatients with thunderclap headache.The average age of onset is 42, but RCVS has been observed in patients aged from 19 months to 70 years. Children are rarely affected. It is more common in females, with a female-to-male ratio of 2.4:1. History
Case studies of the condition first appeared in the 1960s, but it was not then recognized as a distinct entity. In 1983, French researchers published a case series of 11 patients, terming the condition acute benign cerebral angiopathy. Gregory Call and Marie Fleming were the first two authors of a report in which doctors from Massachusetts General Hospital, led by C. Miller Fisher, described 4 patients, alongside 12 previous case studies, with the characteristic symptoms and abnormal cerebral angiogram findings. The name Call-Fleming syndrome refers to these researchers.A 2007 review by Leonard Calabrese and colleagues proposed the name reversible cerebral vasoconstriction syndrome, which has since gained widespread acceptance. This name merges various conditions that were previously treated as distinct entities, including Call-Fleming syndrome, postpartum angiopathy, and drug-induced angiopathy. Other names may still be used for particular forms of the condition. References


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