The altered form of hemoglobin in patients with this condition is called hemoglobin S or sickle hemoglobin. Sickle cell anemia patients often experience episodes of acute pain that are caused by vaso-occlusive crisis VOC. VOC is the most common complication of sickle cell anemia and a frequent reason for emergency department visits and hospitalization. What is VOC?
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These odd cells have a tendency to stick together inside blood vessels, blocking them and shutting off the blood supply to body organs and tissues. This painful event, which can last for several days, is known as a vaso-occlusive crisis. Although vaso-occlusive crises can be managed with pain-relieving drugs and may go away by themselves, serious complications such as infections, lung problems and strokes can occur.
Symptoms of a vaso-occlusive crisis typically include pain, which can vary in its intensity. The pain is felt in different parts of the body such as the belly, spine , ribs and the bones in the limbs. A condition called dactylitis could occur, where the feet or hands swell up painfully.
Sometimes, the abdominal pain can be as severe as that of appendicitis. In the short term, a vaso-occlusive crisis causes pain because it prevents enough blood from reaching tissues, and an attack may last anything from a few minutes to several weeks before resolving.
When attacks occur repeatedly, long-term damage to organs, joints and bones can take place. Ad Vaso-occlusive crisis is more likely to occur when patients have not drunk enough fluids, are extremely cold, or have exercised strenuously.
This means that patients may be able to manage their lifestyles to lower the chance of an attack. Once an attack has occurred, management of a vaso-occlusive crisis frequently involves giving patients suitable drugs to help them cope with their pain. Different types of painkillers may be required depending on whether the pain is severe, mild or moderate.
Fluids may also be given and oxygen may be needed if the chest is affected. Complications of a vaso-occlusive crisis can be life-threatening and are the result of ischemic injuries to tissues and organs. A stroke may occur when blood vessels supplying part of the brain are blocked. If a vaso-occlusive crisis reduces the blood supply to the spleen, this can leave patients prone to infections, as the spleen is an important part of the immune system.
In the chest, damage to the ribs can lead to lung collapse and breathing difficulties. Jaundice may occur in some patients.
Wie „Crise vaso-occlusive“ abkürzen?
Other adhesive interactions require a soluble bridge molecule eg, thrombospondin, VWF. Circulating endothelial cells characterized by an activated phenotype expression of VCAM-1 and E-selectin and increased levels of plasma sVCAM-1 have also been reported and are reflective of continuous endothelial activation. SCD mice indeed exhibit a more dramatic VOC phenotype when the experiment is carried out at nighttime. Circulating leukocytes and platelets also have an activated phenotype. Ischemia-reperfusion injury, release of free hemoglobin and heme secondary to RBC lysis, and increased production of placental growth factor PlGF all may contribute to the inflammatory vasculopathy. Intravascular hemolysis results in release of cell free hemoglobin in the plasma, translocation of hemoglobin to the spaces between the endothelium and the smooth muscle cells, nitric oxide depletion in the plasma and subendothelial spaces, oxidative stress, and hemin release that contribute to the inflammation. Reduction of plasma levels of tissue factor in a sickle cell transgenic mouse model results in decreased plasma levels of IL-6 and soluble VCAM
What Is a Vaso-Occlusive Crisis?
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