What is the definition or description of: sickle cell crisis?

See below: The abnormal red blood cells, carrying an abnormal hemoglobin known as hemoglobin s, are fragile. A person who hassickle cell disease can become more likely to get infections because the damaged cells eventually clog the spleen. A severe attack, known as sickle cell crisis, can cause pain because blood vessels can become blocked or the defective red blood cells can damage organs in the body.

Usually pain.: There are several kinds of crises - pain or vaso-occlusive crisis (blood flow to an area is "clogged" by sickled cells leading to areas of cell death), splenic sequestration crisis (trapping of large volume of blood in the spleen), and aplastic crisis (life-threatening anemia caused by inability to make enough new red blood cells to keep up with the very short life span of sickled red cells).

Sickle crises: Simply put, sickle cell crises generally result from sickled red cells that occlude the small vasculature of various organs. The crises can take several forms depending on where the sickling is occuring usually the most severe in the lung: acute chest crisis; bones/muscles/soft tissue: pain crisis; spleen: splenic sequestration; kidney: papillary necrosis; fingers/toes: dactylitis.