(See also Overview of Hemolytic Anemia Overview of Hemolytic Anemia At the end of their normal life span (about 120 days), red blood cells (RBCs) are removed from the circulation. Hemolysis is defined as premature destruction and hence a shortened RBC life span... read more .)
Excessive shear or turbulence in the circulation causes trauma to red blood cells (RBCs) in the peripheral blood, leading to fragmented RBCs (eg, triangles, helmet shapes) called schistocytes (see photo ). Schistocytes in the peripheral smear are diagnostic. Schistocytes cause high RBC distribution width, reflecting the anisocytosis.
Microangiopathic hemolytic anemia encompasses RBC fragmentation caused by microvascular injury as well as by mechanical devices. Causes of fragmentation hemolysis include
Disseminated intravascular coagulation Disseminated Intravascular Coagulation (DIC) Disseminated intravascular coagulation (DIC) involves abnormal, excessive generation of thrombin and fibrin in the circulating blood. During the process, increased platelet aggregation and coagulation... read more , a consumptive process secondary to other disorders such as sepsis, malignancy, pregnancy complications, trauma or surgery
Stenotic or mechanical heart valves, or prosthetic valve dysfunction (ie, perivalvular leak)
Hemolytic uremic syndrome Hemolytic-Uremic Syndrome (HUS) Hemolytic-uremic syndrome (HUS) is an acute, fulminant disorder characterized by thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney injury. HUS usually occurs in children... read more or related disorders such as the HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count), and systemic sclerosis renal crisis
Rare cases of significant repetitive impact, such as foot strike hemolysis (march hemoglobinuria), karate strikes, swimming, or hand drumming
Treatment addresses the underlying process. Iron deficiency anemia Iron Deficiency Anemia Iron deficiency is the most common cause of anemia and usually results from blood loss; malabsorption, such as occurs in celiac disease, is a much less common cause. Symptoms are usually nonspecific... read more occasionally is superimposed on the hemolysis as a result of chronic hemosiderinuria and, when present, responds to iron-replacement therapy. Keeping the hematocrit > 30 % can reduce hemolysis caused by turbulent flow.