Microangiopathic hemolytic anemia (MAHA) is caused by damage to red blood cells as they pass through abnormally narrowed or obstructed small blood vessels. This intravascular RBC fragmentation leads to non-immune hemolysis. Several factors can contribute to this vascular damage.
Common Causes of MAHA
- Disseminated Intravascular Coagulation (DIC): Widespread blood clotting throughout the body consumes clotting factors, leading to abnormal blood vessel occlusion and red blood cell damage.
- Hemolytic Uremic Syndrome (HUS): A condition characterized by hemolytic anemia, acute kidney failure, and low platelet count. It's often caused by bacterial toxins (like E. coli) damaging the endothelium of the blood vessels.
- Thrombotic Thrombocytopenic Purpura (TTP): Similar to HUS, TTP involves microthrombi formation, resulting in reduced platelet count and hemolytic anemia. Often due to a deficiency or defect of the ADAMTS13 enzyme.
- HELLP Syndrome: Hemolysis, elevated liver enzymes, and low platelet count, often associated with severe preeclampsia in pregnancy.
- Certain Drugs: Some medications can induce MAHA as a side effect.
- Intravascular Devices: Artificial devices like prosthetic heart valves or assist devices can cause abnormal shear stress within the blood vessels, leading to MAHA.
- Malignant Hypertension: Extremely high blood pressure can damage small blood vessels, causing MAHA and renal insufficiency.
- Autoimmune Conditions: Conditions such as vasculitis (inflammation of blood vessels) and lupus nephritis (kidney inflammation associated with lupus) can also trigger MAHA.
- Arteriolar stenosis/thrombosis: Narrowing or blockage of small arteries can cause abnormal shear stress and lead to MAHA.
Understanding MAHA
MAHA is a consequence rather than a single disease. It's a description of the mechanism of hemolysis, not a specific diagnosis. It is crucial to identify the underlying cause to provide appropriate treatment.
