What are the causes of microangiopathic hemolytic anaemia (MAHA)?

Causes of microangiopathic hemolytic anaemia (MAHA)

  • Hemolytic uremic syndrome (HUS)
  • Thrombotic thrombocytopenic purpura (TTP)
  • Accelerated hypertension
  • Septicaemia
  • Vasculitides
  • Connective tissue diseases
  • Malignancy ( Approx 80% are Mucinous adenocarcinoma of either stomach, breast or lungs)
  • Burns
  • Prosthetic valve-induced hemolysis
  • Drugs (ciclosporin, mitomycin)

● MAHA is also known as fragmentation hemolytic anaemia

●RBC fragmentation & hemolysis occur when red cells are forced at high shear stress through the partial vascular occlusion or over abnormal vascular surfaces

●MAHA produces a characteristic blood picture of anaemia, red cell fragments (known as "Split" red cells or schistocytes), thrombocytopenia and increased reticulocytes

● Considerable quantities of LDH are released into the blood from the traumatised RBCs

● Small vessels fibrin deposition and thrombosis, resulting from MAHA may lead to renal damage and oliguric renal failure

●Bleeding and bruising are commonly seen. In pure MAHA, the blood clotting mechanism is usually normal but if often coexists with DIC where clotting is impaired.

☆ MAHA is found in association with some cancers 

Cancers associated with MAHA

Mechanism of occurrence of MAHA in malignancies: Two mechanisms 

1. DIC with intravenous occlusion (often partial) of small vessels by platelet-fibrin thrombi 
2. Intravascular tumour emboli 

• Rapid review of clinical medicine for MRCP part 2, 2nd Edition, by Sanjay Sharma and Rashmi Kaushal Q:152
• Williams Hematology 9th Edition; page 801 & 803

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