MICROANGIOPATHIC HAEMOLYTIC ANAEMIA

Summary

Microangiopathic hemolytic anemia (MAHA) is a condition where red blood cells are mechanically fragmented in the microvasculature due to endothelial injury. This leads to platelet-rich microthrombi formation and shearing of red blood cells, which results in peripheral blood schistocytes. MAHA is characterized by thrombocytopenia and can occur in conditions like thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), and preeclampsia. The breakdown of red blood cells leads to the release of lactate dehydrogenase, bilirubin, and hemoglobin. Treatment is focused on addressing the underlying cause and may include supportive care and transfusions.

Takeaways

• 😀 Microangiopathic Hemolytic Anemia (MAHA) is caused by the mechanical fragmentation of red blood cells in small blood vessels.
• 😀 MAHA is characterized by endothelial injury in the microvasculature, leading to platelet-rich microthrombi formation.
• 😀 The fragmentation of red blood cells results in schistocytes, which can be observed in peripheral blood smears.
• 😀 The breakdown of red blood cells releases substances like lactate dehydrogenase (LDH) and unconjugated bilirubin into the blood.
• 😀 Free hemoglobin is released into the plasma and may appear as pink or dark-colored urine due to hemoglobinuria.
• 😀 Thrombocytopenia (low platelets) is a common feature of MAHA due to the formation of platelet-rich clots.
• 😀 The body compensates for red blood cell loss by releasing young red cells (reticulocytes) into circulation.
• 😀 MAHA can be caused by several conditions, including Thrombotic Thrombocytopenic Purpura (TTP), Hemolytic Uremic Syndrome (HUS), and pre-eclampsia/eclampsia.
• 😀 Other causes of MAHA include vasculitis, Scleroderma renal crisis, antiphospholipid syndrome, and certain medications.
• 😀 Treatment for MAHA depends on the underlying cause and may involve supportive care, transfusions, and management of the primary disease.

Q & A

What causes microangiopathic hemolytic anemia (MAHA)?

MAHA is caused by mechanical red blood cell (RBC) fragmentation in the microvascular system, resulting from endothelial injury that leads to the formation of platelet-rich microthrombi.

How does endothelial injury contribute to MAHA?

Endothelial injury in the microvasculature leads to intravascular clotting and platelet activation, which results in fibrin strand formation, creating platelet-rich microthrombi that shear RBCs.

What are schistocytes, and how are they related to MAHA?

Schistocytes are fragmented RBCs that appear on a peripheral blood film in MAHA. They are the result of mechanical RBC fragmentation as blood passes through platelet-rich microthrombi in damaged microvasculature.

What substances are released when RBCs are broken down in MAHA?

When RBCs are broken down in MAHA, substances like lactate dehydrogenase (LDH), unconjugated bilirubin, and hemoglobin are released. Hemoglobin can appear in the plasma and urine, turning them pink or dark.

What is the significance of unconjugated bilirubin in MAHA?

Unconjugated bilirubin is released from RBC breakdown in MAHA and is not processed by the liver, making it appear in the bloodstream as indirect bilirubin. It contributes to jaundice and other symptoms.

Why does MAHA lead to thrombocytopenia?

Thrombocytopenia in MAHA is caused by the consumption of platelets in the formation of microthrombi, which leads to a reduced platelet count in the circulation.

How does the body compensate for RBC loss in MAHA?

The body compensates by releasing young, immature RBCs (reticulocytes) into circulation, leading to increased reticulocytosis, which is a response to the anemia.

What conditions can cause MAHA?

MAHA can be caused by conditions such as thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), malignant hypertension, preeclampsia, eclampsia, vasculitis, antiphospholipid syndrome, disseminated intravascular coagulation (DIC), certain cancers, and complications from organ transplants and medications.

How is MAHA diagnosed?

MAHA is typically diagnosed through a peripheral blood film, where schistocytes can be observed. Additional laboratory tests to assess LDH levels, bilirubin levels, and haptoglobin can also aid in diagnosis.

What is the treatment for MAHA?

Treatment for MAHA depends on the underlying cause, and it may involve supportive care, transfusions, and therapies specific to the condition, such as addressing endothelial injury or clot formation.