Haemolysis Flashcards
What causes warm autoimmune hemolysis?
(1) IgG autoantibodies
(2) idiopathic
(3) linked to SLE, CLL, drugs, and infections.
(4) Occurs at ≥ 37°C.
Define Haemolysis
hola
Premature red cell destruction, can result in anaemia
What causes cold autoimmune hemolysis?
(1) IgM autoantibodies
(2) linked to infections (EBV, mycoplasma).
(3) Occurs at 0-10°C
(4) can angulate, cause holes in cell (MAC)
What causes alloimmune hemolysis?
The immune system attacks transfused red blood cells
What causes hemolytic transfusion reactions?
(1) Immediate (IgM) intravascular
(2) Delayed (IgG) extravascular
What is the hemolytic disease of the newborn?
Due to Rh or ABO incompatibility, or anti-Kell antibodies
What causes mechanical red cell destruction?
(1) DIC - Disseminated Intravascular Coagulation
(2) HUS - Hemolytic Uremic Syndrome
(3) TTP - Thrombotic Thrombocytopenic Purpura
(4) leaking heart valves
(5) malaria
(6) burns that physically damage red blood cells
What causes hereditary spherocytosis?
A genetic defect causes RBCs to be sphere-shaped instead of biconcave.
= Results in jaundice, and splenomegaly, and can lead to aplastic crises due to parvovirus B19 infection
What is G6PD deficiency?
X-linked condition causing hemolysis triggered by infection, drugs, or fava beans.
More common in Mediterranean/Middle Eastern populations
Why are RBCs particularly susceptible to damage?
Biconcave shape, lack of nucleus, limited metabolic reserve
What is compensated hemolysis?
Increased RBC destruction is matched by increased production, maintaining Hb levels
What is decompensated hemolysis?
RBC destruction exceeds bone marrow production, leading to low Hb levels
What are the consequences of hemolysis?
(1) Reticulocytosis
(2) Erythroid hyperplasia
(3) Excess bilirubin (jaundice, gallstones)
What happens in extravascular hemolysis?
RBCs are destroyed by spleen/liver macrophages
= Leads to jaundice and splenomegaly
What happens in intravascular hemolysis?
RBCs burst in circulation, releasing haemoglobin,
= Leads to hemoglobinemia and hemoglobinuria
What are the clinical features of hemolysis?
jaundice, dark urine (hemoglobinuria), fatigue
What tests confirm hemolysis?
(1) FBC
(2) Reticulocyte count
(3) Unconjugated bilirubin
(4) Blood film (spherocytes, Heinz bodies)
(5) Direct Coombs’ test
What does raised lactate dehydrogenase (LDH) indicate?
It suggests red cell destruction
How is hemolysis treated?
Corticosteroids for autoimmune
IV fluids for transfusion reactions