Signs of anemia - Hemolytic anemia
Signs of anemia - Hemolytic anemia
Hemolytic anemia is a reduction of the life span of the erythrocytes or red blood cell < than 120 days as a result of premature erythrocyte breakdown. The patient appear to be anemic.
The causes of hemolytic anemia can be hereditary or acquired. The hereditary causes includes hereditary spherocytosis and elliptical erythrocytes or elliptocytosis as a result of red cell membrane defect. Hereditary spherocytosis is an autosomal dominant disorder which leads to reduction in production of spectrin which is a structural membrane protein. This will leads to the deformation of erythrocyte or red blood cells.
Other inherited causes include glucose 6 phosphate deficiency ( G6PD) and pyruvate kinase deficiency which also known as metabolic defect . Glucose 6 phosphate deficiency ( G6PD) is a sex linked disorder . It is precipitate by fava bean, dapsone , nitrofurantoin , and sulphonamides. Glucose 6 phosphate ( G6P) is useful to maintain glutathione in a reduced states and involves in the hexose monophosphate shunts. In G6PD , it will leads to susceptibility to oxidative stress. Haemoglobinopathies such as Thalassemia and sickle cell anemia may also causes hemolytic anemia.
The acquired causes of hemolytic anemia may include immune and non immune causes . Immune causes can be divided onto autoimmune and isoimmune. Autoimmune causes are related to warm antibodies and cold antibodies. Warm antibodies ( IgG) bind to agglutinates the red blood cell / erythrocytes at 37 C and leads to intravascular and extravascular hemolysis on the spleen . It may causes by SLE, lymphoma and methyldopa. The cold antibodies ( IgM) which is associated with lymphoma, mycoplasma infection and EBV infection will bind to the red blood cell / erythrocytes and causes intravascular and extravascular hemolysis on the spleen.
The isommune causes may include transfusion reaction and hemolytic disease of the newborn which may leads to hemolytic anemia. Certain drug such as penicillin and quinine may leads to drug - antibody - erythrocytes complex and finally leads to hemolytic anemia.
Other causes may include trauma, infection and paroxysmal nocturnal hemoglobinuria . Trauma may includes microangiopathic hemolytic anemia associated with DIC , hemolytic uremic syndrome, malignant hypertension and pre eclampsia. Microangiopathic hemolytic anemia is associated with fragmentation of red cell in abnormal circulation. Insertion of artificial heart valve may also leads to hemolytic anemia. Malarial and sepsis may contributes to hemolytic anemia and paroxysmal nocturnal hemoglobinuria which is an increase in the lysis of red blood cell / erythrocytes by complement due to reduction in complement degrading protein and decrease in synthesis of protein cellular anchor.
In term of epidemiology inherited cases of hemolytic anemia are common and prevalent in middle east, african and mediterranean. Hereditary spherocytosis which is one of the cause of hemolytic anemia is common in northern europe . Generally hemolytic anemia is common.
Patient may present with anemia, hematuria and jaundice. It is important to ask patient regarding drug history, family history, and travel history .On examination, patient may present with jaundice , pallor ( anemia ) and hepatomegaly and splenomegaly.
The investigation may include full blood count, blood film, urine test, Direct Coomb test, osmotic fragility test and spectrin mutation analysis, Hb electrophoresis and enzyme assays, Ham’s test and bone marrow trephine biopsy.
The full blood test may reveals reduction in Hb ( hemoglobin ), increase in reticulocytes , increase in MCV, increase in unconjugated bilirubin and decrease in haptoglobin . Further test may include blood film. Blood film may reveals leucoerythroblastic picture, nucleated reticulocytes and erythrocytes, macrocytosis and polychromasia. Blood film may also reveals an abnormal cells such as malarial parasites , fragmented red blood cell, erythrocytes Heinz bodies ( it is a denatured Hb, stained with methyl violet present in G6PD ) sickle cell, elliptocytosis and spherocytosis.
Urine test may reveal the present of urobilirubinogen. Hemoglobinuria or hemosiderinuria may present in case of intravascular hemolysis . Direct Coomb test is useful in autoimmune cases of hemolytic anemia. It able to detect erythrocytes coated with antibodies ( warm / cold agglutinins.) by using anti human globulin.
The spectrin mutant analysis and osmotic fragility test are useful to detect any membrane defect or abnormalities while Ham’s test is useful to detect paroxysmal nocturnal hemoglobinuria with lysis of erythrocytes in acidified serum. Enzyme assay and Hb electrophoresis to exclude other causes. Bone marrow biopsy in case of bone marrow aplasia.
The treatment may includes avoiding any contributing factor such as cold condition in case of cold agglutinin and treat any underlying causes. In case of spherocytosis consider lifetime penicillin treatment, folate supplement and vaccination against encapsulated microorganism such as haemophillus influenza, meningococcus and pneumococcus. Splenectomy may require but postponed until > 5 years.
Autoimmune cases that involves warm agglutinins involve treatment with azathioprine, cyclophosphamide, prednisolone, and splenectomy . In case of paroxysmal hemoglobinuria , treatment include blood transfusion ( leucocyte depletion ) , anti coagulant ( warfarin ) if thrombosis develop and bone marrow transplantation which appear to be successful in some case.
In term of complication , most cases of hemolytic anemia may leads to renal failure. In specific case such as spherocytosis, it will leads to gallstone formation, hemolytic crises, megaloblastic anemia, leg ulcer and aplastic anemia. Paroxysmal nocturnal hemoglobinuria may leads to aplastic anemia and leukemia.
In term of prognosis, the patient may lead a normal life and normal life expectancy. There is a reduction in life expectancy in cases such as beta thalassemia, sickle cell anemia and paroxysmal nocturnal hemoglobinuria.
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