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Questions and Answers
Haemolytic anaemia occurs when mature red cells are destroyed faster than they can be made.
Haemolytic anaemia occurs when mature red cells are destroyed faster than they can be made.
True
Chronic disease is a cause of haemolytic anaemia.
Chronic disease is a cause of haemolytic anaemia.
False
Increased levels of bilirubin and LDH in the blood can indicate haemolysis.
Increased levels of bilirubin and LDH in the blood can indicate haemolysis.
True
Rapid haemolysis is a condition that does not require emergency management.
Rapid haemolysis is a condition that does not require emergency management.
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Autoimmune hemolytic anaemia can be caused by IgM autoantibodies during cold agglutinin disease.
Autoimmune hemolytic anaemia can be caused by IgM autoantibodies during cold agglutinin disease.
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Hereditary spherocytosis is an extrinsic cause of haemolytic anaemia.
Hereditary spherocytosis is an extrinsic cause of haemolytic anaemia.
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Peripheral blood smear may show spherocytes in autoimmune hemolytic anaemia.
Peripheral blood smear may show spherocytes in autoimmune hemolytic anaemia.
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Thalassaemia is an example of an abnormality intrinsic to red cells that can cause haemolytic anaemia.
Thalassaemia is an example of an abnormality intrinsic to red cells that can cause haemolytic anaemia.
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A positive DAT indicates the presence of warm autoimmune hemolytic anemia if IgG and/or C3 are positive.
A positive DAT indicates the presence of warm autoimmune hemolytic anemia if IgG and/or C3 are positive.
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In cold autoimmune hemolytic anemia, the DAT shows IgG and C3.
In cold autoimmune hemolytic anemia, the DAT shows IgG and C3.
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Sickle cell disease is caused by a mutation replacing valine for glutamic acid.
Sickle cell disease is caused by a mutation replacing valine for glutamic acid.
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Sickle RBCs can last in circulation for 30-40 days.
Sickle RBCs can last in circulation for 30-40 days.
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Sickle cell trait refers to the co-inheritance of HbS and another abnormal β chain variant.
Sickle cell trait refers to the co-inheritance of HbS and another abnormal β chain variant.
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Increased blood viscosity due to sickle cell disease can lead to tissue hypoxia.
Increased blood viscosity due to sickle cell disease can lead to tissue hypoxia.
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Thalassemia major features abnormal globin chain synthesis but normal globin chains.
Thalassemia major features abnormal globin chain synthesis but normal globin chains.
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Hypoxia, infection, and dehydration can trigger sickling in sickle cell disease.
Hypoxia, infection, and dehydration can trigger sickling in sickle cell disease.
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Autoimmune hemolytic anemia is primarily caused by IgG autoantibodies.
Autoimmune hemolytic anemia is primarily caused by IgG autoantibodies.
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Increased destruction of red blood cells is not considered a cause of anemia.
Increased destruction of red blood cells is not considered a cause of anemia.
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Thalassemia results from an extrinsic abnormality affecting red blood cells.
Thalassemia results from an extrinsic abnormality affecting red blood cells.
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Reticulocytosis is a potential diagnostic indicator of autoimmune hemolytic anemia.
Reticulocytosis is a potential diagnostic indicator of autoimmune hemolytic anemia.
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Cold antibody AIHA is caused by an IgG autoantibody.
Cold antibody AIHA is caused by an IgG autoantibody.
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Sickle cell disease can cause life-threatening rapid hemolysis requiring emergency management.
Sickle cell disease can cause life-threatening rapid hemolysis requiring emergency management.
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Peripheral blood smear in autoimmune hemolytic anemia may reveal fragmented red blood cells.
Peripheral blood smear in autoimmune hemolytic anemia may reveal fragmented red blood cells.
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Warm antibody autoimmune hemolytic anemia is often associated with infections.
Warm antibody autoimmune hemolytic anemia is often associated with infections.
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Thalassaemia major is characterized by a normal rate of globin chain synthesis.
Thalassaemia major is characterized by a normal rate of globin chain synthesis.
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Sickle cell disease can cause vascular occlusion due to the rigidity of sickle-shaped red blood cells.
Sickle cell disease can cause vascular occlusion due to the rigidity of sickle-shaped red blood cells.
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The sickle cell disease mutation results in an increase of HbA levels in the bloodstream.
The sickle cell disease mutation results in an increase of HbA levels in the bloodstream.
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In sickle cell trait, an individual inherits two genes encoding for HbS.
In sickle cell trait, an individual inherits two genes encoding for HbS.
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Osteomyelitis can occur as a complication of sickle cell disease due to the high risk of infections.
Osteomyelitis can occur as a complication of sickle cell disease due to the high risk of infections.
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Cold autoimmune hemolytic anemia is indicated by a positive direct Coombs test showing IgG and C3.
Cold autoimmune hemolytic anemia is indicated by a positive direct Coombs test showing IgG and C3.
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Sickle cells usually have a lifespan of 10-20 days in circulation.
Sickle cells usually have a lifespan of 10-20 days in circulation.
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Chronic hemolytic anemia occurs in both sickle cell disease and thalassemia.
Chronic hemolytic anemia occurs in both sickle cell disease and thalassemia.
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Haemolytic anaemia can be asymptomatic until haemoglobin levels rise to dangerously high levels.
Haemolytic anaemia can be asymptomatic until haemoglobin levels rise to dangerously high levels.
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Thalassaemia is associated with an extrinsic deficiency affecting red blood cells.
Thalassaemia is associated with an extrinsic deficiency affecting red blood cells.
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The presence of spherocytes in a peripheral blood smear is indicative of autoimmune hemolytic anemia.
The presence of spherocytes in a peripheral blood smear is indicative of autoimmune hemolytic anemia.
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Rapid haemolysis can be life-threatening and does not require immediate medical attention.
Rapid haemolysis can be life-threatening and does not require immediate medical attention.
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Cold antibody autoimmune hemolytic anemia is primarily caused by IgM autoantibodies.
Cold antibody autoimmune hemolytic anemia is primarily caused by IgM autoantibodies.
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Sickle cell disease can lead to chronic anemia due to increased red blood cell production.
Sickle cell disease can lead to chronic anemia due to increased red blood cell production.
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G-6PD deficiency is classified as an extrinsic cause of haemolytic anaemia.
G-6PD deficiency is classified as an extrinsic cause of haemolytic anaemia.
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Autoimmune hemolytic anemia may show reticulocytosis in laboratory tests.
Autoimmune hemolytic anemia may show reticulocytosis in laboratory tests.
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Sickle cell disease can be precipitated by hypoxia, acidosis, and hypotension.
Sickle cell disease can be precipitated by hypoxia, acidosis, and hypotension.
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In sickle cell disease, sickle RBCs develop a crescent shape due to the crystallization of insoluble chains in the deoxygenated state.
In sickle cell disease, sickle RBCs develop a crescent shape due to the crystallization of insoluble chains in the deoxygenated state.
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Thalassaemia major is characterized by an excess of globin chain synthesis.
Thalassaemia major is characterized by an excess of globin chain synthesis.
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Sickle cell disease is solely inherited through a single abnormal β-chain variant.
Sickle cell disease is solely inherited through a single abnormal β-chain variant.
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In acute episodes of sickle cell disease, red blood cells can last up to 30 days in circulation.
In acute episodes of sickle cell disease, red blood cells can last up to 30 days in circulation.
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Gall stones and renal failure are complications associated with sickle cell disease.
Gall stones and renal failure are complications associated with sickle cell disease.
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The sickle cell disease mutation leads to increased levels of HbA in the bloodstream.
The sickle cell disease mutation leads to increased levels of HbA in the bloodstream.
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A direct Coombs test positive for IgM indicates cold autoimmune hemolytic anemia.
A direct Coombs test positive for IgM indicates cold autoimmune hemolytic anemia.
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Study Notes
Haemolytic Anaemia
- Haemolytic anaemia is when mature red blood cells are destroyed faster than they can be made.
- This results in high levels of bilirubin and LDH in the bloodstream.
- Haemolytic anaemia can be asymptomatic until haemoglobin levels are dangerously low.
- Rapid Haemolysis can be life-threatening and requires emergency management.
Causes of Haemolytic Anaemia
-
Intrinsic Abnormalities of Red Blood Cells:
- Hereditary Spherocytosis
- Sickle Cell Disease
- Thalassaemia
- G-6PD Deficiency
-
Extrinsic Abnormalities of Red Blood Cells:
- Immune
- Mechanical
Autoimmune Haemolytic Anaemia (AIHA)
-
Types:
- Warm antibody AIHA - caused by an IgG autoantibody, associated with illnesses like Lymphoma, CLL, and collagen vascular diseases.
- Cold antibody AIHA - caused by an IgM autoantibody, seen in cold agglutinin diseases, mycoplasma, and EBV infections.
-
Diagnosis:
- Reticulocytosis, elevated LDH, and indirect hyperbilirubinaemia.
- Peripheral blood smear shows spherocytes and fragmented RBCs.
- Positive DAT (direct Coombs test)
- Warm AIHA: IgG+ and/or C3+
- Cold AIHA: IgG- and C3+
History Taking in Haemolytic Anaemia
- Symptoms: similar to other causes of anaemia but with a more rapid onset.
- Infectious Symptoms: cough, fevers, recent contact with illness.
- Recent Medication: new medications or over-the-counter drugs.
- Recent Travel: potential exposure to malaria.
- Family History: relevant to inherited conditions.
- Previous Transfusions: crucial to check for previous transfusions, even if it was a distant or unknown history.
Inherited Haemoglobin Defects
- Abnormal genetic code in haemoglobin.
- Sickle cell disease mutation:
- Thalassaemia major and minor: Globin chains are normal but the rate of synthesis is reduced.
- Accumulation of abnormal chains leads to structural defects.
Sickle Cell Disease Mutation
- In sickle cell disease, there is a valine for glutamic acid mutation in haemoglobin.
- This leads to increased HbS with RBC aggregation at low oxygen tensions.
Sickle Cell Disease
- Sickle Cell Anaemia: coinheritance of HbS and another abnormal β chain variant.
- Sickle Cell Trait: inheritance of one gene encoding for HbS.
Sickle Cell Disease Inheritance
- It is an autosomal recessive condition.
- Requires inheritance of two copies of the gene to develop sickle cell anaemia.
Sickle Cell Disease Pathology
- Chronic Haemolytic Anaemia
- HbS in deoxygenated state is 50 times less soluble than HbA.
- Insoluble chains crystallize in the red cells, distorting the membrane and causing the cells to become crescent-shaped.
- Sickle RBCs only last 10-20 days.
- Deformed cells are more rigid and cannot pass microcirculation.
- This causes vascular occlusion, leading to tissue hypoxia.
Sickle Cell Disease Clinical Features
- Recurring episodes of severe pain in the limbs: due to vascular occlusion and tissue hypoxia.
-
Precipitating Factors:
- Hypoxia
- Acidosis
- Hypotension
- Infection
- Dehydration
- Hypothermia
Other Complications of Sickle Cell Disease
- Osteomyelitis (infected bones)
- Gall stones
- Renal failure
- Cardiac failure
- Chronic leg ulcers
Haemolytic Anaemia
-
Haemolytic anaemia is a condition where mature red blood cells are destroyed at a faster rate than they can be produced.
-
This can lead to high levels of bilirubin and LDH in the bloodstream which can be detected in blood tests.
-
Haemolytic anaemia can go unnoticed until haemoglobin levels are dangerously low.
-
Rapid haemolysis can be life-threatening and requires urgent medical attention.
Classification of Haemolytic Anaemia
-
Haemolytic anaemia can be classified into immune and non-immune.
-
Immune: This type is caused by the body's immune system attacking red blood cells.
-
Non-immune: This type is caused by factors intrinsic or extrinsic to red blood cells.
Causes of Non-Immune Haemolytic Anaemia
-
Intrinsic to red blood cells:
- Hereditary spherocytosis
- Sickle Cell Disease
- Thalassaemia
- G-6PD deficiency
-
Extrinsic to red blood cells:
- Immune
- Mechanical
Immune Haemolytic Anaemia
-
Warm antibody AIHA is caused by IgG autoantibodies and can be associated with conditions like lymphoma, CLL, and collagen vascular diseases.
-
Cold antibody AIHA is caused by IgM autoantibodies and can occur in conditions like cold agglutinin disease, Mycoplasma infection, and EBV infection.
-
Diagnosis of AIHA includes:
- Reticulocytosis
- Elevated LDH
- Indirect hyperbilirubinaemia
- Peripheral blood smear may show spherocytes, occasional fragmented RBCs
- Positive DAT (direct Coombs test)
- Warm AIHA: IgG+ and/or C3+
- Cold AIHA: IgG- and C3+
History Taking in Haemolytic Anaemia
- Look for symptoms common to other causes of anaemia, but with a shorter onset.
- Look for recent infectious symptoms,
- cough, fevers, or contact with ill individuals
- Look for recent use of medication, including over the counter products
- Look for recent travel, particularly to areas where malaria is present
- Assess family history for haemolytic anaemia
- Assess previous transfusions - this information is critical and may be from unknown or distant history, so check with your lab.
Inherited Haemoglobin Defects
- Inherited haemoglobin defects are caused by abnormal genetic code in haemoglobin.
- Examples include sickle cell disease and thalassaemia.
Sickle Cell Disease
- Sickle cell anaemia involves coinheritance of the HbS gene and another abnormal β chain variant.
- Sickle cell trait involves inheritance of a single HbS gene.
- The sickle cell disease mutation involves a substitution of valine for glutamic acid, which causes increased HbS and red blood cell (RBC) aggregation at low oxygen tensions.
Sickle Cell Disease Inheritance
- Sickle cell disease is an autosomal recessive disorder.
Sickle Cell Disease Pathology
- Sickle cell disease is a chronic haemolytic anaemia.
- HbS in a deoxygenated state is 50 times less soluble than HbA.
- The insoluble chains crystallise within red blood cells, distorting the membrane and leading to a crescent shaped cell appearance.
- Sickle red blood cells have a shortened lifespan of only 10 to 20 days.
- The deformed cells are more rigid, making them unable to pass through the microcirculation.
- This leads to vascular occlusion.
- Structural changes and increased blood viscosity contribute to venous stasis, local obstruction, and tissue hypoxia, which worsens sickling and leads to tissue infarction.
Other Complications of Sickle Cell Disease
- Osteomyelitis (infected bones)
- This happens because the sickle cells are more prone to getting stuck in small blood vessels, making it easier for bacteria to enter bones.
- Gallstones
- These are due to increased bilirubin levels in the bile from haemolysis.
- Renal failure
- Damage to the kidneys can occur due to repeated episodes of sickling in the small blood vessels of the kidneys leading to decreased blood flow.
- Cardiac failure
- High blood pressure and increased workload on the heart due to sickling in the small blood vessels of the heart.
- Chronic leg ulcer
- These may occur because of poor circulation due to sickling in the legs.
Triggers for Sickle Cell Crisis
- Sickling can be spontaneous but can also be triggered by:
- Hypoxia
- Acidosis
- Hypotension
- Infection
- Dehydration
- Hypothermia
- Therefore, these factors should be investigated when a sickle cell crisis occurs.
Thalassaemia
- Thalassaemia is a group of genetic disorders that affect the production of haemoglobin.
- It is caused by a reduction in the synthesis of one or more globin chains, which leads to abnormal haemoglobin production and red blood cell destruction.
- There are two main types of thalassaemia:
- Alpha-thalassaemia
- Beta-thalassaemia
Alpha-thalassaemia
- This is characterized by a deficiency in the production of alpha globin chains.
- Depending on the severity, it can range from mild to fatal.
Beta-thalassaemia
- This is characterized by a deficiency in the production of beta globin chains.
- It can be further classified into:
- Beta-thalassaemia minor (heterozygous)
- This is a mild form with few symptoms.
- Beta-thalassaemia major (homozygous)
- This is a severe form that often requires lifelong blood transfusions.
- Beta-thalassaemia minor (heterozygous)
Key Points to Remember
- Haemolytic Anaemia: A condition where red blood cells are destroyed faster than they can be made.
- AIHA: Immune-mediated destruction of red blood cells.
- Sickle Cell Disease: Caused by a mutation in the haemoglobin gene, leading to abnormal red blood cell shape and function.
- Thalassaemia: A group of genetic disorders that affect the production of haemoglobin.
Haemolytic Anaemia
- Mature red blood cells are destroyed quicker than they can be made.
- Haemolysis is the process of red blood cell destruction.
- Haemolysis can result in high levels of bilirubin and LDH in the bloodstream.
- Haemolytic anaemia can be asymptomatic until haemoglobin levels are dangerously low.
- Rapid haemolysis can be life-threatening and requires urgent medical attention.
Causes of Haemolytic Anaemia
- Abnormality intrinsic to red cells:
- Hereditary spherocytosis
- Sickle cell disease
- Thalassaemia
- G-6PD deficiency
- Abnormality extrinsic to red cells:
- Immune
- Mechanical
Autoimmune Haemolytic Anaemia (AIHA)
- Warm antibody AIHA is caused by an IgG autoantibody.
- Associated with lymphoma, CLL, collagen vascular diseases.
- Cold antibody AIHA is caused by an IgM autoantibody.
- Seen in cold agglutinin diseases, mycoplasma, and EBV infections.
- Diagnosis:
- Reticulocytosis, elevated LDH, and indirect hyperbilirubinaemia.
- Peripheral blood smear may show spherocytes and occasional fragmented RBCs.
- Positive direct Coombs test (DAT):
- Warm AIHA: IgG+ and/or C3+
- Cold AIHA: IgG- and C3+
Inherited Haemoglobinopathies
- Abnormal genetic code in haemoglobin:
- Sickle cell disease mutation: Valine replaces glutamic acid, leading to increased HbS with RBC aggregation at low oxygen tensions.
- Thalassaemia: Globin chains are normal but the synthesis rate is reduced. Accumulation of abnormal chains leads to structural defects.
Sickle Cell Disease
- Sickle cell anaemia: Coinheritance of HbS and another abnormal β chain variant.
- Sickle cell trait: Inheritance of one gene encoding for HbS.
- HbS in a deoxygenated state is 50 times less soluble than HbA.
- Insoluble HbS chains crystallise in the red cells, distorting the membrane and causing the cell to become crescent-shaped (sickle).
- Sickle RBCs have a lifespan of only 10-20 days.
- Deformed cells are more rigid and cannot pass through the microcirculation, leading to vascular occlusion.
- Structural change and increased blood viscosity cause venous stasis, local obstruction, tissue hypoxia, more sickling, and tissue infarction.
Sickle Cell Disease: Precipitating Factors
- Sickling can be spontaneous.
- Factors that can precipitate sickling:
- Hypoxia
- Acidosis
- Hypotension
- Infection
- Dehydration
- Hypothermia
- Look for precipitating features in patients with SCD.
Other Complications of SCD
- Osteomyelitis (infected bones)
- Gallstones
- Renal failure
- Cardiac failure
- Chronic leg ulcers.
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Description
This quiz explores haemolytic anaemia, a condition characterized by the rapid destruction of red blood cells. Participants will learn about its causes, including intrinsic and extrinsic factors, and the different types of autoimmune haemolytic anaemia. Enhance your understanding of this critical medical condition and its management.
