Haemolytic Anaemia Flashcards
Two Types of Haemolytic Anaemia
Hameolytic anaemia occurs when erythropoiesis < haemolysis
If it happens in the circulation = intravascular
If haemolysis happens in the reticuloendothelial system = extravascular
Classification of Haemolytic Anaemia Aetiology
Aetiologies of haemolytic anaemia can be divided into two categories
1) Extrinsic- source outside of RBC
2) Intrinsic- source inside of RBC
Autoimmune Haemolytic Anaemia
- Extrinsic or Intrinsic?
- Pathophysiology and Causes
- Diagnosis
Type 2 hypersensitivity reaction
Causes: idiopathic, infections (EBV, syphyllis, mycoplasma), neoplasms, autoimmune diseases (SLE, RA and UC), drugs (penicilin, alpha-methyldopa)
Coombs +ve
Types of Autoimmune Haemolytic Anaemia and Treatment
Two types of AIHA
1) Warm AIHA by IgG antibodies. Treatment w/ glucocorticoids, immunosuppressants, +/- splenectomy
2) Cold AIHA by IgM antibodies. Presents w/ acrocyanosis that resolves on warming up. Treatment: avoid cold.
Microangiopathic Anaemia
- Extrinsic or Intrinsic?
- Pathophysiology
- Assoc. conditions
- Treatment
Mechanical destruction of RBCs in systemic circulation –> schistiocytes on blood smear.
Assoc. w/ DIC, TTP, HUS, SLE, malignant HTN, pre-eclampsia and eclampsia
Treatment: address underlying cause, supportive management
Macroangiopathic Anaemia
- Extrinsic or intrinsic?
- Pathophysiology and assoc. conditions
- Treatment
Destruction of RBCs in systemic circulation, in large vessels or in heart.
Assoc. w/ mechanical heart valves and stenotic valves (e.g. aortic stenosis)
Blood smear: schistiocytes and echinocytes
Rx. chronic blood transfusions for anaemic episodes, repair/replacement of valves
What infections can cause haemolytic anaemia?
-Extrinsic or Intrinsic?
Malaria and babesiosis
-haemoglobinuria seen
Hereditary Elliptocytosis
- Mode of inheritance
- Presentation
AD inheritance
Mostly asymptomatic, but 10% have severe form –> death in utero.
Protective against malaria
Hereditary Spherocytosis
- Mode of inheritance
- Pathophysiology
- Presentation
- Diagnosis
- Treatment
AD inheritance.
Defect in RBC membrane protein produces spherocytes. Lower SA and higher fragility so get trapped in spleen –> premature removal
Presents w/ jaundice, splenomegaly and pigmented gallstones
+ve osmotic fragility test
Rx. folate supplementation, RBC transfusion and splenectomy
Paroxysmal Nocturnal Haemoglobinuria (PNH)
- Mutation and Pathophysiology
- Presentation
- Diagnosis
- Treatment
Mutation in haematopoeitic stem cells (PIG-A gene) leads to missing RBC surface protein. Causes complement-mediated destruction.
Presents w/ haematuria, mucosal bleeding + petechiae, infections, thrombosis and renal impairment
Diagnosis: flow cytometry CD55/59 -ve RBCs
Rx. bone marrow transplant, anticoagulants, folate, Eculizumab (inhibits C5)
Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency
- Mode of Inheritance and Pathophysiology
- Oxidative Stressors
- Peripheral Blood Smear
- Treatment
X-linked disorder which affects the pentose pathway. Causes reduction in gluthione –> precipitation of Hb.
Asymptomatic until exposed to oxidative stressors:
Drugs- primaquine, sulfonamides
Fava beans
Infections
Peripheral blood smear: heinz bodies and bite cells
Rx. avoid stressors
Pyruvate Kinase Deficiency
- Mode of Inheritance
- Pathophysiology
- Presentation
- Treatment
AR inheritance
ATP production reduced causing reduced RBC survival.
Homozygotes present w/ neonatal jaundice, later haemolysis and splenomegaly
Rx. blood transfusions, iron chelation +/- splenectomy
Which haemoglobinopathies can cause haemolytic anaemia?
Thalassaemia
Sickle Cell
HbC
Extravascular Haemolysis Features (Labs and Presentation)
L Hb and haptoglobin
H LDH and UCB
Jaundice and Splenomegaly
Presentation of Intravascular Haemolysis
L Hb, haptoglobin
H LDH, UCB
Some Hb remains in circulation and binds albumin: H methaealbuminaemia
Some enters kidneys and is excreted directly: haemoglobinuria
Some enters kidneys and is converted to haemosiderin: haemosiderinuria
