haemolytic anaemias

Question 1

define haemolytic anaemia

Answer 1

anaemia due to shortened RBC survival

Question 2

describe haemolysis

Answer 2

shortened RBC survival to 30-80 days
compensation by bone marrow to increase production
increased young cells in circulation = reticulocytes / nucleated RBC

Question 3

findings for haemolytic anaemias

chronic findings

Answer 3

jaundice
pallor
fatigue
splenomegaly

chronic findings:
gallstones, leg ulcers, folate deficiency

Question 4

describe classification of haemolytic anaemia

Answer 4

1. inheritance
2. site of RBC destruction
3. origin of RBC damage

Question 5

describe intrinsic haemolytic anaemia

Answer 5

membrane defects = spherocytosis/elliptocytosis

enzyme defects = G6PD, PK

haemoglobin defects = sickle cell, thalassaemia

Question 6

describe extrinsic haemolytic anaemia

Answer 6

immune mediated

• autoimmune = warm/cold = drug induced
• alloimmune = HDN, haemolytic transfusion

non immune

• red cell fragmentation
• mechanical trauma
• drugs and chemicals
• infections
• march haemoglobulinuria

Question 7

describe membrane disorders

Answer 7

proteases in membrane
hereditary spherocytosis most common membrane disorder (vertical interaction)
horizontal interaction = hereditary ellipocytosis

Question 8

describe the clinical features of hereditary spherocytosis

Answer 8

asymptomatic to severe haemolysis 
neonatal jaundice 
splenomegaly = enlarged spleen cells 
pigment gallstones
reduced EMA binding = binds to band 3
positive family history 
negative direct antibody test

Question 9

describe pyruvate kinase deficiency

Answer 9

lack of ATP produced

Question 10

what is thalassaemia

Answer 10

imbalanced alpha and beta chain production
excess unpaired globin chains are unstable
ineffective erythropoeisis

Question 11

describe difference between beta thalassaemia major and minor

Answer 11

major = severe anaemia, progressive hepatosplenomegaly
bone marrow expansion
iron overload
intermittent infections

minor

• asymptomatic
• confused with fe deficiency
• HbA2 increased in beta trait

Question 12

describe alpha thalassaemia

Answer 12

3 types

1. Hb barts hydrops syndrome = deletion of all 4 globin genes/incompatible with life
2. HbH disease = deletion of 3/4 globin genes
   common in south east Asia
3. that trait = minor
   - normal/mild HA
   MCV and MCH low

Question 13

describe thalassaemia intermedia

Answer 13

clinical manifestations between major and minor 
transfusion independent 
diverse clinical phenotype 
varying symptoms 
increased bilirubin levels 
diagnosis = largely clinical

Question 14

describe sickle cell disease

Answer 14

inherited as a result of inherited HbS
HbS = caused by single nucelotide substitution

HbSS = SS anaemia 
HbAS = heterozygous

Question 15

features of Sickle cell disease

Answer 15

painful/aplastic crisis
infection due to hyposplenism
chest syndrome/splenic sequestration/stroke
renal failure/avascular necrosis bone

Question 16

describe diagnosis of sickle cell anaemia test

Answer 16

solubility test
- expose blood to reducing agent
HbS ppt = positive trait in disease