Haemolytic anaemia

Question 1

What are the 2 classes of haemolytic anaemia?

Answer 1

Acquired: AI, MAHA, Infection, Drugs
Congenital: Membrane defect, Metabolic defect, haemoglobinopathies

Question 2

What metabolic defect can cause haemolytic anaemia?

Answer 2

G6PD deficiency
Intravascular haemolysis
X-linked recessive (ONLY M)
Oxidative stressors precipitate haemolysis

Question 3

How can G6PD deficiency be detected?

Answer 3

Haemoglobinuria for days after oxidative stress

Blood film: Heinz bodies, Bite cells

Question 4

What membrane defect can cause haemolytic anaemia?

Answer 4

Hereditary spherocytosis: normal MCV, loss of central pallor
Extravascular haemolysis
Autosomal dominant

Question 5

How can hereditary spherocytosis be detected?

Answer 5

Osmotic fragility test: give hypotonic solution- RBC lysis

Coombs Test negative

Question 6

Why does Parvovirus B19 have life threatening implications in hereditary spherocytosis?

Answer 6

Can cause aplastic crisis:
Infects BM, preventing production of RBCs so have to rely on those already circulating
In HS lifespan of RBC is only 30 days- will quickly be deficient

Question 7

What type of haemolysis occurs in AI haemolytic anaemia? How is this detected?

Answer 7

Intravascular haemolysis
Coombs’ test
Warm agglutinins: IgG antibodies
Cold agglutinins: IgM antibodies

Question 8

What infection can cause haemolytic anaemia?

Answer 8

Malaria

Question 9

What drugs can cause haemolytic anaemia?

Answer 9

Dapsone (anti-leprosy abx)

Penicillin

Question 10

What occurs in microangiopathic haemolytic anaemia?

Answer 10

Shearing of RBCs as they pass through in small vessels obstructed by platelet aggregates + micro thrombi
Intravascular haemolysis

Question 11

What is seen on blood film in MAHA?

Answer 11

Schistocytes

Question 12

Give 3 types of MAHA

Answer 12

Haemolytic Uraemic Syndrome
Disseminated intravascular Coagulation
Thrombotic Thrombocytopenic Purpura

Question 13

What may be seen on blood tests in haemolytic anaemias?

Answer 13

Hb low
Haptoglobin low (if intravascular, as binds to free Hb)
High Unconjugated BR
High LDH
High reticulocytes (high MCV)

Question 14

What is haemolytic anaemia?

Answer 14

premature erythrocyte breakdown causing shortened erythrocyte life span (< 120 days) with anaemia

Question 15

Describe the epidemiology of haemolytic anaemia

Answer 15

COMMON
Genetic causes prevalent in African, Mediterranean + Middle Eastern
Hereditary spherocytosis is the most common inherited haemolytic anaemia in northern Europe

Question 16

List 4 general signs of haemolytic anaemia

Answer 16

Pallor
Jaundice
Hepatosplenomegaly
Haematuria

Question 17

What investigations other than bloods would you perform for haemolytic anaemia?

Answer 17

U+Es: raised in TTP/ HUS
Folate: deficiency results in macrocytes
Blood Film: to identify abnormal cells
Urine
Direct Coombs’ Test: Tests for AIHA, identifies erythrocytes coated with antibodies
Osmotic fragility test: identifies membrane abnormalities
Hb Electrophoresis or Enzyme Assays: exclude ddx
Bone Marrow Biopsy (rarely performed)

Question 18

What may be seen on a blood film in haemolytic anaemia?

Answer 18

Leucoerythroblastic picture  
Macrocytosis  
Nucleated erythrocytes or reticulocytes  
Polychromasia  
May identify specific abnormal cells such as: 
Spherocytes  
Elliptocytes  
Sickle cells  
Schistocytes 
Bite cells 
Malarial parasites

Question 19

What may be seen in the urine in haemolytic anaemia?

Answer 19

High urobilinogen (increased haem catabolism)
Haemoglobinuria (intravascular haemolysis)
Haemosiderinuria (increased haem catabolism)