Anaemia - Autoimmune haemolytic (Normocytic)

Question 1

Definition

Answer 1

Premature breakdown of RBCs BEFORE their normal lifespan of around 120 days
Two subtypes =
- Warm - most common
- Cold

Question 2

Epidemiology

Answer 2

Women

Family origin
- Mediterranean
- Middle east
- Africa
- SE Asia

Question 3

Risk factors

Answer 3

Autoimmune disorders
- rheumatoid arthritis
- SLE
Lymphoproliferative disorders
- chronic lymphocytic anaemia
- non-Hodgkins’s lymphoma
Prosthetic heart valve

Family history of globinopathy
Drugs
- cephalosporins
- penicillin
- NSAIDS

Question 4

Pathophysiology

Answer 4

Increased red blood haemolysis when body’s antibodies attack
Extrinsic - immune system mistakenly believes own RBC are foreign + secretes antibodies against antigens found on RBC membrane
Intrinsic - primary defect in RBC membrane
Therefore, haemolytic anaemia = extrinsic
Usually, haemolysis happens in the spleen or liver = extravascular haemolytic anaemia
severe cases = haemolysis can happen intravasc = intravascular haemolytic anaemia.

Question 5

Aetiology

Answer 5

Hereditary:
- RBC membrane defects: hereditary spherocytosis
Enzyme defects:
- Glucose-6-phosphate deficiency
Haemoglobinopathies
- B thalassaemia
- A thalassaemia
- Sickle cell anaemia
Autoimmune haemolytic anaemia
IMMUNE = Warm and cold haemolytic anaemia
Non-immune = infections e.g., malaria, bacterial toxins

Question 6

Symptoms

Answer 6

Pallor
Jaundice
Fatigue
SOB
Hepatosplenomegaly
Oliguria from renal insufficiency

Question 7

Signs

Answer 7

High serum UNCONJUGATED BILLIRUBIN
High urinary UROBILINOGEN
High faecal STERCOBILINOGEN
Splenomegaly
Bone marrow expansion
Increased Reticulocytes

Question 8

Diagnosis

Answer 8

FIRST LINE = FBC - Low Hb
High reticulocyte count
Blood film
High Unconjugated bilirubin
LDH = high
Haptoglobin = low
Urinalysis = haemoglobinuria
Present with intravascular anaemia
GOLD STANDARD = Direct Coombs test
- agglutination
- presence of IgG + C3D = warm
- presence of C3D only = cold

Question 9

Treatment

Answer 9

Treat underlying cause
- cold anaemia should avoid cold
- treat underlying infection
Corticosteroids - PREDNISOLONE
If no response to steroids = splenectomy
If no response to splenectomy = RITUXIMAB
Blood transfusions