Haemolytic Uraemic Syndrome

Question 1

Define haemolytic uraemic syndrome

Answer 1

Triad of microangiopathic haemolytic anaemia, acute renal failure and thrombocytopenia

Question 2

What are the causes/risk factors of haemolytic uraemic syndrome/

Answer 2

Glomerular endothelial damage (e.g. by verotoxins) -> exposure of basement membrane ->
platelet aggregation -> microvascular thrombosis -> RBC fragmentation and platelet
destruction -> renal insufficiency
Infection

• Verotoxin (Shiga-toxin) producing E. coli 0157
• Shigella
• Pneumococcal respiratory tract infection (produces neuraminidase)
• HIV

Drugs
• Ciclosporin
• Chemotherapy

Pregnancy

Question 3

What are the symptoms of haemolytic uraemic syndrome?

Answer 3

• Severe colicky abdominal pain
• Watery, bloody diarrhoea
• Malaise
• Fatigue
• Nausea
• Fever

Question 4

What are the signs of haemolytic uraemic syndrome?

Answer 4

• Abdominal tenderness
• Oliguria/anuria
• Haematuria
• Fever
• Pallor
• Slight jaundice
• Bruising
• Generalised oedema
• Hypertension
• Retinopathy

Question 5

What investigations are carried out for haemolytic uraemic syndrome?

Answer 5

• FBC
- Normocytic anaemia 
- High neutrophils 
- Very low platelets 
• U&Es
- High urea 
- High creatinine
- High K+ 
- Low Na+ 
• Clotting
- Normal APTT and fibrinogen levels (abnormality may indicate DIC)
• LFTs
- High unconjugated bilirubin 
- High LDH from haemolysis 
• Blood cultures
•ABG
- Low pH 
- Low bicarbonate 
- Low PaCO2
- Normal anion gap 
• Blood Film
- Schistocytes 
- High reticulocytes and spherocytes 
• Urine
- 1+ g protein/24 hrs
- Haematuria
• Stool Samples
- MC&S
• Renal Biopsy
- Can distinguish between D+ and D- HUS