Haemolytic Uraemic Syndrome

Question 1

What is HUS?

Features?

Answer 1

Haemolytic uraemic syndrome (HUS) occurs when there is thrombosis within small blood vessels throughout the body. This is usually triggered by a bacterial toxin called shiga toxin. It leads to the classic triad of:

Haemolytic anaemia: anaemia caused by red blood cells being destroyed
Acute kidney injury: failure of the kidneys to excrete waste products such as urea
Thrombocytopenia: low platelet count

Question 2

Cause of HUS?

Answer 2

The most common cause is a toxin produced by the e. coli 0157 bacteria, called the shiga toxin. Shigella also produces this toxin. The use of antibiotics and anti-motility medications such as loperamide to treat gastroenteritis caused by these pathogens increases the risk of developing HUS.

Question 3

What does E.coli 057 cause?

Answer 3

E. coli 0157 causes a brief gastroenteritis, often with bloody diarrhoea. The symptoms of haemolytic uraemic syndrome typically start around 5 days after the onset of the diarrhoea.

Question 4

Signs and symptoms of HUS?

Answer 4

Signs and symptoms of HUS may include:

Reduced urine output
Haematuria or dark brown urine
Abdominal pain
Lethargy and irritability
Confusion
Oedema
Hypertension
Bruising

Question 5

Management of HUS?

Answer 5

HUS is a medical emergency and has a 10% mortality. It needs to be managed by experienced paediatricians under the guidance of a renal specialist. The condition is self limiting and supportive management is the mainstay of treatment:

Urgent referral to the paediatric renal unit for renal dialysis if required
Antihypertensives if required
Careful maintenance of fluid balance
Blood transfusions if required

70 to 80% of patients make a full recovery.