B. Haemolytic uraemic syndrome – Explanation
Most cases of haemolytic uremic syndrome develop in children after 2 to 14 days of
diarrhoea often bloody, due to infection with a certain strain of E. coli. Common features
include abdominal pain, fever, features of renal failure like nausea/vomiting can also
occur.
Renal function and electrolytes would show a rise in urea and creatinine. This is due to
dehydration but, if associated with haemolysis and thrombocytopenia, then it would
indicate the onset of HUS.
A brief description:
Henoch-Schönlein purpura (HSP) Vs Haemolytic uraemic syndrome (HUS) Vs
Thrombotic thrombocytopenic purpura (TTP)
| Henoch-Scholein Purpura | HaemolyticUraemic Syndrome | Thrombotic Thrombocytopenic |
|---|---|---|
| Purpura | ||
| – Purpura – Abdomnial pain – Arthritis – Glomerulonephritis – Periarticular disease – Periarticular oedema Features of IgA nephropathy may occur e.g. haematuria, renal failure |
Triad 1. Acute renal failure 2. Microangiopathic haemolytic anaemia (MAHA) 3. Thrombocytopenia |
Pentad (Triad of HUS) + 4. Neurological manifestation 5. Fever |
| Seen in Children | Seen in Children | |
| Usually follows an upper respiratory tract infection |
Associated with E. coli | Inhibition of ADAMTS 13
|
Haemolytic uraemic syndrome (HUS)
HUS consists of a triad of haemolytic anaemia, uraemia, and thrombocytopenia.
The anaemia will be intravascular in nature and will have an abnormal blood smear
showing schistocytes, helmet cells, and fragmented red cells.
LDH and reticulocyte count will be elevated and the haptoglobin decreased.
90% are caused by E. coli strain O157. This produces a verotoxin that attacks
endothelial cells. Occurs after eating undercooked contaminated meat.
Signs and Symptoms:
The classical presenting feature is profuse diarrhoea that turns bloody 1 to 3 days later.
It is rare for the diarrhoea to have been bloody from the outset. About 80-90% of
children from whom the organism is isolated will develop blood in the stool. It is usually
at this stage that they are admitted to hospital.
Most adults infected with E. coli O157 remain asymptomatic.
There is often fever, abdominal pain and vomiting
Management
• Treatment is supportive e.g. Fluids, blood transfusion and dialysis if required
• Do not give antibiotics to those with possible HUS. The organism may release more
toxins as it dies if antibiotics are given and may worsen the disease.
• The indications for plasma exchange in HUS are complicated. As a general rule
plasma exchange is reserved for severe cases of HUS not associated with diarrhoea
