Cite this article as:
Jennifer Watt. Haemolytic Uraemic Syndrome, Don't Forget the Bubbles, 2020. Available at: https://doi.org/10.31440/DFTB.26233
What is HUS?
Haemolytic Uraemic Syndrome is a combination of findings which involves the triad of:
Microangiopathic haemolytic anaemia with red blood cell fragmentation on blood film
Acute renal failure
Thrombocytopenia
What causes HUS?
About 90% of cases follow an infection, most commonly with entero-haemorrhagic E. Coli (EHEC). Other infective causes to be considered include Shigella and Streptococcus pneumoniae.
These infections are commonly contracted by the ingestion of contaminated food or water sources. In the US and UK, E. Coli 0.157 forms part of the natural intestinal microflora of cattle and sheep, therefore infection can be caused by direct contact with animal faeces. This can take place at farms or petting zoos, or via undercooked contaminated meat or dairy products.
The other 10-15% of cases represent atypical HUS and are due to a variety of causes, which will not be discussed here.
How do children present?
In children infected with EHEC about 10-15% of them will go on to develop HUS.
The common presentation includes bloody diarrhoea +/- cramping abdominal pain, fever and/or vomiting. The average onset of HUS after development of diarrhoea is about 7-10 days, with children under the age of 5 at highest risk.
Dependent on the extent of HUS progression, children may present with pallor, oedema, lethargy, or reduced urine output.
How to approach the examination
As with any unwell child, an A to E assessment is critical to rule out any immediate, life threatening complications.
Specific attention should be paid to assessing their fluid status, especially for evidence of dehydration.
*Although they may be oedematous, it is important to assess if they are intra-vascularly dry.
Things to examine for:
Prolonged capillary refill time
Observations: Tachycardia; hypotension or hypertension
Are they are cool peripherally?
Assess fontanelle tension (if applicable)
Dry mucus membranes/reduced skin turgor
Oedema (common locations in children include lower limbs, sacral and peri-orbital)
Is there evidence of neurological sequelae?
Irritable/restlessness
Confusion
Reduced GCS
Key investigations to perform
A. Initial blood samples:
Full blood count with blood film to assess for RBC fragmentation
Management should always be discussed with your local paediatric nephrologist in order to individualise/optimise management.
This is a generalised framework for the approach to management. Treatment involves supportive therapy to allow time for the infection to clear and the HUS process to cease.
1. Fluid Management:
IV access
Assess fluid status
Monitor for electrolyte disturbances and correct as per local guidelines
Daily weight, In/Out fluid balance, close monitoring of patient observations
*Fluid rehydration should be administered cautiously and in the setting of oliguria/anuria and oedema, fluids given should not exceed insensible loss + urine output.
*Evidence has shown that children presenting to hospital with dehydration in the prodromal phase of EHEC-induced HUS have a higher risk of developing an oliguric AKI and the requirement for dialysis. The administration of isotonic fluid in this phase has shown to be nephroprotective.
2. Hypertension:
Can be secondary to fluid overload or as a result of the HUS process
Trial of diuretics or if receiving dialysis, fluid can be offloaded
If unresponsive to diuretics, consider a vasodilator (For example, amlodipine/ nifedipine *hospital dependent)
3. Anaemia:
Target Haemoglobin: 70-100g/L
Avoid excessive transfusion due to the associated risk of development of hyperkalaemia or fluid overload
4. Thrombocytopenia:
Consideration for platelet transfusion if platelets <10 x109
If undergoing surgery may require platelets > 50 x 109
5. Abdominal pain/vomiting:
Secondary to colitis
Regular paracetamol for pain relief
Avoid opiates if possible due to constipating side effects
*NSAIDS like Ibuprofen should not be prescribed*
6. Nutrition:
All patients should be reviewed by a dietician
NG tube and feeding regime
7. Dialysis (Peritoneal Dialysis or Haemodialysis) Indications:
Intractable acidosis
Diuretic resistant fluid overload
Electrolyte abnormalities Hyperkalaemia
Symptoms of uraemia
In children with HUS, peritoneal dialysis is the preferred treatment option as it is a gentler form of dialysis.
Haemodialysis is indicated for children with severe colitis, severe electrolyte abnormalities and those with neurological complications.
HUS Complications
AKI:Oliguria/anuria; hyperkalaemia; hypertension
Neurological: Irritable, confusion, seizures
Bleeding Risk
Cardiac: Hypertensive cardiomyopathy/myocarditis
Gastrointestinal: Severe colitis with bleeding/perforation
Pancreatitis
Pulmonary oedema
Selected references
Mayer CL, Leibowitz CS, Kurosawa S and Stearns-Kurosawa DJ. Shiga Toxins and the Pathophysiology of Hemolytic Uremic Syndrome in Humans and Animals. Toxins (Basel). Nov 2012. [Cited June 2020]; 4 (11): 1261-1287. doi: 10.3390/toxins4111261
Balestracci A et al. Dehydration at admission increased the need for dialysis in hemolytic uremic syndrome children. Pediatr Nephrol. 2012. [ Cited June 2020];27: 1407-1410. Doi: 10.1007/s00467-012-2158-0
Scheiring J. Andreoli SP. Zimmerhackl LB. Treatment and outcome of Shiga-toxin-associated hemolytic uremic syndrome (HUS). Ped Neprhrol. 2008. [Cited June 2020]; 23: 1749-1760. Doi: 10.1007/s00467-008-0935-6
Grisaru Silviu. Management of hemolytic-uremic syndrome in children. Int J Nephrol Renovasc Dis. 2014 [Cited June 2020]; 7: 231-239. Doi: 10.2147/IJNRD.S41837.
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About Jennifer Watt
Aspiring Paediatrician. In my free time I enjoy being in the sun, on the sand and eating all things sweet.
Haemolytic Uraemic Syndrome
Tags: E.Coli, EHEC, haemolytic uraemic syndrome, hemolytic uremic syndrome, HUS
Jennifer Watt. Haemolytic Uraemic Syndrome, Don't Forget the Bubbles, 2020. Available at:
https://doi.org/10.31440/DFTB.26233
What is HUS?
Haemolytic Uraemic Syndrome is a combination of findings which involves the triad of:
What causes HUS?
About 90% of cases follow an infection, most commonly with entero-haemorrhagic E. Coli (EHEC). Other infective causes to be considered include Shigella and Streptococcus pneumoniae.
These infections are commonly contracted by the ingestion of contaminated food or water sources. In the US and UK, E. Coli 0.157 forms part of the natural intestinal microflora of cattle and sheep, therefore infection can be caused by direct contact with animal faeces. This can take place at farms or petting zoos, or via undercooked contaminated meat or dairy products.
The other 10-15% of cases represent atypical HUS and are due to a variety of causes, which will not be discussed here.
How do children present?
In children infected with EHEC about 10-15% of them will go on to develop HUS.
The common presentation includes bloody diarrhoea +/- cramping abdominal pain, fever and/or vomiting. The average onset of HUS after development of diarrhoea is about 7-10 days, with children under the age of 5 at highest risk.
Dependent on the extent of HUS progression, children may present with pallor, oedema, lethargy, or reduced urine output.
How to approach the examination
As with any unwell child, an A to E assessment is critical to rule out any immediate, life threatening complications.
Specific attention should be paid to assessing their fluid status, especially for evidence of dehydration.
*Although they may be oedematous, it is important to assess if they are intra-vascularly dry.
Things to examine for:
Is there evidence of neurological sequelae?
Key investigations to perform
A. Initial blood samples:
B. Stool MC&S + E. Coli PCR
C. Urinalysis + MC&S
How to approach the management of HUS
Management should always be discussed with your local paediatric nephrologist in order to individualise/optimise management.
This is a generalised framework for the approach to management. Treatment involves supportive therapy to allow time for the infection to clear and the HUS process to cease.
1. Fluid Management:
*Fluid rehydration should be administered cautiously and in the setting of oliguria/anuria and oedema, fluids given should not exceed insensible loss + urine output.
*Evidence has shown that children presenting to hospital with dehydration in the prodromal phase of EHEC-induced HUS have a higher risk of developing an oliguric AKI and the requirement for dialysis. The administration of isotonic fluid in this phase has shown to be nephroprotective.
2. Hypertension:
3. Anaemia:
4. Thrombocytopenia:
5. Abdominal pain/vomiting:
*NSAIDS like Ibuprofen should not be prescribed*
6. Nutrition:
7. Dialysis (Peritoneal Dialysis or Haemodialysis) Indications:
In children with HUS, peritoneal dialysis is the preferred treatment option as it is a gentler form of dialysis.
Haemodialysis is indicated for children with severe colitis, severe electrolyte abnormalities and those with neurological complications.
HUS Complications
Selected references
Mayer CL, Leibowitz CS, Kurosawa S and Stearns-Kurosawa DJ. Shiga Toxins and the Pathophysiology of Hemolytic Uremic Syndrome in Humans and Animals. Toxins (Basel). Nov 2012. [Cited June 2020]; 4 (11): 1261-1287. doi: 10.3390/toxins4111261
Kausman. J 517 Haemolytic uraemia syndrome. Royal Hospital for Children- Nephrology. Dec 2013. [Cited June 2020]; Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3509707/
Hughes D. Management and investigation of bloody diarrhoea and haemolytic uraemic syndrome [draft]. GG&C Paediatric Guidelines- Kidney Diseases. Oct 30 2019. [Cited June 2020]; Available from: https://www.clinicalguidelines.scot.nhs.uk/ggc-paediatric-guidelines/ggc-guidelines/kidney-diseases/management-and-investigation-of-bloody-diarrhoea-and-haemolytic-uraemic-syndrome-draft/
Balestracci A et al. Dehydration at admission increased the need for dialysis in hemolytic uremic syndrome children. Pediatr Nephrol. 2012. [ Cited June 2020];27: 1407-1410. Doi: 10.1007/s00467-012-2158-0
Scheiring J. Andreoli SP. Zimmerhackl LB. Treatment and outcome of Shiga-toxin-associated hemolytic uremic syndrome (HUS). Ped Neprhrol. 2008. [Cited June 2020]; 23: 1749-1760. Doi: 10.1007/s00467-008-0935-6
Grisaru Silviu. Management of hemolytic-uremic syndrome in children. Int J Nephrol Renovasc Dis. 2014 [Cited June 2020]; 7: 231-239. Doi: 10.2147/IJNRD.S41837.
About Jennifer Watt
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