see: [Cameron paeds Haemolytic uraemic syndrome](x-devonthink-item://E383FFBD-9FD8-4DE9-B350-0F6F60D3E600?page=1412), [Rosen pediatric infectious diarrheal disease](x-devonthink-item://66D2C685-9DFA-447A-ABEA-25F0D2816992?page=6) see [[microangiopathic haemolytic anaemia]] >[!key points] > Acute diarrhoeal illness with **bloody** stools > caused by ==Shiga toxin== in E coli 0157:H7 > 1. Acute renal failure > 2. thrombotic [[microangiopathic haemolytic anaemia]] > 3. [[thrombocytopaenia]] > commonest cause of [[Acute Renal Failure]] in children <5 years of age Dont confuse with *HSP* which has normal plt, but can have renal issues # presentation - previously-well child with h/o gastroenteritis developed over past 2 weeks. - vomiting, [[Gastroenteritis#Bloody vs non-bloody diarrhoea DDx table|bloody diarrhoea]], cramping abdo pain - afebrile - may seem like a surgical abdomen - had been improving, then gets worse → pale, haematuria, oliguria, and lethargy - loss of apetite - 1/3 of patients with neurological symptoms - irritability - ALOC - [[Seizures]] # findings - *Normal* PT, aPTT, and fibronigen (unlike [[DIC]]) - [[thrombocytopaenia|Platelets low]] (consumed by MAHA process) - schistocytes on blood film - severe anaemia Hb 50-90 - uraemia essentially universal - similar to TTP, but kidney involvement is main feature (vs. CNS involvement in TTP) # 2 types ## diarrhoeal associated D+HUS 90% - 90% of cases - Shiga toxin from E coli EHEC (enterohaemorrhagic strain) aka STEC (shiga toxin-producing E coli) 0157:H7 - also can get from shigella dysenteriae, salmonella typhi, campylobacter (cytotoxin-producing bacteria) ## non-diarrhoeal-assocaited HUS D-HUS 10% - non-enteric infections, eg strep pneumo, HIV # investigations - FBC - anaemia severe; Hb 50-90 - schistocytes, burr cells, helmet cells may be seen - elevated WCC - [[thrombocytopaenia|platlets]] may be as low as 20 - EUC - renal impairment - [[hyponatremia]] - [[hyperkalemia|hyper-K]] - metabolic acidosis - urinalysis → macroscopic haematuria and proteinuria - coags (usually normal) - raised [[Lipase]] reflects pancreatic involvement - blood cultures, urine cultures, and stool culture (for shiga toxin-producing E. coli O157:H7) - CRP ==degree of anaemia or thrombocytopaenia unrelated ot severity of renal dysfunction, but elevated WCC a/w worse prognosis== > there is no specific diagnostic test for HUS; clinical features and findings on blood film (schistocytes, thrombocytopaenia, severe MAHA), coagulation profile (generally normal), elevated creatinine, +/- hyponatraemia, hyperkalemia, acidosis, macroscopic haematuria + proteinuria) can help make dx. > ↑ WCC a/w worse prognosis. **supportive findings on a haemolysis screen:** - bilirubin - high unconjugated - haptoglobin - low - LDH - elevated - blood film- schistocytes - reticulocytes - elevated - [[Coombs test]] - positive - plasma free Hb - elevated # DDx - intussusception - [[DIC]] - ITP - SLE - leukaemia - vasculitis - [[glomerulonephritis|post-strep glomerulonephritis]] # Treatment - ==Abx not advised; unclear risk of increasing HUS== - may increase shiga toxin release - avoid anti-motility treatment of the diarrhoea - **Supportive therapy** may include [[haemodialysis|dialysis]], antihypertensive therapy, blood transfusions and management of neurological complications. - With supportive therapy, 85% of children recover renal function. - careful attention to electrolyte and fluid balance. once intravascular volume restored, ongoing fluid should be limited to ongoing losses - anticipiate hyperkalemia; do not add K to fluids - Tx anaemia with PRBCs target Hb >70 - ==platelet transfusion can WORSEN things== → aggregation of platelets → microthrombi → further damage - only give if severely low and actively bleeding or before surgery - Tx HTN with short acting CCB eg nifedipine or labetalol. - tx seizures with short-acting benzos ## indications for dialysis - severe hyperkalaemia uncontrollably by medical means - fluid overload and pulmonary oedema - significant uraemic symptoms - blood urea > 36 even if electrolytes and H2O balance satisfactory - anuria # Indications for dialysis - severe hyperkalemia - fluid overload/pulm oedema - significant uraemic symptoms - blood urea >36 - anuria # Complications of HUS - stroke - seizures - haemorrhagic colitis, bowel necrosis - myocarditis - pancreatitis - jaundice # Related Questions ## haematuria - [ ] 24Q: [Paediatric Haematuria](x-devonthink-item://B9F58929-18E6-4557-B393-263A6C98DFEF?page=4) -- [Answer](x-devonthink-item://DE4A2FC7-79D2-4B5D-805E-E481F1189654?page=3) - [x] [ACEM SAQ 2019](x-devonthink-item://26098B61-44FF-4CE9-AAEE-00D22F306BA4?page=8) -- [Answer](x-devonthink-item://DC05498E-566B-482B-A92E-5AA2FBFED114?page=6)