[Post-diarrheal haemolytic uremic syndrome: when shall we consider it? Which follow-up?]

Haemolytic uremic syndrome (HUS) is characterized by thrombotic microangiopathy with acute renal failure, haemolytic anaemia with schizocytes and thrombocytopenia. Typical forms (D(+) HUS) are caused by gastrointestinal infection with Escherichia coli species producing verotoxines (or Shiga toxins, STEC). It is estimated that 5-8 % of infected individuals will develop HUS following STEC infection. E. coli O157:H7 is the most commonly involved serotype and can lead to D(+) HUS in 15 % of young infected children. Vehicles of STEC transmission are contaminated food (ground beef, unpasteurised dairy products, unwashed and uncooked fruit and vegetables), person-to-person transmission and contact with farm animals with STEC. After an average incubation period of 3 to 8 days, patients develop painful bloody diarrhoea followed by systemic toxinemia. This may lead to thrombotic microangiopathy with endothelial damage and activation of local thrombosis. Since 1996, the Institut de Veille Sanitaire (InVS) centralises all notified French cases of D(+) HUS in children less than 15 years of age and investigates cases regrouped by time and place for the presence of STEC risk factors. The average annual incidence ranges between 0.6 and one for 100 000 children younger than 15 years and with a peak at 1 year of age. Fifty-one percent of HUS occur between June and September. Patients with a suspicion of STEC infection or bloody diarrhoea should not receive antibiotics, antimotility agents, narcotics and non-steroidal anti-inflammatory drugs. Maintenance optimal hydration provides nephroprotection. The management of HUS remains supportive. Dialysis was required for 46 % of HUS cases in 2009. For similar indication, peritoneal dialysis has to be a first choice treatment. Neurological injury is the most frequent non-renal complication and the first cause of death. Early initiation of plasmapheresis might improve the prognosis. Overall mortality rate ranges between 1 and 5 %. One third of patients suffer from long-term renal morbidity such as proteinuria, arterial hypertension and decrease of glomerular filtration rate. The longer the duration of anuria, the greater the risk of sequellae. Any patient with a history of HUS needs a long-term renal follow-up.