A healthy 9-years-old boy was brought to the Emergency Department for widespread
abdominal pain associated with bloody diarrhoea and significant tenesmus, in the absence of
fever. Blood tests were compatible with an acute
gastroenteritis, even though microbiological tests on stools resulted negative. Given the haemorrhagic
dysentery, the boy was hospitalized to start empiric
antibiotic therapy and intravenous
rehydration. Abdominal ultrasound showed a thickening of colonic walls, mimicking an inflammatory
intestinal disease at the onset (subsequently denied by gastro-colonoscopy). Seven days after the onset of symptoms, blood tests revealed microangiopathic anaemia with negative Coombs test, associated with
thrombocytopenia. Urine dipstick revealed haematuria and
proteinuria in nephritic range. No contraction of diuresis or alteration of renal function were observed (being
creatinine values always within the normal range). Laboratory tests were consistent with the diagnosis of Haemolytic Uremic Syndrome (Hus) at the onset. Approximately 1% of paediatric patients with bloody diarrhoea can develop Hus. Positivity for Escherichia coli is not always evident in the stools. Thus, the triad of
haemolytic anaemia,
thrombocytopenia and
renal failure could be present in only 60% of Hus at the onset. The finding of haematuria and/or
proteinuria on the urine dipstick may be indicative of early kidney damage, allowing for careful monitoring and a
rehydration program that can prevent progression of kidney damage and extrarenal complications.