Leptospira-associated haemolytic uraemic syndrome: a diagnostic challenge

Leptospirosis is a globally prevalent zoonotic infection caused by pathogenic spirochaetes of the genus Leptospira Although typically associated with mild flu-like symptoms or Weil's disease (characterised by jaundice, renal failure and haemorrhagic manifestations), atypical and severe presentations can mimic other systemic disorders. A man in his 40s presented with fever, myalgia along with rapidly progressive jaundice, thrombocytopenia, microangiopathic haemolytic anaemia and acute kidney injury, preceded by a short episode of diarrhoea. The initial working diagnosis was haemolytic uraemic syndrome (HUS) secondary to Shiga toxin-producing Escherichia coli and he was treated with plasma exchange, transfusions and renal replacement therapy. However, stool examinations were negative for Shiga toxin and bacterial pathogens. Subsequent investigations confirmed leptospirosis. He improved significantly after treatment with doxycycline alongside supportive therapy. This case highlights the importance of considering leptospirosis as a differential diagnosis in patients with HUS, particularly in endemic regions, to avoid delays in targeted treatment.