Leptospirosis (Weil’s disease)
Consider leptospirosis in any febrile patient with recent freshwater or animal/rodent urine exposure. Admit and urgently escalate if there is jaundice, acute kidney injury (AKI), pulmonary haemorrhage or hypoxia, shock/sepsis, or meningism.
Epidemiology and transmission
Leptospirosis is a zoonotic infection caused by Leptospira spp. Reservoirs include rats (particularly), cattle, pigs and dogs. Infection follows contamination of skin breaks or mucous membranes by urine‑contaminated water, soil or materials. Human‑to‑human spread is rare. In the UK it is uncommon but seasonal (more cases in summer-autumn) and should be considered when exposure history is compatible (UKHSA/GOV.UK).
Incubation
Typically 7-21 days (range a few days up to ~30 days). Ask about exposures in the preceding month.
Pathogenesis
Leptospires enter through abraded skin or mucosa and disseminate haematogenously. Early disease reflects bacteraemia; immune‑mediated injury then contributes to multiorgan dysfunction (hepatic cholestasis, tubular/interstitial renal injury, pulmonary capillary damage with haemorrhage, coagulopathy).
Clinical features
- Early: abrupt fever, rigors, frontal headache, severe myalgia (classically calves and lumbar region), malaise, nausea. A biphasic pattern (apparent improvement then immune phase) can occur.
- Distinctive sign: conjunctival suffusion - diffuse conjunctival redness without purulent discharge - is a helpful diagnostic clue.
- Common additional features: anorexia, abdominal pain, vomiting, diarrhoea, rash.