A 35-year-old farmer from Kerala presents with 7 days of high fever, conjunctival suffusion, severe myalgia, jaundice, and oliguria. Urine shows proteinuria and casts. Weil-Felix test is negative. IgM ELISA for Leptospira is positive. What confirms the diagnosis of Weil's disease over other diagnoses?
- A Positive Weil-Felix test (OX-19, OX-2, OX-K agglutinins) confirming rickettsial disease
- B Combination of hepatic dysfunction (elevated bilirubin), renal dysfunction (elevated creatinine), and uveitis/conjunctival suffusion in context of positive Leptospira IgM ELISA ✓
- C Positive serum PCR for Rickettsia conorii from a skin biopsy of eschar
- D Blood culture on BCYE agar growing Legionella pneumophila
Explanation
Weil's disease is severe leptospirosis characterised by the classic triad of jaundice + acute kidney injury + uveitis/conjunctival suffusion (Weil's triad), along with thrombocytopenia and bleeding tendencies. Leptospira IgM ELISA becomes positive from day 5–7 and is the preferred serological test; MAT (microscopic agglutination test) is the gold standard but requires live cultures. Weil-Felix is used for rickettsial diseases (negative in leptospirosis). Rickettsial diseases cause an eschar at the bite site (scrub typhus — O. tsutsugamushi) and are confirmed by Weil-Felix (OX-K for scrub typhus) or specific PCR.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.