To the Editor: Rickettsia typhi is an endemic cause of atypical pyrexial illness worldwide.1 Its non-specific presentation can lead to misdiagnoses, with overseas reports of unwarranted laparotomies in affected patients.2,3 We describe a patient with R. typhi infection presenting as cholecystitis, in whom a cholecystectomy was avoided by vigilance for R. typhi.

A 51-year-old businessman presented to a general practitioner with a 5-day history of fever, sore throat, headaches and myalgia. The illness had begun a week after his return to Sydney from a business trip to major cities in Asia, his last stop being Hong Kong. Investigations revealed mild lymphopenia and thrombocytopenia, negative results on screening for malaria, and normal results on chest x-ray. A non-specific viral illness was provisionally diagnosed.

A week later, the patient presented again to a GP with fever, abdominal pain, cough, dehydration and confusion. Investigations revealed lymphopenia (0.7 × 109/L; reference range [RR], 1.5–4 × 109/L], thrombocytopenia (93 × 109/L; RR, 150–400 × 109/L), and raised serum levels of bilirubin (25 μmol/L; RR, 0–17 μmol/L) and hepatic enzymes (alanine aminotransferase, 307 U/L [RR, 5–40 U/L]; alkaline phosphatase, 381 U/L [RR, 30–115 U/L]; aspartate aminotransferase, 389 U/L [RR, 5–40 U/L]; and γ-glutamyl transferase, 364 U/L [RR, < 66 U/L]. Serological tests were negative for hepatitis viruses A, B and C, and dengue and Epstein–Barr viruses. The patient was referred to an emergency department.

On presentation to the hospital, the patient was febrile, with severe right upper quadrant abdominal tenderness, and a slight truncal macular rash. Abdominal computed tomography and ultrasound examination indicated cholecystitis (Box). Acute cholecystitis was diagnosed, and treatment begun with intravenous fluids, ampicillin, gentamicin and metronidazole. Following clinical improvement, the patient was discharged on Day 8 with plans for an elective cholecystectomy.

In view of the atypical symptom complex, serological testing for leptospirosis, syphilis, and rickettsial, amoebic and HIV infection had been requested during his admission. Results received after discharge indicated a R. typhi antibody titre of 1:1024 (RR, < 1:128). Results of the remaining serological tests were negative. The patient was contacted, and the cholecystectomy cancelled. He has remained well.

Murine typhus is a zoonosis caused by R. typhi, and is acquired from rodent flea faeces, either by bite inoculation or inhalation. Hepatobiliary involvement occurs in up to 34% of cases. Histopathology specimens show neutrophilic sinusoidal infiltrates and cloudy swelling of hepatocytes,2 but hepatocyte injury and cholestasis are transient, resolving over 1–3 weeks.

Diagnosis is by serological testing: a single indirect immunofluorescent antibody (IFA) titre against R. typhi of at least 1:400; or a fourfold rise in IFA titre from the acute to the convalescent phase (2 weeks apart). The treatment of choice is doxycycline. Although the clinical course is usually benign, the mortality rate can reach 4%.1

Rickettsial diseases remain an under-reported cause of febrile illness.4 As R. typhi has now been described throughout Australasia,1,5 it is important that murine typhus is excluded in patients with atypical pyrexial illnesses and abnormal liver function results.