When the Treatment is the Cause: Disseminated BCG Infection
A 73-year-old man was referred because of a 2-week history of fever, weight loss and asthenia. He had been diagnosed 2 years previously with a superficial bladder tumour and transurethral resection had been performed. For the last year he had been on maintenance treatment with 3-weekly instillation of BCG every 3 months for the last 10 months. Recent cystoscopy had revealed no evidence of tumour recurrence.

When the symptoms started, the patient had attended the emergency room for fever and confusion. At that time, he was diagnosed with a urinary tract infection, so third generation cephalosporin treatment was initiated and he was discharged home. However, fever persisted as well as anorexia and weight loss and he was therefore referred for an Internal Medicine consultation. The patient also mentioned a discrete dry cough for the last couple of days. Physical examination only revealed a decrease in vesicular breath sounds. Blood tests showed elevation of CRP, ESR and a rise in liver enzymes.

The remainder of the blood parameters were normal. Urinary sediment analysis showed minimal leukocyturia with urine culture persistently negative. Serological test results for hepatotropic viruses were not compatible with acute infection. Chest x-ray was normal and abdominal ultrasound showed diffuse homogeneous hepatomegaly. The patient was admitted to hospital for further study.

A CT scan was performed and showed numerous, small pulmonary nodules scattered throughout the lungs, consistent with miliary tuberculosis. PCR for Mycobacterium tuberculosis complex was negative. In line with the clinical findings and CT scan results, treatment with 300 mg isoniazid, 600 mg rifampin and 1200 mg ethambutol orally once a day was started. Mycobacterium bovis, BCG strain, was then identified by liquid culture medium in several urine samples, weeks after the last BCG instillation. The patient was discharged home once his general condition had improved and fever had resolved.

Learning points:

- It is essential to keep a high index of suspicion of possible, although uncommon, complications in patients treated with BCG immunotherapy.
- Response to treatment should always be evaluated to confirm diagnostic suspicion.

Source: https://www.ejcrim.com/index.php/EJCRIM/article/view/1697/2167