Our patient is a 74-year-old gentleman with a history of Transitional Cell Carcinoma of the bladder diagnosed in 2018, for which he initially underwent transurethral resection of the bladder tumour (TURBT) followed by 4 rounds of adjuvant cisplatin and gemcitabine. He was subsequently found to have a recurrence on routine surveillance cystoscopy 15 months after his initial diagnosis and went on to receive 6 intravesical BCG instillations. There was no known history of concurrent bacterial cystitis or traumatic catheterisation during the time of his BCG therapy, however he did present with an episode of frank haemturia following his second instillation of BCG therapy. He has a history of macular degeneration and chronic lower back pain related to a previous L3 disc herniation but is otherwise fit and active and is not known to be immunocompromised. Approximately 14 months after his last BCG instillation, he presented with a 3-month history of worsening of his chronic lower back pain. He was afebrile and denied any associated weight loss, night sweats or lower limb weakness.
The white cell count was within normal limits, with a CRP of 38. An MRI of the spine subsequently demonstrated evidence of T11/12 discitis with adjacent osteomyelitis of the T11/T12 vertebral bodies and an epidural abscess (Fig. 1). A CT-guided aspirate was performed and was sent for microscopy and culture as well as 16S PCR. Serial blood cultures were negative. The biopsy material became smear positive for acid fast bacilli on day 3. GeneXpert PCR was positive for Mycobacterium tuberculosis complex with subsequent culture growing Mycobacterium bovis BCG strain, confirming epidural abscess due to intravesical BCG. At the time, a brief immunodeficiency screen was performed. Serum globulins were not decreased, HIV and hepatitis serology were negative. Standard anti-tuberculous therapy with rifampicin, isoniazid, pyrazinamide and ethambutol (RIPE) was initiated with vitamin-B6 while awaiting formal mycobacterial culture. Pyrazinamide was subsequently ceased upon confirmation of Mycobacterium bovis on culture, in light of the strains' inherent resistance to this agent. Chest plain film at the time did not reveal evidence of active TB.
The patient was subsequently transferred to our hospital with a severe worsening of lumbar back pain with bilateral radicular features. Neurological examination revealed normal tone and reflexes with 4+/5 power in left ankle dorsiflexion and plantar flexion. All other myotomes were preserved. Sensory and proprioceptive examination was unremarkable. Multimodal analgesia was used to good effect. He continued treatment with magnesium/manganese/pyridoxine complex, Isoniazid 300 mg OD, Ethambutol 1200 mg OD, Rifampicin 600 mg OD. He was commenced on prednisolone 50 mg OD on advice from infectious disease and continued on this for 2 months.
A month later, the patient was reviewed by a neurosurgeon who determined surgical intervention was indicated. He underwent decompression and surgical washout with spinal fusion/bone graft. Operative cultures were obtained and were again positive for Mycobacterium bovis BCG. The patient was managed in a brace post operatively and subsequently graduated off, with a good functional outcome. At present he has had 12 months of anti-TB therapy which he has tolerated well, with normal transaminases, renal function, and no ophthalmological sequelae of ethambutol. He is currently not using any opioid analgesia.