Drug-Resistant Bone, Joint and Spine Tuberculosis: Evolution of Diagnosis and Treatment.

Background: Drug resistant (DR) osteoarticular TB (OATB) is a challenge in view of it being deep seated lesion and paucibacillary disease. Case definition, investigation protocol, treatment of proven DR and those cases where DR could not be demonstrated lacks clarity and evidence. Hence, a series of studies were conducted to develop an algorithm to investigate and treat therapeutically refractory disease (TRD) or presumptive drug resistance (PDR) cases of OATB.

Patients And Methods: 6 studies were conducted. Study one and two evaluated criteria to label TRD/PDR. Three subsequent studies were conducted where TDR/PDR or fresh cases of OATB cases were investigated by AFB smear, Bactec/liquid culture, histology and genotypic DST by CBNAAT & LPA. Sixth study was a retrospective evaluation of all DR cases treated for proven or clinical drug resistance (CDR).

Results: Patient of bone/spine TB on ATT for 5 months or more show poor clinico-radiological treatment response as worsening of lesion, increased spinal deformity, persistent discharging sinus/ulcer, appearance of fresh lesion, recurrence of previous lesion, wound dehiscence of post-operative surgical scar cab labelled as PDR cases. These cases on histology ascertained TB and were proven DR on genotypic and phenotypic DST and are treated successfully. The patients of histologically ascertained TB and no/indeterminate phenotypic and genotypic DST were successfully treated as clinical drug resistance on MDR protocol.

Conclusions: We described an algorithm. We must suspect PDR(TRD) based on criteria described. The tissue must be procured and submitted for AFB smear, histology and phenotypic and genotypic DST for diagnosis of TB. Genotypic and phenotypic DST will be useful to prove (90% instances) type of drug resistance. Remaining on strong clinical suspicion of DR and yet inconclusive on phenotypic/genotypic DST (<10%), may be treated as CDR as MDR. The adverse drug reactions and hepatic side-effects should be monitored diligently and these cases to be treated till healed status is demonstrated.