Case Presentation: 87-year-old woman presented with a tender mass in her right shoulder. Her shoulder had been painful for a year and she had been diagnosed with arthritis as an outpatient. Her pain was refractory to steroid injections and NSAIDS. She denied constitutional symptoms or respiratory complaints. Her past medical history included well-controlled diabetes. Exam revealed a 2cm tender mass with erythema, necrosis, and limited range of motion and clear lungs. She had normal renal and liver function, a stable anemia (hematocrit at 30%), but elevated ESR 42 mm/hr and CRP 3.1 mg/L. MRI and CT suggested tumor vs. abscess with invasion into glenohumoral joint. She had surgical resection of the mass which showed necrotic tissue surrounded by inflammation and caseating granulomas. AFB stain was negative but subsequent PCR analysis was positive for Mycobacterium tuberculosis (MTB). Further history revealed the patient’s brother had been treated for MTB in the 1990s. She was isolated with airborne precautions and underwent CT scan of her chest which revealed bilateral upper lobe nodular densities as well as left-sided pleural thickening. Induced sputum samples were AFB smear negative but all cultures grew MTB. She was discharged with treatment for active MTB infection with appropriate follow up.
Discussion: Osteomyelitis from MTB is a known complication of disseminated (miliary) MTB infection. Chronic and subacute presentations are most common, as is the case in our patient. Most frequent sites of involvement of miliary MTB are lymphatics, liver, bone and joints including the spine. Most cases present with non-specific or constitutional symptoms. Retrospective analyses have shown that concomitant pulmonary symptoms vary widely (18%-91%) and can be absent in histopathologically confirmed cases. In adults, bone or joint MTB should be suspected in individuals at risk for MTB with bone or joint pain (including back pain) with or without focal swelling or fever. It can have an indolent course in soft tissue including cold abscess, as in this case. Pain is often the first symptom. Imaging findings are non-specific and include soft-tissue swelling and bone demineralization, sand complete articular destruction can occur. CT / MRI may detect lesions not identified on plain radiograph, but tissue biopsy and pathology are necessary to confirm the diagnosis. Factors contributing to this unusual case presentation are advanced age and repeated intra-articular steroid injections that created relative immunocompromise in the articular micro-environment or systemic absorption causing disease activation. Despite disseminated disease, this patient’s pulmonary pathogen inoculum was low as she was found to have negative sputum AFB smears (only positive in 33-36% of cases), but had positive respiratory sputum cultures. At least 5 to 10,000 bacilli per mL are needed to detect MTB with AFB smear; by contrast, 10 to 100 organisms are needed for a positive culture. Thus, AFB smears are positive in 33-36% of cases and they are not as sensitive as sputum culture. Rigid bronchoscopy does not significantly increase the detection rate (9-27% positive). The positive predictive value of AFB smear microscopy is 50 – 80% percent.
Conclusions: MTB osteomyelitis should be considered for those with risk factors who present with an indolent disease course. Hospitalists need to consider active pulmonary MTB infection in these patients even with a lack of pulmonary symptoms. Negative sputum AFB smears should not delay treatment if clinical suspicion is high.
To cite this abstract:Berry AR, Clemons JE. Shoulder Pain and Paucity of Pulmonary Symptoms:tb or Not Tb. Abstract published at Hospital Medicine 2016, March 6-9, San Diego, Calif. Abstract 437. Journal of Hospital Medicine. 2016; 11 (suppl 1). https://www.shmabstracts.com/abstract/shoulder-pain-and-paucity-of-pulmonary-symptomstb-or-not-tb/. Accessed July 19, 2019.