A 70 year old female with recently diagnosed right sacroiliitis presented with worsening right hip pain. Five months prior to admission, patient was hospitalized at an outside hospital for right hip pain and fevers. Imaging was suggestive of sacroiliitis. Cultures were negative for pathogens and biopsy showed inflammation. Patient was diagnosed with likely autoimmune inflammatory disease and sent home.
Patient was initiated on prednisone with transient improvement but pain eventually progressed. Given the patient’s worsening symptoms, her rheumatologist planned to prescribe a trial of Etanercept. While awaiting insurance approval, patient had significant acute worsening of her pain 3 days prior to admission prompting her presentation to the emergency department. Patient acknowledged subjective fevers, chills and decreased appetite. Exam was noted for a temperature of 102.7 and significant pain with active and passive ROM of the right hip. Labs showed an ESR of 94 mm/hr, with a normal WBC .
CT showed erosive changes at the right sacroiliac joint with soft tissue material extending into the right iliacus muscle concerning for infectious vs inflammatory arthritis.
CT guided biopsy was consistent with inflammatory process with negative cultures. Orthopedics was consulted and performed surgical drainage and washout. Tissue and fluid samples again showed no organisms, however, rare acid fast bacilli were noted in the fluid. Additional PCR testing confirmed mycobacterium species. Cytopathology report was compatible with necrotizing granulomatous inflammation. Also of note, patient was found to be Quantiferon Gold positive. Patient was started on RIPE therapy, consisting of Rifampin, Isoniazid, Pyrizinamide, and Ethambutol.
Discussion:
Since the 1950s, the incidence of tuberculosis (TB) in the United States has shown a logarithmic decline. From 1993 to 2014, according to the CDC, there were 341,511 reported cases of TB. 19% of total cases were extrapulmonary of which 10% were instances of skeletal TB. With declining incidences and low prevalence, TB is often overlooked as a possible culprit in a patient presenting with joint pathology, leading to delayed diagnoses or misdiagnoses.
TB arthritis can occur in any joint, but most commonly affects the hip or knee. It usually presents as progressive swelling, pain and loss of joint function over the course of weeks to months. A characteristic finding is a “cold” joint with absent erythema and warmth that would be present in most other acute infections. Constitutional symptoms, fever and weight loss occur in only about 30 percent of cases.
Conclusions:
In presentations of progressive subacute/chronic joint diseases of unknown etiology, TB arthritis should be considered and the appropriate workup pursued. Special consideration should also be given to the role of PCR in the diagnosis of TB arthritis, given the high sensitivity and specificity as well as shorter turnaround time compared to more conventional techniques.