A rare case report: Brucellosis as an extreme cause of shoulder subluxation and rotator cuff tendinopathy

Abstract

Rationale: Shoulder subluxation and rotator cuff tendinopathy is commonly associated with degeneration or trauma, and brucellosis has been reported to be correlated with shoulder subacromial bursitis, arthritis. However, brucellosis as a cause of shoulder subluxation and rotator cuff tendinopathy has never been reported in the English medical literature. Patient concerns: A 46-year-old man complained of left shoulder weakness and limited movement ongoing for 1 month. He was primarily diagnosed with shoulder subluxation and rotator cuff tear based on magnetic resonance imaging, and was advised to undergo arthroscopic rotator cuff surgical repair. Diagnoses: Although rotator cuff tear was diagnosed in another hospital, some doubts remained. First, a tendon profile with a relative high signal in T2-weighted magnetic resonance images in the supraspinatus tear area still existed. The findings were clearly different from the usual full-thickness rotator cuff tear, and no tendon profile could be found in the tear area. Second, degenerative rotator cuff tear mainly occurs in the aged population and this patient was relatively young, without a history of trauma. His left shoulder was painless but the weakness and the limited movement were extreme and all of these factors did not support the diagnosis of rotator cuff tear. Some infectious disease was suspected to be the cause and relevant laboratory tests were conducted. This patient was eventually diagnosed as having brucellosis-associated shoulder subluxation and rotator cuff tendinopathy based on positive serum standard tube agglutination test and buffer plate agglutination test for brucellosis. Interventions: Oral drug therapy with rifampicin and doxycycline was used for 8 weeks. Outcomes: A complete response with normal shoulder strength and movement was achieved at 8 weeks. At the one-year follow-up no signs of recurrence were detected. Lessons: Brucellosis-associated shoulder subluxation and rotator cuff tendinopathy may be misdiagnosed as a rotator cuff tear in magnetic resonance imaging and be further managed with indeterminate arthroscopic repair. A comprehensive understanding of the patient’s previous medical history, imaging and laboratory data and a careful physical examination are of great clinic value for the accurate diagnosis of the condition and the subsequent prognosis of the patient.