Sternoclavicular joint arthropathy mimicking radiculopathy in a patient with concurrent C4-5 disc herniation

Background: Patients with sternoclavicular joint arthropathy, which can result from septic arthritis, often present with localized sternoclavicular pain as well as shoulder pain. Such pain may be similar to the presenting symptoms of cervical intervertebral disc herniation. Clinical presentation: A 47-year-old female presented with 1 month of significant pain in the neck as well as right anterior chest and deltoid. The patient was found to have reduced strength in the right deltoid muscle on physical examination. MRI revealed a C4-C5 herniated nucleus pulposus. The patient underwent successful C4-C5 anterior cervical discectomy, but subsequently developed painful swelling in the region of the right sternoclavicular joint with limited motor strength in the right shoulder and arm. A needle biopsy of the mass yielded negative results, but her erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) numbers did respond to antibiotics, consistent with infection of the sternoclavicular joint. A follow-up CT scan (6.5 months postoperatively) revealed apparent resolution right sternoclavicular joint arthropathy, thought the patient continued to experience pain. 15 months postoperatively, the patient was prescribed methotrexate due to persistent pain and mild weakness arising from a possible rheumatologic inflammation. 19 months postoperatively, the patient had full strength of the right shoulder and arm and visible decrease in swelling at the sternoclavicular joint. More than three years postoperatively, the patient was diagnosed with multiple myeloma, which was appropriately treated. At follow-up four years postoperatively, the patient had an MRI showing new C6-C7 herniated nucleus pulposus, but no longer had any right shoulder or chest pain or associated weakness. Conclusion: This case demonstrates that sternoclavicular joint arthropathy results in symptoms that can mimic the presenting symptoms of shoulder or cervical spine pathology, such as shoulder and neck pain, necessitating careful diagnosis and management.