[Gout of the manubriosternal joints: A case report]

Gout is a metabolic disorder caused by abnormalities in purine metabolism and/or impaired uric acid excretion. It is characterized by the deposition of monosodium urate crystals in joints or connective tissues, leading to recurrent episodes of acute arthritis. Gout can be categorized into two major types based on its etiology: primary and secondary. The majority of gout cases are associated with impaired uric acid excretion. The natural course of gout can be divided into three stages: (1) asymptomatic phase; (2) acute arthritis phase and intercritical phase; (3) chronic gouty arthritis and tophaceous phase. Acute gouty arthritis typically presents with sudden, severe joint pain, accompanied by redness, swelling, warmth, and tenderness of the affected joint and surrounding soft tissues. When large joints are involved, joint effusion may occur. Acute gouty arthritis often develops at night or in the early morning, is self-limiting, and usually resolves within two weeks. The most common site of acute gout flare-ups is the first metatarsophalangeal joint, followed by the midfoot, ankle, knee, wrist, fingers, and elbow joints. Acute gout attacks rarely affect the axial joints. Pain in these affected areas is often accompanied by limited function, significantly impacting a patient' s daily activities and quality of life. Uncommon sites of gout involvement, as well as gout with normal serum uric acid levels, can easily lead to misdiagnosis. Therefore, a comprehensive diagnosis requires a detailed medical history, physical examination, laboratory tests, and imaging studies. This case report describes a 19-year-old male who was admitted with recurrent anterior chest pain. The diagnosis at another hospital suggested ankylosing spondylitis. Physical examination revealed significant tenderness, redness, and swelling of the bilateral sternoclavicular joints, with local warmth and mildly restricted movement. MRI of the sacroiliac joints showed no significant abnormalities, and serum uric acid levels were normal. Chest dual-energy CT scans revealed multiple tophi in the sternum, bilateral clavicles, scapulae, multiple ribs, and along the edges of the sternum. Based on the patient' s medical history, physical findings, and imaging studies, a diagnosis of gout was confirmed. Treatment included urate-lowering therapy, pain management, and dietary adjustments. During a two-year follow-up period, the patient did not experience recurrent anterior chest pain, and multiple serum uric acid tests consistently showed levels below 300 μmol/L. Repeat chest dual-energy CT scans indicated significant reduction of tophi in the sternoclavicular joints and other affected areas.