Differential Diagnosis for Left Arm Pain near AC Joint after Gymnastics Injury

Single Most Likely Diagnosis

• AC Joint Separation or Sprain: The patient's recent injury during gymnastics and the location of the pain near the AC joint make this diagnosis the most likely. The AC joint is prone to injuries, especially during activities that involve falling or direct blows to the shoulder.

Other Likely Diagnoses

• Clavicle Fracture: A fracture of the clavicle is a common injury in gymnastics, and the pain is often localized to the area near the AC joint.
• Shoulder Contusion or Bruise: A direct blow to the shoulder during gymnastics could result in a contusion or bruise, causing pain in the affected area.
• Rotator Cuff Strain: The rotator cuff muscles and tendons surround the shoulder joint and could be injured during gymnastics, leading to pain near the AC joint.

Do Not Miss Diagnoses

• Pneumothorax: Although less likely, a pneumothorax (collapsed lung) could occur if the patient experienced a severe injury to the chest or shoulder, and it is crucial to rule out this potentially life-threatening condition.
• Vascular Injury: An injury to the blood vessels near the shoulder, such as the subclavian artery or vein, could lead to severe complications if not promptly diagnosed and treated.

Rare Diagnoses

• Scapular Fracture: A fracture of the scapula is relatively rare but could occur due to a severe fall or direct blow to the shoulder during gymnastics.
• Osteochondral Defect: An osteochondral defect, which involves damage to the cartilage and underlying bone, could be a rare cause of shoulder pain, especially if the patient has a history of repetitive trauma or stress to the joint.