25-Year-Old With Shoulder Pain

Differential Diagnosis

• Glenohumeral joint osteoarthritis
• Acromioclavicular joint separation
• Pneumothorax
• Pneumoperitoneum

Diagnosis

The correct diagnosis is pneumoperitoneum as the imaging reveals air under the right hemidiaphragm. Although musculoskeletal causes of shoulder pain are common, other non-orthopedic causes should be in the differential, including gastrointestinal, cardiopulmonary, and neurologic sources.

What to Look For

• Free air under the diaphragm on upright chest or abdominal x-ray
• Pneumomediastinum, pleural effusion, pneumothorax and subcutaneous emphysema may also occasionally be seen on x-ray
• Patient may present with abdominal and/or chest pain along with shoulder pain

Pearls for Urgent Care Management

• If no recent trauma, pneumoperitoneum is usually the result of a gastrointestinal tract perforation
• This requires immediate transfer to the emergency department for further evaluation and management
• Fluid resuscitation is the initial treatment