Differential Diagnosis for Left Upper Back Pain with Position of Comfort with Arms Overhead

• Single Most Likely Diagnosis
  • Musculoskeletal strain: The position of comfort with arms overhead suggests that the pain is alleviated by reducing tension or strain on the muscles of the upper back, which is consistent with musculoskeletal strain. This is a common condition that can result from overuse, poor posture, or direct injury to the muscles or ligaments in the upper back.
• Other Likely Diagnoses
  • Thoracic outlet syndrome: This condition involves compression of the nerves and/or blood vessels that pass through the thoracic outlet (the space between the collarbone and first rib). Symptoms can include pain in the upper back, shoulder, and arm, which may be relieved by changing the position of the arms, such as holding them overhead.
  • Rib fracture or costochondritis: Fracture of the ribs or inflammation of the cartilage that connects the ribs to the breastbone (costochondritis) can cause upper back pain. The pain may be positional and could potentially be relieved by certain movements or positions, such as holding the arms overhead.
• Do Not Miss Diagnoses
  • Pulmonary embolism: Although less likely, pulmonary embolism is a life-threatening condition that requires immediate medical attention. It can cause sudden onset of chest or back pain that may worsen with deep breathing or certain positions. The fact that the pain is in the upper back and has a position of comfort does not rule out this diagnosis.
  • Aortic dissection: This is a serious condition where there is a tear in the inner layer of the aorta. It can cause severe, tearing chest or back pain that may radiate to the upper back. The pain's characteristics and the patient's overall clinical presentation are critical in suspecting this diagnosis.
• Rare Diagnoses
  • Pancoast tumor: A type of lung cancer located at the top of the lung, which can cause shoulder and upper back pain due to invasion of the nearby structures. The pain may have a variety of characteristics, including being worse at night or relieved by certain positions.
  • Spinal tumors or infections: Tumors or infections affecting the spine, such as osteomyelitis or spinal metastases, can cause back pain that may have specific positions of relief or exacerbation, depending on the location and nature of the lesion.