Differential Diagnosis for Right Upper Arm Pain
The patient presents with right upper arm pain that developed 15 days ago without a specific incident, fall, or trauma. The pain is constant, worse with movement, and located anteriorly and posteriorly. Given the information, the differential diagnosis can be categorized as follows:
Single Most Likely Diagnosis
- Rotator Cuff Tendinitis or Strain: This is a common condition that can cause arm pain, especially with movement. The gradual onset and worsening of pain with movement are consistent with this diagnosis. The lack of specific trauma does not rule out this condition, as it can result from repetitive strain or overuse.
Other Likely Diagnoses
- Bursitis: Inflammation of the bursae around the shoulder joint can cause pain, especially with movement. The symptoms of bursitis can overlap with those of rotator cuff tendinitis.
- Muscle Strain: A strain in the muscles of the upper arm could cause pain, especially if the strain is significant enough to cause persistent discomfort.
- Referred Pain from the Cervical Spine: Sometimes, pain from the cervical spine can refer to the arm, especially if there is a herniated disc or osteoarthritis affecting nerve roots.
Do Not Miss Diagnoses
- Fracture: Although the patient denies any trauma, it's crucial to consider the possibility of an occult fracture, especially if the pain is severe and not improving with conservative management.
- Neurological Conditions (e.g., Radiculopathy, Brachial Plexopathy): Conditions affecting the nerves can cause arm pain and must be considered, especially if there are symptoms like numbness, tingling, or weakness.
- Vascular Conditions (e.g., Thoracic Outlet Syndrome): Compression of the vascular structures can cause arm pain and is a critical diagnosis not to miss due to potential complications.
Rare Diagnoses
- Infectious or Inflammatory Arthritis: Conditions like septic arthritis or rheumatoid arthritis can cause joint pain and stiffness but are less common presentations for upper arm pain without systemic symptoms.
- Tumor: Although rare, a tumor in the bone, muscle, or soft tissue could cause persistent and worsening pain and must be considered in the differential diagnosis, especially if the pain does not respond to typical treatments.