Differential Diagnosis for Shoulder Pain
The patient presents with a positive painful arc test, positive drop test, and tenderness with palpation of the anterior shoulder on the left upper extremity (LUE). Based on these findings, the differential diagnosis can be categorized as follows:
Single Most Likely Diagnosis
- Subacromial Impingement Syndrome: This condition is characterized by inflammation of the tendons of the rotator cuff as they pass under the acromion, leading to pain and limited mobility. The positive painful arc test and drop test are indicative of this condition, as they suggest mechanical impingement of the rotator cuff tendons.
Other Likely Diagnoses
- Rotator Cuff Tendinopathy: This refers to degenerative changes in the rotator cuff tendons, which can cause pain and weakness in the shoulder. The tenderness with palpation of the anterior shoulder supports this diagnosis.
- Bicipital Tendinopathy: Inflammation of the long head of the biceps tendon can cause anterior shoulder pain, especially with palpation and certain movements.
- Adhesive Capsulitis (Frozen Shoulder): Although less likely given the specific tests mentioned, early stages of frozen shoulder can present with pain and limited mobility, which might be confused with impingement syndrome.
Do Not Miss Diagnoses
- Fracture (e.g., Humeral Head or Scapula): Although less common, a fracture could present with similar symptoms, including pain with movement and palpation. Missing this diagnosis could lead to improper healing and significant long-term disability.
- Infection (e.g., Septic Arthritis or Osteomyelitis): Infections in the shoulder joint or bone can cause severe pain, tenderness, and limited mobility. These conditions are medical emergencies requiring prompt diagnosis and treatment.
- Neer's Type III Acromion: A hooked acromion can cause significant impingement on the rotator cuff, leading to chronic pain and dysfunction. While not immediately life-threatening, missing this anatomical variation could lead to prolonged suffering and necessitate surgical intervention.
Rare Diagnoses
- Tumor (Benign or Malignant): Tumors affecting the bone, soft tissue, or nerves around the shoulder can cause pain and limited mobility. Although rare, these conditions are critical to diagnose early for effective treatment.
- Referred Pain from Cervical Spine: In some cases, pain from the cervical spine can refer to the shoulder, mimicking local pathology. This is less likely given the specific tests positive for shoulder pathology but remains a consideration in the differential diagnosis.