Partial infraspinatus tear with bursitis following an mRNA vaccination: a case report.

We report a case of a shoulder injury related to vaccine administration (SIRVA) that developed symptoms 2 weeks following a coronavirus disease 2019 (COVID-19) vaccination and improved after receiving both intraarticular and subacromial corticosteroid injections. Presentation of case: A 52-year-old Thai female without preexisting shoulder pathology and symptom had developed left shoulder pain for 3 days. Two weeks prior to shoulder pain, she received an mRNA COVID-19 vaccination. She positioned her arm in combined internal rotation with 60° of arm abduction. Her symptoms were pain in all directions of shoulder motion and tenderness at the bicipital groove and over the deltoid area. The testing of the rotator cuff power of the infraspinatus tendon showed pain. Intervention and outcome: An MRI showed infraspinatus tendinosis with a low-grade (almost 50%) bursal-surface tear at the footprint of the superior fiber with associated overlying subacromial-subdeltoid bursitis. She was treated with both intraarticular and subacromial corticosteroid injections (triamcinolone acetate (40 mg/ml) 1 ml+1% lidocaine with adrenaline 9 ml). She did not respond to oral naproxen but responded well to intraarticular and subacromial corticosteroid injections. Relevance and impact: The best way to deal with SIRVA is to prevent this condition by using the correct injection technique. First, the injection site should be two or three fingerbreadths below the mid-acromion process. Second, the needle's direction should be perpendicular to the skin. Third, using the correct needle penetration depth.