From the Guidelines
Severe left shoulder pain is most likely caused by a combination of rotator cuff injuries, frozen shoulder, osteoarthritis, bursitis, tendinitis, labral tears, referred pain from cardiac or diaphragmatic issues, and nerve impingement, with the exact mechanism depending on the underlying cause, as suggested by the most recent study 1. The rotator cuff, a group of four muscles and tendons stabilizing the shoulder joint, often tears or becomes inflamed through overuse, trauma, or age-related degeneration.
- Frozen shoulder involves progressive stiffening of the joint capsule,
- while osteoarthritis causes cartilage breakdown between the humeral head and glenoid.
- Bursitis involves inflammation of fluid-filled sacs that cushion the joint. Importantly, left shoulder pain can sometimes indicate a heart attack (especially in women) when accompanied by chest pressure, shortness of breath, and sweating, as noted in 1. Treatment depends on the underlying cause, typically starting with rest, ice, anti-inflammatory medications like ibuprofen (400-800mg three times daily with food), and physical therapy, as recommended in 1. Persistent or severe pain, especially with cardiac symptoms, requires immediate medical attention to determine the exact mechanism and appropriate treatment, as emphasized in 1. In cases of hemiplegic shoulder pain, proper positioning, maintenance of shoulder range of motion, and motor retraining may be beneficial, as suggested in 1. Additionally, acupuncture in combination with standard therapeutic exercise may be a safe and effective adjuvant for the treatment of hemiplegic shoulder pain, as noted in 1.
From the Research
Mechanism of Pain
The mechanism of severe left shoulder pain can be complex and multifaceted.
- Referred pain is a common but less understood symptom that originates from somatic tissues, and it can arise from pathologies primarily involving local tissue or from lesions in distant structures 2.
- Central sensitization of convergent neurons and peripheral reflexes of dichotomizing afferent fibers are two theories proposed to explain the pathological mechanism of referred pain 2.
- The use of quantitative sensory testing has provided evidence that peripheral and central sensitization mechanisms play a relevant role in localized and widespread chronic pain syndromes 3.
- Pain is associated with different types of trigger factors including social, physiological, and psychological, and determining potential drivers of the sensitization process is critical for effective management 3.
Possible Causes of Left Shoulder Pain
- Peptic ulcer disease can cause referred pain in the left shoulder, and it is estimated that approximately 10% of patients presenting with upper abdominal pain have a peptic ulcer as the cause of their symptoms 4.
- Non-steroidal anti-inflammatory drugs (NSAIDs) can also cause gastrointestinal adverse effects, including peptic ulcer disease, which can lead to left shoulder pain 4, 5.
- Other possible causes of left shoulder pain include musculoskeletal disorders, nerve compression, and other medical conditions.
Diagnosis and Treatment
- Diagnosis of the underlying cause of left shoulder pain is crucial for effective treatment, and it may involve imaging studies, laboratory tests, and physical examination.
- Treatment of left shoulder pain depends on the underlying cause, and it may include medication, physical therapy, and other interventions 2, 3.
- Proton pump inhibitors (PPIs) have been shown to be effective in preventing and treating NSAID-induced ulcers and reducing the risk of recurrence 4, 6, 5.