Sharp pain in the left shoulder can be concerning, often prompting individuals to seek its origin. While frequently stemming from common musculoskeletal issues, this pain can sometimes indicate underlying conditions warranting prompt attention. The shoulder’s intricate structure and proximity to vital organs contribute to a broad spectrum of potential causes, from minor injuries to more serious health concerns. Understanding these sources helps determine when medical evaluation is necessary.
Common Musculoskeletal Causes
The shoulder joint and its surrounding tissues are frequent sources of sharp pain. A prevalent issue involves the rotator cuff, a group of muscles and tendons stabilizing the shoulder. Injuries like tendinitis or tears occur when these tendons become inflamed or damaged from overuse or trauma. This can cause sharp, acute pain with certain movements, or a persistent ache that worsens at night.
Bursitis is another common musculoskeletal cause, characterized by inflammation of the bursae, small fluid-filled sacs that cushion bones, tendons, and muscles within the joint. When inflamed, these sacs cause sharp pain, swelling, and tenderness. Pain may be sudden or gradual, often intensifying with overhead arm movements or when lying on the affected side.
Adhesive capsulitis, known as frozen shoulder, can also cause sharp pain, progressing from a dull ache to stiffness and restricted motion. This condition involves the thickening and tightening of the shoulder capsule, leading to pain and reduced movement. Sprains and strains, from overstretching or tearing ligaments and muscles, can also produce sudden, sharp pain, along with swelling or bruising.
Arthritis, a degenerative joint condition, also contributes to shoulder pain. Osteoarthritis, a “wear-and-tear” type, causes sharp pain, stiffness, and reduced motion as protective cartilage breaks down. Inflammatory conditions like rheumatoid arthritis can also lead to shoulder pain due to joint lining swelling.
Referred Pain from Other Body Systems
Sharp left shoulder pain can originate from areas beyond the musculoskeletal system, known as referred pain. This occurs when pain signals from internal organs travel along shared nerve pathways, manifesting as discomfort in a distant location like the shoulder. For example, irritation of the diaphragm, innervated by the phrenic nerve, often causes referred shoulder pain.
Cardiac issues are a common cause of referred left shoulder pain, particularly with angina or a heart attack. When the heart muscle doesn’t receive enough oxygen-rich blood, pain can radiate from the chest to the left shoulder, arm, jaw, or back. This pain may be sharp, dull, or feel like pressure, and can worsen with physical activity or stress.
A ruptured spleen, located in the upper left abdomen beneath the diaphragm, can cause irritation from internal bleeding. This manifests as sharp left shoulder pain, known as Kehr’s sign, because the blood irritates the underside of the diaphragm, sending pain signals to the shoulder.
Pancreatitis, inflammation of the pancreas, can cause referred pain to the left shoulder blade. Pain from pancreatitis originates in the upper left or middle abdomen and may radiate to the back or below the left shoulder blade. This pain can become more severe after eating, especially fatty foods, and may worsen when lying flat.
Lung conditions, such as pleurisy or pneumonia, can also result in referred shoulder pain. Pleurisy, an inflammation of the lung lining, often causes sharp chest pain that intensifies with deep breaths or coughing, and this discomfort can extend to the shoulder. Nerve compression from the neck, known as cervical radiculopathy, can also cause sharp, radiating pain in the left shoulder and arm, sometimes with numbness or tingling.
When to Seek Medical Attention
While many causes of sharp left shoulder pain are not severe, certain symptoms warrant immediate medical evaluation. If the pain is sudden, intense, or crushing, especially when accompanied by chest pressure, shortness of breath, dizziness, or sweating, it could indicate a heart attack. These symptoms require emergency medical attention.
Seek prompt medical care if the pain occurs after an injury, such as a fall, and is accompanied by a visible deformity, swelling, or an inability to move the arm. Other signs include sudden weakness or numbness in the arm, or pain that does not improve after a few weeks of self-care. Persistent pain that interferes with sleep, limits daily activities, or is associated with fever or redness around the joint should also be assessed by a healthcare professional.