Shoulder Pain: Beyond Musculoskeletal Causes, Referred Pain, and When to Seek Medical Attention

What disease has a symptom of shoulder pain?

Shoulder pain, while commonly associated with musculoskeletal issues, can also be a significant symptom of various underlying systemic diseases, often due to referred pain pathways or direct impingement on structures.

Beyond Musculoskeletal: Understanding Referred Shoulder Pain

While direct injury, overuse, or degenerative conditions of the shoulder joint itself are the most frequent causes of shoulder pain, it is crucial for fitness professionals and enthusiasts alike to understand that pain in the shoulder region can originate from pathologies in distant parts of the body. This phenomenon, known as referred pain, occurs when nerve signals from internal organs or other body regions converge on the same spinal cord segments that receive sensory input from the shoulder. The brain then interprets these signals as originating from the shoulder, even though the actual problem lies elsewhere. Recognizing these non-musculoskeletal causes is vital for appropriate medical referral and diagnosis.

Cardiovascular Conditions

Pain radiating to the shoulder can be a critical sign of cardiac distress, particularly in the left shoulder and arm.

• Myocardial Infarction (Heart Attack): A heart attack occurs when blood flow to a part of the heart is blocked. Pain can radiate from the chest to the left shoulder, arm, neck, jaw, or back. This referred pain is due to the shared neural pathways of the heart and the left arm/shoulder at the C8-T1 spinal levels.
  • Associated Symptoms: Chest pressure, tightness, squeezing, or aching; shortness of breath; nausea; lightheadedness; cold sweats.
• Angina: This is chest pain or discomfort caused by reduced blood flow to the heart muscle. Like a heart attack, it can cause referred pain to the left shoulder and arm, though it is typically triggered by exertion and relieved by rest or medication.

Gastrointestinal Conditions

Certain abdominal conditions can manifest as shoulder pain, primarily through irritation of the diaphragm.

• Gallstones/Cholecystitis: Inflammation of the gallbladder, often due to gallstones, can cause severe upper right abdominal pain that refers to the right shoulder or scapula. This occurs because the phrenic nerve, which innervates the diaphragm, shares nerve roots (C3-C5) with the nerves supplying the right shoulder.
• Diaphragmatic Irritation:
  • Peptic Ulcer Disease: A severe ulcer that irritates the diaphragm can cause referred pain to the shoulder, often the left.
  • Pancreatitis: Inflammation of the pancreas can cause pain that radiates to the back and sometimes the left shoulder.
  • Gastroesophageal Reflux Disease (GERD): While less common, severe, chronic GERD can sometimes cause referred pain to the chest and shoulder, mimicking cardiac symptoms.
  • Splenic Rupture: Though acute and traumatic, a ruptured spleen causes severe left upper quadrant pain that typically refers to the left shoulder (Kehr's sign) due to diaphragmatic irritation.

Pulmonary Conditions

Lung and pleural pathologies can also lead to shoulder pain.

• Pancoast Tumor (Lung Cancer): This is a rare type of lung cancer that develops in the apex (top) of the lung. As it grows, it can invade nearby structures such as the brachial plexus (a network of nerves that supply the arm and shoulder), ribs, and vertebrae, causing severe pain in the shoulder, arm, and hand.
  • Associated Symptoms: Horner's syndrome (drooping eyelid, constricted pupil, decreased sweating on one side of the face), muscle weakness, and atrophy in the hand.
• Pleurisy: Inflammation of the pleura (the membranes lining the lungs and chest cavity) can cause sharp chest pain that worsens with breathing. If the inflammation affects the diaphragmatic pleura, pain can be referred to the shoulder via the phrenic nerve.

Neurological Conditions

Nerve compression or irritation originating in the neck can often manifest as shoulder pain.

• Cervical Radiculopathy: This condition occurs when a nerve root in the cervical spine (neck) is compressed or irritated, often due to a herniated disc, spinal stenosis, or degenerative changes. Pain, numbness, tingling, or weakness can radiate from the neck down into the shoulder, arm, and hand. The specific location of pain depends on which nerve root is affected.
• Thoracic Outlet Syndrome (TOS): This involves compression of nerves (brachial plexus) or blood vessels (subclavian artery/vein) in the space between the collarbone and first rib. TOS can cause pain, numbness, tingling, and weakness in the shoulder, arm, and hand.

Systemic/Inflammatory Conditions

Generalized inflammatory or autoimmune conditions can also cause shoulder pain as part of their broader symptom profile.

• Polymyalgia Rheumatica (PMR): An inflammatory disorder causing muscle pain and stiffness, predominantly in the shoulders and hips. The stiffness is often worse in the morning and can be debilitating.
  • Associated Symptoms: Fatigue, fever, weight loss, and general malaise.
• Fibromyalgia: A chronic disorder characterized by widespread musculoskeletal pain, fatigue, and tenderness in specific areas, including the shoulders.
• Rheumatoid Arthritis (RA): An autoimmune disease that causes chronic inflammation of the joints. While it often affects smaller joints first, it can involve larger joints like the shoulders, leading to pain, swelling, stiffness, and reduced range of motion.
• Systemic Lupus Erythematosus (SLE): Another autoimmune disease that can cause joint pain and inflammation, including in the shoulders.

When to Seek Medical Attention

While many cases of shoulder pain are benign and resolve with conservative management, it is critical to recognize when medical evaluation is warranted, especially when non-musculoskeletal causes are suspected. Seek immediate medical attention if shoulder pain is accompanied by:

• Chest pain, pressure, or tightness.
• Shortness of breath, dizziness, or sweating.
• Sudden onset of severe, unexplained shoulder pain.
• Pain that does not change with movement or position.
• Pain accompanied by fever, chills, or unexplained weight loss.
• Pain following significant trauma.
• Pain that radiates down the arm with numbness, tingling, or weakness.
• Persistent pain that worsens over time despite rest or conservative measures.

Conclusion

Shoulder pain is a complex symptom that can originate from a wide array of sources, extending far beyond the typical musculoskeletal injuries. As informed individuals, understanding the potential for referred pain from cardiovascular, gastrointestinal, pulmonary, neurological, and systemic conditions is paramount. While this knowledge is valuable for recognizing red flags and guiding appropriate action, it is essential to remember that self-diagnosis is not a substitute for professional medical evaluation. Any persistent, severe, or concerning shoulder pain, particularly when accompanied by other systemic symptoms, warrants prompt consultation with a healthcare professional to ensure accurate diagnosis and timely intervention.