From the Research
Left upper quadrant (LUQ) pain that radiates to the scapula is typically not due to nerve dermatomes from embryonic life, but rather due to referred pain from inflamed organs like the spleen, pancreas, or stomach. This occurs through shared visceral innervation pathways rather than dermatome relationships, as supported by studies on the effects of non-steroidal anti-inflammatory drugs (NSAIDs) on acute pancreatitis, such as the one published in 2022 1. The mechanism involves convergence of visceral and somatic sensory inputs at the spinal cord level, causing the brain to misinterpret the pain's origin. Some key points to consider include:
- Splenic issues may refer pain to the left shoulder (Kehr's sign) via irritation of the diaphragm and phrenic nerve.
- Pancreatic inflammation can also cause left-sided back pain through direct inflammation of retroperitoneal tissues.
- Understanding these pain referral patterns is important for accurate diagnosis of abdominal conditions, as the location of referred pain often provides clues about which organ system is affected.
- A study from 2022 1 found that prior exposure to NSAIDs reduces the rate of organ failure and in-hospital mortality in acute pancreatitis, highlighting the potential benefits of NSAIDs in managing abdominal pain.
- However, it's also important to note that NSAIDs can rarely cause acute pancreatitis, as reported in a case study from 2019 2. Overall, the most recent and highest quality study 1 suggests that LUQ pain radiating to the scapula is more likely related to referred pain from abdominal organs rather than nerve dermatomes from embryonic life.