Mechanism of Pain in Right Lower Quadrant Abdominal Pain
The steady, aching pain precisely localized to the right lower quadrant and accentuated by coughing and movement is most consistent with parietal peritoneal irritation (somatic pain). 1
Pain Mechanism Classification
The clinical presentation described represents somatic pain arising from irritation of the parietal peritoneum, which is distinct from visceral pain in several key characteristics:
Somatic (Parietal) Pain Features
- Precisely localized to a specific anatomic region (in this case, the right lower quadrant) 1
- Steady and aching in quality rather than cramping or colicky 2
- Accentuated by movement, coughing, or jarring due to stretching of the inflamed peritoneum 1, 2
- Transmitted via somatic nerve fibers that innervate the parietal peritoneum, providing precise localization 2
Clinical Significance
This pain pattern strongly suggests localized peritoneal inflammation, most commonly from:
- Appendicitis (the most common surgical cause of right lower quadrant pain requiring surgery) 1, 2, 3
- Other inflammatory processes involving the parietal peritoneum in the right lower quadrant 3, 4
The parietal peritoneum is innervated by somatic nerves that correspond to the dermatomes of the overlying abdominal wall, allowing for precise anatomic localization 2. When inflamed structures (such as an inflamed appendix) contact the parietal peritoneum, the resulting irritation produces sharp, well-localized pain that worsens with any maneuver that stretches or moves the peritoneum 1.
Diagnostic Implications
The presence of peritoneal signs (pain with coughing and movement) indicates the need for urgent imaging evaluation, typically with CT abdomen and pelvis with IV contrast, which demonstrates 85.7-100% sensitivity and 94.8-100% specificity for appendicitis 1. This imaging approach identifies not only appendicitis but also alternative diagnoses in 23-45% of cases presenting with right lower quadrant pain 1, 5.
Critical Clinical Pitfall
Do not rely solely on the absence of fever to exclude serious pathology, as fever is absent in approximately 50% of appendicitis cases 5. The presence of localized peritoneal signs (pain with movement and coughing) is a more reliable indicator of parietal peritoneal inflammation requiring further evaluation 1, 2.