Abdominal pain - classification, etiology, and pathogenesis.
Abdominal pain is a subjective sensation of discomfort or pain localized to the region between the chest and pelvis, caused by various visceral or somatic mechanisms.
Classification
- 1 By mechanism (pathophysiological type)
- 2 By onset
Etiology
Gastrointestinal causes
- Gastritis, peptic ulcer disease.
- Gastroenteritis.
- Appendicitis.
- Cholecystitis, biliary colic.
- Pancreatitis.
- Bowel obstruction or ischemia.
- Inflammatory bowel disease.
Hepatobiliary and pancreatic causes
- Hepatitis.
- Biliary colic due to gallstones.
- Chronic or acute pancreatitis.
Genitourinary causes
- Urinary tract infection.
- Nephrolithiasis (renal colic).
- Pelvic inflammatory disease.
- Ectopic pregnancy.
- Ovarian torsion or cyst rupture.
Vascular causes
- Mesenteric ischemia.
- Aortic aneurysm rupture.
Metabolic or systemic
- Diabetic ketoacidosis.
- Porphyria.
- Hypercalcemia.
Pathogenesis
Visceral pain
- Triggered by distension, stretching, or ischemia of hollow organs or capsules (e.g., biliary colic from duct obstruction).
- Poorly localized due to sparse sensory innervation.
- Accompanied by autonomic symptoms: nausea, sweating.
Parietal (somatic) pain
- Due to inflammation or irritation of the parietal peritoneum (e.g., peritonitis in appendicitis).
- Well localized, sharp, and aggravated by movement or coughing.
Referred pain
- Shared segmental nerve pathways cause pain to be felt at a site distant from the diseased organ (e.g., scapular pain from gallbladder irritation).