


Abdominal pain

Abdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of a person's abdominal pain can be quite difficult, because so many diseases can result in this symptom.





Types and mechanisms

1. The pain associated with inflammation of the parietal peritoneum is steady and aching, and worsened by changes in the tension of peritoneum caused by pressure or positional change, and is often accompanied by tension of the abdominal muscles contracting to relieve such tension.

2. The pain associated with obstruction of the hollow viscera is often intermittent or "colicky"

3. The pain associated with abdominal vascular disturbances (thrombosis or embolism) can be sudden or gradual in onset, and can be severe or mild. Pain associated with the rupture of an abdominal aortic aneurysm may radiate to the back, flank, or genitals.

4. Pain that is felt in the abdomen may be "referred" from elsewhere (e.g., a disease process in the chest, like a subdiaphragmatic abscess, may cause pain in the abdomen), and abdominal processes can cause radiated pain elsewhere (e.g. gall bladder pain—in cholecystitis or cholelithiasis—is often referred to the shoulder).

Selected causes

* parietal peritoneal inflammation

o due to infection: perforated appendix in appendicitis, pelvic inflammatory disease

o due to chemical irritation: perforated gastric or peptic ulcer; pancreatitis, Mittelschmerz, ruptured ectopic pregnancy

o miscellaneous (familial Mediterranean fever)

* mechanical obstruction of hollow viscera such as the small intestine, the large intestine, the biliary tree (e.g. by gallstones), or the ureter (e.g. by urinary calculi)

* vascular disturbances: embolism, thrombosis, vascular rupture, torsional occlusion, sickle cell anemia

* abdominal wall injury: mesenteric traction, muscle trauma, muscular infection

* distention of visceral surfaces such as the hepatic or renal capsule

* referred pain from the thorax (pneumonia, coronary occlusion), the spine (radiculitis secondary to arthritis), genitals (testicular torsion)

* metabolic disturbance: lead poisoning, Black widow spider bite, uremia, diabetic ketoacidosis, porphyria, C1-esterase inhibitor deficiency, adrenal insufficiency

* neurogenic pain: tabes dorsalis, herpes zoster, Lyme disease (Lyme radiculitis or Bannwarth syndrome)

* functional pain, irritable bowel syndrome

