ABDOMINAL PAIN
Michael M Kline MD Division of Gastroenterology
Keck School of Medicine
AIMS
1. Pain Receptors 2. Pain Pathways 3. Physiological Mechanisms 4. Referred Pain 5. Acute Abdomen
PAIN RECEPTORS
Mechanical a. stretch b. torsion c. contraction d. distention Chemical and other a. products of inflammation b. pH changes c. temperature
PAIN PATHWAYS 1ST Order neurons
Travel with sympathetic nerves from the viscera to the spinal cord
2nd Order neurons Located in the dorsal horn a. travel with the spinothalamic and spinorecticular
tract to the brain stem Pain inhibition occurs at this site b. inhibitory local neurons (Gate theory) c. descending inhibitory fibers from the CN 3rd Order neurons Carry information to higher centers
NEURONAL PATHWAYS
PAIN PATHWAYS 2nd Order neurons
Located in the dorsal horn a.travel contra lateral with the spinothalamic and
spinorecticular tract to the brain stem b.travel ipsilateral with post synaptic dorsal
column Pain inhibition/modulation occurs at this site c. inhibitory local neurons (Gate theory) d. descending inhibitory fibers from the CN 3rd Order neurons Carry information to higher centers
NEURONAL PATHWAYS
PAIN PATHWAYS
2nd Order neurons Pain inhibition/modulation occurs at this site b. inhibitory local neurons (Gate theory) c. descending inhibitory fibers from the CN
GATE CONTROL THEORY
PAIN PATHWAYS
3rd Order neurons Carry information to higher centers
NEURONAL PATHWAYS
PATHOPHYSIOLOGICAL MECHANISMS
1. Visceral organ obstruction ie: small bowel obstruction due to adhesions, large bowel obstruction 2ndary to intra-luminal Ca.
2. Abnormal motility ie: small and /or large bowel pseudobstruction, Hirschsprungs disease.
3. Mucosal irritation ie: gastric and duodenal ulcer. Ulcerative colitis.
4. Vascular insufficiency ie: mesenteric angina, ischemic colitis
5. Peritoneal irritation ie: appendicitis, cholycystitis, pancreatitis, perforated viscus.
6. Metabolic aberrations ie. Porphyria, heavy metal poisoning.
7. Psycho pathology ie: irritable colon syndrome, non ulcer dyspepsia, chronic abdominal pain syndrome.
8. Referred pain ie: pain from a visceral source usually felt on the skin at site somewhat distant from the viscera involved.
REFERRED PAIN
Visceral pain felt at a site distant from the involved viscera ie: acute appendicitis felt initially in the upper abdomen.
REFERRED PAIN
REFERRED PAIN PATTERNS
ACUTE ABDOMEN
SUDDEN, UNEXPECTED PAIN DEVELOPING OVER A PERIOD OF 24 HOURS OR LESS.
ABDOMINAL PAIN ONSET
1. Sudden (seconds) a Perforation or rupture of viscus, abscess,
hematoma,peptic ulcer, abdominal aortic aneurysm, esophagus, ectopic pregnancy, pneumothorax
b. Infarction of gut, heart, lung
ABDOMINAL PAIN ONSET
Rapid (minutes) a. Colic: biliary, ureteral, small bowel obstruction b. Inflammatory: pancreatitis , diverticulitis,
peptic ulcer, appendicitis, cholecystitis, pneumonitis
c. Ischemia: Strangulation of obstructed intestine, mesenteric ischemia, torsion, volvulus
ABDOMINAL PAIN ONSET
Gradual (hours) a. Inflammation: appendicitis, cholecystitis,
pancreatitis, gastritis, IBD, diverticulitis, salpingitis, cystitis, intra abdominal abscess
b. Obstruction: of small bowel or colon, urinary retention, incarerated hernia, ectopic pregnancy.
c. Neoplastic: Perforating or penetrating tumors
DIAGNOSTIC STUDIES
1. Fecal leukocytes 2. Stool culture 3. Stool guaiac (OB) 4. Stool fat 5. Hepatitis serology for A,B,C,D and E 6. Liver enzymes 7. Amylase/Lipase 8. Paracentesis
DIAGNOSTIC STUDIES
9. EGD (endoscopy) 10. Flexible sigmoidscopy 11. Colonoscopy 12. Barium studies 13. Abdominal ultrasound, CAT and MRI 14. M to A capsule
ABDOMINAL PAINAIMSPAIN RECEPTORSPAIN PATHWAYSNEURONAL PATHWAYSPAIN PATHWAYSNEURONAL PATHWAYSPAIN PATHWAYSGATE CONTROL THEORYPAIN PATHWAYSNEURONAL PATHWAYSPATHOPHYSIOLOGICAL MECHANISMSSlide Number 13REFERRED PAINREFERRED PAINREFERRED PAIN PATTERNSACUTE ABDOMENABDOMINAL PAIN ONSETABDOMINAL PAIN ONSETABDOMINAL PAIN ONSETDIAGNOSTIC STUDIESDIAGNOSTIC STUDIES