A dull vague pain comes from the viscera which are innervated by autonomic nerves. This pain means there is distention or muscular contraction going on. It is poorly localized: Upper area means stomach, duodenum, liver, pancreas; umbilical means small intestine, proximal colon, appendix; lower area means distal colon or genitourinary tract.

A sharp pain that is well localized comes from the parietal peritoneum which is innervated by somatic nerves. This pain signal means there is inflammation from infectious or chemical irritation.

peritonitis may be caused by a perforation, inflammation (appendicitis, if reticulitis, strangulating intestinal obstruction, pancreatitis, pelvic inflammatory disease, mesenteric ischemia), intraperitoneal blood (ruptured aneurysm, trauma, ectopic pregnancy)

could our case be some type of a hematoma due to trauma irritating the peritoneum? Is the ectopic pregnancy causing bleeding?

Peritonitis causes fluid to head into peritoneal cavity. This causes dehydration and electrolyte imbalance. Kidney and liver failure and DIC can follow. Masklike face appearance can be seen.

Pain can also go to the scapula (biliary colic), the groin (renal colic), and shoulder (blood or infection irritating the diaphragm).

Acute waves of sharp pain: Renal/biliary colicWaves of dull pain: Intestinal obstructionSharp constant pain worsened by movement: PeritonitisSevere pain: kidney stone, peritonitis, pancreatitisLack of motion helps: Peritonitisand in a good