Editing The acute abdomen (section)

=== History ===

* Age/demographics
** Think about which conditions are likely
* Exact time and mode of onset
** Sudden onset - think perforated ulcer, acute pancreatitis, ruptured AAA/ectopic, ovarian torsion
* Pain
** Character
** Radiation
** Shifting
*** Irritation of somatic nerves
*** Either direct inflammation of an organ, or fluid (e.g. gastric contents moving to RIF in perforated ulcer)
** Postural 
*** Retroperitoneal pain is worse when lying back
** Worse with eating - SBO, biliary colic, pancreatitis, diverticulitis, bowel perforation
** Better with eating - non-perforated PUD or gastritis
* Vomiting
*# Severe irritation of peritoneal/mesenteric nerves
*#* Vomiting will be early
*# Obstruction of an involuntary muscular tube
*#* Vomiting can be later
*#* Early vomiting in SBO indicates high obstruction
*#* Pain almost always prior to vomiting in appendicitis
** Acute gastritis - non-bilious
** Obstructions - bilious
*** First gastric contents, then bilious, then yellow-green, then yellow, then orange/brown faeculent 
** In surgical conditions, vomiting will come after pain. The vomiting is secondary to stimulation of medullary afferent fibres triggered by visceral afferent pain fibres. In medical causes of vomiting, the vomiting often precedes abdominal pain.
* Bowels
* Menstruation