D. Referred pain
Referred pain arises from a deep visceral structure but is superficial at the presenting site (Fig. 11-1).
It results from central neural pathways that are common to the somatic nerves and visceral organs.
Examples include biliary tract pain (referred to the right inferior scapular area) and diaphragmatic irritation from any source, such as subphrenic abscess (referred to the ipsilateral shoulder).
II. Evaluation of Acute Abdominal Pain
Evaluation of the acute abdomen remains heavily influenced by patient history and physical exam findings. Ancillary imaging and lab tests can help to complete the diagnosis and guide treatment decisions.
A. History of present illness
Onset and duration of pain
Sudden onset of pain (within seconds) suggests perforation or rupture [e.g., perforated peptic ulcer or ruptured abdominal aortic aneurysm (AAA)]. Infarction, such as myocardial infarction or acute mesenteric occlusion, can also present with sudden onset of pain.
Rapidly accelerating pain (within minutes) may result from several sources.
Colic syndromes, such as biliary colic, ureteral colic, and small-bowel obstruction.
Inflammatory processes, such as acute appendicitis, pancreatitis, and diverticulitis.
Ischemic processes, such as mesenteric ischemia, strangulated intestinal obstruction, and volvulus.
Gradual onset of pain (over several hours) increasing in intensity may be caused by one of the following:
Inflammatory conditions, such as appendicitis and cholecystitis.
Obstructive processes, such as nonstrangulated bowel obstruction and urinary retention.
Other mechanical processes, such as ectopic pregnancy and penetrating or perforating tumors.