The location of pain is not well localized, but often has an

embryologic basis that aids in determining the diagnosis.

Epigastric pain occurs in patients with stretching of foregut organs (stomach to duodenum, including biliary tree

• Older and immunocompromised patients may have an

atypical presentation of disease.

• The white blood cel l count is an unreliable predictor of

disease and should not be used in isolation to confirm

or exclude a critical diagnosis.

and pancreas). Periumbilical pain represents pathology of

midgut organs (distal duodenum to transverse colon).

Suprapubic pain is due to problems of the hindgut organs

(distal transverse colon, rectum, and urogenital tract).

Parietal pain is due to irritation of the parietal peritoneum.

The patient is more readily able to localize the pain ( eg, left

lower quadrant pain in diverticulitis), but when the entire

peritoneal cavity is involved, the pain is diffuse. Referred

pain is defined as pain experienced at a site distant from its

source. Its anatomic basis lies in afferent nerves from different locations sharing the same spinal cord segment.

Abdominal pain may be referred from organs above the

diaphragm (eg, myocardial infarction causing epigastric

pain). Alternatively, abdominal pathology may refer pain

to sites above the diaphragm (eg, splenic rupture causing

shoulder pain).

Older and immunocompromised patients warrant special consideration as higher risk groups. Older patients

have a greater incidence of vascular catastrophes and surgical disease, with as high as 40% of patients older than

65 years requiring operative intervention (Table 26-1).

Compared with younger counterparts, older patients are

more likely to have atypical presentations, have nonspecific

symptoms, and present later in the disease course. In addition to being vulnerable to opportunistic pathogens,

irnmunocompromised patients may not develop peritoneal

1 1 2

ACUTE ABDOMINAL PAIN

Table 26-1 . Causes of abdominal pain in patients <50

and >50 years of age.

Age <50 Ofo Age >50 %

Nonspecific abdominal 40 Nonspecific abdominal 20

pain pain

Appendicitis 32 Cholecystitis 16

Cholecystitis 6 Appendicitis 15

Obstruction 3 Obstruction 12

Pancreatitis 2 Pancreatitis 7

Diverticulitis < 0.1 Diverticulitis 6

Hernia < 0.1 Cancer 4

Vascular < 0.1 Hernia 3

Cancer < 0.1 vascular 2

findings despite a serious underlying infection owing to

their blunted immune response. For both these popula ­

tions, a low threshold must be maintained to pursue critical diagnoses.