ulcer formation, it is not necessarily the primary factor, and
many patients with ulcers have normal or even subnormal rates
of acid secretion.
Many factors, including genetic susceptibility, drugs, alco-
hol, bile salts, and an excessive secretion of acid and pepsin, may
contribute to ulcer formation. The major factor, however, is the
presence of a bacterium,
that is present in
the stomachs of a majority of patients with ulcers or
(inﬂ ammation of the stomach walls). Suppression of these bac-
teria with antibiotics usually helps heal the damaged mucosa.
Once an ulcer has formed, the inhibition of acid secre-
tion can remove the constant irritation and allow the ulcer to
heal. Two classes of drugs are potent inhibitors of acid secre-
tion. One class of inhibitors acts by blocking a speciﬁ c class of
histamine receptors (H
) found on parietal cells, which stimu-
late acid secretion. An example of an H
is cimetidine. The second class of drugs directly inhibits the
-ATPase pump in parietal cells. Examples of these so-
called proton pump inhibitors are omeprazole and lansopra-
zole. Although both classes of drugs are effective in healing
(a) Video endoscopy of the upper GI tract: The physician passes
the endoscope through the mouth (or nose) down the esophagus,
stomach, and into the duodenum. A light source at the tip of the
endoscope illuminates the mucosa. The tip also has a miniature
video chip, which transmits images up the endoscope to a video
recorder (image shown in Figure 15–34b). Local treatments can
be applied and small tissue samples (biopsies) can be taken with the
endoscope. Earlier versions of this device used ﬁ beroptic technology.
(b) Image of duodenal ulcer taken through an endoscope (shown in
Figure 15–34a). The entire ulcer is about 2 cm across (the width of
(b) Courtesy of Fernando Carballo, M.D.