Learning medicine is hard work! Osmosis makes it easy. It takes your lectures and notes to create
a personalized study plan with exclusive videos, practice questions and flashcards, and so
much more. Try it free today! Peptic refers to the stomach, and an ulcer
is a sore or break in a membrane, so peptic ulcer disease describes having one or more
sores in the stomach – called gastric ulcers – or duodenum – called duodenal ulcers- which
are actually more common. Normally, the inner wall of the entire gastrointestinal
tract is lined with mucosa, which consists of three cell layers. The innermost layer is the epithelial layer
and it absorbs and secretes mucus and digestive enzymes. The middle layer is the lamina propria and
it has blood and lymph vessels. The outermost layer of the mucosa is the muscularis
mucosa, and it’s a layer of smooth muscle that contracts and helps with the break down
food. Now in the stomach, there are four regions
– the cardia, the fundus, the body, and the pyloric antrum. There’s also a pyloric sphincter, or valve
at the end of the stomach, which closes while eating, keeping food inside for the stomach
to digest. The epithelial layer in different parts of
the stomach contains different proportions of gastric glands which secrete a variety
of substances. Having said that, the cardia has mostly foveolar
cells that secrete mucus which is a mix of water and glycoproteins. The fundus and the body have mostly parietal
cells that secrete hydrochloric acid and chief cells that secrete pepsinogen, which is an
enzyme that digests protein. Finally, the antrum has mostly G cells that
secrete gastrin in response to food entering the stomach. These G cells are also found in the duodenum
and the pancreas, which is an accessory gland of the gastrointestinal tract. Now, gastrin stimulates the parietal cells
to secrete hydrochloric acid, and also stimulates the growth of glands in the epithelial layer. In addition, the duodenum has Brunner glands
which secrete mucus rich in bicarbonate ions. In fact, with all of the digestive enzymes
and hydrochloric acid floating around, the stomach and duodenal mucosa would get digested
if not for the mucus coating the walls and bicarbonate ions secreted by the duodenum
which neutralizes the acid. Since the stomach walls are constantly exposed
to the acid, they have a thick mucus layer than the duodenum which is only momentarily
exposed to the acid. In addition, the blood flowing to the stomach
and duodenum brings in even more bicarbonate which again helps neutralize the hydrochloric
acid. Finally, small signalling molecules called
prostaglandins get secreted in the stomach and duodenum. And they stimulate mucus and bicarbonate secretion,
as well as vasodilation of the nearby blood vessels which allows more blood to flow to
the area, and this promotes new epithelial cell growth, it also inhibits acid secretion. The main cause of gastric and duodenal ulcers
is infection with H. pylori bacteria, especially in low-income countries and settings. H. pylori are gram-negative bacteria that
colonize the gastric mucosa and release adhesins that help them adhere to gastric foveolar
cells as well as proteases that cause damage to mucosal cells. The majority of individuals with H. pylori
don’t develop any problems, but sometimes it causes a patchy pattern of damage that
starts in the antrum, and then spreads to the rest of the stomach and eventually into
the duodenum. Over time the damage erodes deeper and deeper
into the mucosa, eventually causing ulcers. Another cause of gastric ulcers, and less
so duodenal ulcers, are nonsteroidal anti-inflammatory drugs, or NSAIDS, like ibuprofen. NSAIDs inhibit the enzyme cyclooxygenase which
is involved in the synthesis of inflammatory prostaglandins. Reducing the level of prostaglandins over
a prolonged period of time, though, leaves the gastric mucosa susceptible to damage,
and over time ulcers can start to develop. A rare cause of peptic ulcer disease is Zollinger
Ellison syndrome, which is due to a tumor called a gastrinoma. A gastrinoma is a neuroendocrine tumor that
is typically located in the duodenal wall or pancreas, and secretes abnormal amounts
of gastrin. Excess gastrin stimulates parietal cells to
release excess hydrochloric acid, which overwhelms normal defense mechanisms and allows ulcers
to develop in the first portion of the duodenum or even in the distal duodenum or jejunum. Peptic ulcers that result from any of these
mucosa-damaging-mechanisms are usually small, round “punched out” holes in the mucosa. The ulcers usually have a clean base because
the hydrochloric acid secretions and the constant churning is bit like a dishwasher actually
keeping debris out of the ulcer! Typically, beneath the base is a layer of
scar tissue and blood vessels, and occasionally the ulcers can bleed if the erosion goes deep. Gastric ulcers typically form in the lesser
curvature of the antrum. Duodenal ulcers on the other hand usually
develop right after the pyloric sphincter and there’s usually Brunner gland hypertrophy
– which is a consequence of the body trying to produce more mucus to protect the damaged
area. Very deep ulcers can erode into underlying
blood vessels and can cause bleeding, which is a problem that is extremely dangerous when
there’s a nearby artery. That’s because hemorrhage into the gastrointestinal
tract can happen and this rapid loss of a lot of blood can ultimately lead to shock. Two well-known dangerous spots are when there’s
a gastric ulcer on the lesser curvature of the stomach eroding into the left gastric
artery, and a duodenal ulcer on the posterior wall of the duodenum eroding into the gastroduodenal
artery. Another complication is perforation, which
is when an ulcer erodes all the way through the wall of the stomach or duodenum, allowing
gastrointestinal contents -like undigested food and gastric secretions to get into the
peritoneal space – which is usually sterile. Perforation is a well-known complication of
duodenal ulcers on the anterior wall of the duodenum. When they perforate, air starts to collect
under the diaphragm, irritating the phrenic nerve, and sending referred pain up to the
shoulder. Finally, and very rarely, long-standing duodenal
ulcers near the pyloric sphincter, can sometimes have so much edema or scarring that they obstruct
the normal passage of gastric contents into the intestines resulting in gastric outlet
obstruction, this can quickly lead to nausea or vomiting since the food literally can’t
get by. The main symptom of gastric and duodenal ulcers
is epigastric pain, which is an aching or burning in the upper abdomen. Other symptoms are bloating, belching, and
vomiting. Classically, gastric ulcer pain increases
while eating a meal due to the physical presence of the food, as well as the hydrochloric acid
production stimulated by the process of eating, on the other hand duodenal ulcer pain decreases
while eating a meal. This may be why gastric ulcers are associated
with weight loss, while duodenal ulcers are associated with weight gain. Peptic ulcers can be diagnosed with upper
endoscopy, which is when a tube is snaked through the esophagus, into the stomach and
then the proximal duodenum in order to see the ulcer itself. Usually, during the procedure, a biopsy is
done to make sure that there are no signs of malignant cells and to see if there are
signs of an H. pylori infection. Treatment of peptic ulcers depends on the
underlying cause. If there’s an H. pylori infection, it’s
usually cured with a combination of antibiotics and acid-lowering medications, specifically
proton pump inhibitors. Substances that can worsen peptic ulcers include
NSAIDs, as well as alcohol, tobacco, and caffeine, so it’s best to stop using all of those
as soon as possible. And in really extreme cases, surgery may be

Leave a Reply

Your email address will not be published. Required fields are marked *