FACTORS INFLUENCING GASTRIC SECRETION
Gastric secretion is also influenced by some factors which increase the gastric secretion by stimulating gastric mucosa such as:
1. Alcohol
2. Caffeine.
COLLECTION OF GASTRIC JUICE
In human beings, the gastric juice is
collected by using Ryle tube. The tube is made out of rubber or plastic. It is passed
through nostril or mouth and through esophagus into the stomach. A line is
marked in the tube. The entrance of the tip of the tube into stomach is
indicated when this line comes near the mouth. Then, the contents of stomach
are collected by means of aspiration.
GASTRIC ANALYSIS
For analysis, the gastric juice is
collected from patient only in the morning. Analysis of the gastric juice is
done for the diagnosis of ulcer and other disorders of stomach.
Gastric juice is analyzed for the
following:
1. Measurement of peptic activity
2. Measurement of gastric acidity:
Total acid, free acid
(hydrochloric acid) and combined acid.
METHODS OF GASTRIC
ANALYSIS
1. Fractional Test
Meal (FTM)
After overnight fasting, the gastric
juice is collected. Then, the patient takes a small test meal called fractional
test meal (FTM).
Typical test meals are:
i. A piece of bread and a cup of tea
ii. Wheat biscuit and 400 mL of water
iii. 300 mL of oatmeal gruel.
Fractional gastric
analysis
After the ingestion of a test meal,
gastric juice is collected at every 15th minute for a period of two and a half
hours. All these samples are analyzed for peptic activity and acidity.
2. Nocturnal
Gastric Analysis
Patient is given a clear liquid diet
at noon and at 5 pm. At 7.30 pm, the tube is introduced into the patients’s stomach.
Then from 8 pm to 8 am, hourly samples of gastric juice are collected and
analyzed.
3. Histamine Test
After overnight fasting, the stomach
is emptied in the morning by aspiration. Then histamine is injected
subcutaneously (0.01 mg/kg). Histamine
stimulates secretion of hydrochloric acid in the stomach. After 30
minutes, 4 samples of gastric juice
are collected over a period of 1 hour at 15 minutes interval and analyzed.
1. GASTRITIS
Inflammation of
gastric mucosa is called gastritis. It may be acute or chronic. Acute gastritis is characterized
by inflammation of superficial layers of mucus membrane and infiltration
with leukocytes, mostly neutrophils. Chronic gastritis involves inflammation of
even the deeper layers and infiltration with more lymphocytes. It results in the
atrophy of the gastric mucosa, with loss of chief cells and
parietal cells of glands. Therefore, the secretion of gastric
juice decreases.
Causes of Acute
Gastritis
i. Infection with bacterium Helicobacter
pylori
ii. Excess consumption of alcohol
iii. Excess administration of Aspirin
and other nonsteroidal antiinflammatory drugs (NSAIDs)
iv. Trauma by nasogastric tubes
v. Repeated exposure to radiation
(rare).
Causes of Chronic
Gastritis
i. Chronic infection with Helicobacter
pylori
ii. Longterm
intake of excess alcohol
iii. Longterm
use of NSAIDs
iv. Autoimmune disease.
Features
Features of gastritis are
nonspecific. Common feature is abdominal upset or pain felt as a diffused burning sensation. It is
often referred to epigastric
pain. Other features are:
i. Nausea
ii. Vomiting
iii. Anorexia (loss of appetite)
iv. Indigestion
v. Discomfort or feeling of fullness
in the epigastric region
vi. Belching (process to relieve
swallowed air that is accumulated in stomach).
2. GASTRIC ATROPHY
Gastric atrophy is the condition in
which the muscles of the stomach shrink and become weak. Gastric glands also
shrink, resulting in the deficiency of gastric juice.
Cause
Gastric atrophy is caused by chronic
gastritis called chronic atrophic gastritis. There is atrophy of gastric
mucosa including loss of gastric
glands. Autoimmune
atrophic gastritis also
causes gastric atrophy.
Features
Generally, gastric atrophy does not
cause any noticeable symptom. However, it may lead to achlorhydria (absence of
hydrochloric acid in gastric juice) and pernicious anemia. Some patients
develop gastric cancer.
3. PEPTIC ULCER
Ulcer means the erosion of the surface
of any organ due to shedding or sloughing of inflamed necrotic tissue that lines the organ.
Peptic ulcer means an ulcer in the wall of stomach or duodenum, caused by
digestive action of gastric juice. If peptic ulcer is found in stomach, it is
called gastric
ulcer and
if found in duodenum, it is called duodenal ulcer.
Causes
i. Increased peptic activity due to
excessive secretion of pepsin in gastric juice
ii. Hyperacidity of gastric juice
iii. Reduced alkalinity of duodenal
content
iv. Decreased mucin content in gastric
juice or decreased protective activity in stomach or
duodenum
v. Constant physical or emotional
stress
vi. Food with excess spices or smoking
(classical causes of ulcers)
vii. Longterm use of NSAIDs (see
above) such as Aspirin, Ibuprofen and Naproxen
viii. Chronic
inflammation due to Helicobacter
pylori.
Features
Most common feature of peptic ulcer is
severe burning pain in epigastric region. In gastric ulcer, pain occurs while
eating or drinking. In duodenal ulcer, pain is felt 1 or 2 hours after food
intake and during night. Other symptoms accompanying pain are:
i. Nausea
ii. Vomiting
iii. Hematemesis (vomiting blood)
iv. Heartburn (burning pain in
chest due to regurgitation
of acid from stomach into esophagus)
v. Anorexia (loss of appetite)
vi. Loss of weight.
4. ZOLLINGER-ELLISON
SYNDROME
ZollingerEllison syndrome
is characterized by secretion of excess hydrochloric acid in the stomach.
Cause
This disorder is caused by tumor of
pancreas. Pancreatic tumor produces a large quantity of gastrin. Gastrin increases
the hydrochloric acid secretion in stomach by stimulating the parietal cells of
gastric glands.
Features
i. Abdominal pain
ii. Diarrhea (frequent and watery,
loose bowel movements)
iii. Difficulty in
eating
iv. Occasional hematemesis.
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