FACTORS INFLUENCING GASTRIC SECRETION

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.