The following points highlight the three major diseases of gastrointestinal tract:- 1. Diseases of the Mouth 2. Diseases of the Oesophagus 3. Peptic Ulcer.
Gastrointestinal Tract: Disease # 1. Diseases of the Mouth:
Lesions primarily nutritional in origin are angular stomatitis, cancrumoris, nutritional parotitis and nutritional glossitis. Glossitis is often a presenting feature in pellagra, the sprue syndrome, pernicious anemia and iron deficiency anemia of long standing.
i. The Tongue:
(a) The tongue may be dry in mouth breathers and coated with whitish yellow fur in those persons who smoke excessively.
(b) A clean red tongue which is inflamed and painful (acute glossitis) suggests an acute primary deficiency of some members of the Vitamin B complex.
(c) A clean pale and smooth tongue (chronic atrophic glossitis) suggests pernicious anemia or a long-standing iron-deficiency anemia.
(d) A local ulcer may be due to an ill-fitting denture or malignant disease, but rarely nowadays syphilis or tuberculosis.
ii. The Teeth, Gums and Mouth:
(a) A bad taste in the mouth may be due to pyorrhoea.
(b) Inflammatory and hemorrhagic lesions in the mouth and gums can result from many causes, e.g., infections, haemolytic streptococci, drug reactions and blood diseases (acute leukemia, aplastic anemia).
(c) Any inflammatory condition of the mouth may contribute to a nutritional disorder.
If lesions are causing pain on chewing or swallowing, a fluid or semiliquid diet must be given until the condition is brought under control.
Gastrointestinal Tract: Disease # 2. Diseases of the Oesophagus:
(a) Difficulty in swallowing (dysphagia) is the main feature and may lead to choking and even inhalation of food causing pneumonia or death. Dysphagia results from a functional defect with failure of onward movement of the peristaltic waves; alternatively the wave may be adequate but a block caused by spasm, inflammation or malignant disease prevents the food from getting through the affected area.
(b) Appropriate relaxation and contraction of the smooth muscle at the cardia allow food to enter the stomach and prevent regurgitation of stomach contents into the oesophagus. If this neuromuscular mechanism is disturbed, dysphagia or heartburn may ensue.
(c) Dysphagia may be produced by a neurological disorder which damages the motor pathway between the cerebral cortex and peripheral muscle. Common causes are stroke and achalasia.
(a) It means indigestion or difficulty in digestion. Any gastrointestinal symptom associated with the taking of food is called dyspepsia, e.g., nausea, heartburn, epigastria pain, discomfort or distension.
(b) Dyspepsia may be a symptom of any organic disorder of the alimentary canal. It may also be caused by disease or disorder of structure outside the alimentary tract, e.g., the gall-bladder, pancreas, etc.
(c) It may be a symptom of a general disease, e.g., chronic nephritis and cardiac failure.
Dyspepsia and Acid Secretion:
(a) When dyspepsia occurs with achlorhydria, it is probably due to chronic gastritis, cancer of the stomach or disease of the gallbladder or to emotional states.
(b) Hyperchlorhydria may be found in peo-pie who have never suffered from dyspepsia. It is frequently found in patients with duodenal ulcer.
(c) Hydrochloric acid may be partially responsible for the pain and dyspepsia of the acute stage of peptic ulcer.
Management of Dyspepsia:
(a) Dyspepsia in young people may be due to overworking or over-worrying or eating meals when excessively tired or has been smoking excessively or taking too much alcohol. The patient should be advised to give up such habits. His symptoms will clear up rapidly.
(b) Dyspepsia occurring in middle age for the first time accompanied by weight loss should be carefully investigated without delay.
(c) Patients with functional dyspepsia need dietary advice. Patient may find that certain foods bring on their symptoms whereas other can be taken with impurity. Hence bland diets have been prescribed.
Gastrointestinal Tract: Disease # 3. Peptic Ulcer:
The term peptic ulcer is used because it appears to develop from a loss of ability of the mucosa to withstand the digestive action of pepsin and HCl. A balance exists between acid pepsin secretion and mucosal resistance. In patients with gastric ulcer, the secretion of acid is often within normal limits, but patients with duodenal ulcer nearly always have a high output of acid.
The great importance of gastric hyper secretion is supported by the intractable peptic ulceration of the Zollinger-Ellison syndrome in which gastrin produced by a tumour of the non- β-islet cells of the pancreas stimulates excessive gastric secretion by day and by night.
Mucin is a protective agent. It adheres to the stomach wall as a thin but resistant coating. It is secreted in response to local, nervous and hormonal influences.
Caffeine, ethanol, aspirin, and nicotine promote peptic ulcers. Peptic ulcers occur more frequently in persons with blood group “O” than in those in other groups and possibly with those with HLA-B5 antigens.
i. Clinical Features and Diagnosis:
(a) The commonest symptom is pain or discomfort in the upper central abdomen. It is usually described as burning or gnawing in character. The pain comes and goes and is related to meals.
(b) In duodenal ulcer it usually occurs when the stomach is empty and is relieved by meals. The pain of gastric ulcer often comes shortly after eating.
(c) Other symptoms are loss of weight, heartburn or vomiting. In some patients an ulcer causes no symptoms until a complication such as haemorrhage occurs.
(d) An ulcer bleeds slowly and there is melaena (black stools) and anemia. With a larger haemorrhage there is usually haematemesis; the blood which is vomited is changed to a dark brown colour.
(e) The spasm of the pyloric canal can give rise to a characteristic feeling of sickness and distension; this prevents some patients from taking food which would relieve their symptoms.
(f) Acid output is usually above the normal range in patients with duodenal ulcer, and low or absent in patients with carcinoma of the stomach.
ii. Medical Treatment:
Principles of treatment:
1. Rest, both physical and psychological.
2. A bland diet, given in small amounts at frequent intervals.
3. Drugs—antacids and secretory inhibitors.
4. Giving up smoking.
(a) Cimetidine and allied drugs by blocking the H2 receptors in the gastric mucosa reduce acid secretion. This relieves symptoms and may promote healing. The drug is given throughout the day for one to three months. These drugs have no adverse effects. Some physicians keep patients on the drugs for longer in the hope of preventing recurrence.
(b) Insoluble antacid powders (aluminium hydroxide, mangesium oxide or trisilicate) usually bring immediate relief of pain. Giving up smoking: The early deaths are not due to surgery or disease of the stomach but mainly to disease known to be associated with smoking (carcinoma of the lung, chronic bronchitis and coronary heart disease).
(a) Patients should avoid large meals by taking small amounts at a time for a number of times. This will reduce the risk of exposing the gastric and duodenal mucosa to excessive amounts of acid.
(b) When a patient has severe symptoms with pylorospasm or has had haemorrhage he should be given milk, eggs and fruit juice as the main ingredients.
(c) It is important to take Vitamin C since some patients have low reserves as a result of previous self-imposed dietary restrictions.
(a) When a patient curtails his business and social activities, symptoms are often relieved.
(b) Both physical and mental rest promote healing of an ulcer.
(c) Because of anxiety and emotional difficulties, they often need simple psychological support and hence they are admitted to hospital. Otherwise not required to be admitted to hospital.
Complications of medical treatment:
(a) Scurvy may result from the intake of milk diets for a long period by adults. An excess of soluble alkalis can lead to alkalosis with tetany. A condition known as the milk alkali syndrome may occur in patients who have taken large amounts of milk (more than 1 litre daily) and soluble alkali over long periods. Weakness, anorexia and lethargy are the characteristic features and there may be psychological disturbances.
(b) Hypercalcaemia may give rise to calcification in the kidneys and elsewhere.
(a) Ingestion of alcohol, drugs or other chemical irritants may be responsible for gastritis.
(b) The commonest drug causing gastritis is aspirin, often taken for headaches and menstrual pain.
(c) Atrophic gastritis may be due to an autoimmune reaction and this is responsible for the failure to secrete intrinsic factor and HC1 in pernicious anemia. It is also present in patients with severe iron deficiency anemia.
(d) It may also be present in metabolic disorders, e.g., uremia, carcinoma of the stomach.
(e) Clinical features are mild anorexia, vague discomfort, nausea and heartburn to severe and repeated vomiting accompanied by diarrhoea if there is associated enteritis. Sometimes the clinical picture may simulate acute peptic ulcer, and massive gastric haemorrhage may occur. Nausea, abdominal fullness, heartburn and pain occur before breakfast and improve as the day goes on.
(a) The symptoms are nausea, pain and vomiting and commonly follow an excess of alcohol, aspirin or other drugs.
(b) Treatment consists of stopping alcohol or the drug, sometimes washing out the stomach and giving alkalis.
(c) Water and electrolyte losses can be replaced by an oral rehydration fluid. With improvement of the condition the patient is given small feeds of milk and gradually returns to a normal diet within 1 to 2 days.
Disorders of the intestine:
The small intestine is the main site of absorption of nutrients. Normally absorption of all nutrients begins in the jejunum and is completed in the ileum except that of water and electrolytes which is completed in the colon.
Diarrhoea leads to depletion of water and electrolytes and may be due to disorders of the small or large intestine. The malabsorption syndrome arises when there is failure of digestion and absorption due to disorders of the small intestine. Failure to absorb fat is the main feature leading to steatorrhoea. Disorders of the colon leads to constipation.
Acute diarrhoeal diseases:
These diseases are caused by infections of the small and large intestine by pathogenic viruses, bacteria or protozoa. The term covers illnesses such as acute gastroenteritis, bacterial food poisoning, traveller’s diarrhoea, infantile diarrhoea and weanling diarrhoea, as well as the specific infections, bacillary dysentery and cholera.
The losses of water and electrolytes in the diarrhoea lead to dehydration of the body. If the diarrhoea is severe, death from dehydration may occur within one or two days, especially in young children, in the very old and in the undernourished.
The serious dehydration can be prevented by giving an oral dehydration solution (ORS) early in the disease. The solutions used consist mainly of common salt, sodium bicarbonate and glucose or other source of carbohydrate. They are cheap and can be administered safely by any mother in a primitive home.
i. Clinical features:
(a) The diarrhoea is usually accompanied by abdominal discomfort and nausea and often by vomiting.
(b) Fever, if present, is seldom high.
(c) When there is severe dehydration, there is circulatory collapse with a marked fall in blood pressure. This may be fatal or lead to death later from acute renal failure.
(d) Infections not only interfere with intestinal absorption but the cholera toxin causes active secretion of chloride by the intestinal mucosa. Then with the chloride, sodium and water flow out from the tissues into the lumen of the gut. In severe cholera as much as 1 litre of fluid may be lost in an hour. By this way death from cholera may arise within a few hours of the onset of the disease.
(e) Vomiting also increases the fluid loss and the accompanying loss of acid leads to an alkalosis which is a cause of drowsiness.
(f) Sweating may lead to a loss of a litre or more during the course of a hot day in the tropics by an adult, even when at rest. Fever also leads to sweating.
(g) An attack of diarrhoea reduces food intake. Repeated attacks in a young child cause protein-energy malnutrition. In this way infections are responsible for retarded growth and development of young children in poor communities and also for a large part of the deaths from malnutrition.
(a) WHO has recommended an oral rehydration solution which comprises of the followings?
The solution was first developed in Bangladesh for the treatment of cholera and weanling diarrhoea. It is there firmly established.
(b) Absorption of oral fluids is fully dependent on a good blood supply to the alimentary canal. Circulatory collapse, detected by a fall in blood pressure, indicates a need to replace fluid intravenously. This is also necessary when vomiting is severe.
(c) In young children, a lower concentration of NaCl may be desirable to avoid any risk of hypernatremia.
(d) Intestinal loss of potassium should be replaced and sodium bicarbonate (NaHCO3) may be needed to correct acidosis caused by starvation; rarely NH4Cl may be required to correct alkalosis arising from vomiting.
(e) Most physicians do not prescribe any antibiotic drug for an attack of acute diarrhoea. They select the appropriate drug after microbiological diagnosis.
Lack of digestive secretions and injury to the epithelial surface of the small intestine impair absorption of nutrients. The clinical features of under-nutrition and malnutrition for a long time is known as the malabsorption syndrome.
i. Clinical features:
(a) Loss of weight and edema in cases of long standing.
(b) Chronic diarrhea with abdominal discomfort and distension.
(c) Steatorrhea, increased fat in the feces, is frequently present, its severity depends on the amount of fat in the diet.
(d) There is usually diarrhea with a bulky stool that has an offensive smell and floats on water.
(e) Anemia is usually present due to impaired absorption of iron and folic acid.
(f) Nutritional glossitis, angular stomatitis and peripheral neuropathy arise from the deficiency of the B group vitamins.
(g) Prolonged failure of calcium absorption may lead to evidence of osteomalacia and to tetany.
(h) Haemorrhages may occur due to Vitamin K deficiency.
Sprue is the name given to a tropical disease in which the presenting features are sore mouth, fatty diarrhoea and associated secondary manifestations of under-nutrition and malnutrition.
Although there is defective absorption of fat, the absorption of water, electrolytes, glucose, vitamins and minerals is also impaired. These defects are associated with atrophy of the jejunal villi.
Sprue is a serious disease and may prove fatal without proper medical and dietary care. Full recovery is possible with proper treatment and if they leave the tropics.
(a) The cause of intestinal obstruction is mechanical or due to paralysis of the intestinal muscle (paralytic ileus).
(b) The common causes of mechanical obstruction are external hernias, volvulus, tumours of the colon, adhesions due to previous inflammatory disease or operation.
(c) Paralytic ileus is usually a consequence of peritonitis, resulting from any cause, e.g., a gastric or intestinal perforation or an abdominal operation.
(a) The chief features are vomiting, complete constipation and colicky pain which may be absent or slight in paralytic ileus.
(b) A serious loss of water and electrolytes results from the vomiting and from the stagnation of intestinal secretions in the dilated paralyzed loops.
(c) The loss of fluid from the circulation from the latter source may be several litres in 24 hours and this may lead to pre-renal uremia.
(d) The loss of potassium causes apathy, mental confusion and muscular weakness.
(a) Since intestinal obstruction is always serious it should be treated only in a hospital where surgical and biochemical help are available.
(b) Immediate operation is required for the relief of mechanical obstruction while it is strongly contraindicated in paralytic ileus.
(c) In paralytic ileus the distension of the paralyzed gut must be treated by continuous suction through a tube passed into the stomach or jejunum, and continued until the bowel recovers from its paralyzed state.
(d) In both types of obstruction the loss of fluid and electrolytes must be made good by appropriate infusions, and intravenous feeding is often needed.
Constipation is delay in passage of the feces. The presence of food in the stomach is a stimulus to a gastro colic reflex which causes movements of the colon and these may lead to feces entering the rectum. The reflex usually occurs after the first meal of the day. In some people the presence of liquid in the stomach initiates the reflex and a drink on rising may be sufficient to stimulate defecation.
Some healthy people do not defecate every day and a few do so once or twice a week. They should not be considered constipated, and constipation should only be diagnosed when delay in defecation causes discomfort and indigestion.
The two common causes of constipation are a small fecal bulk and persistent neglect of the call to defecate. Many diseases are associated with constipation. The bulk of the feces is mainly water and the amount of water depends on the amount of dietary fibre present and the capacity of the fibre to bind water. Low fibre diets cause constipation.
If the call to defecate is persistently neglected, the reflex mechanism becomes less sensitive and constipation results. Going to the toilet should become a habit early in life. Gastrointestinal diseases give rise to constipation and the irritable bowel syndrome.
Carcinoma of the colon and rectum sometimes present as constipation. Constipation is common in psychiatric disorders which cause depression. Any neurological disease causing lesions in the lumbal cord may affect the reflex centres responsible for defecation and lead to constipation.
Pregnant women and old people are often constipated. The pressure of the gravid uterus on the colon may delay movements of the contents. In old people the sensitivity of the neuromuscular reflexes in the colon may be impaired or they may become less aware of the presence of feces in the rectum.
When constipation occurs due to low intake of dietary fibres, there is often pain in the left side of the abdomen along the line of descending colon, and the feces may be passed as hard pellets. Passage of feces relieves the pain.
When the call to defecate is repeatedly ignored, a mass of inspissated fecal matter may accumulate in the descending colon. The fluid contents of the colon may run down the side of the mass and cause a watery diarrhoea.
(a) The intake of dietary fibre should be increased by the consumption of fruits and vegetables. The fibre has got water-holding capacity. The fruits and vegetables are oranges, apples, carrots and cabbages.
(b) A young child should be advised to go to the toilet at a regular time each day. An adult should not neglect to go to the toilet due to laziness, hurry or a lack of suitable accommodation. Once the reflex has been lost, it cannot be regained to move the bowels at the same time each day.
(c) Many laxatives are available. Their continued use may lead to excessive losses of potassium, sodium and water in the feces and is not recommended. Two mild laxatives that are recommended for short periods are lactulose and senna.
Lactulose is a sugar which is not absorbed in the small intestine but passes to the colon where it is partially broken down by bacteria. It reduces the absorption of water from the colon and increases the bulk of the feces. Senna is a glycoside which is broken down in the small intestine to emodin; this is absorbed into the blood stream and stimulates the muscles of the colon for 6 to 12 hours after administration of the senna.