Dr. YK Amdekar suggests using a multifactorial approach while treating diarrhoea, stressing on the need for taking an elaborate patient history to correctly establish the cause and begin treatment.

 

Before you begin, take a quick quiz to test your knowledge.

 

What is diarrhoea?

It is defined as a change in bowel pattern that results in loose stools with increased frequency and child appears sick. Stool of normal consistency but passed more than 1-2 times a day may not justify the definition of diarrhoea and so also an occasional loose stool with normal frequency does not mean diarrhoea.

The first part of the definition – change in bowel pattern - is also important. This is because a young infant on exclusive breast feeds may pass as many as 10-15 loose, often watery stools per day and is not considered to be abnormal as there is no change in bowel pattern. Such an infant has always been passing loose frequent stools and it is physiological, not pathological. It is substantiated by infant being happy in spite of many loose stools, feeds well and also gains weight well.

Generally pathological stools – diarrhoea – makes a child sick and not happy, often with loss of appetite and dehydration depending on the amount of water loss. Thus, individual bowel pattern must be considered in relevance to diarrhoea especially when it is of mild degree, as it may simply be within normal limits for that individual.

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What is dysentery?

Diarrhoea associated with stools containing mucus and/or blood is referred to as dysentery. It is usually a disease of the large intestine – colon and is accompanied by abdominal pain. It represents severe inflammation and so the child is quite sick. However, a small amount of mucus in stools without blood or abdominal pain may not be called as dysentery and such a patient may not be sick. Mucus in stools indicates any source of irritation and not necessarily an infection. Dysentery is a type of diarrhoea mostly due to large intestinal disease. Whereas diarrhoea without mucus and blood generally represents small intestinal disease.

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How does diarrhoea occur?

If small intestinal contents are not absorbed properly, diarrhoea results. Small intestine receives consumed food partly after digestion. If food is not digested properly, it is not absorbed. Besides the amount of consumed food or fluid, much larger amounts of fluid are secreted by the small intestine. An adult may consume about 1.5 litres of fluid in a day but the small intestine of an adult secretes another 8.5 litres of the fluid and hence small intestine has a load of about 10 litres of fluid to be absorbed every day.

Normally, 80-85% of fluids are absorbed by the small intestine and only a small amount is delivered to the large intestine. If small intestine fails to absorb fluids, it results in a large amount of watery diarrhoea. If small intestine secretes larger amount of fluids than normal due to any disease as what happens in cholera, even normal small intestinal absorptive capacity cannot cope up with such a huge amount of secreted fluid, resulting in profuse diarrhoea with serious consequences such as hypovolemic shock.

Thus, when small intestinal secretions exceed absorption ability, diarrhoea results. It is clear how small intestinal diarrhoea produces a large amount of watery stools with resultant dehydration while large intestinal diarrhoea has a small amount of stool without dehydration but often with mucus and blood.

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What is indigestion?

This term is used loosely by layperson and may represent different problems related to gastrointestinal dysfunction. It may not even relate to digestion problem and really does not connote any specific disease or defect. If digestion is affected, it should be ideally be called as maldigestion – meaning abnormal digestion.

Digestion refers to breaking down of nutrients to smaller molecules that can be further absorbed. Proteins have to be hydrolysed to amino acids, complex carbohydrates to simple sugars referred to as monosaccharide and fats to small molecules of fatty acids. Digestion starts with chewing of food and salivary amylase helping in the first phase of carbohydrate digestion.

Stomach helps in digestion of proteins and pancreatic enzymes and bile along with small intestinal enzymes are responsible for the final process of digestion. If food is not digested, it cannot be properly absorbed and this results in diarrhoea. Maldigestion and malabsorption both present with diarrhoea.

Maldigestion is due to pancreatic disease or bile salt deficiency while malabsorption is the disease of the small intestine. It is the proximal part of the small intestine - jejunum that helps in absorption of most of the nutrients except vitamin B12 and bile salts that are absorbed by the distal part of the intestine – ileum.

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How to know which nutrients are not absorbed?

If weight loss is significant, it is calories that are not absorbed. Carbohydrates are the main source of calories and its malabsorption results in diarrhoea with gaseous abdominal distension and anal excoriation due to acidic stools. This is due to fermentation of unabsorbed carbohydrates in the colon by bacteria that produce gas and acidic stools. Protein malabsorption leads to oedema. Stools due to fat malabsorption are greyish white and foul smelling, often large in volume.

Anaemia may be a feature of iron, vitamin B12 or folic acid malabsorption. Calcium deficiency causes tetany, vitamin D deficiency rickets and vitamin K deficiency bleeding. Of course, all such deficiencies occur commonly due to deficient food intake of these substances rather than malabsorption.

Type of stools and resulting deficiency signs may suggest which nutrients are not absorbed from the intestine. This helps especially when nutrient intake is normal and still deficiency signs appear suggesting abnormal intestinal function.

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What are the causes of diarrhoea?

Infective causes: Acute diarrhoea is commonly caused by enteroviral infections in healthy infants and toddlers. Such infections are rare beyond toddler age and are not preventable even with good hygienic care. They are referred to as democratic infections as they occur in all socioeconomic groups.

1. Bacterial infections such as E.coli, Salmonella or Campylobacter are seen in malnourished children as well those who are exposed to contaminated food.
2. Toxins produced by Vibrio cholerae results in the most severe form of diarrhoea.
3. Diarrhoea is caused by toxins produced by bacterial infections such as Shigella but also may result from infection at sites other than intestines such as urinary tract infection (UTI) and is referred to as parenteral diarrhoea – meaning other than enteral infection. It occurs typically in infants and young children.
4. Other infections causing diarrhoea include parasites such as giardiasis and cryptosporidium and fungal infection mostly in immunocompromised patients. Tuberculosis does not present with diarrhoea as a major symptom.

Non-infective inflammatory causes:

1. Autoimmune disorders such as inflammatory bowel disease – commonly Crohn’s disease in children and ulcerative colitis in adults are not uncommon in children. They mimic infections as they also present with fever, stool microscopy showing pus cells and neutrophilic leucocytosis.
2. Kawasaki disease – generalised autoimmune multisystem disease – may also present with diarrhoea.

Non-inflammatory causes:

1. Acute malabsorption of carbohydrates as in case of transient lactose intolerance commonly occurs after viral infection. As lactase enzyme resides in the most superficial part of the mucosa, it is first to be disturbed resulting in lactose malabsorption as happens in viral infection. However, it is self-limiting. Congenital lactase deficiency is extremely rare. Children and adults who are not used to consume milk or milk products are likely to experience diarrhoea when exposed to such products. It is due to disuse atrophy of enzyme – lactase.
2. Drugs such as magnesium-containing antacids, H2 receptor antagonists such as cimetidine and ranitidine, proton pump inhibitors such as lansoprazole and omeprazole, digoxin and methyldopa are known to cause diarrhoea.
3. Irritable bowel syndrome refers to diarrhoea due to psychological factors such as stress, anxiety etc. Autoimmune disorders are not uncommon in children. Irritable bowel syndrome is seen more frequently now due to stressful life even in children.
4. Hunger diarrhoea occurs in infants who are poorly fed and greenish stools – stool containing bile in an ever hungry infant is a clue to diagnosis. 
5. Rarely hormonal disorders such as thyrotoxicosis and VIPoma also cause diarrhoea.
6. Diarrhoea is commonly caused by infections not only GI infections but also parenteral infections such as UTI.

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Limitations of laboratory tests in diarrhoea

Routine stool microscopy is not helpful in diarrhoea as the presence of mucus, few pus cells or even RBCs are non-specific abnormalities that are present in infections, non-infective inflammation as well as any other cause of intestinal irritation. It may pick up parasitic infection though it is not related to acute diarrhoea.

Stool should not be tested for lactose in acute diarrhoea as its presence does not equate to lactose intolerance. Stool culture has no place in routine clinical practice. Specific tests may be required for conditions such as celiac disease or inflammatory bowel disease.

Thus, stool test is not necessary to arrive at a diagnosis in case of diarrhoea. Aetiology of diarrhoea is guessed by history alone.

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Should diarrhoea be controlled?

Infections being the most common causes of diarrhoea, it is nature’s attempt to expel irritants – germs and inflammatory exudates – for effective cure. Hence it is not logical to attempt control of diarrhoea and in fact, it may be harmful. But useful constituents that are lost in diarrhoea must be replaced and they include water and electrolytes. It is best done by oral rehydrating solution (ORS) or any equivalent home-made solution that contains the ideal composition of sugar with sodium, potassium and bicarbonates as in “limbu-pani”. Coconut water is another natural alternative.

Zinc is known to hasten recovery from diarrhoea and is the only drug to be prescribed in addition to ORS. Probiotics may help to a small extent but are not necessary for acute diarrhoea. There is no need for diet restriction. Soya milk formula is not necessary for acute diarrhoea. Of course, specific therapy for bacterial or parasitic infections is obviously necessary.

ORS and Zinc is a standard treatment for diarrhoea that has no specific curative therapy. Probiotics have limited benefit and binding agents, enzymes and digestives have no role in the treatment of diarrhoea. Fortunately, binding agents are not prescribed anymore and so neither are anti-motility drugs.

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Chronic diarrhoea is a multifactorial problem contributed by malnutrition, persistent infection, allergy to animal proteins, malabsorption, bile acid irritation and often worsened by drugs and hence must be properly evaluated. It is beyond the scope of this article. Recurrent episodes of infective diarrhoea may be mistaken for chronic diarrhoea but a child with recurrent diarrhoea does recover completely in between episodes as against chronic diarrhoea that is persistent and so presents with progressive loss of weight.

Diarrhoea in children is referred to as “nutritional disease” because not only is it more common in malnourished children but diarrhoea itself promotes malnutrition and disturbs intestinal function. Hygiene is a common culprit, especially in bottle-fed infants. Recurrent diarrhoeal episodes may leave behind permanent defect in digestion and absorption. Hence prevention of diarrhoea is most important.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.