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Health Blog by Dr.Uday Nair


Diarrhoea is a term that is used to describe stools that are more liquid and frequent than normal. There is no absolute definition of what constitutes diarrhoea, but various definitions are utilized for the purpose of research, such as three or more unformed stools within 24 hours. Dysentery is a term used for diarrhoea when there is evidence that the organisms are invading the intestinal wall, causing pus, mucus, and blood to appear in the stool. There is often fever and abdominal cramps as well.

Causes of Diarrhoea and Dysentery

Diarrhoea may be caused by a temporary problem like an infection, or a chronic problem like an intestinal disease. A few of the common causes of diarrhoea are :

Viral infection : Many viruses cause diarrhoea, including rotavirus, Norwalk virus, cytomegalo virus, herpes simplex virus, and viral Hepatitis virus.
Bacterial infections : Several types of bacteria, consumed through contaminated food or water, can cause diarrhoea. Common culprits include Campylobacter, Salmonella, Shigella, and Escherichia coli.
Food intolerances : Inability to digest some component of food, such as lactose, the sugar found in milk.
Parasites : Parasites can enter the body through food or water and settle in the digestive system. Parasites that cause diarrhoea include Giardia lamblia, Entamoeba histolytica, and Cryptosporidium.
Reaction to medicines : Antibiotics, blood pressure medications, and antacids containing magnesium are known to cause diarrhoea in some.
Intestinal diseases : Diseases like inflammatory bowel disease or celiac disease can also lead to diarrhoea.
Functional bowel disorders : Irritable bowel syndrome, in which the intestines do not work normally, can result in diarrhoea.

Bacteria and viruses that can cause diarrhoea have an incubation period of a few hours up to 2-3 days. Protozoa such as Giardia and E. histolytica have an incubation period of 7-14 days. Food poisoning generally occurs within2-8 hours after eating the toxin.

Bacterial diarrhoeas invariably have an abrupt onset. That means the patient can tell the exact time of the day that he/she began to feel ill. Often, the illness begins in the middle of the night, or early morning. The patient suffers sudden cramps and feels the urge to defecate, and the result is a very liquid stool. As soon as he gets back to bed, he has to run again. Bacterial diarrhoea can be accompanied by nausea, vomiting, and fever, but the diarrhoea can occur all by itself.

With Giardia, the day starts with a couple of loose bowel motions and the rest of the day the bowels are normal. In the evening there may be one or two more loose stools. The night is peaceful. The cycles repeat the next day. After a few days, there will be a grumbly feeling in the intestines, increased gas, and a growing sense of fatigue.

Amoebic diarrhoea presents as a chronic, low-grade diarrhoea that alternates every 1-3 days. The patient experiences diarrhoea for a day or so, then no diarrhoea the next day, and then diarrhoea again. Gradually he/she experiences weight loss and fatigue, and comes to the doctor after being sick for a month or more. Amoebic dysentery is a severe form of amoebic infection that causes severe crampy diarrhoea with multiple small bowel movements, often with blood.

Some people develop diarrhoea after stomach surgery or removal of the gall bladder. The reason may be a change in how quickly food moves through the digestive system after stomach surgery or an increase in bile in the colon that can occur after gall bladder surgery.

Diarrhoea can be either acute(short term) or chronic(long term). The acute form, which lasts less than four weeks, is usually related to a bacterial, viral, or parasitic infection. Chronic diarrhoea lasts more than four weeks and is usually related to functional disorders like IBS or inflammatory bowel diseases.

Symptoms and Signs of Diarrhoea and Dysentery

Diarrhoea may be accompanied by cramping abdominal pain, bloating, nausea, or an urgent need to defecate. Depending on the cause, a person may have fever or blood stools. Prolonged diarrhoea leads to dehydration. The signs of dehydration include.

1 Thirst
2 Less frequent urination
3 Dry skin
4 Fatigue
5 Light-headedness
6 Dark-coloured urine

Diagnosis of Diarrhoea and Dysentery

History is the single most useful tool in determining the probable cause of diarrhoea.

Stool examination

Presence of white blood cells or red blood cells, which can be indirect signs of bacterial infection ( such as Shigella). The organisms that can be identified by stool examination are the

protozoa : Giardia, Entamoeba histolytica, Cycolospora, and Cryptosporidium.

When should a doctor be consulted

Although usually not harmful, diarrhoea can become dangerous or signal a more serious problem. The doctor should be consulted if any of the following occurs :

1 Presence of signs of Dehydration.
2 Severe pain in the abdomen or rectum.
3 Fever of 102o F or higher
4 Blood in stool or black, tarry stools.
5 Diarrhoea for more than three days. 

Treatment of Diarrhoea and Dysentery

In most cases, replacing lost fluid to prevent dehydration is the only treatment necessary. This is the main treatment in viral diarrhoea. However, a variety of medications exist to help ease the discomfort and length of diarrhoea. These are :
Drugs that provide symptomatic relief without shortening the infection. These are bowel paralysers ( lomotil, Imodium, dicyomine) and bulk formers (kaolin land pectate). These are not recommended for people whose diarrhoea is caused by a bacterial infection or parasite, as stopping the diarrhoea traps the organism in the intestines, prolonging the problem. Instead, antibiotics are usually prescribed.
Drugs that are aimed at curing the infection, like antibiotics and antiprotozoals. Bacterial diarrhoea can be safely cured with an antibiotic. ,The antibiotics used are either norfloxacin or ciprofloxacin. The length of illness can usually be reduced to 1-2 days with treatment. 

Preventing Dehydration of Diarrhoea and Dysentery

Dehydration occurs when the body has lost too much fluid an electrolytes ( the salts potassium and sodium). The fluid and electrolytes lost during diarrhoea need to be replaced promptly- the body cannot function properly without them. Although water is extremely important in preventing dehydration, it does not contain electrolytes. To maintain electrolyte levels, one should drink the juice of half a lemon with a pinch of salt, a teaspoon of sugar and a glass of water. This is also known as Oral Rehydration Solution (ORS). It is also commercially available in a variety of flavours. A glass of ORS should be consumed for every loose motion.

Tips about Food for Diarrhoea and Dysentery

Until diarhoea subsides, milk products, greasy, high-fibre, or very sweet foods should be avoided, as these aggravate diarrhoea. As diarrhoea improves soft, bland foods like bananas, plain rice, boiled potatoes and bread can be added to the diet.

Prevention of Diarrhoea and Dysentery

The best way to avoid getting diarrhoea is to be conscious of how one can avoid eating or drinking substances that may be contaminated with stool. However, the cleanliness maintained to restaurants at which one has food is something that may not be obvious, and over which one has no control. A few ordering tips may help prevent some cases of diarrhoea:

Many vegetables and fruits become contaminated on their surfaces, either in the fields or in transit to markets. The insides stay clean, and can be eaten safely after the skin is removed.
Sufficient heat destroys all microorganisms and their toxins. Any food item which is thoroughly cooked or heated throughout, and is served while still hot is safe to eat.
Water served at hotels and restaurants may not have been boiled, and should be avoided. Ice is often made from untreated water, and freezing does not kill the organisms that can cause diarrhoea. 
Carbonated soft drinks are safe because carbonation lowers the pH of the drink (making it acidic) , and this acidic environment kills all the bacteria.
Beer would be a safe choice. Stronger alcoholic beverages would be safe in themselves, but any drink mixed with water will not make it safe to drink. 

Water Purification and Personal Hygiene

There are three main methods of decontaminating water: (i) heat (boiling) ; (ii) chemical disinfection (iodine or chlorine); and (iii) filtration. The first two methods are equally effective. Filtration alone almost never renders water safe to drink because of the presence of viruses that can't be filtered. Filtration must be used in conjunction with chemical treatment in this setting. Boiling has the advantage of not altering the flavour of the water. Chemical decontamination does not require wood or fuel, but can add a slight taste to the water.

There are tow different end points in water purification: disinfection ( to make it safe to drink), and sterilization ( which would make it safe to use in surgery, for example). Therefore, for the purpose of drinking water, disinfection should be the goal. All organisms that can cause diarrhoea begin to get killed at 140oF (65oC). The length of time that water takes to go from 140oF to boiling point ( 212oF; 100oC) is sufficient to decontaminate the water for drinking. A few bacteria exist as hardly 'spores', which can resist high temperatures for a certain length of time. The boiling time of 20 minutes has been suggested to sterilize water and completely eliminate these spores. However, the spores cannot cause diarrhoea when ingested. Therefore, just bringing water to a boil renders it safe to drink.

Many brands of filters are marketed to the public to purify drinking water. A filter has to have an absolute filter side of 0.2 microns or less in order to filter out pathogenic bacteria. Giardia and amoebic cysts are easy to filter, as they are 5-8 microns in size. Viruses are more than 8 times smaller than a 0.2 micron filter pore, so they can readily pass through. This is why chemical treatment is necessary in addition to filtration. 

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