Diarrhea

Clinically, diarrhea is defined as three or more loose stools or watery bowel movements daily, or a frequent increase above an individual’s baseline. The normal diary stool can weigh as much as 300 g/mg when high fiber diet is consumed. Hence, the frequent passage of formed stool is not diarrhea.

Diarrhea can be divided into three types:
1. Acute diarrhea (≤ 14 days)
2. Persistent diarrhea (>14 and ≤30 days)
3. Chronic diarrhea (> 30 days in duration)

Key questions on the history
1. How long is the history?
2. Are there systemic symptoms–fever, tachycardia, or vomiting?
3. Is there blood in the stool?
4. Any contact with people or family members showing the same symptoms?
5. If they have taken any drugs or other remedies?
6. Any decrease in urine output?

On examination:
– Always look for signs of dehydration and malnutrition.
– Measure temperature, pulse, and B.P.
– Look for signs, including skin turgor, alertness, irritability, and consciousness.

Nepal is a developing country. Diarrhea, either acute or persistent, is very common due to infected food, water, and poor personal hygiene. It occurs either due to ingestion of entero-pathogens that multiply in the gut, or ingestion of preformed toxin in food contaminants with enterotoxin producing microorganisms.

Pathophysiology
Diarrhea results from an excess of stool water due to abnormal net intestinal water and electrolyte transport.

There are three mechanisms that may contribute to diarrhea:
1. Reduction of net water absorption by as little as 1% (9-10 L/daily normal absorption)
2. Rapid transit that reduces time available for water absorption.
3. Change in composition of stool solids that may alter stool consistence.

Diarrheal outbreak is seen in many places of Nepal in this season. Most common organisms that lead to the outbreak are:
– E Coli
– Giardiasis
– Entamoebahistolytic
– Outbreaks of cholera

Cholera causes significant morbidity and mortality, and is one of the major public health problems in lower socio-economic groups. The most common types of cholera found in Nepal are sero group 01 and serotype Ogawa. There were also a few multidrug-resistant Vibrio cholera seen in Nepal. It is a major problem and an increasing global burden. Regular surveillance of outbreaks is very important for effective cholera management.
In October last year, Vibrio cholera outbreak in Kapilvastu district killed at least four people. The National Public Health Laboratory has recently confirmed four cases from Kathmandu. Vibrio cholera 01 Ogawa serotype has been confirmed in stool samples of all the infected patients. The World Health Organization has mentioned cholera as a global threat to public health.

Pathophysiology of cholera
Vibrio cholera produces several toxins that interact with adenylataecyclase in enterocyte in regulatory system of intestine to produce a secretory state and voluminous diarrhea.
Acute diarrhea is classified according to the presence or absence of blood in the stool. Causes of acute diarrhea with blood include:
– Enterohemorrhagic E Coli
– Campylobacter
– Salmonella
– Yersinia
– Amoebic dysentery
– Bacillary dysentery
– Shigellosis

Causes of acute diarrhea without blood include:
– Viruses: Rotavirus , Norwalk , Adenovirus, etc.
– Bacteria: Shigella, Salmonella, E. Coli Enterotoxigenic , Enteropathogenic, Cholera , Clostridia
– Protozoa: Giardia, Cryptosporidiosis, Cyclospora, and
– Systemic sepsis.

Dehydration
The most severe threat posed by diarrhea is dehydration. During a diarrheal episode, water and electrolytes (sodium, chloride, potassium, and bicarbonate) are lost through liquid stool, vomit, sweat, urine, and breathing. Dehydration occurs when these losses are not replaced. The degree of dehydration is rated on a scale of three.

• Severe dehydration (at least two of the following signs)
o lethargy/unconsciousness
o sunken eyes
o unable to drink, or drink poorly
o skin pinch goes back very slowly ( ≥2 seconds)

• Some dehydration (two or more of the following signs)
o restlessness, irritability
o sunken eyes
o drinks eagerly, thirsty
• No dehydration (not enough signs to classify as some or severe dehydration).

Management of suspected cholera
Cholera differs from acute diarrhea of other causes in three ways:
a. It occurs in large epidemics that involve both children and adults
b. Voluminous watery diarrhea may occur, leading rapidly to severe dehydration with hypovolaemic shock
c. For cases with severe dehydration, appropriate antibiotics may shorten the duration of the illness.

Initial treatment of dehydration from cholera
For patients with severe dehydration and shock, the initial intravenous infusion should be given very rapidly to restore an adequate blood volume, as evidenced by normal blood pressure and a strong radial pulse. Typically, an adult weighing 50 kg and with severe dehydration would have an estimated fluid deficit of five liters. Of this, two liters should be given within 30 minutes, and the remainder within three hours. With cholera, unusually large amounts of ORS solution may be required to replace large continuing losses of watery stool after dehydration is corrected. The amount of stool lost is greatest in the first 24 hours of illness, being largest in patients who present with severe dehydration.
After being rehydrated, patients should be reassessed for signs of dehydration at least every one-two hours, and more often if there is profuse ongoing diarrhea. If signs of dehydration reappear, ORS solution should be given more rapidly. If the patient become tired, vomits frequently, or develops abdominal distension, ORS solution should be stopped and rehydration should be given: IV with Ringer’s Lactate Solution (50 ml/kg in three hours), with added potassium chloride. After this, it is usually possible to resume treatment with ORS solution. If possible, suspected cholera patients should be treated under observation until diarrhea stops, or is infrequent and of small volume. This is especially important for those who present with severe dehydration.

Prevention and treatment
Key measures to prevent diarrhea include:
• Access to safe drinking water
• Use of improved sanitation
• Hand washing with soap
• Good personal and food hygiene
• Health education about how infections spread
• Cholera vaccination.

Key measures to treat diarrhea include:
• Rehydration: with oral rehydration salts (ORS) solution. ORS is a mixture of clean water, salt, and sugar. It costs a few rupees per treatment. ORS is absorbed in the small intestine and replaces the water and electrolytes lost in the feces.
• Zinc supplements: zinc supplements reduce the duration of a diarrhea episode by 25% and are associated with a 30% reduction in stool volume in children.
• Rehydration: with intravenous fluids in case of severe dehydration or shock.
• Nutrient-rich foods: the vicious circle of malnutrition and diarrhea can be broken by continuing to give properly cooked nutrient-rich foods, but dairy products, as well as alcohol and caffeine, should be avoided. Also, fiber intake should be decreased for a few days.
• Consulting a health professional, in particular for management of persistent diarrhea, or when there is blood in stool, or if there are signs of dehydration.
• Antimotility agents to be avoided, because of risk of precipitating toxic megacolon
• Indication of antibiotics: community acquired diarrhea, lab proven cases of Giardia, E Coli, Entamoeba histolytica , travelers’ diarrhea. pathogens Shigella, Vibrio cholera, Salmonella typhi, and Clostridium.

 

References
1. Oxford textbook of Gastroenterology
2. WHO Guidelines for diarrhea
3. Sleisenger gastroenterology