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Acute Diarrhoea Beyond the age of 3 months, diarrhoea is easily defined as 3 consecutive stools of greater fluidity than normal. Below 3 months of age, while more severe forms give no trouble with diagnosis, milder diarrhoeas are often difficult to differentiate from normal breast milk stools. From therapeutic point of view, diarrhoeas are usually defined as acute and chronic or persistent. Pathogenesis Of Acute Diarrhoea It is traditional to classify acute diarrhoeas depending on the site of infection in the GI tract into
It is easy to understand the pathogenesis of Large bowel diarrhoea (Dysentery) where in the infective organism invades the mucous membranes producing an inflammatory response and exudate besides ulceration. These explain the presence of mucous and blood and the need for antibiotics. In the small bowel however, thanks to the built in local immune system (GALT/MALT) the organism cannot invade and cause ulcerations, bleeding or inflammatory exudate. Instead, diarrhoea is mediated through toxins which following absorption into intestinal mucosa, causes profound alterations in the absorptive / secretory functions through CAMP / GMP etc. The end result in most cases of bacterial infections of the small bowel is excessive uncontrolled secretion of bicarbonate, chloride and water along with other minerals by the crypt cells. Simultaneous paralysis of Na+ K+ ATP ase pump produced by the absorbed toxin prevents reabsorption of the secreted bicarbonate and chloride resulting in large watery diarrhoea. The us of ORS in AWD is designed to bypass this absorptive defect by stimulating the Na - glucose pump. The equimolar concentration of glucose and sodium in WHO ORS does this trick and helps prevent dehydration. The inability of the organism to invade the mucosa and the capacity of the gut immune mechanism to handle the intraluminal organisms allows the physician the flexibility of withholding antibiotics in AWD even when it is due to bacterial infection. The primary goal of the physician in AWD is to replace the water and electrolytes lost and thereby prevent dehydration while the body's own immune system eliminates the organism responsible for the diarrhoea. Diarrhoeas of less than 15 days duration are called acute and are presumed to be infective in origin. When it exceeds 15 days it is called chronic / persistent / protracted and they will be discussed later. Further evaluation and management of a case diagnosed as acute diarrhoea depends on the following easily elicitable information.
Age Children of the age of 3 months and above with acute diarrhoea benefit from the rationalised rule of the thumb approach given below. Children < 3 months of age and grossly under nourished ones may still benefit from the approach but require individualised analysis and greater emphasis on identification and treatment of sepsis. Small Bowel / Large Bowel Diarrhoea The differentiation is simple and the following points help. Dehydration In the absence of dehydration, acute watery diarrhoea is a classic example of "Masterly inactivity and watchful expectancy" and parental counselling. Since, AWD is essentially a self limiting disease, the physician's responsibility is to prevent dehydration and/or identify it early and treat it if present. Symptoms
Signs
From treatment point of view, dehydration is usually classified as no dehydration, some dehydration and severe dehydration. Some Dehydration When symptoms and/or signs of dehydration are present. Severe Dehydration In the presence of shock and lethargy it is referred to as severe.
Once large bowel diarrhoea (dysentery) is diagnosed the next step is to differentiate between the 2 commonest causes of dysentery - bacillary and amoebic.
May be considered when the child presents with toxemia, dehydration, abdominal distension, oliguria and needs hospitalisation. Rarely are they required in O.P. management of acute bacillary dysentery. Lack of response to II line of drugs should always raise the suspicion of possible non dysenteric cause of rectal bleed. Bacillary dysentery resistant to nalidixic acid is quite uncommon. Management Of Small Bowel Diarrhoea (acute watery diarrhoea)
Reassess the child every 2 hours. If hydration status is not improving give IV drip more rapidly and start on ORS as soon as the child can drink. Reassess the child after 3-6 hours and choose appropriate further line of management (Plan A, B or C). Severe dehydration is a life threatening complication in diarrhoea and requires very close monitoring. Where facilities are available, it should include monitoring of urine output, electrolytes, urea, creatine, glucose levels besides level of dehydration. A septic work up and investigation for cholera (in endemic areas) are also part of Plan C management. The above regimen generally holds good for all AWD with dehydration cases from 3 months age and above, though severe dehydration children require individualised scrutiny monitoring and therapy. Below 3 months however while plan A,B,C approach can still work, a greater emphasis on identification of sepsis and its therapy are required. One must also remember that complications of dehydration are more pronounced in the below 3 months group and in many cases the rate of correction achieved by ORS may not be sufficient. Most viral diarrhoeas produce transient reduction in intestinal disaccharidase levels especially lactase and that may aggravate the watery diarrhoea. However, most viral diarrhoeas do not require any reduction in milk feeds even if the stool shows significant amount of reducing substances. Some physicians however do reduce milk if the diarrhoea goes beyond 7 days (sub acute diarrhoea) and the child continues to have large volume frothing, watery stools with peri-anal excoriation. General guidelines may not be possible in this situation and the decision to reduce or stop milk in post-viral osmotic diarrhoeas of more than 7 days duration will need to be made on case by case basis. |