Case A 10 kg. male presents to your office with watery stools and a low grade fever. There is no blood in the stool and the child is approximately 5% dehydrated. How would workup and treat this child?

Evaluation of the child with diarrhea

1. History
1. recent travel
2. known exposures
3. recent use of antibiotics
4. attendance in daycare
5. previous state of health
2. Physical exam
1. previous weight- often not available 
2. Assess for level of dehydration 
1. Mild dehydration( 3-5%)- mucous membranes are slightly dry but vital signs are normal and there is normal capillary refill and skin turgor. Tears are usually present and child is alert.
2. Moderate dehydration (6-9%)- increased heart and respiratory rate and slightly prolonged capillary refill, and tenting of the skin. Lack of tears and the child isbecoming listless.
3. Severe dehydration(>10%)- blood pressure is decreased and the child is very lethargic. Mucous membranes are very dry. Skin is cold and clammy.

1. Viral- usually watery diarrhea without blood. Often have accompanying vomiting and fever.
1. Rotovirus-usually infants and toddlers.
2. Norwalk virus
3. Adenovirus
2. Bacterial- either invasive or produce toxins
1. Salmonella- invasive Causes short-lived illness with fever, vomiting, sometimes bloody stools. Usually doesn't require treatment
2. Shigella- invasive. Causing bloody, mucousy stools. Usually requires antibiotic treatment. May be associated with seizures
3. Campylobacteria- usually watery but also may cause bloody stools. May require antibiotic treatment in severe prolonged cases with Erythromycin
4. Yersinia- 10% bloody diarrhea and often with accompanying systemic symptoms. No treatment necessary in most cases.
5. E. Coli
6. Staphylococcal-responsible for food poisoning. Toxin is in the food and symptoms frequentlyappear 6-12 hours after ingestion. Often with vomiting. Short lived. 
3. Protozoan
1. Cryptosporidium- watery stools usually without blood. Common in immunocompromised population,
2. Giardia- often from contaminated water in certain areas. Bloating and abdominal pain is present Usually not bloody.

Most cases of acute diarrhea do not require any laboratory investigations. If the child has bloody stools, cultures may be indicated and if the there is severe dehydration electrolytes should be checked.

Most cases can be treated with oral rehydration solutions. Exceptions are for severely dehyrated children, if there is persistent vomiting, or the child refuses to drink. Oral rehydration solutions should contain 75-90 meq of sodium, glucose, and potassium. The closest over-the -counter solution availabe are Pedialyte and Infalyte. The child's losses and maintenance requirements should be calculated and small amounts at a time should be offered to meet these requirements. If you give too much at one time you may induce vomiting. Soft drinks, juices, sport drinks, and tea should be avoided because they lack electrolytes and are hyperosmolar. They may induce more diarrhea. It is important to emphasize to the parents that this mode of treatment will not decrease the amount of stool initially. 

The child in the case has a deficit of 500cc (50cc/kg.). Maintenance requirement of 40cc/hr., and to correct the deficit after 6 hours, needs about 125cc./hr. 2 tbs./15 minutes will provide the child's needs. Ongoing losses should be corrected with 10cc/kg per stool. 

If the mother is nursing, breastfeeding shouldn't be interupted and if formula feeding may be continued. It has been shown that starving may lead to villous atrophy so feeding is recommended. The BRAT diet and other foods high in carbohydrates are recommended to enhance fluid and sodium absorption.

Any medication that slows intestinal motility and allow overgrowth of organisms should be avoided. Imodium and Lomotil can also cause ileus, bloating, respiratory depression, and drowsiness.

Pepto-Bismol has anti-secretory, anti-inflammatory, and anti-bacterial effects. Its use may under emphasize the role of fluid replacement.

Kao Pectate is an adsorbent and may lead to decreased intestinal motility, therefore it should be avoided.

Antimicrobials are usefull in certain situations 

Yogurt and Lactobaccillus- further investigation is needed before recommending it routinely, but some preliminary data show usefulness. 

Use of lactose free formula has not been proven of value nor has I/2 strength formulas 

References
1. Lasche and Dugan.  Managing Acute Diarrhea Contemporary Pediatrics February 1999
2. American Academy of Pediatrics. Practice Parameter: the management of acute gastroenteritis in young children. Pediatrics 1996 97 424-436
3. Atherly-John Yvonne, et al. A Randomized Trial of Oral vs. Intravenous Rehydration in a Pediatric Emergency Room. Archivive of Pediatrics and Adolescent Medicine. Dec 2002 Page 1240
4. Shilkofski N. Escherichia coli 0157:H7 Pediatrics in Review February 2004
5. MMWR. Managing Acute Gastroenteritis Among Children. Oral Rehydration, Maintenance, and Nutritional TherapyPediatrics August 2004
6. Thielman NM, Guerrant RL. Clinical Practice. Acute infectious diarrhea. N Engl J Med. 2004. Jan 1; 350(1):38-47. Review
7. Spandofer P. Oral Versus Intravenous Rehydration of Moderately Dehydrated Children: A Randomized Controlled Trial . Pediatrics Feb. 2005
8. Keating J. Chronic Diarhhea.  Pediatrics in Review.  January 2005
9. Vernacchio L. et al.  Diarrhea in American Infants and Young Children in the Community Setting: Incidence, Clinical Presentation, and Microbiology.  Pediatric Infectious Disease Journal  Vol 25(1) Jan. 2006
10. Dennehy P. Rotavirus.  Contemporary Pediatrics December 2005
11. Bass E et al.  Rotavirus.  Pediatrics in Review May 2007
12. Hyponatremia  Pediatrics in Review November 2007