Gastroenteritis medical therapy

Gastroenteritis Microchapters
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Differential Diagnosis
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Medical Therapy

The objective of treatment is to replace lost fluids and electrolytes. The person's usual foods and drinks should not be withheld, but consumed as the person is able to tolerate them.

Rehydration

Regardless of cause, the principal treatment of gastroenteritis (and of all other diarrheal illnesses) in both children and adults is rehydration, i.e. replenishment of water lost in the stools. Depending on the degree of dehydration, this can be done by giving the person oral rehydration therapy (ORT) or through intravenous delivery. ORT can begin before dehydration occurs, and continue until the person's urine and stool output return to normal.

People taking diuretics ("water pills") need to be cautious with diarrhea and may need to stop taking the medication during an acute episode, as directed by the health care provider.

Dietary therapy

Centers for Disease Control and Prevention recommendations for infants and children include: Breastfed infants should continue to be nursed on demand. Formula-fed infants should continue their usual formula immediately upon rehydration in amounts sufficient to satisfy energy and nutrient requirements, and at the usual concentration. Lactose-free or lactose-reduced formulas usually are unnecessary. Children receiving semisolid or solid foods should continue to receive their usual diet during episodes of diarrhea. Foods high in simple sugars should be avoided because the osmotic load might worsen diarrhea; therefore, substantial amounts of soft drinks (carbonated or flat), juice, gelatin desserts, and other highly sugared liquids should be avoided. Fatty foods should not be avoided, because maintaining adequate calories without fat is difficult, and fat might have an added benefit of reducing intestinal motility. The practice of withholding food for ≥24 hours is inappropriate.

Zinc

The World Health Organization recommends that infants and children receive a dietary supplement of zinc for up to 2 weeks after onset of gastroenteritis.

Pharmacotherapy

Antibiotics

When the symptoms are severe, one usually starts empirical antimicrobial therapy. Antibiotics should be directed toward the causative pathogens, as shown from the culture results. When empirical therapy is decided, the antibiotic regimen is chosen based on the expected pathogen from:

Source of infection from patient history:

• Food-borne outbreak: Salmonella, shiga-toxigenic E. coli, yersinia, cyclospora
• Water-borne transmission: Vibrios, giardia, intestinalis Cryptosporidium
• Seafood, shellfish: Vibrio, norovirus, Salmonella
• Poultry: Campylobacter, salmonella
• Beef, raw seed sprouts: Shiga toxin–producing E. coli(STEC),enterohemorrhagic E. coli
• Eggs: Salmonella
• Mayonnaise and cream: Staphylococcus, clostridium perfringens, salmonella
• Pies: Salmonella, campylobacter jejuni, cryptosporidium, giardia intestinalis
• Antibiotics, chemotherapy: Clostridium difficile
• Person to person: Shigella, rotavirus

Incubation period

• < 6 h: Preformed toxin of S. aureus and bacillus cereus
• 6–24 h: Preformed toxin of C. perfringens and B. cereus
• 16–72 h: Noroviruses, ETEC, Vibrio, salmonella, shigella, campylobacter, yersinia, Shiga toxin– producing E. coli, giardia, cyclospora, cryptosporidium

Antibiotics usually are not given for the non infectious gastroenteritis, but they are used for gastroenteritis due to some bacteria.

In cases with shiga toxin-producing E. coli, avoid antimicrobials or anti-motility drugs, as they may enhance toxin release and increase the risk of hemolytic uremic syndrome (HUS).

In Clostridium difficile infection, antibiotic discontinuation with avoidance of antiperistaltic medication is recommended. Sever cases with toxic megacolon requires surgical intervention (e.g. colectomy, or loop ileostomy coupled with antegrade colonic irrigation with vancomycin and intravenous metronidazole).

Antibiotics Used in the Treatment of Cholera Preferred Regimen Adult dose ▸ Doxycycline 300 mg once Pediatric dose ▸ Doxycycline 2 mg/kg once (not recommended) Alternative Regimen Adult dose ▸ Azithromycin 1.0 g as a single dose, only once OR ▸ Ciprofloxacin 500 mg q12h x 3 days, or 2.0 grams as a single dose Pediatric dose ▸ Azithromycin 20 mg/kg one single dose OR ▸ Ciprofloxacin 15 mg/kg q 12 h x 3 days

Antibiotics Used in the Treatment of Shigellosis Preferred Regimen Adult dose ▸ Ciprofloxacin 500 mg q12 h x 3 days, or 2.0 g as a single dose only once Alternative Regimen Adult dose ▸ Pivmecillinam 400 mg 3–4 times q24h x 5 days OR ▸ Ceftriaxone 2–4 g as a single daily dose Pediatric dose ▸ Pivmecillinam 20 mg/kg q6h x 5 days OR ▸ Ceftriaxone 50–100 mg/kg/day IM x 2–5 days

Antibiotics Used in the Treatment of Amebiasis Adult dose ▸ Metronidazole 750 mg q8h x 5 days Pediatric dose ▸ Metronidazole 10 mg/kg q8h x 5 days

Antibiotics Used in the Treatment of Giardiasis Preferred Regimen Adult dose ▸ Metronidazole 250 mg q8h x 5 days Pediatric dose ▸ Metronidazole 5 mg/kg q8h x 5 days Alternative Regimen Adult dose ▸ Tinidazole 50 mg/kg orally in a single dose OR ▸ Ornidazole 2g as a single dose

Antibiotics Used in the Treatment of Campylobacter Preferred Regimen Adult dose ▸ Azithromycin 500 mg po q24h x 3 days Pediatric dose ▸ Azithromycin 30 mg/kg po single dose-early after disease onset Alternative Regimen Adult dose ▸ Ciprofloxacin 500 mg po q12h x 3 days

Antidiarrheal agents

Loperamide is an opioid analogue commonly used for symptomatic treatment of diarrhea. It slows down gut motility, but does not cross the mature blood-brain barrier to cause the central nervous effect of other opioids. In too high doses, loperamide may cause constipation and significant slowing down of passage of feces, but an appropriate single dose will not slow down the duration of the disease. Although antimotility agents have the risk of exacerbating the condition, this fear is not supported by clinical experience according to Sleisenger & Fordtran's Gastrointestinal and Liver Disease and the Oxford Textbook of Medicine. Nevertheless, Harrison's Principles of Internal Medicine discourages the use of antiperistaltic agents and opiates in febrile dysentery, since they may mask, or exacerbate the symptoms. All these textbooks agree that in severe colitis antimotility drugs should not be used.

Loperamide prevents the body from flushing toxins from the gut, and should not be used when an active fever is present or there is a suspicion that the diarrhea is associated with organisms that can penetrate the intestinal walls, such as E. coli O157:H7 or salmonella.

Loperamide is also not recommended in children, especially in children younger than 2 years of age, as it may cause systemic toxicity due to an immature blood brain barrier, and oral rehydration therapy remains the main stay treatment for children.

Bismuth subsalicylate (BSS), an insoluble complex of trivalent bismuth and salicylate, is another drug that can be used in mild-moderate cases.

Combining an antimicrobial drug and an antimotility drug, seems to be effective more rapidly.

Antiemetic drugs

If vomiting is severe, antiemetic drugs may be helpful. However, these drugs are not recommended for treatment of acute gastroenteritis in children.