Gastroenteritis medical therapy

Gastroenteritis Microchapters
Patient Information
Overview
Classification
Differential Diagnosis
Prevention

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ;Associate Editor(s)-in-Chief: Mohamed Moubarak, M.D. [2]

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).

Antimicrobial Regiemn

• Immunocompetent

• Bacterial

• 1. Shigella species

• Preferred regimen (1):

• Adult dose: TMP-SMZ, 160 and 800 mg, respectively bid for 3 days (if susceptible ) OR Fluoroquinolone (e.g., 300 mg Ofloxacin, 400 mg Norfloxacin, OR 500 mg Ciprofloxacin bid for 3 days)
• Pediatric dose: TMP-SMZ, 5 and 25 mg/kg, respectively bid for 3 days

• Preferred regimen (2):

• Adult dose: Nalidixic acid 1 g/d for 5 days OR Ceftriaxone; Azithromycin
• Pediatric dose: Nalidixic acid, 55 mg/kg/d for 5 days

• 2. Non-typhi species of Salmonella

• Preferred regimen: Not recommended routinely, but if severe or patient is younger than 6 monthes or older than 50 year old or has prostheses, valvular heart disease, severe atherosclerosis, malignancy, or uremia, TMP-SMZ (if susceptible) OR Fluoroquinolone, bid for 5 to 7 days; Ceftriaxone, 100 mg/kg/d in 1 or 2 divided doses

• 3. Campylobacter species

• Preferred regimen: Erythromycin 500 mg bid for 5 days

• 4. Escherichia coli species

• 4.1. Enterotoxigenic

• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, bid, for 3 days (if susceptible), OR Fluoroquinolone (e.g., 300 mg Ofloxacin, 400 mg Norfloxacin, or 500 mg Ciprofloxacin bid for 3 days)

• 4.2. Enteropathogenic

• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, bid, for 3 days (if susceptible), OR Fluoroquinolone (e.g., 300 mg Ofloxacin, 400 mg Norfloxacin, or 500 mg Ciprofloxacin bid for 3 days)

• 4.3. Enteroinvasive

• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, bid, for 3 days (if susceptible), OR Fluoroquinolone (e.g., 300 mg Ofloxacin, 400 mg Norfloxacin, or 500 mg Ciprofloxacin bid for 3 days)

• 4.4. Enterohemorrhagic

• Preferred regimen: Avoid antimotility drugs; role of antibiotics unclear, and administration should be avoided.

• 5. Aeromonas/Plesiomonas

• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, bid for 3 days (if susceptible), Fluoroquinolone (e.g., 300 mg Ofloxacin, 400 mg Norfloxacin, or 500 mg Ciprofloxacin bid for 3 days)

• 6. Yersinia species

• Preferred regimen: Antibiotics are not usually required; Deferoxamine therapy should be withheld; for severe infections or associated bacteremia treat as for immunocompromised hosts, using combination therapy with Doxycycline, Aminoglycoside, TMP-SMZ, OR Fluoroquinolone

• 7. Vibrio cholerae O1 or O139

• Preferred regimen (1): Doxycycline 300-mg single dose
• Preferred regimen (2): Tetracycline 500 mg qid for 3 days
• Preferred regimen (3): TMP-SMZ 160 and 800 mg, respectively, bid for 3 days
• Preferred regimen (4): single-dose Fluoroquinolone

• 8. Toxigenic Clostridium difficile

• Preferred regimen: Offending antibiotic should be withdrawn if possible; Metronidazole, 250 mg qid to 500 mg tid for 3 to 10 days

• Parasites

• 1. Giardia

• Preferred regimen: Metronidazole 250-750 mg tid for 7-10 days

• 2. Cryptosporidium species

• Preferred regimen: If severe, consider Paromomycin, 500 mg tid for 7 days

• 3. Isospora species
• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, bid for 7 to 10 days

• 4. Cyclospora species

• Preferred regimen: TMP/SMZ, 160 and 800 mg, respectively, bid for 7 days

• 5. Microsporidium species

• Preferred regimen: Not determined

• 6. Entamoeba histolytica

• Preferred regimen (1): Metronidazole 750 mg tid for 5 to 10 days AND Diiodohydroxyquin 650 mg tid for 20 days
• Preferred regimen (2): Metronidazole 750 mg tid for 5 to 10 days AND Paromomycin 500 mg tid for 7 days

• Immunocompromised

• Bacterial

• 1. Shigella species:

• Preferred regimen (1):

• Adult dose: TMP-SMZ, 160 and 800 mg, respectively bid for 7 to 10 days (if susceptible ) OR Fluoroquinolone (e.g., 300 mg Ofloxacin, 400 mg Norfloxacin, OR 500 mg Ciprofloxacin bid for 7 to 10 days)
• Pediatric dose:TMP-SMZ, 5 and 25 mg/kg, respectively bid for 7 to 10 days

• Preferred regimen (2):

• Adult dose: Nalidixic acid 1 g/d for 7 to 10 days OR Ceftriaxone; Azithromycin
• Pediatric dose: Nalidixic acid, 55 mg/kg/d for 7 to 10 days

• 2. Non-typhi species of Salmonella

• Preferred regimen: Not recommended routinely, but if severe or patient is younger than 6 monthes or older than 50 old or has prostheses, valvular heart disease, severe atherosclerosis, malignancy, or uremia, TMP-SMZ (if susceptible) OR Fluoroquinolone, bid for 14 days (or longer if relapsing); ceftriaxone, 100 mg/kg/d in 1 or 2 divided doses

• 3. Campylobacter species

• Preferred regimen: Erythromycin, 500 mg bid for 5 days (may require prolonged treatment)

• 4. Escherichia coli species

• 4.1. Enterotoxigenic

• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, bid for 3 days (if susceptible), OR Fluoroquinolone (e.g., 300 mg Ofloxacin, 400 mg Norfloxacin, or 500 mg Ciprofloxacin bid for 3 days) (Consider fluoroquinolone as for enterotoxigenic E. coli)

• 4.2. Enteropathogenic

• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, bid,for 3 days (if susceptible), OR Fluoroquinolone (e.g., 300 mg Ofloxacin, 400 mg Norfloxacin, or 500 mg Ciprofloxacin bid for 3 days)

• 4.3. Enteroinvasive

• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, bid,for 3 days (if susceptible), OR Fluoroquinolone (e.g., 300 mg Ofloxacin, 400 mg Norfloxacin, or 500 mg Ciprofloxacin bid for 3 days)

• 4.4. Enterohemorrhagic

• Preferred regimen: Avoid antimotility drugs; role of antibiotics unclear, and administration should be avoided.

• 5. Aeromonas/Plesiomonas

• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, bid for 3 days (if susceptible), Fluoroquinolone (e.g., 300 mg ofloxacin, 400 mg norfloxacin, or 500 mg Ciprofloxacin bid for 3 days)

• 6. Yersinia species

• Preferred regimen: Doxycycline, Aminoglycoside (in combination) or TMP-SMZ or Fluoroquinolone

• 7. Vibrio cholerae O1 or O139

• Preferred regimen: Doxycycline, 300-mg single dose; or Tetracycline, 500 mg qid for 3 days; or TMP-SMZ, 160 and 800 mg, respectively, bid for 3 days; or single-dose Fluoroquinolone

• 8. Toxigenic Clostridium difficile

• Preferred regimen: Offending antibiotic should be withdrawn if possible; Metronidazole, 250 mg qid to 500 mg tid for 3 to 10 days

• Parasites

• 1. Giardia

• Preferred regimen: Metronidazole, 250-750 mg tid for 7-10 days

• 2. Cryptosporidium species

• Preferred regimen: Paromomycin, 500 mg tid for 14 to 28 days, then bid if needed; highly active antiretroviral therapy including a protease inhibitor is warranted for patients with AIDS

• 3. Isospora species

• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, qid for 10 days, followed by TMP-SMZ thrice weekly, or weekly Sulfadoxine (500 mg) and Pyrimethamine (25 mg) indefinitely for patients with AIDS

• 4. Cyclospora species
• Preferred regimen: TMP-SMZ, 160 and 800 mg, respectively, qid for 10 days, followed by TMP-SMZ thrice weekly indefinitely

• 5. Microsporidium species

• Preferred regimen: Albendazole, 400 mg bid for 3 weeks; highly active antiretroviral therapy including a protease inhibitor is warranted for patients with AIDS

• 6. Entamoeba histolytica

• Preferred regimen: Metronidazole, 750 mg tid for 5 to 10 days, plus either Diiodohydroxyquin, 650 mg tid for 20 days, or Paromomycin, 500 mg tid for 7 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.