Diarrhea and Constipation
Traveler’s Diarrhea
Etiology
Diarrheal disease in travelers may be caused by a variety of bacterial, viral, and parasitic organisms, which are most often transmitted by food and water. Bacteria account for 50% to 80% of TD in developing countries; the most common organism is enterotoxigenic Escherichia coli, followed by Salmonella species, Campylobacter jejuni, and Shigella species (Table 44-1).
Table 44-1
Major Pathogens in Traveler’s Diarrhea (Travel to Developing Tropical Regions)
| AGENT | FREQUENCY (%) |
| Bacteria | 50-80 |
| Enterotoxigenic Escherichia coli | 5-50 |
| Enteroaggregative E. coli | 5-30 |
| Salmonella species | 1-15 |
| Shigella species | 1-15 |
| Campylobacter jejuni | 1-30 |
| Aeromonas species | 0-10 |
| Plesiomonas shigelloides | 0-5 |
| Other | 0-5 |
| Viruses | 0-20 |
| Rotavirus | 0-20 |
| Norovirus | 1-20 |
| Protozoa | 1-5 |
| Giardia lamblia | 0-5 |
| Entamoeba histolytica | 0-5 |
| Cryptosporidium parvum | 0-5 |
| Unknown | 10-40 |
Signs and Symptoms
1. Acute diarrhea can be accompanied by nausea, loss of appetite, abdominal cramps, low-grade fever, and malaise (Table 44-2).
Table 44-2
Pathophysiologic Syndromes in Diarrheal Disease
| SYNDROME | AGENT |
| Acute watery diarrhea | Any agent, especially with toxin-mediated diseases (e.g., enterotoxigenic Escherichia coli, Vibrio cholerae) |
| Febrile dysentery | Shigella, Campylobacter jejuni, Salmonella, enteroinvasive E. coli, Aeromonas species, Vibrio species, Yersinia enterocolitica, Entamoeba histolytica, inflammatory bowel disease |
| Vomiting (as predominant symptom) | Viral agents, preformed toxins of Staphylococcus aureus or Bacillus cereus |
| Persistent diarrhea (>14 days) | Protozoa, small bowel bacterial overgrowth, inflammatory or invasive enteropathogens (Shigella, enteroaggregative E. coli) |
| Chronic diarrhea (>30 days) | Small-bowel injury, inflammatory bowel disease, irritable bowel syndrome (postinfectious), Brainerd diarrhea |
2. Symptoms begin as early as 8 to 12 hours after contaminated food or water has been ingested.
3. Dysentery (i.e., invasive disease) is present in 10% to 15% of cases, particularly associated with Shigella, C. jejuni, or Salmonella.
4. Dehydration (manifestations include tachycardia, orthostatic vital signs, dry mucous membranes, dark yellow urine and decreased urine output, lethargy, poor skin turgor) may be present and is most common in pediatric and geriatric populations.
5. Vomiting as the predominant symptom suggests food intoxication secondary to enterotoxin produced by Staphylococcus aureus, Bacillus cereus, or Clostridium perfringens, or gastroenteritis secondary to viruses, such as rotavirus in infants or norovirus in any age-group.
6. An abdominal examination of persons with TD often shows mild tenderness, but there should not be signs of peritonitis.
7. With persistent diarrhea (longer than 14 days’ duration), consider possible infection with intestinal parasites such as Giardia lamblia, Entamoeba histolytica, Cryptosporidium, Isospora, Cyclospora, or less common entities including the following:
a. Pseudomembranous enterocolitis (Clostridium difficile) after recent antibiotic use or spontaneously
b. Lactase deficiency induced by small-bowel pathogens
c. Viral enteropathogens such as rotavirus or Norwalk virus
d. Small-bowel bacterial overgrowth syndrome
e. Strongyloides stercoralis or Trichuris trichiura
Treatment (Tables 44-3 and 44-4)
Table 44-3
Nonspecific Drugs for Symptomatic Therapy in Adults
| AGENT | THERAPEUTIC DOSE |
| Attapulgite | 3 g initially, then 3 g after each loose stool or every 2 hr (not to exceed 9 g/day); should be safe during pregnancy and childhood. (available in 600-mg tablets or liquid 600 mg/tsp) |
| Loperamide | 4 mg initially; this is usually sufficient. If nonresponsive, can give 2 mg (one capsule) after each loose stool not to exceed 8 mg (four capsules)/day; do not use in dysenteric or febrile diarrhea |
| Bismuth subsalicylate | 30 mL or two 262-mg tablets every 30 min for eight doses; may repeat on day 2 |
| Probiotics | Dose according to package, because products and formulations vary. Daily dose may make diarrhea less severe and shorten its duration; consider in postinfectious or postantibiotic diarrhea |
Table 44-4
Oral Agents for Self-Treatment of Traveler’s Diarrhea
| AGENT | ADULT DOSE | PEDIATRIC DOSE* |
| Norfloxacin | 400 mg bid for up to 3 days | Not recommended |
| Ciprofloxacin† | 500 mg bid for up to 3 days | 20 to 30 mg/kg/day in two divided doses for up to 3 days; maximum dose 500 mg |
| Ofloxacin† | 200 mg bid for up to 3 days | 7.5 mg/kg q12h for up to 3 days; maximum dose 200 mg |
| Levofloxacin† | 500 mg once daily for up to 3 days | 10 mg/kg once daily for up to 3 days; maximum dose 500 mg |
| Azithromycin‡ | 1000 mg single dose | 10 mg/kg once daily (single dose); maximum dose 1000 mg |
| Rifaximin | 200 mg tid for up to 3 days | ≥12 years: 200 mg tid for up to 3 days |
bid, Twice a day; tid, three times a day.
*Self-treatment of traveler’s diarrhea in children is controversial.
†Not licensed for this indication in children younger than 18 years.
‡Preferred agent for children.
Courtesy UpToDate.
1. TD typically runs a self-limited course of less than 1 week. Although recovery without antimicrobial treatment normally occurs in healthy adults, most travelers choose to avoid the inconvenience and discomfort of diarrhea by seeking medical treatment.
2. Severe, watery TD can cause life-threatening fluid loss. Treating serious dehydration is an urgent priority, especially in older persons, young children, and infants. Fluid replacement is the cornerstone of therapy.
a. Treating dehydration often significantly decreases malaise.
b. Urine volume (decreased urine output for an adult is less than 500 mL in a 24-hour period) and color (one field indicator of dehydration is dark-yellow urine) can serve as markers of adequate hydration and should be monitored.
c. If patients are otherwise healthy and not dehydrated, adequate oral intake can be achieved with soft drinks, fruit juice, broth, and soup, along with salted crackers. In those with excessive fluid losses and dehydration, oral rehydration therapy with electrolyte solutions containing glucose should be instituted. Reduced osmolarity (245 mOsm/L compared with the previous 311 mOsm/L) oral rehydration solutions (ORSs) are now recommended by the World Health Organization (WHO) for treating acute diarrhea (Table 44-5). The lower osmolarity reduces stool output (volume), vomiting, and the need for intravenous (IV) therapy. Rehydration Project is a nonprofit, international development group that maintains an up-to-date website on rehydration options (http://rehydrate.org/ors/low-osmolarity-ors.htm).
Table 44-5
Reduced Osmolarity Oral Rehydration Solution
| REDUCED OSMOLARITY ORS | mmol/L |
| Sodium | 75 |
| Chloride | 65 |
| Glucose, anhydrous | 75 |
| Potassium | 20 |
| Citrate | 10 |
| Total Osmolarity | 245 |
• Add one packet of ORS to 1 L (1 qt) of clean drinking or boiled water (after cooled). Many pharmacies or clinics may still stock the “old” WHO 1975 formula. It can be used to make a lower osmolarity solution that still meets new WHO parameters by mixing it in 1.2 L (1.2 qt) of water rather than in 1 L.
• Sports drinks such as Gatorade also provide adequate fluid replacement if diluted to about to about one-half their strength (add 0.5 L [0.5 qt] of water to 1 L [1 qt] of Gatorade). Full-strength sports drinks are often more hypertonic than 245 mOsm/L (the osmolality of Gatorade is approximately 360 mOsm/L) and may delay gastric absorption.
• A number of other ORSs are also available for children, including Pedialyte, Rehydralyte, Ricelyte, Infalyte, and Resol.
3. To make an improvised ORS, one of the following methods can be used:
a. Add 30 mL (6 tsp) of sugar and 2.5 mL (
tsp) of salt to 1 L (1 qt) of clean drinking water (or boiled water that has cooled).
b. Add 2.5 mL (
tsp) salt, 5 mL (1 tsp) baking soda, 40 mL (8 tsp) sugar, and 236 mL (8 oz) orange juice, diluted to 1 L (1 qt) with water.
4. Fluids should be given at rates of 50 to 200 mL/kg/24 hr, depending on the patient’s hydration status.
5. Treatment with IV fluids is indicated for patients with severe dehydration and for those who cannot tolerate oral fluids.
6. Total food abstinence is unnecessary and not recommended. Patients should be encouraged to eat easily digested foods such as bananas, applesauce, rice, potatoes, noodles, crackers, toast, and soups. Dairy products should be avoided, because transient lactase deficiency can be caused by enteric infections. Caffeinated beverages and alcohol, which can enhance intestinal motility and secretions, should be avoided.
