Chapter 39: Gastrointestinal Infections

INTRODUCTION

• Gastrointestinal (GI) infections are among the more common causes of morbidity and mortality around the world. Most are caused by viruses, and some are caused by bacteria or other organisms. In underdeveloped and developing countries, acute gastroenteritis involving diarrhea is the leading cause of mortality in infants and children younger than 5 years of age. In the United States, there are 179 million episodes of acute gastroenteritis each year, causing over 600,000 hospitalizations and over 5000 deaths.

• Public health measures such as clean water supply and sanitation facilities, as well as quality control of commercial products are important for the control of most enteric infections. Sanitary food handling and preparation practices significantly decrease the incidence of enteric infections.

REHYDRATION, ANTIMOTILITY, AND PROBIOTIC THERAPY

• Treatment of dehydration includes rehydration, replacement of ongoing losses, and continuation of normal feeding. Fluid replacement is the cornerstone of therapy for diarrhea regardless of etiology.

• Initial assessment of fluid loss is essential for rehydration. Weight loss is the most reliable means of determining the extent of water loss. Clinical signs such as changes in skin turgor, sunken eyes, dry mucous membranes, decreased tearing, decreased urine output, altered mentation, and changes in vital signs can be helpful in determining approximate deficits (Table 39–1).

• The necessary components of oral rehydration solution (ORS) include glucose, sodium, potassium chloride, and water (Table 39–2). ORS should be given in small frequent volumes (5 mL every 2–3 min) in a teaspoon or oral syringe.

• Severely dehydrated patients should be resuscitated initially with lactated Ringer solution or normal intravenous (IV) saline. Guidelines for rehydration therapy based on the degree of dehydration and replacement of ongoing losses are outlined in Table 39–1.

• Early refeeding as tolerated is recommended. Age-appropriate diet may be resumed as soon as dehydration is corrected. Early initiation of feeding shortens the course of diarrhea. Initially, easily digested foods, such as bananas, applesauce, and cereal may be added as tolerated. Foods high in fiber, sodium, and sugar should be avoided.

• Antimotility drugs such as diphenoxylate and loperamide offer symptomatic relief in patients with watery diarrhea by reducing the number of stools. Antimotility drugs are not recommended in patients with many toxin-mediated dysenteric diarrheas (ie, enterohemorrhagic Escherichia coli [EHEC], pseudomembranous colitis, and shigellosis).

• Individual studies have not shown significant benefit from probiotics and meta-analyses have shown conflicting results. Probiotics should not be recommended for prophylaxis or treatment of initial antibiotic-associated diarrhea.