Gastrointestinal 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 approximately 211 million episodes of acute gastroenteritis each year, causing over 900,000 hospitalizations and over 6000 deaths.
Rehydration therapy
- 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 Clinical Assessment of Degree of Dehydration in Children Based on Percentage of Body Weight Lossa).
- Weight loss of 9% to 10% is considered severe and requires intravenous fluid replacement with Ringer’s lactate or 0.9% sodium chloride. Intravenous therapy is also indicated in patients with uncontrolled vomiting, the presence of paralytic ileus, stool output greater than 10 mL/kg/h, shock, or loss of consciousness.
- The necessary components of oral rehydration therapy solutions include glucose, sodium, potassium, chloride, and water (Table Comparison of Common Solutions Used in Oral Rehydration and Maintenance).
- The maintenance phase should not exceed 100 to 150 mL/kg/day and is generally adjusted to equal stool.
- 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.
Bacterial Infections
Invasive (dysentery-like) Diarrhea
Acute viral gastroenteritis
Rotaviruses
- The highest frequency of rotavirus-associated diarrhea appears in children between the age of 2 to 3 years. The exact mechanism by which the rotaviruses cause diarrhea is not known.
- Clinical manifestations of rotavirus infections vary from asymptomatic (which is common in adults) to severe nausea, vomiting, and diarrhea with dehydration. Symptoms are characterized initially by nausea and vomiting. Diarrhea occurs in most patients and lasts for 1 to 9 days, but some patients experience only loose stool with no increase in frequency. Other signs and symptoms include fever, respiratory symptoms, irritability, lethargy, pharyngeal erythema, rhinitis, red tympanic membranes, and palpable cervical lymph nodes. Dehydration and electrolyte disturbances occur more frequently in children.
- Treatment of rotavirus-associated vomiting and/or diarrhea is directed at prevention or correction of dehydration.
Norwalk and norwalk-like agents
- Norwalk-like viral gastroenteritis is characterized by sudden onset of abdominal cramps with nausea and/or vomiting. Although adults frequently experience nonbloody diarrhea, children experience vomiting more often. Other frequent complaints are myalgias, headache, and malaise, which are accompanied by fever in about 50% of cases. Signs and symptoms generally last only 12 to 48 hours.
- The disease is generally self-limiting and does not require therapy. On occasion, oral rehydration may be required. Rarely is parenteral hydration necessary.