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  • Most of the time vomiting and/or diarrhea are caused by gastroenteritis.
  • Life-threatening causes of vomiting include bowel obstructions, increased intracranial pressure, diabetic ketoacidosis, and inborn errors of metabolism.
  • Life-threatening causes of diarrhea include toxic megacolon, Escherichia coli 0157, and pseudomembranous enterocolitis.
  • Most dehydrated patients with gastroenteritis can be treated with oral rehydrating solutions.
  • Most cases of gastroenteritis resolve without antibiotic therapy.
  • New vaccines against rotavirus have so far been found to be safe and effective.


Vomiting is the forceful expulsion of the contents of the stomach. Diarrhea is defined as frequent (three or more per day) loose or liquid bowel movements. There are several general classifications of diarrhea. In secretory diarrhea there is an increase in secretion or decrease in absorption of intestinal liquid; such diarrhea is often toxin mediated. In inflammatory diarrhea there is damage to the intestinal mucosa. Osmotic diarrhea occurs when liquid is lost accompanying a high intestinal osmotic load. Inappropriately increased intestinal motility can also cause diarrhea. Separately or in combination, vomiting and diarrhea constitute one of the most common manifestations of childhood illness. Diarrheal illnesses remain one of the most common causes of childhood death, especially in impoverished countries.1,2


By far the most common cause of vomiting and/or diarrhea is acute infectious gastroenteritis, which in the majority of cases resolves with minimal intervention. However, before the diagnosis of gastroenteritis is established, other potentially life-threatening illnesses that can present with vomiting and/or diarrhea must be excluded. For the most part, this can be accomplished by a careful history and physical examination.


The history regarding the patient who is vomiting focuses on the duration of the illness, the frequency of the vomiting, the character/color of the contents vomited, and associated abdominal pain. Most acute infectious illnesses result in frequent vomiting of a short duration; a history of protracted or intermittent vomiting can imply an underlying anatomic lesion. In infants of 2 to 6 weeks of age, pyloric stenosis should be considered. Bilious vomiting is rare in infants and children, and always raises the suspicion of a bowel obstruction, especially a malrotation, with or without a volvulus. Vomiting associated with persistent, severe, or localized abdominal pain suggests peritonitis. Vomiting accompanied by a headache raises the possibility of increased intracranial pressure. The history regarding diarrhea focuses on the duration of the problem, the frequency of the stools, and the presence of blood or mucus in the stools. Most acute gastrointestinal infections in the developed world are caused by viruses, and result in frequent, watery stools; the presence of blood or mucus in the feces increases the possibility of a bacterial or inflammatory illness.15 Frank rectal bleeding suggests an anatomic lesion, such as an intussusception, Meckel's diverticulum, or juvenile polyps. Protracted diarrhea (lasting weeks) suggests a malabsorption syndrome or inflammatory bowel disease.


The physical examination of the patient with vomiting and/or diarrhea focuses on excluding life-threatening illness and ascertaining ...

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