Diarrhea, Acute
Catherine C. Wiley
INTRODUCTION
Acute diarrhea is defined as stools with increased water content and frequency for a period of <5 to 7 days. Most cases of acute diarrhea are of infectious (predominantly viral) origin and are self-limited. Approximately 5% of children with acute diarrhea require medical evaluation. Acute diarrhea is occasionally the presenting symptom of a life-threatening condition. The differential diagnostic considerations for acute diarrhea overlap with those for chronic diarrhea (see Chapter 28, “Diarrhea, Chronic”).
DIFFERENTIAL DIAGNOSIS LISTInfectious Causes
Viruses
Rotavirus
Enteric adenoviruses
Caliciviruses (e.g., Norovirus)
Enteroviruses
Astroviruses
Bacteria
Salmonella species
Shigella species
Campylobacter species
Yersinia enterocolitica
Pathogenic Escherichia coli
Aeromonas
Clostridium difficile
Vibrio species
Parasites
Giardia species
Cryptosporidium species
Entamoeba histolytica
Blastocystis hominis
Systemic
Otitis media
Urinary tract infection (UTI)
Hepatitis
Sepsis
Toxic Causes
Foodborne illness
Pharmacologic agents—iron, laxatives, and antibiotics
Plant or mushroom toxicity
Household cleaners or soap
Serotonin syndrome
Neonatal drug withdrawal
Metabolic or Genetic Causes
Adrenal insufficiency
Congenital adrenal hyperplasia (CAH)
Disaccharidase deficiency
Hyperthyroidism
Inflammatory Causes
Appendicitis
Inflammatory bowel disease
Eosinophilic gastroenteritis
Miscellaneous Causes
Dietary factors—malnutrition, specific food intolerance (e.g., lactose or fructose intolerance), overfeeding, and sorbitol
Other malabsorption—celiac disease and cystic fibrosis
Systemic illness—hemolytic uremic syndrome (HUS), Henoch-Schönlein purpura (HSP) and immunodeficiency
Functional—irritable bowel syndrome
DIFFERENTIAL DIAGNOSIS DISCUSSION
Infectious Diarrhea
Etiology
Infectious diarrhea can be viral, bacterial, or parasitic in origin. Transmission is usually by the fecal–oral route. A specific causative agent is not identified in most patients with infectious diarrhea.
Clinical Features
Infectious diarrhea most often affects young children, especially those in childcare. Children commonly present with crampy abdominal pain, vomiting, and 6 to 10 watery bowel movements per day. Associated symptoms (e.g., fever, vomiting, abdominal pain, rash, joint pain) often support an infectious cause. On examination, the abdomen is usually nondistended and soft, with diffuse or no tenderness. Bowel sounds may be hyperactive.
Although the clinical syndrome is rarely specific for a particular pathogen, diagnostic clues do exist (Table 27-1). The history may also provide clues regarding the cause:
There is a seasonal predilection for many pathogens; viral infections are more common during the winter, and bacterial infections occur more frequently in the summer.
The abrupt onset of diarrhea, with no vomiting prior to the onset of diarrhea, suggests bacterial enteritis.
Bloody diarrhea and fever are seen most commonly in bacterial enteritis, although parasitic (Cryptosporidium) infection should be considered in children with these symptoms who attend daycare.
A history of contact with other ill individuals, child-care attendance, travel, or certain exposures may provide clues regarding the specific causative agent. For example, Giardia lamblia infection is more common in individuals who drink well water or contaminated water while camping, and Campylobacter, Salmonella, and G. lamblia can be transmitted through contact with pets. Infectious organisms common to the child-care setting include rotavirus and other viruses, Giardia, Cryptosporidium, Campylobacter, and Shigella species.
Swimming in contaminated water is a common source of exposure to infectious organisms, particularly Shigella, Giardia, Cryptosporidia, and Entamoeba species and E. Coli 0157:H7. Many waterborne parasites are resistant to chlorination.
Clostridium difficile infection occurs predominantly in children who have received antibiotics during the preceding 3 weeks.
Antacid therapy with H2 blockers or proton pump inhibitors increases susceptibility to bacterial pathogens.
TABLE 27-1 Common Causes of Infectious Diarrhea | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Evaluation
Methylene blue staining of the stool can be used to screen outpatients who may require a bacterial stool culture and may occasionally identify G. lamblia. Although the presence of sheets of polymorphonuclear leukocytes suggests bacterial enteritis and the need for bacterial stool culture, the absence of leukocytes does not eliminate the possibility of a bacterial infection. A jar specimen provides a better yield than does a diaper or swab specimen.
Stool culture is generally recommended for patients who are hospitalized or are in child-care or institutional settings, and those who have underlying chronic conditions, severe or bloody diarrhea, toxic appearance, exposure to bacterial enteritis, or persistent diarrhea on dietary therapy. Some laboratories only test for Campylobacter, Yersinia, and pathogenic E. coli by special request. C. difficile culture and toxin analysis may be helpful in children with antibiotic exposure. (Of note, the asymptomatic carrier rate for C. difficile is 30% to 50% in neonates and 3% after 12 months of age.)
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