Pediatric Gastroenteritis Clinical Presentation

Pertinent information in individuals with suspected gastroenteritis includes the following:

• Presence or absence of vomiting
• Frequency, duration, and character of diarrhea
• Travel history
• Contacts with sick individuals
• Antibiotic use
• Seafood ingestion
• Possible ingestion of toxic substances
• Chronic illness

Determine the amount and type of fluids ingested for the past 24 hours and the child's urine output.

Seizures in a patient with diarrhea should raise the possibility of gastroenteritis caused by Shigella species, enterohemorrhagic Escherichia coli, or an electrolyte imbalance.

A US study of 28 patients noted that patients may experience afebrile convulsions in the course of mild acute gastroenteritis without having dehydration and abnormal blood analysis results, a symptom previously reported almost solely from Asian countries. The authors suggest that awareness in this situation may avoid extra and possibly needless investigations.^[1]

Hyponatremia is more common than hypernatremia.

• Consider hyponatremic dehydration in children who have been fed bland and dilute fluids (eg, tea, rice water, dilute formula).
• Consider hypernatremic dehydration in patients who have been drinking mainly salt solutions and other hypertonic solutions, who have been losing hypotonic fluids (eg, profuse watery diarrhea), and who present with a depressed sensorium beyond what would be expected from the apparently mild signs of dehydration.

The criterion standard and most accurate clinical indicator of the extent of dehydration is the percentage loss of body weight during the illness, which represents the child's fluid deficit.

Other vital clinical findings include the following:

• Thirst
• Listlessness
• Dry mucous membranes
• Sunken fontanelles
• Sunken eyes
• Absence of tears
• Decreased skin turgor
• Decreased capillary filling time
• Tachycardia
• Weak pulse
• Reduced blood pressure

Examine the stools to check for mucus, blood streaks, or gross blood.

Tenting or loss of skin turgor (eg, when pinched skin does not return to the original flat shape) usually occurs in moderate-to-severe cases of dehydration yet is not always present in dehydration. Tenting or skin turgor loss seldom occurs with hypernatremic dehydration, a condition in which doughy skin is more common.

Bacterial infections cause most gastroenteritis cases in less affluent nations.

• The most important causal agent in these countries is diarrhea-causing E coli (eg, enteropathogenic [EPEC], enterotoxigenic [ETEC], enteroaggregative [EAEC], enteroinvasive [EIEC], enterohemorrhagic [EHEC]).
• Other bacteria that cause gastroenteritis less often include Campylobacter, Aeromonas, Shigella, and Salmonella species.
• Vibrios species, especially Vibrios cholerae, play major roles in epidemics. In seafood poisoning, Vibrio parahaemolyticus is associated with gastroenteritis.

Viral infections cause 30-40% of gastroenteritis cases in affluent countries.

• Rotavirus accounts for about 3.5 million cases per year and as many as 110,000 hospital admissions for diarrhea.

  • Rotavirus is the single most important cause of dehydrating diarrhea in both developed and developing countries. It produces severe diarrhea, accounting for most episodes in children younger than 2 years who require hospitalization for diarrhea and dehydration.^[2]
  • Rotavirus incidence has a distinct seasonal pattern.
  • Rotavirus infection occurs most frequently in children aged 3-15 months and may occur in children as old as 24 months, although the vast majority of children have acquired antibodies by that age.
  • Rotavirus is transmitted by fecal oral spread with secondary spread via respiratory route.
  • A rotavirus vaccine has been available in the United States since 2006 (see Deterrence/Prevention).
• Norwalk virus is responsible for outbreaks of gastroenteritis in older children and adults. Unlike rotavirus, which affects mainly children, the Norwalk virus causes illness in all age groups.
• Enteric adenoviruses account for 5-20% of hospitalizations for acute diarrhea. Compared to rotavirus and Norwalk virus, enteric adenoviruses have a longer incubation period (ie, 8-10 d compared with 1-3 d), and the diarrhea associated with adenoviruses lasts longer (ie, 5-12 d compared with 5-7 d for rotavirus and 1-2 d for Norwalk). Astroviruses and caliciviruses each account for 3-5% hospitalizations for acute diarrhea.
• Additional information about viral gastroenteritis can be obtained from The Centers for Disease Control and Prevention (CDC).

The most common bacterial agents in the United States are Salmonella, Shigella, Campylobacter, and Yersinia species and E coli. Enteroaggregative E coli has recently been shown to be an unrecognized cause of community-acquired diarrhea in infants in the United States. Campylobacter jejuni affects approximately 2 million people in the United States annually. Clostridium difficile is the most common cause of pseudomembranous colitis, a condition often observed in patients who develop severe diarrhea during or following a course of antibiotics. Clindamycin is the most common antibiotic identified, although almost all antibiotics have been implicated.

• In patients with sickle cell disease, Salmonella species are the most frequent cause of gastroenteritis.
• Giardia lamblia is the only parasite frequently isolated from patients with diarrhea. Other parasites include Cryptosporidium parvum and Cyclospora cayetanensis.
• Nonpathogenic isolates include Entamoeba coli, Endolimax nana, Iodamoeba butschlii, and Blastocystis hominis.
• In patients with human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS), Mycobacterium avium is another causative agent, in addition to the other bacteria mentioned above. Protozoal agents include Cryptosporidium species, Isospora belli, G lamblia, Entamoeba histolytica, Cyclospora species, and microsporidia. Viral causes include cytomegalovirus and rotavirus.
• Persistent infectious diarrhea may be caused by Shigella, Giardia, and Cryptosporidium species, EPEC, EAEC, and Entamoeba histolytica.
• Additional information on bacterial foodborne and diarrheal diseases is available from the CDC.