Diarrhea in Children: A Merck Manual of Patient Symptoms podcast
Diarrhea is frequent loose or watery bowel movements that deviate from a child's normal pattern.
Diarrhea may be accompanied by anorexia, vomiting, acute weight loss, abdominal pain, fever, or passage of blood. If diarrhea is severe or prolonged, dehydration is likely. Even in the absence of dehydration, chronic diarrhea usually results in weight loss or failure to gain weight.
Diarrhea is a very common pediatric concern and causes about 1.5 million deaths/yr worldwide. It accounts for about 9% of hospitalizations in the US among children aged < 5 yr.
For diarrhea in adults, see Diarrhea.
Mechanisms of diarrhea may include the following:
Osmotic diarrhea results from the presence of nonabsorbable solutes in the GI tract, as with lactose intolerance. Fasting for 2 to 3 days stops osmotic diarrhea.
Secretory diarrhea results from substances (eg, bacterial toxins) that increase secretion of chloride ions and water into the intestinal lumen. Secretory diarrhea does not stop with fasting.
Inflammatory diarrhea is associated with conditions that cause inflammation or ulceration of the intestinal mucosa (eg, Crohn disease, ulcerative colitis). The resultant outpouring of plasma, serum proteins, blood, and mucous increases fecal bulk and fluid content.
Malabsorption may result from osmotic or secretory mechanisms or conditions that lead to less surface area in the bowel. Conditions such as pancreatic insufficiency and short bowel syndrome and conditions that speed up transit time cause diarrhea due to decreased absorption.
The causes and significance of diarrhea (see Table 5: Some Causes of Diarrhea) differ depending on whether it is acute (< 2 wk) or chronic (> 2 wk). Most cases of diarrhea are acute.
Acute diarrhea usually is caused by
Most gastroenteritis is caused by a virus; however, any enteric pathogen can cause acute diarrhea.
Chronic diarrhea usually is caused by
Chronic diarrhea can also be caused by anatomic disorders and disorders that interfere with absorption or digestion.
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History of present illness focuses on quality, frequency, and duration of stools, as well as on any accompanying fever, vomiting, abdominal pain, or blood in the stool. Parents are asked about current or recent (within 2 mo) antibiotic use. Clinicians should establish elements of the diet (eg, amounts of juice, foods high in sugars or sorbitol). Any history of hard stools or constipation should be noted. Clinicians should also assess risk factors for infection (eg, recent travel; exposure to questionable food sources; recent contact with animals at a petting zoo, reptiles, or someone with similar symptoms).
Review of systems should seek symptoms of both complications and causes of diarrhea. Symptoms of complications include weight loss and decreased frequency of urination and fluid intake (dehydration). Symptoms of causes include urticarial rash associated with food intake (food allergy); nasal polyps, sinusitis, and poor growth (cystic fibrosis); and arthritis, skin lesions, and anal fissures (inflammatory bowel disease).
Past medical history should assess known causative disorders (eg, immunocompromise, cystic fibrosis, celiac disease, inflammatory bowel disease) in the patient and family members.
Vital signs should be reviewed for indications of dehydration (eg, tachycardia, hypotension) and fever.
General assessment includes checking for signs of lethargy or distress. Growth parameters should be noted.
Because the abdominal examination may elicit discomfort, it is advisable to begin the examination with the head. Examination should focus on the mucous membranes to assess whether they are moist or dry. Nasal polyps; psoriasiform dermatitis around the eyes, nose, and mouth; and oral ulcerations should be noted.
Examination of the extremities focuses on skin turgor, capillary refill time, and the presence of petechiae, purpura, other skin lesions (eg, erythema nodosum, pyoderma gangrenosum), rashes, and erythematous, swollen joints.
Abdominal examination focuses on distention, tenderness, and quality of bowel sounds (eg, high-pitched, normal, absent). Examination of the genitals focuses on presence of rashes and signs of anal fissures or ulcerative lesions.
The following findings are of particular concern:
Interpretation of findings:
Antibiotic-related, postinfectious, and anatomic-related causes of diarrhea are typically clear from the history. Determination of the time frame helps establish whether diarrhea is acute or chronic. Establishing the level of acuity is also important. Most cases of acute diarrhea have a viral etiology, are low acuity, and cause fever and nonbloody diarrhea. However, bacterial diarrhea can lead to serious consequences; manifestations include fever, bloody diarrhea, and possibly a petechial or purpuric rash.
Symptoms associated with chronic diarrhea can vary and those of different conditions can overlap. For example, Crohn disease and celiac disease can cause oral ulcerations, a number of conditions can cause rashes, and any condition can lead to a poor growth pattern. If the cause is unclear, further tests are done based on clinical findings (see Table 5: Some Causes of Diarrhea).
Testing is unnecessary in most cases of acute self-limited diarrhea. However, if the evaluation suggests an etiology other than viral gastroenteritis, testing should be directed by the suspected etiology (see Table 5: Some Causes of Diarrhea).
Specific causes are treated (eg, gluten-free diet for children with celiac disease).
General treatment focuses on hydration, which can usually be done orally. IV hydration is rarely essential. (Caution: Antidiarrheal drugs [eg, loperamide] are not recommended for infants and young children.)
Oral rehydration solution (ORS) should contain complex carbohydrate or 75 mEq/L glucose and 75 mEq/L Na (total 245 mOsm/L solution). Sports drinks, sodas, juices, and similar drinks do not meet these criteria and should not be used. They generally have too little Na and too much carbohydrate to take advantage of Na/glucose cotransport, and the osmotic effect of the excess carbohydrate may result in additional fluid loss.
ORS is recommended by the WHO and is widely available in the US without a prescription. Premixed solutions are also available at most pharmacies and supermarkets.
Small, frequent amounts are used, starting with 5 mL q 5 min and increasing gradually as tolerated (see Oral Rehydration). Generally, 50 mL/kg is given over 4 h for mild dehydration, and 100 mL/kg is given over 4 h for moderate dehydration. For each diarrheal stool, an additional 10 mL/kg (up to 240 mL) is given. After 4 h, the patient is reassessed. If signs of dehydration persist, the same volume is repeated.
Diet and nutrition:
Children with an acute diarrheal illness should eat an age-appropriate diet as soon as they have been rehydrated and are not vomiting. Infants may resume breast milk or formula.
For chronic nonspecific diarrhea of childhood (toddler's diarrhea), dietary fat and fiber should be increased, and fluid intake (especially fruit juices) should be decreased.
For other causes of chronic diarrhea, adequate nutrition must be maintained, particularly of fat-soluble vitamins.
Last full review/revision August 2013 by Deborah M. Consolini, MD
Content last modified October 2013