Diarrhea

Diarrhea: Excerpt from The 5-Minute Pediatric Consult

Daniel H. Leung, MD

Diarrhea - BASICS

Diarrhea - description

Diarrhea is an increase in frequency, volume, or fluidity of a patient’s stool as compared to the normal bowel movement pattern. Diarrhea can classically be categorized as acute or persistent. Acute diarrhea typically presents abruptly with increased fluid content of the stool >10 mL/kg/d and lasts <14 days. Persistent diarrhea can also begin acutely and last for ≥14 days. Tenesmus, perianal discomfort, and incontinence may occur. Diarrhea is caused whenever there is disruption of the normal intestinal balance of electrolytes and water. Malabsorption, maldigestion, cellular electrolyte pump dysfunction, and intestinal colonization or invasion by microorganisms can cause diarrhea.

Diarrhea - DIAGNOSIS

Diarrhea - signs & symptoms

General goal: It is important to determine the type of diarrhea (osmotic vs. secretory) as this will alter your diagnostic and therapeutic plan.

• Phase 1, secretory diarrhea: Absorption of intestinal fluid and electrolytes is accomplished through multiple cellular pumps transporting sodium, glucose, and amino acids. Factors that interrupt these pumps (e.g., cholera toxin, prostaglandin E, vasoactive intestinal peptide, secretin, acetylcholine) can cause a severe active isotonic secretory state manifested by profuse diarrhea, dehydration, and acidosis.
• Phase 2, osmotic diarrhea: In general, the solute composition of intestinal fluid is similar to that of plasma. Osmotic diarrhea occurs when poorly absorbed or nonabsorbable solute is present in the intestinal lumen. This can occur with the ingestion of nonabsorbable sugars (e.g., sorbitol), cathartics (e.g., magnesium citrate), carbohydrate malabsorption secondary to mucosal damage (e.g., lactose), maldigestion (e.g., pancreatic dysfunction), rapid transit of intestinal fluid, or with a rare congenital transport defect.

Diarrhea - history

• A distinction should be made between acute and chronic diarrhea. The cause of acute diarrhea is almost always related to an infection, a medication, or the addition of a new food.
• Travel history: Questions should be asked regarding travel to areas where drinking water is contaminated (e.g., Entamoeba in Mexico) or food handling/preparation is prolonged or unsanitary (e.g., Campylobacter, Bacillus cereus, or Escherichia coli). Exposure to freshwater streams or ponds (e.g., Cryptosporidium, Giardia) may also be important to address.
• Adolescents: Questions should be asked regarding body image and weight. Laxative abuse causing an osmotic diarrhea is common among adolescents who have an eating disorder or athletes attempting to lose weight rapidly.
• Systemic symptoms: Questions regarding fever, GI bleeding, rashes, or vomiting are vital. Certain GI infections and inflammatory bowel disease have specific associated systemic symptoms.
• Hematochezia: The occurrence of acute, bloody stools and fever generally indicates a bacterial infection. However, these same symptoms coupled with fatigue, poor urine output, and history of easy bruising may suggest hemolytic uremic syndrome (HUS). Bloody stools in combination with a history of crampy abdominal pain, arthritis, and purpuric rash can indicate Henoch-Schönlein purpura (HSP), a completely different entity. The quantification and description of the bloody stool may also be helpful (e.g., currant jelly-like stools of intussusception vs. bright red blood from milk-protein allergy). Chronic bloody diarrhea, abdominal pain, and weight loss are characteristic of inflammatory bowel disease.
• The age of the child is important because a number of diseases present between birth and 3 months of life including cystic fibrosis, milk or soy protein allergy, and congenital enteropathies. In a previously well infant who has had a recent viral illness with subsequent protracted diarrhea, the diagnosis of postviral enteritis should be suspected. This disorder is characterized by severe mucosal injury resulting in transient disaccharidase deficiency and potentially prolonged malabsorption. Chronic nonspecific diarrhea of childhood or “toddler’s diarrhea” should be considered in otherwise normal preschool-aged children who have 2–10 watery stools per day without other symptoms and/or cause who have increased juice intake. Lactose intolerance commonly occurs in many older children and adults, with >95% occurrence rate in some ethnic groups.
• Chronic diarrhea with weight loss: Inflammatory or immunologic disorders such as ulcerative colitis, Crohn disease, and celiac disease must be ruled out. Celiac disease is an immune-mediated enteropathy caused by a permanent sensitivity to gluten in genetically susceptible individuals. It occurs in roughly 1:130 of the US population with a genetic predisposition and should be considered in any child with chronic diarrhea and poor weight gain.

Diarrhea - physical exam

• Child’s growth parameters: Previous measurements and growth curves are necessary to make an accurate evaluation. Findings of a chronically malnourished child with years of weight loss or poor growth velocity would indicate a divergent differential diagnosis from that of a healthy-appearing child with a history of normal growth.
• Arthritis and rash: Diarrhea accompanied by these signs can occur in diseases such as inflammatory bowel disease, celiac disease, HSP, and specific bacterial infections.
• Hydration: Capillary refill >3 seconds, tachycardia without pain or fever, and dry mucous membranes provide clues to dehydration.
• Nail bed clubbing: This finding may direct questioning to rule out cystic fibrosis or chronic inflammatory bowel disease.
• Masses: A right lower quadrant mass could suggest an abscess (e.g., terminal ileitis in Crohn disease or appendiceal abscess) or intussusception (e.g., irritable child with currant jelly-like stools).

Diarrhea - tests

Diarrhea - lab

• Stool culture: Stool examination for blood, mucus, inflammatory cells, and micro-organisms is an important first step in determining the cause of the diarrhea. Stool cultures for parasites (e.g., Giardia, Cryptosporidium, Entamoeba), bacterial pathogens (e.g., Salmonella, Campylobacter, Shigella, Yersinia, Aeromonas, Plesiomonas), viral particles and Clostridium difficile toxin should be appropriately obtained in all children with unexplained diarrhea.
• Stool pH and reducing substances: These tests are useful in identifying carbohydrate malabsorption. A stool pH <5–6 and stool reducing substances >0.5–1% is suggestive.
• Stool osmolality and electrolytes:
  • Stool osmolality, stool Na, and stool K can be used to calculate an ion gap and differentiate between secretory and osmotic diarrhea.
  • Ion gap = Stool osmolality – 2(Na + K)
  • Ion gap >100 indicates an osmotic cause of diarrhea.
• Hemoccult: This very sensitive and specific test is helpful in distinguishing truly heme + stools from ingested foods/drinks with artificial or natural red coloring.
• 72-hour quantitative fecal fat evaluation: This is a sensitive test for steatorrhea. Patients need to be placed on a high-fat diet (2–4 g/kg) for a minimum of 1 day prior to testing. Over 3 days, all stool is collected, refrigerated, and tested. A diet record needs to be performed for the 3 days that correspond to the stool collection period. The coefficient of fat absorption is calculated: Grams of fat ingested – grams of fat excreted/grams of fat ingested × 100. Normal values are as follows: Premature infants: 60–75%; newborns: 80–85%; children 10 months to 3 years: 85–95%; children >3 years: 93%. When fat malabsorption is present, disorders of pancreatic function (e.g., cystic fibrosis, Shwachman syndrome) or severe intestinal disease should be suspected.
• Lactose breath test: This noninvasive test measures hydrogen levels. It is based on the principle that hydrogen gas is produced by colonic bacterial fermentation of malabsorbed carbohydrates. When abnormal in older healthy-appearing children, primary lactose deficiency is likely. However, in young children, a secondary lactase deficiency should be considered and small-bowel disease should be ruled out.
• D-Xylose test: This serum test is an indirect measure of functional small bowel surface area. D-xylose absorption in the blood occurs independent of bile salts, pancreatic enzymes, and intestinal disaccharidases. A specific dose of D-xylose (1 g/kg, maximum 25 g) is given orally after an 8-hour fast, and the serum level of D-xylose is determined after 1 hour. Levels <15–20 mg/dL in children is abnormal and suggestive of disorders that alter or disrupt intestinal mucosa absorption.
• Endoscopy and colonoscopy:
  • Direct visualization of the intestinal mucosa as well as intestinal culture, disaccharidase collection, and biopsies can provide clues to diagnosis.
• Celiac panel: This includes a tissue transglutaminase (TTG), IgA level, and endomysial antibody (EMA)

Diarrhea - differencial diagnosis

• Acute diarrhea:
  • Dietary causes: Sorbitol, fructose, lactose, and intolerance to specific foods (beans, fruit, peppers, etc.)
  • Infectious causes: Bacterial (e.g., Escherichia coli, C. difficile) and viral (e.g., rotavirus, Norwalk agent, adenovirus)
  • Medications: Antibiotics, laxatives
  • Vitamin deficiency: Zinc, niacin
• Chronic diarrhea:
  • Allergic/Autoimmune: Milk/soy protein allergy, eosinophilic enteritis, HSP, celiac disease, or autoimmune enteropathy
  • Immunodeficiency: HIV/AIDS, chronic granulomatous disease, Hyper IgM, SCID
  • Anatomic abnormalities: Short intestinal tract (e.g., h/o necrotizing enterocolitis or Hirschsprung s/p repair), malrotation
  • Bile salt malabsorption
  • Congenital causes: Cystic fibrosis, microvillus inclusion disease, tufting enteropathy, or IPEX syndrome
  • Encopresis
  • Endocrine disorders: Hyperthyroidism, diabetes, congenital adrenal hyperplasia
  • Bacterial overgrowth (e.g., blind loop, ostomy)
  • Inflammatory bowel disease: Ulcerative colitis, Crohn disease
  • Intestinal lymphangiectasia: Primary and secondary
  • Irritable bowel syndrome
  • Lactose intolerance: Primary, secondary, and congenital
  • Pancreatic exocrine dysfunction: Shwachman-Diamond syndrome, cationic trypsinogen deficiency, Jeune syndrome, Pearson syndrome, and Johansson-Blizzard syndrome
  • Postinfectious enteropathy
  • Secretory tumors (VIPoma, somatostatinoma, gastrinoma)

Diarrhea - TREATMENT

Diarrhea - initial stabilization

Diarrhea can lead to significant dehydration. Any child suspected of clinical dehydration should be closely observed. Only if oral rehydration is ineffective is IV therapy indicated. Culture-negative GI bleeding associated with severe abdominal pain and diarrhea should always be treated urgently.

Diarrhea - general measures

Rehydration is the cornerstone of treatment:

• Oral rehydration therapy with glucose concentrations of 111 mmol/L with 90 mmol/L sodium is recommended.
• IV rehydration is indicated for patients who are severely dehydrated and unable to tolerate oral feedings.

Diarrhea - diet

• Breast feeding should continue during episodes of gastroenteritis, as it promotes mucosal healing and recovery.
  • It was traditionally believed that bowel rest was beneficial for formula-fed infants. Many studies have now shown that return feeding after 4–6 hours promotes a faster recovery.
• Antibiotics:
  • Vibrio cholerae, Shigella, and Giardia lamblia require antimicrobial therapy (i.e., trimethoprim/sulfasoxazole, azithromycin, tetracycline, ciprofloxacin, metronidazole).
  • Prolonged courses of enteropathogenic Escherichia coli, Yersinia in sickle cell patients, and Salmonella species infections in the very young febrile or bacteremic infant require antimicrobial therapy.
• Micronutrient supplementation:
  • Zinc supplementation during episodes of acute diarrhea has been shown to decrease severity and duration as well as preventing future episodes in malnourished children.
  • Many studies also point to vitamin A possibly shortening duration of diarrheal illness, but this is inconclusive.
• Probiotics: Lactobacillus rhamnosus GG has been shown to shorten the duration of diarrheal illness and viral shedding (e.g., rotavirus).

Diarrhea - FOLLOW UP

Diarrhea - disposition

Diarrhea - issues for referral

The occurrence of diarrhea in children is quite common and almost always can be managed by the primary care physician. A decision to pursue subspecialty evaluation rests with the primary care physician and the family. Children who present with growth failure, noninfectious heme-positive diarrhea, or unexplained chronic diarrhea should be considered for referral to a pediatric gastroenterologist.

Diarrhea - bibliography

1. Ali SA, Hill DR. Giardia intestinalis. Curr Opin Infect Dis. 2003;16:453–460.
2. Baldassano RN, Liacouras CA. Chronic diarrhea: A practical approach for the pediatrician. Pediatr Clin North Am. 1991;38:667–685.
3. Castelli F, Saleri N, Tomasoni LR, et al. Prevention and treatment of traveler’s diarrhea. Focus on antimicrobial agents. Digestion. 2006;73(Suppl 1):109–118.
4. Fontaine O. Oral rehydration therapy: A critical component in integrated management of childhood illness. J Pediatr Gastroenterol Nutr. 2000;30:490.
5. Gore JI, Surawicz C. Severe acute diarrhea. Gastroenterol Clin North Am. 2003;32:1249–1267.
6. Hartling L, Bellemare S, Wiebe N, et al. Oral versus intravenous rehydration for treating dehydration due to gastroenteritis in children. Cochrane Database Syst Rev. 2006;3:CD004390.
7. Hoque KM, Binder HJ. Zinc in the treatment of acute diarrhea: Current status and assessment. Gastroenterology. 2006;130(7):2201–2205.
8. Huebner ES, Surawicz CM. Probiotics in the prevention and treatment of gastrointestinal infections. Gastroenterol Clin North Am. 2006;35(2):355–365.
9. Robayo-Torres CC, Quezada-Calvillo R, Nichols BL. Disaccharide digestion: Clinical and molecular aspects. Clin Gastroenterol Hepatol. 2006;4(3):276–287.
10. Thielman NM, Guerrant RL. Clinical practice. Acute infectious diarrhea. N Engl J Med. 2004;350:38–47.
11. Waters V, Ford-Jones EL, Petric M, et al. Rotavirus Epidemiology Study for Immunization Study Group. Etiology of community-acquired pediatric viral diarrhea: A prospective longitudinal study in hospitals, emergency departments, pediatric practices and child care centers during the winter rotavirus outbreak, 1997 to 1998. Pediatr Infect Dis J. 2000;19:843–848.

Diarrhea - CODES

Diarrhea - icd9

787.91 Diarrhea

Book Source Details

• Book Title: The 5-Minute Pediatric Consult
• Author(s): M. William Schwartz MD; et al.
• Year of Publication: 2008
• Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.

More About Traveler's diarrhea

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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.

More About This Book: Title: The 5-Minute Pediatric Consult Authors: M. William Schwartz MD; et al. Publisher: Lippincott Williams & Wilkins Copyright: 2008 ISBN: 0-7817-7577-9

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