Significance: 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.
Significance: 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 E. coli). Exposure to freshwater streams or ponds (e.g., Cryptosporidium, Giardia) may also be important to address.
Significance: A variety of antibiotics can be associated with C. difficile colitis or antibiotic-related diarrhea.
Significance: 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.
Significance: conditions with genetic susceptibility (e.g., inflammatory bowel disease, celiac disease)
Significance: It is important to ask about concomitant fever, GI bleeding, rashes, or vomiting. Certain GI infections and inflammatory bowel disease have specific associated systemic symptoms.
Significance: 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. Bloody stools in combination with a history of crampy abdominal pain, arthritis, and purpuric rash can indicate HSP, a completely different entity. Chronic bloody diarrhea, abdominal pain, and weight loss are characteristic of inflammatory bowel disease.
Significance: indicates fat malabsorption (e.g., cystic fibrosis)
Significance: 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.
Significance: Postviral enteritis should be suspected. This disorder is characterized by severe mucosal injury resulting in transient disaccharidase deficiency and potentially prolonged malabsorption.
Significance: Chronic nonspecific diarrhea of childhood or "toddler's diarrhea" should be considered.
Significance: commonly occurs in many older children and adults, with >95% occurrence rate in some ethnic groups
Significance: 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 and related prolamine in genetically susceptible individuals. Occurs in ~1:130 of the U.S. population with a genetic predisposition and should be considered in any child with chronic diarrhea and poor weight gain
Significance: 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.
Significance: Diarrhea accompanied by these signs can occur in diseases such as inflammatory bowel disease, celiac disease, HSP, and specific bacterial infections.
Significance: occur in inflammatory bowel disease and celiac disease
Significance: Capillary refill >3 seconds, tachycardia without pain or fever, and dry mucous membranes provide clues to dehydration.
Significance: This finding may direct questioning to rule out cystic fibrosis or chronic inflammatory bowel disease.
Significance: 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).
Significance: Stool examination for blood, mucus, inflammatory cells, and microorganisms 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 C. difficile toxin should be appropriately obtained in all children with unexplained diarrhea.
Significance: These tests are useful in identifying carbohydrate malabsorption. A stool pH <5-6 and stool-reducing substances >0.5-1% is suggestive of malabsorption.
Significance: Stool osmolality, stool Na, and stool K can be used to calculate an ion gap and differentiate between secretory and osmotic diarrhea.
Significance: Sensitive and specific test is helpful in distinguishing truly heme-positive stools from ingested foods/drinks with artificial or natural red coloring. Stool positive for blood is suggestive of infectious (C difficile) and organic etiologies (inflammatory bowel disease).
Significance: 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.
Significance: This noninvasive test measures hydrogen levels and or methane. 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 lactase deficiency is likely. However, in young children, a secondary lactase deficiency should be considered and small-bowel disease should be ruled out.
Significance: 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.
Significance: Calprotectin is a neutrophilic protein detected in stools in inflammatory conditions.
Significance: Direct visualization of the intestinal mucosa as well as intestinal culture, disaccharidase collection, and biopsies can provide clues to diagnosis.
Significance: This includes a tissue transglutaminase, IgA level, and endomysial antibody.