Diarrhea – Chronic, No Blood or Weight Loss

Differential Diagnosis

• Osmotic: Presence of nonabsorbable solute, pH <5, volume <200 mL/day, normal electrolytes, stops with fasting
• Secretory: Mostly due to toxins, pH >6, volume >200 mL/day, no response to fasting, stool Na >70 mEq/L, negative reducing substances
• Toddler's diarrhea: Chronic nonspecific diarrhea, onset 3 months to 3 years of age, average 4–6 stools daily, due to excessive juice intake or low-fat diet
• Excessive intake of nonabsorbable solutes (lactulose, sorbitol, magnesium hydroxide)
• Congenital lactose deficiency: Very rare in infancy, but may occur in extremely premature infants; adult-onset type of hypolactasia may be seen in older children (over age 5), autosomal recessive, 15% white adults, 85% of black adults, 90% of Asian adults
• Secondary lactase deficiency: Follows a viral gastroenteritis, most commonly rotavirus, may persist for months
• Fructose intolerance
• Sucrase-isomaltase deficiency: Autosomal recessive, found in 0.2% of North Americans, symptoms commence on starting sucrose or glucose polymer-containing foods
• Glucose-galactose malabsorption: Rare, autosomal recessive disorder
• Infections
  –Giardiasis (most common infectious cause of chronic diarrhea in toddlers)
  –Cryptosporidium
  –Microsporidium
• Irritable bowel syndrome (IBS)
  –Abnormality of intestinal motility and pain perception with no organic basis
  –Abdominal pain associated with intermittent diarrhea or constipation
• Bacterial overgrowth: Enteric bacteria colonizes the upper small intestine
• Trehelase deficiency (trehelose is the sugar found in mushrooms)
• Zinc deficiency
  –Acrodermatitis enteropathica is typical rash
• Low-fat diet

Workup and Diagnosis

• History
  –Weight loss
  –Daycare setting, ill contacts
  –Diet history: Type and amount of fluids daily (intake of >150 mL/kg/day with normal weight and height suggests toddler's diarrhea)
  –Frequency of stool and consistency
  –Associated symptoms: Abdominal pain, bloating, flatulence, rash, fever, or vomiting
  –Onset of symptoms and relation to ingestion of milk, sucrose, or glucose
  –Worsening with stress (typical for IBS)
  –Exposure to lakes, well water (suggestive of parasite)
  –Travel history
  –Excessive “sugar free” gum chewing (sorbitol)

• Stool examination
  –Gross examination (blood, mucus, undigested food)
  –Color is not helpful
  –Occult blood test (not detected in IBS)
  –pH: Stool pH <5 indicates osmotic diarrhea from reducing sugars (sucrose and trehelose are nonreducing)
  –Stool cultures, O&P, Clostridium difficile toxin
• More studies only if all of above failed to reveal cause
• Hydrogen breath test
  –Detects carbohydrate malabsorption (lactose, sucrose, fructose, glucose) and bacterial overgrowth
• Stool electrolytes if secretory diarrhea is suspected

Treatment

• Treatment is directed at cause
• Chronic nonspecific diarrhea
  –Restriction of fluid intake to <90 mL/kg/day
  –Reduction of fruit juices (<8 ounces/day)
  –Elimination of sorbitol-containing juices
• Carbohydrate malabsorption
  –Trial elimination or reduction of offending sugar
  –Lactase (Lactaid) for lactose intolerance
  –Sucrase (Sucraid) for sucrase-isomaltase deficiency
• Small intestine bacterial overgrowth
  –Antibiotic therapy with metronidazole alone or in combination with ampicillin or Bactrim
  –Surgery for partial small bowel obstruction
• Low-fat diet: Increase fat intake to approximately 40% of total daily calorie intake
• Irritable bowel syndrome
  –Anticholinergic therapy or antidepressants
• Acrodermatitis enteropathica: Zinc supplements