Some Causes of Diarrhea
Cause | Suggestive Findings | Diagnostic Approach |
|---|---|---|
Acute | ||
Antibiotics (eg, broad-spectrum antibiotics, multiple concomitant antibiotics) | Temporal relationship of onset of diarrhea with taking of antibiotics | Clinical evaluation |
Bacteria (eg, Campylobacter species, Clostridioides difficile (formerly Clostridium difficile), Escherichia coli [can cause hemolytic-uremic syndrome], Salmonella species, Shigella species, Yersinia enterocolitica)* | Fever, bloody stool, abdominal pain Possibly petechiae or pallor (in patients with hemolytic uremic syndrome) History of contact with animals (E. coli) or reptiles (Salmonella) History of eating undercooked food (Salmonella) Recent (< 2 months) antibiotic use (C. difficile) Day care center outbreak | Stool culture Fecal leukocytes If patients appear ill, complete blood count, renal function tests, and blood culture If patient has recently been given antibiotics, stool testing for C. difficile toxin |
Food allergy or food poisoning | Allergy: Urticarial rash, lip swelling, abdominal pain, vomiting, diarrhea, difficulty breathing within minutes to several hours after eating Poisoning: Nausea, vomiting, abdominal pain, diarrhea several hours after ingestion of contaminated food | Clinical evaluation |
Parasites (eg, Giardia intestinalis [lamblia], Cryptosporidium parvum)* | Abdominal bloating and cramping, foul-smelling stools, anorexia Possibly history of travel, use of contaminated water source | Microscopic examination of stool for ova and parasites Stool antigen or PCR tests |
Viruses (eg, astrovirus, calicivirus, enteric adenovirus, rotavirus)* | < 5 days of diarrhea with no blood Often vomiting Possibly fever Contact with infected people Appropriate season for the infection | Clinical evaluation |
Chronic | ||
Delayed passage of stool > 48 hours after birth Possibly long-standing history of constipation Bilious vomiting, abdominal distention, ill appearance | Abdominal x-ray Barium enema Rectal biopsy | |
History of bowel resection (eg, for necrotizing enterocolitis, volvulus, or Hirschsprung disease) | Clinical evaluation | |
Abdominal bloating, flatus, explosive diarrhea Diarrhea after ingestion of dairy products | Clinical evaluation Sometimes hydrogen breath test Sometimes test for reducing substances in stool (to check for carbohydrates) and stool pH (< 6.0 indicates carbohydrates in stool) | |
Cow's milk protein intolerance (milk protein allergy) | Vomiting Diarrhea or constipation Hematochezia Anal fissures Failure to thrive | Symptom resolution when cow's milk protein is eliminated Sometimes endoscopy or colonoscopy |
Excessive juice intake | History of excessive juice or sugary drink intake (> 120–180 mL [4–6 oz] per day) | Clinical evaluation |
Chronic nonspecific diarrhea of childhood (toddler's diarrhea) | Age 6 months–5 years 3–10 loose stools/day typically during the day while awake and sometimes immediately after eating Sometimes undigested food visible in stool Normal growth, weight gain, activity, and appetite | Clinical evaluation |
Immunodeficiency (eg, HIV infection, IgA deficiency, or IgG deficiency) | History of recurrent skin, respiratory tract, or intestinal infections Weight loss or poor weight gain | HIV test Complete blood count Immunoglobulin levels |
Inflammatory bowel disease (eg, Crohn disease, ulcerative colitis) | Bloody stools, crampy abdominal pain, weight loss, anorexia Possibly arthritis, oral ulcerations, skin lesions, rectal fissures | Colonoscopy |
Eosinophilic gastroenteritis | Abdominal pain, nausea, vomiting, weight loss | Complete blood count for peripheral blood eosinophilia Sometimes IgE level Endoscopy and/or colonoscopy |
Celiac disease (gluten enteropathy) | Symptom onset after introduction of wheat into diet (typically after age 4–6 months) Failure to thrive Recurrent abdominal pain Bloating Diarrhea or constipation | Complete blood count Serologic screening for celiac disease (IgA antibody to tissue transglutaminase) Endoscopy for duodenal biopsy |
Failure to thrive Repeated episodes of pneumonia or wheezing Fatty and foul-smelling stools Bloating, flatus | 72-Hour fecal fat excretion Sweat test Genetic testing | |
Sometimes psoriasiform rash, angular stomatitis | Zinc levels | |
Constipation with encopresis | History of hard stools Fecal incontinence | Abdominal x-ray |
* Can also cause chronic diarrhea. | ||
PCR = polymerase chain reaction. | ||