Chronic diarrhea resident survival guide

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mugilan Poongkunran M.B.B.S [2]


Chronic diarrhea is defined as a decrease in fecal consistency with or without increased stool frequency for more than 4 weeks.[1]


Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. Chronic diarrhea does not have any life threatening causes.

Common Causes

Fatty Diarrhea

Inflammatory Diarrhea

Osmotic Diarrhea

Secretory Diarrhea


Initial Management

Adults with chronic diarrhea (> 4 weeks)
Characterize the symptoms:

❑ Onset (congenital, abrupt or gradual)
❑ Pattern (continuous or intermittent)
❑ Duration
❑ Stool characteristics (watery, bloody or fatty)
Abdominal pain
Weight loss
❑ Fecal incontinence

Obtain a detailed history:
❑ Aggravating factors (diet or stress)
❑ Over-the-counter drugs or use of prescription
❑ Previous evaluations (objective records, radiograms or biopsy specimens)
❑ Radiation therapy or surgery
❑ Factitious diarrhea (eating disorders, laxative ingestion, secondary gain or malingering)
❑ Systemic disease (cancer, diabetes, HIV, hyperthyroidism)

Elicit the epidemiological factors:
❑ Travel before the onset of illness
❑ Exposure to contaminated food or water

❑ Illness in other family members
Examine the patient:

Assess the volume status:
❑ General condition
❑ Thirst
Blood pressure
❑ Eyes
❑ Mucosa

Perform a general physical exam:

❑ Skin (flushing, rashes or dermatographism)
❑ Oral cavity (ulcers)
❑ Cardiovascular system (murmur)
❑ Respiratory system (wheezing)
Thyroid (mass)
Abdomen (ascites, hepatomegaly, mass or tenderness)
❑ Anorectal (Abscess, blood, fistula or sphincter competence)
❑ Extremities (edema)
Order routine laboratory tests:

CBC and differential
Serum electrolytes
❑ Total serum protein and albumin
Thyroid function tests

Start altered diet:
❑ Stop lactose products
❑ Avoid alcohol and high osmolar supplements
❑ Drink 8-10 large glasses of clear fluids (fruit juices, soft drinks etc)
❑ Eat frequent small meals (rice, potato, banana, pastas etc)

Start oral rehydration therapy or intravenous fluids depending on the hydration status
Any specific obvious diagnosis through history and examination?
Chronic infection (outbreaks or endemic areas)
❑ Trial of oral metronidazole 500 mg TID for 5 days for protozoal diarrhea
❑ Oral ciprofloxacin 500 mg BD X 3 days for enteric bacterial diarrhea

Medication induced:
❑ Discontinuation of the drug

Irritable bowel syndrome (chronic abdominal pain and altered bowel habits in the absence of any organic disorder)
❑ Trial of antispasmodic agents (oral dicyclomine 20 mg QID),OR
TCA's(amitriptyline 10-25 mg OD), OR
SSRI (fluoxetine 20-40 mg OD), OR

No resolution of the diarrhea

This management is as per the American Gastroenterological Association guidelines for the evaluation and management of chronic diarrhea.[1]

Additional Management

Classify diarrhea by the results of the stool analysis:
Stool osmotic gap >50 mOsm/kg
Stool osmotic gap <50 mOsm/kg
Fecal occult blood (+), WBC (+), lactoferrin (+), calprotectin(+)
Fecal fat (+)
Osmotic diarrhea
Secretory diarrhea
Inflammatory diarrhea
Fatty diarrhea
❑ Check the pH of the stool
Low pH
High pH
❑ Evaluate for ingestion of magnesium or antacids
❑ Evaluate for laxative abuse
1. Exclude infection by any/combination of the following tests:
Stool culture
❑ Microscopic evaluation for ova and parasites
❑ Stool antigen test for Giardia
Small bowel aspirate or breath H2 test to rule out bacterial overgrowth
1. Exclude structural disease by any/combination of the following tests:

Small bowel radiographs
Sigmoidoscopy or colonoscopy with biopsy
CT abdomen
UGI scopy and small bowel biopsy

1. Exclude structural disease by any/combination of the following tests

Small bowel radiographs
CT abdomen
Small bowel biopsy and aspirate for quantitative culture

❑ Take a careful dietary history
❑ Order breath H2 test (lactose), OR ❑ Order lactase measurement in a mucosal biopsy
❑ Order stool alkanization test
❑ Order chromatographic and chemical tests
2. Exclude structural disease by any/combination of the following tests:

Small bowel radiographs
Sigmoidoscopy or colonoscopy with biopsy
CT abdomen
Biopsy of the proximal small bowel mucosa

2. Exclude infection by any/combination of the following tests:

Stool culture: Standard Aeromonas, Plesiomonas, Tuberculosis etc
❑ Stool for ova and parasites
Clostridium toxin assay
❑ Other specific test (Serology, ELISA, immunofluorescence to rule out virus and parasites)

2. Exclude exocrine pancreatic insufficieny by any/combination of the following tests:

Secretin test
❑ Stool chymotrypsin activity
Bentiromide test
❑ Others (D-xylose absorption tests / Schilling test)

3. Order selective testing:
❑ Cholestyramine test for bile acid diarrhea
❑ Plasma peptides (Gastrin, calcitonin, vasoactive intestinal polypeptide or somatostatin)
❑ Urine (5-hydroxyindole acetic acid, metanephrine or histamine)
❑ Others (TSH, ACTH stimulation test, serum protein electrophoresis or serum immunoglobulins)
Confirmatory diagnosis
Specific treatment per results and symptomatic treatment
No response
Administer empirical therapy

❑ Adequate hydration
❑ Opiates or octreotide



  • In chronic diarrhea, always assess first the volume status and adequate intravascular volume. Ccorrecting fluid and electrolyte disturbances take priority over identifying the causative agent.
  • Check for the presence of warning signs before starting symptomatic therapy.
  • Report to the public health authorities in case of suspected outbreaks.
  • At least one fecal culture should be performed in the evaluation of immunocompetent patients with chronic diarrhea, to rule out Aeromonas or Pleisiomonas which are rarer causes of chronic diarrhea among immunocompetent patients than among immunocompromised patients.[2]
  • Always do a 48- or 72-hour quantitative stool collection in the work-up of chronic diarrhea except in unavoidable circumstances where you can go for spot stool analysis.
  • The osmotic gap is calculated from electrolyte concentrations in stool water by the following formula : 290 - 2([Na+] + [K+]). The osmolality of stool within the distal intestine should be used for this calculation rather than the osmolality measured in fecal fluid, because measured fecal osmolality begins to increase in the collection container almost immediately when carbohydrates are converted by bacterial fermentation to osmotically active organic acids.
  • Analysis for laxatives should be done early in the evaluation of diarrhea of unknown etiology or with patient history suggestive of laxative abuse.
  • An endoscope that allows specimens to be obtained from the proximal and distal duodenum and/or proximal jejunum should be the best investigation of choice in presence of steatorrhea indicating small intestinal malabsorptive disorder as the most likely etiology.
  • Radiographic studies of the stomach and colon should be complementary to endoscopy and colonoscopy because barium-contrast radiograms can better detect fistulas and strictures.
  • Empirical therapy is used as an initial treatment before diagnostic testing or after diagnostic testing has failed to confirm a diagnosis or when there is no specific treatment or when specific treatment fails.


  • Don't treat patients with severe diarrheal dehydration using 5% dextrose with 1/4 normal saline, as using solutions with lower amounts of sodium (such as 38.5 mmol/L in 1/4 saline with 5% dextrose ) would lead to sudden and severe hyponatremia with a high risk of death.[3]
  • Oral rehydration therapy is contraindicated in the initial management of severe dehydration, in patients with frequent and persistent vomiting (more than four episodes per hour), and painful oral conditions such as moderate to severe thrush.
  • Avoid opium or morphine in most cases of diarrhea because of its abuse potential, except for high-volume secretory states that responds to a sufficiently high doses of these drugs.
  • Loperamide should be avoided in patients with significant abdominal pain, fever and bloody diarrhea that suggests inflammatory diarrhea.[4]
  • Dont't do any diagnostic tests that would disturb the normal eating pattern, aggravate diarrhea, diminish diarrhea, add foreign material to the gut, or risk an episode of incontinence during a 48- or 72-hour quantitative stool collection.
  • All but essential medications should be avoided, and any antidiarrheal medication begun before the 48- or 72-hour quantitative stool collection period should be held.


  1. 1.0 1.1 "American Gastroenterological Association medical position statement: guidelines for the evaluation and management of chronic diarrhea". Gastroenterology. 116 (6): 1461–3. 1999. PMID 10348831.
  2. Rautelin H, Hänninen ML, Sivonen A, Turunen U, Valtonen V (1995). "Chronic diarrhea due to a single strain of Aeromonas caviae". Eur J Clin Microbiol Infect Dis. 14 (1): 51–3. PMID 7537217.
  3. "" (PDF). Retrieved 2 January 2014. External link in |title= (help)
  4. "" (PDF). Retrieved 2 January 2014. External link in |title= (help)

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