Chronic Diarrhea

Definition:  Diarrhea, continuous for >1 month, or recurrent episodes that come & go. As opposed to Acute Diarrhea, the chronic form is never caused by a Virus. Viruses just don’t last that long.

The following is the clinician’s condensed thought-process when face-to-face with a patient. For more in-depth discussion and explanations, see Chronic Diarrhea — Full Text.

Causes of Chronic Diarrhea

xxSuspect / Diagnose by General Clinician   • Irritable Bowel Syndrome (IBS) • Inflammatory Bowel Disease (IBD) • Celiac Disease • Bacteria / Parasites • Malabsorption Syndromes • Post-Cholecystectomy Surgery (gallbladder) • Lactose Intolerance • Colon Cancer • Medications, Laxative Abuse • HIV • Hyperthyroidism

xxxxLet Gastroenterologist Consider It • Chronic Pancreatitis • Chronic Diverticulitis • Diabetic Autonomic Neuropathy • Adrenal Insufficiency (Addison’s Disease) • Carcinoid tumors, Mastocytosis, & other xx xxxxVery Rare Diseases and Infections x x x x

1.  Probably diagnose Irritable Bowel Syndrome (IBS) or Lactose Intolerance

• Far and away the most common causes
• See below at the end for treatment suggestions
• Note difference between Irritable Bowel Syndrome (IBS) & Inflammatory Bowel Disease (IBD)

2.  Before making above diagnoses: Order Basic Laboratory Tests:

2a.  Initial Tests

• Complete Blood Count — for Colon Cancer, IBD, Celiac Disease if iron-deficiency (low hemoglobin)
  • will suggest IBD if there’s Anemia of Chronic Disease
• Fecal Calprotectin &/or Fecal Lactoferrin (stool tests) — if normal, IBD unlikely; esp. if both normal
• Sedimentation Rate / CRP — significant elevation suggests IBD, maybe Cancer with metastases.
• Total Protein & Albumin (blood tests) — Elevation of serum globulin suggests IBD; low albumin suggests nutritional deficiency
• Tissue-Transglutaminase Antibody (tTG), IgA fraction  —  for Celiac Disease
• Stool for Giardia Antigen — easiest test for Giardia (see “parasites” in link)
• TSH  —   for Hyperthyroidism (unlikely as cause)
• HIV Antigen-Antibody (standard test) — for HIV

2b.  Possible Tests (they usually turn out negative)

• Stool Culture for various Bacteria  —  Especially for immunocompromised persons
• Stool Ova & Parasites for various Parasites  —  Only order for Men-having-Sex-with-Men; or for Persons Lived / Traveled in poor countries (must order at least 3 separate specimens)
• Stool for C. difficile —  Suspect C. Difficile (see “bacteria” in link) if antibiotic use before diarrhea began; if recent hospitalization; also in immunocompromised patients
• Fecal Fat (maybe)  —  If frequent greasy, foul-smelling stools, for Malabsorption

3. If tests abnormal, we Diagnose & Treat; some we refer for Colonoscopy:

• Possible IBD (elevated Fecal Calprotectin &/or Fecal Lactoferrin; Sedimentation Rate / CRP)
• Possible Celiac Disease (elevated tTG-IgA Antibody)
• Possible Colon Cancer (low Hemoglobin on CBC suggesting Iron-Deficiency Anemia)

4.   If tests all normal  >>> seek “Red Flags“:

Diseases in bold require Gastroenterology Referral for diagnosis or confirmation.  They include:

• Weight Loss……………..……..……………….……could be one of many serious illnesses
• Bloody Diarrhea…………..………………..……….maybe IBD, Colon Cancer, Amebic dysentery
• Severe Diarrhea, esp. if also at night………..…needs colonoscopy
• Significant abdominal pain also………..………We order CT Scan for Tumors outside the Lumen
• Age >50 (at onset)……..…………….……….…….age for Colon Cancer
• Greasy, Malodorous Stools……………….……….Malabsorption
• AIDS (advanced; not just HIV)………..……..…. AIDS Infection (mainly for Cytomegalovirus)
• Family History (IBD, Colon Cancer)……………..IBD, Cancer (by colonoscopy)
• Immunocompromised……………………………..Needs extensive work-up

5.  Tests All Normal & NO Red Flags >>>   Diagnose Irritable Bowel Syndrome (IBS)

• See IBS link above for Diagnostic Criteria for IBS with Diarrhea
• Try Treatment: More fiber in diet; psyllium (Metamucil®); loperamide (Imodium®)
• Consider avoiding dairy products if possible Lactose Intolerance
• If no improvement:  Refer to Gastroenterologist to rule out rare diseases

See Chronic Diarrhea — Full Text for more in-depth explanations and discussions.