Diarrhea – WGO 2008

3 categories
  1. Acute Diarrhea: presence of ≥ 3 loose, waterly stools within 24hr
  2. Dysentery: bloody diarrhea, visible blood and mucous present
  3. Persistent diarrhea: Episodes of diarrhea lasting >14 days
Main symptoms
  1. Fever: common and associated with invasive pathogens
  2. Bloody stools: invasive & cytotoxin releasing pathogens
    • Suspect EHEC in the absence of fecal leukocytes
    • Not with viral agents & enterotoxins releasing bacteria
  3. Vomiting: Frequently in viral diarrhea & illness caused by ingestion of bacterial toxins (S aureus)
  • Infection
  • Preformed toxin
  • Med-induced
  • Initial presentation of chronic diarrhea (see objective 7)
Inflammatory Non-inflammatory
Definition Disruption of intestinal mucosa Intestinal mucosa intact
Site Usually colon Usually small intestine
Sigmoidoscopy Usually abn mucosa seen Usually normal
Symptoms Bloody (notalways)Smallvolume,high frequencyOften lower abdominal cramping with urgency + tenesmusMay have fever + shock Watery, little or no bloodLarge volumeUpper/ periumblical pain / cramp + shock
Ix Fecal WBC and RBC positive Fecal WBC negative
Etiology YersiniaShigellaSalmonellaE. Coli (EHEC0157:H7)E.histolyticaCampylobacter & C Difficile
Significance Higher yield with stool C&S (campylobacter, salmonella, shigella,ecoli)Can progress to life-threatening megacolon, perforation, hemorrhage.Abx may benefit Lower yield with stool C&S.Chief life-threatening problem is electrolyte disturbances / fluid depletionAbx unlikely to be helpful
  • Stool frequency, bloody, abd pain,
  • duration (~1 wk for viral & bacterial – except C Diff & > 1 w for parasitic),
  • travel, food, recent abx
  • Vol depletion: VS, U/O, axillae, skin turgor, mental status
  • Fever, abd tenderness, ileus, rash
Red flags / Warning signs: req further evaluation
  • Fever,
  • unintentional wt loss >10lb
  • Anemia
  • blood or pus in stools / hematochezia or melena / positive FOB
  • >6 stools / day, severe dehydration, signific abd pain,
  • immunosupp., elderly, hosp-acquired
  • duration > 7 days or symptoms refractory to Tx
  • nocturnal defecation
  • Fam Hx of colon cancer or IBD
  • Hemolytic uremic syndrome
  • C difficile infection / toxic megacolon
  • Toxic shock syndrome

1 In all patients with diarrhea

a) Determine hydration status,
b) Treat dehydration appropriately.

The initial evaluation should focus on
  1. Assessing the severity of the illness & the need for rehydration
    • Signs of dehydration in adults:
      • HR>90bpm, absence of palpable pulse
      • postural HoTN, Supine HoTN
      • Drug tongue, sunken eyeballs, skin pinch
    • Chidren
      • No dehydration: normal alertness, no sunken eyes, normal drinking, immediate skin pinch
      • Mild dehydration (≥2): restless / irritable, sunken eyes, drinks eagerly, slow skin pinch (<2sec)
      • Severe dehydration (>2): Abnormally sleepy or lethargic (dull mental state & can’t be fully awakened), sunken eyes, drinking poorly or not at all, very slow skin pinch (>2sec)
    • Maintaining adequate intravascular volume & correcting fluid and electrolyte disturbances take priority over the identification of the causing agent
  2. identifying likely causes on the basis of the Hx and clinical findings
Oral rehydration therapy (ORT)
  • Rehydration – water & electrolytes are administered to replace losses
  • Maintenance fluid therapy: along with appropriate nutrition
    • Food should be started 4hr after starting ORT or IV fluid
    • Frequent, small meals throughout the day with energy & micronutrient rich foods (grains, fruits, vegetables, meats)
    • Avoid canned fruit juices – hyperosmolar & can aggravate diarrhea
  • If po route not tolerated (persistent vomiting), NG feeding can be used
  • Rice-based ORS better to standard ORS for Tx of cholera
  • PO C/I in hemodynamic shock or with abdominal ileus – use IV fluid


  • For traveler’s diarrhea, bismuth or rifaximin useful for prophylaxis and empiric Rx
  • Abx Tx if any of the following symptoms are present:
    • Severe traveler’s diarrhea > 4 unformed stools / day, fever, blood, pus or mucous in the stool
    • > 8 stools per day
    • symptoms >1 week
    • Imunocompromised
    • Hospitalized pt
  • FQ x 5-7 d reasonable empiric abx for non-hospital-acquired inflammatory diarrhea
  • Probiotics (no good evidence)
  • Loperamide to reduce stool frequency – consider if no fever or bloody stool
  • C. Diff Tx
    1. Mild (< 6BM/d, temp <38C, WBC<15, no peritoneal Sx or SIRS, age <65)
      • Metronidazole 500mg po tid x 10-14 days (IV if poor po or ileus)
    2. Moderate (6-12 BM/d, temp 38-39C, WBC 15-25, visible LGIB, >65yo)
      • Vanco 125-500mg po qid x 10-14 days
      • Add Metronidazole 500 mg IV tid if not improved by 48 hr
    3. Severe (>12BM/d, temp >39C, WBC >25, no bowel sounds, ↑ abd pain)
      • Vanco po + Metronidazole IV; PR vancomycin if ileus.
      • CT, urgent Sx consult RE colectomy
      • Consider IVIG

2  In patients with acute diarrhea, use history to establish the possible etiology (e.g., infectious contacts, travel, recent antibiotic or other medication use, common eating place for multiple ill patients).

  • Travel / Camping
  • Homosexual contacts
  • Outbreaks (Foodborne) – salmonella,shiga-toxin E. coli, Yersinia,cyclospora
    • Person-to-person: shigella, rotavirus
  • Seafood / shellfish: vibrio, norovirus, salmonella
  • Extra-intestinal signs of IBD
  • Family Hx (IBD)
  • Antibiotics: C. Difficile
  • Diet:
    • chicken, turkey, (poultry) – campylobactor, salmonella
    • egg (salmonella)
    • beef: shiga-toxin E coli, EHEC
    • Waterborne: Cryptosp., Giardia, vibrio
    • Mayonnaise: staphyloc., clostridium, salmonella
    • Pies: salmonella, campylob., cryptosp., Giardia
  • Steatorrhea
  • Weight loss
  • Immunosuppressed / chemo: C difficile
  • Laxatives
  • Tumor Hx

3  In patients with acute diarrhea who have had recent hospitalization or recent antibiotic use, look for clostridium difficile.

Ix: C. Difficile toxin Indicated recent / remote

  1. antibiotic use
  2. hospitalization
  3. nursing home
  4. recent chemotherapy

4  In patients with acute diarrhea, counsel about the timing of return to work/school (re: the likelihood of infectivity).

5  Pursue investigation, in a timely manner, of elderly with unexplained diarrhea, as they are more likely to have pathology.

  1. Stool C&S unnecessary for immunocompetent pt who present within 24hr after the onset of acute, watery diarrhea
  2. Stool C&S is indicated in pt who are
  • dehydrated or febrile
  • having blood/pus in their stool
  • severe, inflammatory, or persistent diarrhea
  • an Outbreak is suspected
  • Fecal WBC (high false +/-), stool C&S,
  • blood Cx if SIRS +,
  • C. Diff (if recent hosp or abx)
  • stool O & P if >10d, travel to endemic area, exposure to unpurified HxO, community outbreak, daycare, HIV + or MSM
  • CT/KUB if toxic megacolon, sig. if immunosuppr or Cx –

Community-acquired / traveler’s diarrhea
  • C&S for salmonella, shigella, campylobacter
  • E. coli 0157:H7 + shiga-like toxin (hx of bloody diarrhea / hemolytic-uremic syndrome)
  • C Dificile toxins A & B (recent Abx, chemotherapy, hospitalization)
Nosocomial diarrhea (onset >3d after hospitalization)
  • Test for C difficile
  • Salmonella, shigella, campylobactor (if outbreak, >65yr with coexisting conditions, immunocompromised, neutropenic, systemic enteric infection is susptected)
  • Shiga toxin – producing E coli (if bloody diarrhea)
Persistent diarrhea (>14d)
  • EPEC
  • Consider protozoa: Giardia, cryptosporidium, cyclospora, isospora belli
  • Screening for inflammation
Immunocompromised (HIV+)
  • Test for microsporidia, mycobacterium avium complex, CMV, strongyloides

6  In a young person with chronic or recurrent diarrhea, with no red flag symptoms or signs, use established clinical criteria to make a positive diagnosis of irritable bowel syndrome (do not overinvestigate).


  • Functional bowel dz, onset usually in young adulthood, F>M
  • If Hx consistent with Rome III criteria,
    • no alarm symptoms “red flags”,
    • no family Hx of IBD / colorectal cancer,
    • limited Ix required
  • CBC, TSH, albumin, CRP, TTG serology with protein electrophoresis
  • Stool for C&S, O&P, fat excretion if diarrhea present
  • Consider sigmoidoscopy
Dx: IBS Rome III Criteria

≥12 wk in the past 12 mo of abdominal discomfort or pain that has 2/3 features:

  1. Relieved with defecation
  2. Associated with a change in frequency of stool
  3. Associated with a change in consistency of stool
IBS less likely in presence of “Red flag” features
  • Wt loss
  • Fever
  • Nocturnal defecation
  • Anemia
  • Blood or pus in stool
  • Abnormal gross findings on flexible sigmoidoscopy
Supportive, but not essential to the Dx of IBS:
  • Abnormal stool frequency (>3/d or <3/wk)
  • Abnormal stool form (lumpy / hard / loose / wter) >1/4 of defecations
  • Abnormal stool passage (straining, urgency, feeling of incomplete evacuation) >1/4 of defecations
  • Pasage of mucus >1/4 of defecation
  • Bloating
  • Reassurance – 80% improve over time, normal life expectancy, explanation, support, aim for realistic goals – most have intermittent episodes
  • Relaxation therapy, biofeedback, hypnosis, stress reduction
Pain difficult to control
  • Antispasmodic meication before meal (hyoscine, pinaverium, trimebutine)
  • Increase dietary fibre (bran or psyllium)
Diarrhea predominant
  • Increase dietary fibre to increase stool consistency
  • Loperamide (imodium) & diphenoxylate (Lomotil)
  • Cholestyramine 4g Qid
Constipation predominant:
  • exercise, increase fibre in diet
  • osmotic / other laxatives

7  In patients with chronic or recurrent diarrhea, look for both gastro-intestinal and non-gastro- intestinal symptoms and signs suggestive of specific diseases (e.g., inflammatory bowel disease, malabsorption syndromes, and compromised immune system).

  1. Medications (cause ↑ secretion / motility / cell death / inflammation, change flora)
    • PPI, colchicine, abx, HxRA, SSRIs, ARBs, NSAIDs, chemo, caffeine
  2. Osmotic (↑ osmotic gap, – fecal fat, ↓ diarrhea w/ fasting)
    1. Lactose intolerance
      • can be acquired after gastroenteritis, med illness, GI surgery
      • Clinical: bloating, flatulence, discomfort, diarrhea
      • Dx: Hydrogen breath test or empiric lactose-free diet
      • Rx: lactose-free diet, use of lactaid milk and lactase enzyme tablets
    2. Other: lactulose, laxatives, antacids, sorbitol, fructose intake
  3. Malabsorption (↑ osmotic gap,↑ fecal fat, ↓ diarrhea w/ fasting)
    1. Celiac Dx
      • Immune rxn in genetically predisposed pts to gliadin (gluten – wheat protein) causing small bowel inflammatory infiltrate → crypt hyperplasia, villus atrophy → impaired intestinal absorption
      • Other s/sx: Fe/folate defic anemia, osteoporosis, dermatitis herpetiformis (pruritic papulovesicular); ↑ AST/ALT
      • Dx: IgA antitisssue tranglutaminase ; small bowel bx & response to gluten-free diet definitive
      • Rx: gluten-free diet
      • C/I: risk of T-cell lymphoma and small bowel adenocarcinoma
    2. Whipple’sdz:infxn with T.whipplei
      • S/Sx: fever, LAN, edema, arthritis, CNS changes, gray-brown skin pigmentation, oculomasticatory myorhythmia (eye oscillations + mastication muscle contraction)
      • Rx: 3rd-gen ceph x 1-014 d → bactrim for >1 yr
    3. Bacterial Overgrowth:
      • ↑ small instestinal bacteria from incompetent/absent ileocecal valve – fat & CHO malabsorption
      • Dx: + 14C-xylose & H+ breath tests
      • Rx: cycled abx: Metronidazole and FQ / rifaximin
    4. Pancreatic insufficiency
      • From chronic pancreatitis or pancreatic cancer
      • ↓Bile acids due to ↓ synthesis (cirrhosis) or cholestasis (PBC)
      • Leads to malabsorption
    5. Other: short bowel resection, Crohn’s dz, chrnoic mesenteric ischemia, eosinophilic gastroenteritis, intestinal lymphoma, tropical sprue
  4. Inflammatory (+ fecal WBC or lactoferrin or calprotectin, + FOB, fever,abd pain)
    • Infection – particularly parasitic, CMV, TB
    • IBD
    • Radiation enteritis, ischemic colitis, neoplasia (colon ca, lymphoma)
  5. Secretory (normal osmotic gap, no change to diarrhea after NPO, nocturnal diarrhea)
    • Hormonal: VIP (VIPoma), serotonin (carcinoid), thyroxine, calcitonin (medullary ca), gastrin (Zollinger-Ellison), glucagon, substance P
    • Laxative abuse
  6. Motility (normal osmotic gap)
    • IBS (see above)

Stool osm gap = Osm-stool (290) – 2x (Na-stool + K – stool)
  • <50 = secretory / motility
  • >50 = osmotic / malabsorptionn (Fecal Fat + = malabsoprtion)

Posted in 26 Diarrhea, 99 Priority Topics, FM 99 priority topics, GI

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