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Diarrhea- C. diff. Is Negative – Now What?
Erin Jenkins Wessling
Division of Gastroenterology
Objectives:
• Understand when laboratory evaluation is indicated in acute diarrhea
• Review important history aspects in evaluation of chronic diarrhea
• Discuss common causes of osmotic diarrhea
• Recognize “red flags” that prompt further evaluation and referral
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Definition
• Diarrhea: 3 or greater bowel movements per day of loose consistency • Alternate definition by weight - > 200 g / day,
• Acute Diarrhea: • for ≦14 days
• Chronic Diarrhea• Diarrhea for ≧ 30 days
Physiology in health:
• 9-10 L fluid enters jejunum daily (salivary, gastric pancreatic, and biliary secretions)
• 90% absorbed in small bowel
• 800-1000 mL enters colon
• 90% absorbed on colon – 100 mL excreted in stool
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Acute Diarrhea
• Typically infectious, esp. viral
• supportive care/ oral hydration
• No workup unless C. diff suspicion, dysenteric (blood), high risk traveler, or moderate to severe with fever, symptoms > 7 days
• Exception for “public health situation”
American College of Gastroenterology Clinical Guideline: Diagnosis, Treatment, and Prevention of Acute Diarrheal Infections in Adults - May 2016
GI Pathogen Panel
• Culture independent methods preferred
• C. difficile can be false positive
• Will this change management?
• Avoid O and P if no travel/ immigration history
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Chronic Diarrhea Evaluation
1. Take a good history
• frequency/ consistency
• Pain
• Blood
• Nocturnal symptoms
• Triggers: food, stress?
• Weight loss
• Medications/ supplements
Chronic Diarrhea Evaluation
2. Perform a good physical exam• Weight change• Nutritional status/ appearance• Rectal exam for select patients
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Chronic Diarrhea Evaluation
3. Identify “red flags” that proceed directly to colonoscopy +/- endoscopy or clinic referral
• Blood, nocturnal bowel movements, significant weight loss, behind on colorectal cancer screening, iron deficiency anemia
Chronic Diarrhea Evaluation
4. Consider non – invasive workup; if positive, proceed to further testing:
• CBC, CMP, CRP, celiac testing ( tTGIgA, IgA), TSH
• Fecal calprotectin
• Other stool testing ( stool electrolytes)
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Chronic diarrhea – history clues
• Verify if true diarrhea vs. incontinence of formed stool/ frequent passage hard stool
• Diarrhea alternating with constipation and associated with pain, no “red flags” = irritable bowel syndrome
• Blood suggests infectious or inflammatory
• Nocturnal indicates possible secretory/ inflammatory and needs workup
• Weight loss and laboratory/ clinic evidence of malabsorption suggests organic problem – not function/ irritable bowel and not dietary
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Case Follow Up
• Blood work showed mild iron deficiency anemia, tTGA positive at 125 ( normal less than 8).
• EGD with duodenal biopsies confirmed Celiac disease
• Doing well at 3 month f/u –tTGA normal
Celiac Disease Clinical Pearls
• Diagnosis with positive labs AND confirmatory biopsies on gluten FULL diet
• Can be missed at EGD unless proper duodenal biopsies taken ( high suspicion)
• Treatment with gluten free diet
• Dietitian consult, check vitamin/ mineral levels, annual celiac serologiesonce normal, bone mineral density screening
• tTGA / serum IgA screening ( don’t need full panel)
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Clinical Case #2
• Intermittent diarrhea is often dietary (osmotic)
• Patient was drinking Dr. Pepper while working to stay awake (high fructose corn syrup)
• Decreased rectal tone made symptoms more extreme
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Clinical Case 2 – Osmotic diarrhea
• Lactose and high levels of fructose are main offenders
• Sugar alcohols ( sorbitol, etc).
• Low FODMAP diet eliminates fermentable sugars from diet
• Low FODMAP studied in IBS –D, helpful in functional diarrhea
AGA patient education page
Osmotic vs. Secretory• Stool osmotic gap= 290 mosm/kg – 2 ( stool Na + K)
Osmotic Secretory
Osmotic gap > 100 <50
History Usually resolves with fasting
-Persists even with fasting-high volume, sometimes electrolyte disturbance
Common Causes -Lactose, fructose, sucrose intolerance-Mag. Antacids or Mag supplements-Sorbitol, Xylitol, sucralose,
-Infections-Bile salt/ acid-Neuroendocrine-Microscopic colitis -Diabetic diarrhea
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Clinical Case #3 – C. Diff is negative…
Colon biopsies show microscopic colitis-2 subtypes behave similarly, different microscopic appearance- QOL disease – no progression or
malignancy risk
Up To Date - images
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Clinical Case # 3 – Microscopic Colitis
• Most commonly in elderly females
• NSAID, PPI, SSRI medications increase risk
• Treated with budesonide, topical corticosteroid x 8 weeks
• 1/3 will not need further treatment, 2/3 may need maintenance or recurrent treatment
• Increased risk among those with celiac
• Not evaluated at “screening colon” – need random biopsies
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Clinical Case #4
• Fecal calprotectin – measures a protein in neutrophils – marker in inflammation
• Good for “ ruling out” IBD
• 93% sensitive, 94 % specific for Crohn’s or ulcerative colitis
• May be less sensitive for isolated ileal disease
• All positive tests should be followed up with colonoscopy
De’Angelo et al. Digestion 2017.
Irritable Bowel Syndrome - Diarrhea
• If no red flags, don’t need investigation other than r/o celiac disease • ( all testing done would be negative) • Treatment of IBS – D in past has included:
• Dietary modification • Anti-motility – loperamide• Fiber for stool bulking • Tri-cyclic anti-depressant • Antispasmotic ( dicyclomine/ hyoscyamine) – help with cramping and decrease
motility • Non – absorbable antibiotic ( rifaxamin)• Eluxadoline
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Diarrhea Clinical Pearls
• Good history and physical paramount
• For acute severe diarrhea, PCR based stool testing preferred over culture or O and P
• Make sure celiac testing is done before going gluten free
• Osmotic diarrhea from diet or meds is common; low FODMAP diet may be helpful
• Microscopic Colitis is diagnosed only when colonic biopsies taken
• Fecal calprotectin can be helpful non – invasive method of excluding IBD
Sources:
• Schiller et. al. Clin Gastroenterol Hepatol. 2017 Feb; 15(2) 182-193
