Algorithm for the diagnosis of chronic diarrhea. It is usually impractical to test

Approach to Diarrhea - Differential Diagnosis and Workup Algorithm Acute Diarrhea (MINT): • Medications • Infections: Inflammatory diarrhea, Watery diarrhea • Necrosis • Toxic (e.g., radiation, ingestions ischemia) Chronic Diarrhea: • Inflammatory diarrhea • Watery diarrhea • Fatty diarrhea (stool osm gap > 50) Matthew Ho, MD PhD @MatthewHoMD #Diarrhea #Differential #Diagnosis #Algorithm #gastroenterology

Chronic Diarrhea - Workup Osmotic: • Consider food diary and trial avoiding certain foods or meds, Consider diagnostic fast, Stool osmotic gap > 125mOsm/kg, Lactose hydrogen breath test if lactose intolerance suspected, Colonoscopy unnecessary, but if performed, may show melanosis coli in laxative abuse Secretory: • Consider diagnostic fast, Stool osmotic gap < 50mOsm/kg, Consider CT A/P, Consider testing of specific hormones Malabsorptive: • Assessment of stool fat (Sudan stain of stool, 72 hr stool collection on gm fat/day diet), Endoscopy (EGD +/- ERCP +/- colonoscopy), Abdominal imaging (CT, ultrasound, or MRCP), Consider serologic testing for celiac and/or testing for fecal elastase-1 Hypermotility: • TSH, Consider testing for celiac disease Inflammatory: • Colonoscopy, Fecal calprotectin, Stool testing for C.diff (particularly if recent hospitalization or antibiotics) - Dr. Eric Strong @DrEricStrong - Strong Medicine https://www.youtube.com/c/EricsMedicalLectures/ #Chronic #Diarrhea #Workup #diagnosis #differential #testing #evaluation

Investigation of Chronic Diarrhea #Chronic #Diarrhea #Diagnosis #Algorithm #Workup

Algorithm for the Evaluation of Chronic Diarrhea (< 7 days) Exclude: 1. Causes of acute diarrhea 2. Lactose intolerance 3. Irritable bowel syndrome 4. Previous gastric surgery or ileal resection 5. Parasitic infections 6. Medications 7. Systemic disease - Fecal leukocytes and occult blood - Colonoscopy with biopsy - Small bowel imaging with barium, CT, or MR enterography - Stool electrolytes, osmolality, weight/24 h, quantitative fat Increased fecal fat: Malabsorption syndromes, Pancreatic insufficiency, Bacterial overgrowth Normal fecal fat: Lactose intolerance, Sorbitol, lactulose, Laxative abuse Normal stool weight: Irritable bowel syndrome, Factitious diarrhea Increased stool weight: Secretory laxative abuse (1000 g/24 h) #Chronic #Diarrhea #management #algorithm #workup #diagnosis #differential

Chronic Diarrhea - Differential Diagnosis Algorithm Steatorrhea - Maldigestive • Pancreatic Insufficiency - Primary Malabsorption • Celiac Disease • Mucosal Disease • Ileal Crohn's Disease - Secondary Malabsorption • Bacterial Overgrowth • Liver Cholestasis • Mesenteric Ischemia • Short Bowel Resection Large Bowel (Small Volume/ Bloody / Painful / Tenesmus / Urgency) - Motility • Irritable Bowel Syndrome • Hyperthyroid - Inflammatory • Inflammatory Bowel Disease • Radiation CoIits • Ischemic Colitis - Secretory • Villous Adenoma • Colon Cancer • Microscopic Colitis Disordered Motility • Irritable Bowel Syndrome (diagnosis of exclusion) • Diabetic Neuropathv • Hyperthyroidism Osmotic • Magnesium, Phosphate, Sulfate • Carbohydrate Mala bsorption • Lactose Intolerance Mucosal • Crohn's Disease (Screen with CBC, albumin, ESR, endoscopy) • Celiac Disease (screen with TTG) • Chronic Inflammation • Whipple's Disease Mucosal Tumor • Gastrinoma • Carcinoid Syndrome • Mastocystosis Neoplastic Tumor • Adenocarcinoma • Lymphoma #Chronic #Diarrhea #SmallBowel #Differential #Diagnosis #Algorithm

Diarrhea Workup and Management Algorithm in Transplant Patients First Tier Microbiologic-Testing: 1. C. difficile PCR (Stool) 2. CMV qPCR (Serum/Blood) 3. Norovirus PCR (Stool) 4. Bacterial culture (Stool) * If available consider multiplex PCR for Broad range of enteric pathogens First Tier Microbiologic-Testing: 1. Ova and Parasite evaluation (stool) 2. Giardia and Cryptosporidium EIA (Stool) 3. Breath test for bacterial overgrowth If above testing negative and diarrhea persists: 1. Adjust IS medications *Reduce dose of change to different agent 2. Colonoscopy +/- EGD *Especially if concern for PTLD, GVHD or IBD 3. Empiric therapy with probiotic or anti-motility agents 4. Evaluate for malabsorption #Diarrhea #Workup #Management #Algorithm #Transplant #diagnosis #differential

Chronic Cough - Diagnosis Algorithm Cough is the most common presenting symptom to primary care. If a cough lasts more than 8 weeks, it has become a chronic cough. Here is an approach to managing this entity. #Chronic #Cough #Diagnosis #Algorithm #Differential

Solid Organ Transplant - Diarrhea - Diagnostic and Workup Algorithm 1st Tier Microbiologic Testing: CDiff (stool), CMV qPCR/NAT (serum/blood), Bacterial Culture or PCR (stool) for bacterial pathogens 2nd Tier Microbiologic Testing: Norovirus or viral PCR (stool), Ova and Parasites (stool), Giardia and Cryptosporidium EIA (stool), Breath test of bacterial overgrowth If above negative: 1) Adjust IS medications 2) Colonoscopy +/- EGD 3) Empiric Therapy with probiotic or anti-motility agents 4) Evaluate for malabsorption #Diarrhea #Transplant #SolidOrgan #Diagnosis #Workup #Algorithm

Post-Transplant Diarrhea - Diagnosis and Management Algorithm Post-transplant diarrhea (≥ 3 loose or liquid stools per day) • Malabsorption workup in case of chronic diarrhea • Stop non immunosuppressive drugs associated with diarrhea • First-line microbiological stool Investigations (#) ± Plasma CMV PCR Adaptation of IS drug regimen • MMF dose reduction or switch to EC-MPS or switch to Aza if MPA dose < 50% doses recommended (Norovirus++) • Tacrolimus dose reduction (5-8 ng/mL) or switch to cyclosporine • mTORi withdrawal, switch to CNI • CNI withdrawal, switch to mTORi #Transplant #Diarrhea #Diagnosis #Management #Algorithm #nephrology #renal #kidney

Algorithm for the Evaluation of Acute Diarrhea (< 7 days) Are the following present? 1. Severe illness: T > 38.50C, abdominal pain, bloody diarrhea, > 6 stools/24 h, dehydration 2. Immunocompromised patient: AIDS, post-transplantation 3. Elderly patient (> 70 yrs) Send stool for following: 1. Fecal leukocytes 2. Routine stool culture 3. C difficile assay, if recent hospitalization or antibiotics 4. Ova and parasite testing, if: a. Diarrhea > 10 days b. Travel to endemic region c. Community water-borne outbreak d. HIV infection or men who have sex with men Consider empiric antibiotic therapy while awaiting culture, if: 1. Fecal leukocyte positive 2. Bloody diarrhea, fever, abdominal pain 3. Dehydration or > 8 stools/24 h 4. Immunocompromised 5. Hospitalization required #Acute #Diarrhea #management #algorithm #workup #diagnosis