Diarrhea is loosely defined as passage of abnormally liquid or unformed Stool at an increased frequency. For adults on a typically western Diet, stool weight exceeding 200g/d Can generally be considered diarrheal.

 Secretory diarrhea  Osmotic diarrhea  Inflammatory ( exudative ) diarrhea  Motility ( dismotile ) diarrhea  Anatomic ( decreased absorptive surface) Pathophysiologic classification of diarrhea

Secretory diarrhea  Increased secretion and / or decreased absorption of electrolytes.  Large volume watrey stool,no blood, no FSG, no pus, no response to fasting.  Small intestine type diarrhea.

Some causes of Secretory diarrhea  Cholera,Ecoli, and Salmonella toxins.  Serotonine,VIP,Calcitonine,Bile acids.  Castrol oil, Biscodyl, Senna,  Villus atrophy ( Celiac sprue, Int. lymphoma).  Collagen vascular dis. ) ( SLE, MCTD

OSMOTIC DIARRHEA  Non absorbable,osmoticlly active molecules in gut lumen.  Watrey stool, no blood, no pus in the stool.  Improves with fasting.  May have high FSG. FSG = 280 – (fecal Na + fecal K ) * 2 FSG = 280 – (fecal Na + fecal K ) * 2

Some causes of osmotic diarrhea  Disacaridase deficiencies.  Lactulose, Manitol, Sorbitol, Mg ++  Sulfate, phosphate (Laxatives).  Sodium citrate ingestion.  Steatorrhea, generalized malabsoption.  Rotavius induced diarrhea.

EXUDATIVE DIARRHEA  Destruction of intestinal mucosa.  Small frequent bloody stools with pus, and tenesmus.  Fever  Large intestine type diarrhea.

Some causes of exudative diarrhea  Entero-invasive E.coli  Shigella  E. histolitica  Ulcerative colitis  Ischemic colitis

Acute i if < 2 weeks Persistent i i i if 2 to 4 weeks Chronic f > 4 weeks

Epidemiology of Acute Diarrhea  Worldwide, >1000,000,000 people/year  5 -8 million deaths / year in developing countries.  3000/year mortality in US.

High risk groups for diarrhea  Travelers. 40 % of tourists develop diarrhea 40 % of tourists develop diarrhea Most commonly duo to ETEColi Most commonly duo to ETEColi  Consumers of certain foods. Picnic, restaurant, undercooked hamberger, seafoods(raw) Picnic, restaurant, undercooked hamberger, seafoods(raw)  Immunodeficient persons  Daycare participants and their family members.  Institutionalized persons.

Gastrointestinal Viruses Virus type Major risk group Seasonality Dx test Rx Rotavirus Children< 3 y Winter ELISA ORS (groupA) (groupA) Adenovirus children< 3y year-round ELISA ORS (types 40,41) Calicivirus young unknown EM(?) ORS children children Astrovirus young winter EM(?) ORS children children Norwalk like children, winter EM (?) ORS viruses adults viruses adults

Factors that influence virulance of entric pathogens  Inoculum size (Shigella,EPEC,giardia )  Adherence  Toxin production ( enterotoxin, cytotoxin, neurotoxin )  Invasion  Normal flora of the host  Gastric acid  Intestinal motility  Immunity

Major Causes of Acute Diarrhea  INFECTIONS (Including Travelers Diarrhea) Bacterial : Campylobactre Species, C.difficile, E.coli, Salmonella eneritides, Shigella Species Parasitic/protozoal : E. histolytica, Giardia lambilia,Cryptosporidium,Cyclospoa Viral : Adenovirus, Norwalk virus, Rotavirus,AIDS, Others Fungal  FOOD POISONING : B.Cereus, C. Perfringens, Salmonella species, S.aureus, Vibrio species, Shigella species, Camppylobacter.jejuni, E.coli  MEDICATIONS  RECENT INGESTION OF LARGE AMOUNT OF POORLY ABSORBABLE SUGARS  INTESTINAL ISCHEMIA  FECAL IMPACTION  PELVIC INFLAMMATION  GRAFT VS HOST DISEASE

MAJOR CAUSES OF CHRONIC DIARRHEA  IBS  IBD  Ischemic bowel disease  Chronic bacterial / mycobacterial infection  Parasitic & fungal infections  Radiation enteritis  Malabsorption Syndromes  Medications, Alcohol  Colon cancer, Villous Adenoma,intestinal Lymphoma  Diverticulitis  Previous Surgery ( gastrectomy, vagatomy, intestinal resection )  Endocrine causes  Fecal impaction  Heavy metal poisoning  Epidemic idiopathic chronic diarrhea

Indications for evaluation a patient with acute diarrhea Indications for evaluation a patient with acute diarrhea 1. Profuse diarrhea with dehydration. 2. Grossly bloody diarrhea. 3. Fever > or = 38.5 C 4. New community outbreaks. 5. Associated sever abdominal pain in patients older than 50 years. 6. Elderly (> or = 70). 7. Immunocompromised patients.

TESTS THAT MAY BE USEFUL IN EVALUATION OF PATIENTS WITH ACUTE DIARRHEA  Stool Exam for: WBCs, Ova of parasites, Culture for bacteria & virus, Clostridium difficile toxin, Giardia, Entameba, Viral antigens ( Rotavirus ) WBCs, Ova of parasites, Culture for bacteria & virus, Clostridium difficile toxin, Giardia, Entameba, Viral antigens ( Rotavirus )  Blood test for: CBC, Na, K, BUN, Creatinine, CBC, Na, K, BUN, Creatinine, Culture Culture  Flexible Sigmoidoscopy  Abdominal Radiograph

Acute diarrhea Hx & P.Ex Likely noninfecutios Likely infectious Mild Moderate Activities altered Severe (Incapacitated) Institue fluid & electrolyte replacement Observe Resolves Fever >38.bloody stool, fecal WBCs Immunocompromised or elderly host Stool microbiology study Evaluate & Rx No Yes Persist Antidiarrheal agents Pathogen found Yes Specific Rx No Empiric Rx +further evaluation

Empiric treatment in acute diarrhea  Moderately to severly ill patients with febrile desentry. Give Ciprofluxacin 500 mg bid for 3-5 days. Give Ciprofluxacin 500 mg bid for 3-5 days.  Suspected Giardiasis Rx with Metronidazole 250 mg qid for 7 days.  Moderately to severly ill patients with febrile desentry. Give Ciprofluxacin 500 mg bid for 3-5 days. Give Ciprofluxacin 500 mg bid for 3-5 days.  Suspected Giardiasis Rx with Metronidazole 250 mg qid for 7 days.

Indications of antibiotic coverage wether or not a causative organism is discovered in acute diarrhea 1. Immunecompromised patient. 2. Mechanical heart valves or recent vascular graft. 3. Elderly.

Antibiotic prophylaxis is indicated for travelers (to high risk countries), with 1. Gastric achlorhydria 2. IBD 3. Immunocompromise Give Co-trimoxazole or Ciprofluxacine Give Co-trimoxazole or Ciprofluxacine

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