2Definition: Diarrhea : abnormal increase in stool liquidity, stool frequency, and stool weight (more than 200 grams per day).Diarrhea :< 2 weeks: acute> 2 weeks: chronic
3Acute Diarrhea Infection: non-inflammatory Traveler’s diarrhea Other medical disease: Acute diverticulitis, superior mesenteric arterial/venous thrombosis, Ischemic bowel disease, IBDDrugs: Virtually all medicationsmagnesium- or phosphate-containing antacids or supplements, antiarrhythmics, broad-spectrum antibiotics, antineoplastics, antihypertensives, bile acids, cholinergic agents, laxatives, NSAID, potassium supplements, and prostaglandins.Medicinal elixirs contain high amounts of sorbitol, which can have a cathartic effect on the bowel (1 dose….) eg. acetaminophen, theophylline, and cimetidine (not listed)Immunocompromised and food allergy
4TRAVELER'S DIARRHEAWhenever a person travels from one country to another—particularly if the change involves a marked difference in climate, social conditions, or sanitation standards and facilities—diarrhea is likely to develop within 2–10 days
5There may be up to ten or even more loose stools per day, often accompanied by abdominal cramps, nausea,occasionally vomiting, and rarely fever. The stools do not usually contain mucus or blood, and aside from weakness, dehydration, and occasionally acidosis, there are no systemic manifestations of infection.The illness usually subsides spontaneously within 1–5 days, although 10% remain symptomatic for a week or longer, and in 2% symptoms persist for longer than a month .
6Bacteria cause 80% of cases of traveler's diarrhea, with enterotoxigenic E coli, Shigella species, and Campylobacter jejuni being the most common pathogens.Less common causative agents include Aeromonas, Salmonella, noncholera vibrios, Entamoeba histolytica, and Giardia lamblia. Contributory causes may at times include unusual food and drink, change in living habits, occasional viral infections (adenoviruses or rotaviruses), and change in bowel flora
7Noninflammatory Diarrhea Watery, nonbloody diarrhea associated with periumbilical cramps, bloating, nausea, or vomiting (singly or in any combination) suggests small bowel enteritis caused by either a toxin-producing bacterium (enterotoxigenic E coli [ETEC], Staphylococcus aureus, Bacillus cereus, C perfringens) or other agents (viruses, Giardia) that disrupt the normal absorption and secretory process in the small intestine.
8Prominent vomiting suggests viral enteritis or S. aureus food poisoning. Though typically mild, the diarrhea (which originates in the small intestine) may be voluminous (ranging from 10 to 200 mL/kg/24 h) and result in dehydration with hypokalemia and metabolic acidosis due to loss of HCO3– in the stool (eg, cholera). Because tissue invasion does not occur, fecal leukocytes are not present.
9Enteric FeverA severe systemic illness manifested initially by prolonged high fevers, prostration, confusion, respiratory symptoms followed by abdominal tenderness, diarrhea, and a rash is due to infection with Salmonella typhi or Salmonella paratyphi, which causes bacteremia and multiorgan dysfunction
10EvaluationIn over 90% of patients with acute diarrhea, the illness is mild and self-limited and responds within 5 days to simple rehydration therapy or antidiarrheal agentsPatients with signs of inflammatory diarrhea manifested by any of the following require prompt medical attention:high fever (> 38.5 °C),bloody diarrhea,abdominal pain, ordiarrhea not subsiding after 4–5 days.Similarly, patients with symptoms of dehydration must be evaluated (excessive thirst, dry mouth, decreased urination, weakness, lethargy)
11Physical examination should note the patient's general appearance, mental status, volume status, and the presence of abdominal tenderness or peritonitisPeritoneal findings may be present in C difficile and enterohemorrhagic E coli.
12Hospitalization is required in patients with severe dehydration, toxicity, or marked abdominal pain. Stool specimens should be sent in all cases for examination for fecal leukocytes and bacterial cultures
13TreatmentMost cases of acute diarrhea are self- limited, and specific therapy is not necessary.Preventing dehydration and restoring fluid losses. IV/PO Oral intake should be encouraged to minimize the risk of dehydration.The misconception that the bowel needs to be at rest or that oral intake will worsen the diarrheal illness should be abandoned.Avoid milk and other lactose-containing products, Caffeine-containing productsGlucose-containing electrolyte solutions
14Pseudomembranous colitis ---Clostridium difficile Clostridium difficile ¼ of antibiotic- associated diarrhea.¾ no etiologic agent is identified, diarrhea– mild– abdominal pain(-). respond to...Antibiotics :clindamycin, ampicillin, amoxicillin, and cephalosporinsThe clinical presentation varies
16The diagnostic test: Treatment Prevention ? Pus cell, stool OB ? Gram stain? Culture? Tissue culture assay for the cytotoxicity of toxin B? ELISA: detect toxinTreatmentOral metronidazole(500mg po tid or 250mg po qid ) or oral vancomycin hydrochloride for 10 to 14 daysoral metronidazole is preferredApproximately 15% of patients experience relapse…Prevention
18Medications and toxins associated with diarrhea AntibioticsAntiretroviral agentsAntineoplastic agentsAnti-inflammatory agents (NSAIDs, gold, 5-ASA)Antiarrhythmics (quinidine)Antihypertensives (β blockers)Oral hypoglycemics (metformin, acarbose)Antacids (magnesium-containing)Acid-reducing agents (H2 blockers, PPIs)ColchicineProstaglandin analogs (misoprostol)TheophyllineVitamin and mineral supplementsHerbal productsHeavy metals
19CHRONIC DIARRHEA Etiology The causes of chronic diarrhea may be grouped into six major pathophysiologic categories
20Osmotic DiarrheasAs stool leaves the colon, fecal osmolality is equal to the serum osmolality, ie, approximately 290 mosm/kg. Under normal circumstances, the major osmoles are Na+, K+, Cl–, and HCO3–. The stool osmolality may be estimated by multiplying the stool (Na+ + K+) × 2 (multiplied by 2 to account for the anions)
21The most common causes of osmotic diarrhea are disaccharidase deficiency (lactase deficiency), laxative abuse, and malabsorption syndromes .Osmotic diarrheas resolve during fasting. Osmotic diarrheas caused by malabsorbed carbohydrates are characterized by abdominal distention, bloating, and flatulence due to increased colonic gas production.
22Malabsorptive Conditions The major causes of malabsorption are small mucosal intestinal diseases, intestinal resections, lymphatic obstruction, small intestinal bacterial overgrowth, and pancreatic insufficiencyIn patients with suspected malabsorption, quantification of fecal fat should be performed
23Secretory ConditionsIncreased intestinal secretion or decreased absorption results in a watery diarrhea that may be large in volume (1–10 L/d) but with a normal osmotic gapMajor causes include:endocrine tumors (stimulating intestinal or pancreatic secretion),bile salt malabsorption (stimulating colonic secretion), andlaxative abuse
24Inflammatory Conditions Diarrhea is present in most patients with inflammatory bowel disease (ulcerative colitis, Crohn's disease, microscopic colitis). A variety of other symptoms may be present, including abdominal pain, fever, weight loss, and hematochezia
25Motility DisordersAbnormal intestinal motility secondary to systemic disorders or surgery may result in diarrhea due to rapid transit or to stasis of intestinal contents with bacterial overgrowth resulting in malabsorption
26Chronic Infections Cyclospora, and the intestinal nematodes Immunocompromised patients, especially those with AIDS, are susceptible to a number of infectious agents that can cause acute or chronic diarrheaChronic diarrhea in AIDS is commonly caused by Cryptosporidium, cytomegalovirus, Isospora belli, Cyclospora, and Mycobacterium avium complex.
27Factitial DiarrheaApproximately 15% of patients with chronic diarrhea have factitial diarrhea caused by laxative abuse or factitious dilution of stool
28Irritable Bowel Syndrome Rome Criteria:Recurrent abdominal pain or discomfort at least 3 days per month for the past 3 months, associated with 2 or more of:- Improvement wih defecation- Onset associated with a change in frequency of stool- Onset associated with a change in form (appearance) of stool
29Periods of constipation common Long history, passage of mucus, exacerbation by stressDiarrhea during waking hours, urgencyCoexistence with other functional disordersAgainst IBS: Recent onset, nocturnal diarrhea, bleeding, weight loss, voluminous or greasy stool, abnormal blood testsRule out celiac sprue!Functional diarrhea: Recurrent loose stools without pain.
31HistoryDefine patient’s complaint of diarrhea (change in consistency, presence of urgency or incontinence)Stool characteristics (blood, mucus, oil, pus, food particles) and volumeDuration, pattern of onsetRelation to prandial stateNocturnal diarrheaWeight lossTravel historyRisk factors for HIV infectionDietary profile and medication reviewFamily history of IBDOther systemic symptoms
32Physical examinationPhysical findingDiagnosisSkin changesCeliac sprue (dermatitis herpetiformis)Mastocytosis (urticaria pigmentosa)Amyloidosis (macroglossia, purpura)Addison’s disease (hyperpigmentation)Glucagonoma (migratory necrolytic erythema)Carcinoid syndrome (flushing)Degos’ disease (malignant atrophic papulosis)Peripheral neuropathy, orthostatic hypotensionAmyloidosisThyroid noduleMedullary carcinoma of the thyroidRight-sided cardiac murmur, hepatomegalyCarcinoid syndromeArthritisIBD, Whipple’s, infectionsLymphadenopathyAIDS, lymphomaPeripheral vascular disease/abdominal bruitsMesenteric vascular insufficiencyMore helpful to determine severity rather than etiologyHemodynamics, temperature, signs of toxicityHelpful clues:
34Stool AnalysisDirected testing for confirmation based on clinical suspicion, or “broad net” cast in difficult casesCategorize diarrhea into watery, inflammatory, fattyTimed collection is best, spot tests on random stool sample more practical- Occult blood- White blood cells- pH- Sudan stain for fat- Cultures- Laxative screen- Electrolytes, osmolality
35Stool Analysis Occult blood and white blood cells: - Primarily define inflammatory diarrhea- Wright stain: Sensitivity 70%, specificity 50% for leukocytes- Fecal calprotectin and lactoferrin less operator dependent, but test characteristics in chronic diarrhea not well definedpH:- Low pH (< 6) generally indicative of carbohydrate malabsorptionSudan stain:- Fatty diarrhea (steatorrhea)- Gold standard: Quantitative estimation of stool fat on collected specimen- Qualitative estimation feasible on random sample,- Semiquantitative methods (number and size of fat globules) correlate well with quantitative collection
36Stool Analysis Stool cultures: - Infection: Usually inflammatory diarrhea- Bacterial infection rarely cause of chronic diarrhea in immunocompetent host - Routine cultures are low yield and not recommended (but done anyway!)- Special techniques for Aeromonas and Plesiomonas- Ova and Parasites- Always consider giardiasis (stool ELISA for Giardia antigen)
37Stool Analysis Stool electrolytes: Measured stool osmolality: Stool osmotic gap: 290 – 2([Na+] + [K+])- Gap < 50 mOsm/Kg: Pure secretory diarrhea- Gap > 125 mOsm/Kg: Pure osmotic diarrhea- Gap mOsm/kg: Mixed or mild carbohydrate malabsorptionMeasured stool osmolality:- Not used to calculate gap- Useful in cases of unexplained diarrhea- Low measured stool osmolality (< 290 mOsm/Kg) suggestive of contamination with water or dilute urine