1. DIARRHEA BY
DR: RAMY A. SAMY

2. Definition: Diarrhea :
abnormal increase in stool liquidity, stool frequency, and stool weight (more than 200 grams per day).
Diarrhea :
< 2 weeks: acute
> 2 weeks: chronic

3. Acute Diarrhea Infection: non-inflammatory Traveler’s diarrhea
Other medical disease: Acute diverticulitis, superior mesenteric arterial/venous thrombosis, Ischemic bowel disease, IBD
Drugs: Virtually all medications
magnesium- 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

4. TRAVELER'S DIARRHEA
Whenever 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

5. There 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 .

6. Bacteria 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

7. Noninflammatory 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.

8. Prominent 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.

9. Enteric Fever
A 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

10. Evaluation
In 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 agents
Patients with signs of inflammatory diarrhea manifested by any of the following require prompt medical attention:
high fever (> 38.5 °C),
bloody diarrhea,
abdominal pain, or
diarrhea not subsiding after 4–5 days.
Similarly, patients with symptoms of dehydration must be evaluated (excessive thirst, dry mouth, decreased urination, weakness, lethargy)

11. Physical examination should note the patient's general appearance, mental status, volume status, and the presence of abdominal tenderness or peritonitis
Peritoneal findings may be present in C difficile and enterohemorrhagic E coli.

12. Hospitalization 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

13. Treatment
Most 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 products
Glucose-containing electrolyte solutions

14. Pseudomembranous 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 cephalosporins
The clinical presentation varies

16. The diagnostic test: Treatment Prevention ? Pus cell, stool OB
? Gram stain
? Culture
? Tissue culture assay for the cytotoxicity of toxin B
? ELISA: detect toxin
Treatment
Oral metronidazole(500mg po tid or 250mg po qid ) or oral vancomycin hydrochloride for 10 to 14 days
oral metronidazole is preferred
Approximately 15% of patients experience relapse…
Prevention

17. Medically Important Diarrhea
Inflammatory, bloody diarrhea
Severe volume depletion
High fever
Sever abdominal pain
Duration > 3 days
Community outbreak
Impaired host

18. Medications and toxins associated with diarrhea
Antibiotics
Antiretroviral agents
Antineoplastic agents
Anti-inflammatory agents (NSAIDs, gold, 5-ASA)
Antiarrhythmics (quinidine)
Antihypertensives (β blockers)
Oral hypoglycemics (metformin, acarbose)
Antacids (magnesium-containing)
Acid-reducing agents (H2 blockers, PPIs)
Colchicine
Prostaglandin analogs (misoprostol)
Theophylline
Vitamin and mineral supplements
Herbal products
Heavy metals

19. CHRONIC DIARRHEA Etiology
The causes of chronic diarrhea may be grouped into six major pathophysiologic categories

20. Osmotic Diarrheas
As 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)

21. The 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.

22. Malabsorptive Conditions
The major causes of malabsorption are small mucosal intestinal diseases, intestinal resections, lymphatic obstruction, small intestinal bacterial overgrowth, and pancreatic insufficiency
In patients with suspected malabsorption, quantification of fecal fat should be performed

23. Secretory Conditions
Increased 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 gap
Major causes include:
endocrine tumors (stimulating intestinal or pancreatic secretion),
bile salt malabsorption (stimulating colonic secretion), and
laxative abuse

24. Inflammatory 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

25. Motility Disorders
Abnormal 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

26. Chronic 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 diarrhea
Chronic diarrhea in AIDS is commonly caused by Cryptosporidium, cytomegalovirus, Isospora belli, Cyclospora, and Mycobacterium avium complex.

27. Factitial Diarrhea
Approximately 15% of patients with chronic diarrhea have factitial diarrhea caused by laxative abuse or factitious dilution of stool

28. Irritable 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

29. Periods of constipation common
Long history, passage of mucus, exacerbation by stress
Diarrhea during waking hours, urgency
Coexistence with other functional disorders
Against IBS: Recent onset, nocturnal diarrhea, bleeding, weight loss, voluminous or greasy stool, abnormal blood tests
Rule out celiac sprue!
Functional diarrhea: Recurrent loose stools without pain.

30. Practical approach Routine laboratory tests (CBC, albumin, ESR/CRP)
History
Physical examination
Routine laboratory tests (CBC, albumin, ESR/CRP)
Stool analysis
Categorize:
Watery diarrhea
Inflammatory diarrhea
Fatty diarrhea
Secretory
Osmotic

31. History
Define patient’s complaint of diarrhea (change in consistency, presence of urgency or incontinence)
Stool characteristics (blood, mucus, oil, pus, food particles) and volume
Duration, pattern of onset
Relation to prandial state
Nocturnal diarrhea
Weight loss
Travel history
Risk factors for HIV infection
Dietary profile and medication review
Family history of IBD
Other systemic symptoms

32. Physical examination
Physical finding
Diagnosis
Skin changes
Celiac 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 hypotension
Amyloidosis
Thyroid nodule
Medullary carcinoma of the thyroid
Right-sided cardiac murmur, hepatomegaly
Carcinoid syndrome
Arthritis
IBD, Whipple’s, infections
Lymphadenopathy
AIDS, lymphoma
Peripheral vascular disease/abdominal bruits
Mesenteric vascular insufficiency
More helpful to determine severity rather than etiology
Hemodynamics, temperature, signs of toxicity
Helpful clues:

34. Stool Analysis
Directed testing for confirmation based on clinical suspicion, or “broad net” cast in difficult cases
Categorize diarrhea into watery, inflammatory, fatty
Timed 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

35. Stool 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 defined
pH:
- Low pH (< 6) generally indicative of carbohydrate malabsorption
Sudan 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

36. Stool 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)

37. Stool 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 malabsorption
Measured 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

39. THANK YOU