GI 7 lecture

Question 1

Define diarrhea and the 3 main different time-based categories

Answer 1

Increased stool frequency (>3 BMs/day) or liquid feces
1) Acute: <14 days
2) Persistent: 14-30 days
3) Chronic: >30 days

Question 2

List the most common etiologies of acute diarrhea

Answer 2

Medications, infectious agents, inflammatory disease (IBD, ischemic colitis), malabsorption (pancreatic malabsorption, celiac, lactose intol,) secretory (laxative abuse) motility (functional, IBS, hyperthyroidism)

Question 3

List some associations with acute diarrhea

Answer 3

1) Community outbreaks: virus or common food source
2) Close contact illness: infectious etiology
3) Ingestion of improperly stored/prepared/unpasteurized food: food poisoning
-Pregnant/immune compromised-> listeriosis
4) Day care, camping, swimming: Giardia, Cryptosporidium
5) Recent travel: traveler’s diarrhea – usually bacterial; diarrhea accompanied by at least one of the following: n/v, abdominal pain or cramps, fever, or blood in the stool.
6) Recent antibiotic use: C. difficile

Question 4

Describe non-inflammatory acute diarrhea

Answer 4

1) Watery, non-bloody with periumbilical cramps, bloating, nausea, or vomiting
2) Suggests small bowel source
3) Virus, toxin-producing bacterium, or protozoa (ie, Giardia)
4) Typically mild
5) May lead to dehydration (hypokalemia, metabolic acidosis)
6) No leukocytosis (no tissue invasion)

Question 5

Describe inflammatory acute diarrhea

Answer 5

1) Fever & bloody diarrhea indicates tissue damage caused by invasion or toxin
2) Small-volume diarrhea (<1L/day), LLQ cramps, urgency, & tenesmus
3) Fecal leukocytes (or lactoferrin (inflammation of the gut)) usually present
4) E. coli O157:H7 (STEC/ETEC)
5) Distinguish from acute ulcerative colitis

Question 6

> 90% ______________________ diarrhea is mild & self-limited (testing unnecessary unless outbreak or high-risk for transmission)

Answer 6

acute non-inflammatory

Question 7

Differentiate Gastroenteritis vs food poisoning

Answer 7

1) Gastroenteritis = n/v/d/ abd cramps, fever most commonly caused by norovirus and typically self limiting. Very easily spread.
2) Food poisoning = caused by eating contaminated/ raw/undercooked foods can have similar symptoms to GE though less often diarrhea and typically starts with vomiting.
-Can be caused by Staph aureus. Occurs 1-6 hrs after ingesting contaminated foods. Not passed person to person.

Question 8

Shigella:
1) What are the symptoms?
2) How do you test for it?

Answer 8

1) Mucoid or bloody diarrhea with abdominal cramps and fever typically occurs 1-7 days following exposure.
2) Routine stool studies, though need C&S because can be resistant to some ATBs

Question 9

Salmonella: How do you test for it?

Answer 9

routine stool cultures.

Question 10

How is campylobacter transmitted? Explain

Answer 10

undercooked contaminated poultry in resource-rich settings. (Studies from various locations, including the United States, indicate that 70 - 80 % of retail poultry is contaminated with Campylobacter!!!)

Question 11

Campylobacter:
1) What are the symptoms?
2) What is the testing?

Answer 11

1) Symptoms – watery +/- bloody diarrhea usually starts 1-3 days following exposure.
2) Routine stool cultures with special plates

Question 12

Vibrio:
1) What does it cause?
2) How is it transmitted?

Answer 12

1) Diarrhea, can also cause skin infection that rapidly develops into bacteremia and systemic disease, particularly in immunocompromised patients and those with chronic liver disease.
2) Consumption of raw seafood and shellfish, particularly from warmer areas during the summer months.

Question 13

Describe testing for suspected vibrio

Answer 13

IfVibrio is suspected (because of exposure history ex/travel or seafood consumption) the laboratory should be alerted to test for it specifically. Isolation requires a selective medium, which most laboratories do not use for routine stool cultures.

Question 14

EnterotoxigenicE. coli: (ETEC)
1) What are the symptoms?
2) How do you test for it?

Answer 14

1) Diarrhea 1-3 days after travel to in resource-limited areas. Watery stools without blood or fever.
2) The lab should be alerted to test for it specifically. The diagnosis can be made using DNA probes to identify toxin genes.

Question 15

Shiga toxigenicE. coli(STEC):
1) What does it cause and how is it transmitted?
2) What are the symptoms?
3) How do you test for it?

Answer 15

1) diarrhea from undercooked meats, raw produce, and unpasteurized milk and juices. (AKA enterohemorrhagic e coli 0157 EHEC)
transmission = undercooked beef, unpasteurized milk, raw produce
2) abrupt onset bloody, watery diarrhea with abdominal pain; Usually self – limited in 5-8 days.
3) the laboratory should be alerted to test for it specifically.

Question 16

How do you Tx STEC?

Answer 16

Supportive care. DO NOT GIVE ATBs, can increase risk of HUS.

Question 17

Prompt medical evaluation of acute diarrhea is indicated in what situations?

Answer 17

1) Signs of inflammatory diarrhea (fever >101°F), >WBC 15,000/mL, bloody diarrhea, or severe abdominal pain)
2) Profuse watery diarrhea & dehydration
3) Assess for:
-Frail older patients, nursing home residents and homeless
-Immunocompromised patients (AIDS, post-transplantation)
-Exposure to antibiotics
-Hospital-acquired diarrhea (onset >3 days of hospitalization)
-Systemic illness

Question 18

Acute diarrhea:
1) What should PE include?
2) When should a pt be hospitalized?

Answer 18

1) Vitals, emphasis on level of hydration, mental status, & presence of abdominal tenderness
2) severe dehydration, organ failure, marked abdominal pain, or altered mental status

Question 19

Acute diarrhea:
1) When should you do Stool studies (microbial assessment)?
2) What should you do for pts with h/o antibiotic exposure?

Answer 19

1) For bloody stools (dysentery,) severe illness, or persistent diarrhea >7 days
2) C. diff testing

Question 20

Acute diarrhea: What should you tell the pt to do with their diet?

Answer 20

1) Comfort: avoid fats, milk products, caffeine, & alcohol; encourage bowel rest soft, bland foods, broth
2) Encourage flat/uncarbonated beverages & soft/easily digestible, bland foods (BRATS diet: bananas, rice, applesauce, toast; soups)

Question 21

Describe rehydration in acute diarrhea

Answer 21

PO hydration containing sodium, potassium, chloride, & bicarbonate or citrate (Pedialyte, oral rehydration solution)
IV fluids preferred in severe dehydration

Question 22

Describe antidiarrheals

Answer 22

Discontinue if diarrhea worse despite therapy
Loperamide (Imodium) 4 mg PO initially, then 2 mg PO after each loose stool (max 8 mg/24 hr)
Bismuth subsalicylate (Pepto-Bismol) 2 tabs (or 30 mL) PO QID for traveler’s diarrhea
Diphenoxylate/atropine (Lomotil) contraindicated in acute diarrhea (may cause toxic megacolon)

Question 23

Acute diarrhea: If rapid testing not available & stool cultures pending, consider treatment for what?

Answer 23

Non-hospital-acquired diarrhea
Moderate-severe fever, tenesmus, or bloody stools, n/v
No suspicion for STEC-bloody diarrhea from contaminated water source, contact with farm animals, undercooked beef
(Shiga toxic e coli. Ex/ 0157.H7)

Question 24

True or false: Abx can do more harm than good for acute diarrhea

Answer 24

True

Question 25

Who should you consider Empiric Antibiotic Therapy for with acute diarrhea?

Answer 25

Immunocompromised significant dehydration

Question 26

Treatment w specific abx is recommended for which infectious parasitic diarrhea?

Answer 26

Amebiasis, giardiasis, cryptosporidiosis, cyclosporiasis,

Question 27

Who with acute diarrhea should you admit?

Answer 27

Severe dehydration (IVF) Severe or worsening bloody diarrhea Severe abdominal pain Signs of severe infection or sepsis Severe or worsening diarrhea in immunocompromised or age >70 Signs of hemolytic-uremic syndrome (can get from STEC)

Question 28

Traveler's diarrhea: 1) Define 2) 80% cases caused by what? Explain

Answer 28

1) Develops in individuals from resource-rich settings during or within 10 days of returning from travel to resource-limited countries or regions 2) Bacteria (most common STEC, Shigella, & Campylobacter)

Question 29

Traveler's diarrhea: 1) What are most common among viral pathogens? 2) Causative bacteria, viruses, & parasites most often transmitted by what? Explain

Answer 29

1) Rotavirus 2) Food & water; highest risk in regions with poor sanitation & hygiene

Question 30

Describe the features of traveler's diarrhea

Answer 30

1) >10 loose stools per day 2) Frequent abdominal cramps, nausea, occasional vomiting, but rarely fever 3) Watery stools without fever (ETEC) 4) Possible bloody stools & fever with invasive bacterial pathogens (Shigella, Campylobacter, Salmonella) 5) Usually resolves 1-5 days 6) ***Significant risk factor for development of IBS*** 7) Stool culture if fever or bloody diarrhea

Question 31

Describe how to prevent traveler's diarrhea

Answer 31

1) Avoid fresh foods & most water sources 2) "Boil it, cook it, peel it or forget it" 3) Drink only boiled or commercially bottled beverages (carbonated drinks usually safe, but not ice!) 4) Avoid raw, poorly-cooked food 5) Avoid food from street vendors 6) Avoid ice cubes & locally frozen foods/drinks 7) Avoid salads (veggies washed in local water)

Question 32

Describe prophylactic meds for traveler's diarrhea

Answer 32

1) May provide supply of antimicrobials prior to trip 2) Prophylaxis for significant underlying disease (IBD, AIDS, DM, heart disease in elderly, pts on immunosuppressants) & essential personnel Start upon entry to foreign country, continue 1-2 days after leaving foreign country Ciprofloxacin 500 mg Rifaximin 200 mg 3) Prophylaxis not recommended for stays >3 weeks

Question 33

Describe treatment for traveler's diarrhea

Answer 33

1) Most cases self-limited; treat with antidiarrheals & hydration (as with acute diarrhea) 2) Fever and/or bloody diarrhea in areas where toxin-producing bacteria is major cause (Latin America, Africa): single PO dose ciprofloxacin 750 mg (or levofloxacin 500 mg, or ofloxacin 200 mg) -Bloody diarrhea that persists despite single dose fluoroquinolone, take single dose azithromycin 1000 mg -Pregnant women in areas of prevalent invasive bacteria, azithromycin is DOC 3) Rifaximin approved (except for invasive disease)

Question 34

Non-infectious diarrhea: Describe malabsorption syndromes

Answer 34

1) Pale, greasy, voluminous, foul-smelling stools, weight loss despite adequate food intake, oil droplets in toilet, stool sticks to bowl 2) Includes chronic pancreatitis, Celiac Disease, small intestinal bacterial overgrowth (SIBO)

Question 34

Differentiate between non-inflammatory vs inflammatory diarrhea

Answer 34

1) Non-inflammatory Watery, non-bloody, mild cramps, n/v, self-limited Duration <7 days 2) Inflammatory Blood or pus, fever, abdominal cramps, urgency, tenesmus

Question 34

Non-infectious diarrhea: Describe IBS

Answer 34

small-to-moderate volume frequent loose stools, urgency, incontinence with flares, mucus, correlation with stress and meals,

Question 35

Non-infectious diarrhea: Describe Post-cholecystectomy diarrhea

Answer 35

bilious diarrhea, usually postprandial, worse after fatty or greasy foods

Question 35

Traveler's diarrhea: 1) List 2 indications for referral 2) List 3 indications for admission

Answer 35

1) Cases refractory to treatment or immunocompromised patient 2) Severe dehydration -Fever -Hemodynamically unstable

Question 36

Non-infectious diarrhea: Describe microscopic colitis

Answer 36

: 4-9 watery stools/day; may be >15/day Common in middle aged females

Question 36

Non-infectious diarrhea: Describe the 2 IBDs

Answer 36

1) Crohn’s Disease: diarrhea, abdominal pain, weight loss, +/-fever, rectal bleeding 2) Ulcerative Colitis (UC): diarrhea +/- blood, frequent small stools, abdominal pain, urgency, tenesmus, incontinence

Question 37

Non-infectious diarrhea: Describe how meds can cause it

Answer 37

Many can cause diarrhea **Requires thorough review of current medications Notorious offenders: metformin, laxatives (linzess, lactulose), magnesium, colchicine, antibiotics, sugar substitutes (Sorbitol), vitamin C

Question 38

Post diarrhea complications: Describe Reactive Arthritis

Answer 38

1) Onset of joint pain within 2 weeks post-enteric infection 2) Most common association: Salmonella, Shigella, and Campylobacter 3) Likely related to a dysregulation of an immune/inflammatory response 4) Frequently associated with HLA-B27

Question 39

Post diarrhea complications: Describe GBS

Answer 39

Autoimmune response against peripheral nerves Likely related to a dysregulation of an immune/inflammatory response Onset of symptoms 1-3 weeks following acute viral or bacterial infection Acutely progressive; neuropathy peaks within 4 weeks Up to 72% report enteric infection preceding onset of GBS Most common associated enteric pathogen is Campylobacter

Question 40

Post diarrhea complications: Describe IBS

Answer 40

Persistent diarrhea, chronic abdominal discomfort & change in bowel function Studies show persistent symptoms months to years after inciting infection Up to 32% incidence of IBS after enteric infection Likely related to a dysregulation of an immune/inflammatory response

Question 41

Describe abx associated diarrhea

Answer 41

Occurs during antibiotic exposure Dose related Resolves spontaneously after discontinuation Usually mild, self-limited & does not require lab work-up Pathogenesis: most cases due to changes in colonic bacterial fermentation of carbohydrates & not due to C. difficile

Question 42

Abx assoc. diarrhea: Describe the clinical features of C. Diff

Answer 42

1) Mild to moderate; greenish, foul-smelling watery diarrhea 5–15+ times per day with lower abdominal cramps; mucus but seldom bloody 2) Mild -mod abdominal tenderness 3) Most have WBC counts >15,000 4) Severe or fulminant disease -10-15%; fever, hemodynamic instability, abdominal distention, pain, tenderness -Most have profuse diarrhea (up to 30 stools/day)

Question 43

How does C. diff produce diarrhea?

Answer 43

Prior antibiotic administration causes alteration of the normal enterocolonic bacterial flora Most virulent C. diff strains produce toxins A & B after colonizing the intestinal flora The toxins induce colonic epithelial damage, mucosal inflammation, & mucosal fluid secretion, resulting in diarrhea

Question 44

How is C. Diff diagnosed?

Answer 44

1) + C. difficile cytotoxin or C. difficile toxin B gene in stool samples 2) Nucleic acid amplification testing (NAAT) alone or part of algorithm 3) Pseudo membranes observed on sigmoidoscopy are characteristic 4) Abdominal CT may show colonic wall thickening

Question 45

What should you do for C. Diff patients? (before actual management)

Answer 45

1) Patients with suspected C. difficile infection should be placed on contact precautions preemptively pending diagnostic evaluation. 2) Hand sanitizer does not kill C. diff; must use soap & water 3) Send stool studies for GDH enzyme and toxin A & B testing (quick turnaround)

Question 46

Describe how to manage C. Diff

Answer 46

1) Management based on severity & episode type -Non-severe, severe, fulminant colitis -Initial, 1st/2nd/3rd or subsequent episode 2) Antibiotic agents used: Metronidazole Fidaxomicin $$$$ Rifaximin$$$ Oral vancomycin 3) **Fecal microbiota transplant (FMT) $$$