MGH PM - Gastroenterology II Flashcards
1
Q
Acute diarrhea means …?
A
<4wk.
2
Q
Acute diarrhea - Acute infectious etiologies - Non inflammatory:
A
Predom. disruption small intestine absorp. and secretion.
==> Voluminous diarrhea, N/V, (-) fecal WBC and FOB.
3
Q
Acute diarrhea - Acute infectious etiologies - Preformed toxin:
A
“Food poisoning”,
<24h dur. S.aureus (meats and dairy).
B. cereus (fried rice).
C.perfringens (rewarmed meats).
4
Q
Acute diarrhea - Acute infectious etiologies - Viral - Rotavirus:
A
Outbreak person to person (PTP), daycare; lasts 4-8 d.
5
Q
Acute diarrhea - Acute infectious etiologies - Viral - Norovirus:
A
50% OF ALL DIARRHEA.
Winter outbreaks; PTP and food/water. No immunity.
==> Lasts 1-3 d. Vomiting prominent.
6
Q
Acute diarrhea - Acute infectious etiologies - Bacterial - E.coli (toxinogenic):
A
> 50% of traveler’s diarrhea.
==> Cholera-like toxin; <7d.
7
Q
Acute diarrhea - Acute infectious etiologies - V.cholerae (Lancet 2012):
A
Contam H2O, fish, shellfish.
==> 50 cases/y in US Gulf Coast.
==> Severe dehydration and electrolyte depletion.
8
Q
Acute diarrhea - Acute infectious etiologies - Parasitic - Giardia:
A
Streams/outdoor sports, travel, outbreaks. Bloating.
==> Acute (profuse, watery) ==> Chronic (greasy, malodorous).
9
Q
Acute diarrhea - Acute infectious etiologies - Parasitic - Cryptosporidia:
A
Water-borne outbreak; typically self-limited, can cause chronic infxn if immunosupp.
==> Abd pain (80%), fever (40%). (NEJM 2002).
10
Q
Acute diarrhea - Acute infectious etiologies - Cyclospora:
A
Contaminated produce.
11
Q
Acute diarrhea - Acute infectious etiologies - Inflammatory:
A
- Predom. colonic invasion.
- Small vol diarrhea.
- LLQ cramps.
- Tenesmus.
- Fever.
- Typically (+) fecal WBC or FOB.
12
Q
Acute diarrhea - Acute infectious etiologies - Bacterial - Campylobacter:
A
Undercooked poultry, unpasteurized milk, travel to Asia.
==> Carried by puppies and kittens.
==> Prodrome; abd pain ==> Pseudoappendicitis;
==> c/b GBS, reactive arthritis.
13
Q
Acute diarrhea - Acute infectious etiologies - Bacterial - Salmonella (non typhoidal):
A
- Eggs, poultry, milk.
- Bacteremia in 5-10%.
==> 10-33% of bacteremic Pts >50y develop aortitis.
14
Q
Acute diarrhea - Acute infectious etiologies - Bacterial - Shigella:
A
Low inoculum; PTP spread. Abrupt onset.
==> Often gross blood and pus in stool; UP UP WBC.
15
Q
Acute diarrhea - Acute infectious etiologies - Bacterial - E.coli (O157:H7 and inv/hemorrhagic non-O157:H7):
A
Undercooked beef, unpasteurized milk, raw produce; PTP.
==> O157 and non-O157 sp. (40%) produce Shiga toxin ==> HUS (typically in children). Gross blood in stool.
16
Q
Acute diarrhea - Acute infectious etiologies - Bacterial - V.parahaem.:
A
Undercooked seafood.
17
Q
Acute diarrhea - Acute infectious etiologies - Bacterial - Salmonella typhi:
A
Travel to Asia. Systemic toxicity, relative bradycardia, rose spot, rash, ileus ==>Pea-soup diarrhea, bacteremia.
18
Q
Acute diarrhea - Acute infectious etiologies - Bacterial - Yersinia:
A
Undercooked pork; unpasteurized milk, abd pain ==> “Pseudoappendicitis” (aka mesenteric adenitis).
19
Q
Acute diarrhea - Acute infectious etiologies - Bacterial - Aeromonas, Plesiomonas, Listeria:
A
Meats and cheese.
20
Q
Acute diarrhea - Acute infectious etiologies - Parasitic - E.histolytica:
A
Contaminated food/water, travel (rare in US).
==> Liver abscess.
21
Q
Acute diarrhea - Acute infectious etiologies - Viral - CMV:
A
Immunosuppressed; dx by shell vial cx of colon bx.
22
Q
Acute diarrhea - Evaluation (NEJM 2009, Gastro 2009) - Hx:
A
Stool freq, bloody, abd pain, duration of sxs [1 wk for viral and bacterial (except C.diff), >1wk for parasitic], travel, food, recent abx.
23
Q
Acute diarrhea - Evaluation (NEJM 2009, Gastro 2009) - PEx:
A
Vol depletion (VS, UOP, axillae, skin turgor, MS), fever, abd tenderness, ileus, rash.
24
Q
Acute diarrhea - Evaluation (NEJM 2009, Gastro 2009) - Further evaluation if WARNING SIGNS:
A
- Fever.
- Signific abd pain.
- Blood or pus in stools.
- > 6 stools/d.
- Severe dehydration.
- Immunosupp.
- Elderly.
- Duration >7 d.
- Hosp-acquired.
25
Acute diarrhea - Evaluation (NEJM 2009, Gastro 2009) - Etiology established in only ...?
3% of community-acquired diarrhea.
26
Acute diarrhea - Evaluation (NEJM 2009, Gastro 2009) - Laboratory:
1. Fecal WBC [high false (+) and (-)].
2. Positive fecal calprotectin or lactoferrin Se/Sp >90%).
3. Stool cx.
4. BCx.
5. Lytes.
6. C.diff (if recent hosp or abx).
7. Stool O&P (if >10 d, travel to endemic area, exposure to unpurified H2O, community outbreak, daycare, HIV(+) or MSM).
+/- Stool ELISAs (viruses, Crypto, Giardia), serologies (E.histolytica), special stool cx.
27
Acute diarrhea - Evaluation (NEJM 2009, Gastro 2009) - Imaging/endoscopy:
CT/KUB if ? toxic megacolon.
==> Sig/colo if immunosupp or cx (-).
28
Acute diarrhea - Evaluation (NEJM 2009, Gastro 2009) - Ddx:
Infx vs. preformed toxin vs. med-induced vs. initial presentation of chronic diarrhea.
29
Acute diarrhea - Treatment - If none of the above WARNING SIGNS and Pt able to take POs:
Supportive Rx only: Oral hydration, loperamide, bismuth subsalicylate (avoid cholinergics).
30
Acute diarrhea - Treatment - If moderate dehydration:
50-200 mL/kg/d of oral solution (1/2 tsp salt, 1 tsp baking soda, 8 tsp sugar, & 8 oz OJ diluted to 1L w/ H2O) or Gatorade, etc.
==> If severe, LR IV.
31
Acute diarrhea - Treatment - For traveler's diarrhea:
Bismuth or rifaximin useful for prophylaxis and empiric Rx.
32
Acute diarrhea - Treatment - Non-hosp-acquired inflammatory diarrhea?
Empiric abx reasonable ==> FQ x 5-7 d.
==> Abx rec for Shigella, cholera, Giardia, amebiasis, Salmonella if Pt > 50y or immunosupp or hospitalized, ? Campylobcter (if w/in 4 d of sx onset).
==> AVOID abx if suspect E.coli O157:H7 as may increase risk of HUS.
33
C.diff-associated diarrhea (CDAD) - Pathogenesis:
1. Ingestion of C.difficile spores ==> Colonization when colonic flora Dd by abx or chemo ==> Release of toxin A/B ==> Colonic mucosal necrosis + inflammation ==> Pseudomembranes.
2. Incr. toxigenic strain (NAP 1/027) incr. mort. + LOS (esp. in elderly) (NEJM 2008).
3. Additional risk factors: elderly, nursing home residents, IBD, PPI (CID 2011).
34
CDAD - Clinical manifestations (a spectrum of disease):
1. Asx colonization: <3% healthy adults; 20% in hospitalized patients on abx.
2. Acute watery diarrhea (occ bloody) +/- mucus often w/ lower abd pain, fever, UP UP UP WBC.
3. Pseudomembranous colitis: Above sx + pseudomembranes + bowel wall thickening.
4. Fulminant colitis (2-3%): TOXIC MEGACOLON (colon dilation >6cm on KUB, colonic atony, systemic toxicity) and/or bowel perforation.
35
CDAD - Diagnosis - Only test if ...?
SYMPTOMATIC - Test LIQUID stool (unless concern for ileus).
36
CDAD - Diagnosis - Stool EIA:
Detects toxin B and/or A (1-2% strains make A).
==> Fast (2-6h).
==> Most often used.
37
CDAD - Diagnosis - PCR:
Quick, becoming test of choice (Mayo 2012).
38
CDAD - Diagnosis - Alternative:
2-step method:
==> Check glutamate dehydrogenase (GDH) EIA (high Se, (+) even if no toxin production) ==> Then if (+), check cytotoxin assay or toxinogenic cx.
39
CDAD - Diagnosis - Consider flex sig id ...?
Dx uncertain and/or evidence of no improvement w/ standard Rx.
40
CDAD - Treatment (Infect Control Hosp Epidemiol 2010) - Start ...?
==> Contact precautions.
==> If possible d/c abx ASAP.
==> Stop antimotility agents.
41
CDAD - Treatment (Infect Control Hosp Epidemiol 2010) - Mild-moderate (WBC <15k, Cr<1.5 x baseline, age <65y and no peritoneal sx):
MNZ 500mg PO tid x 10-14d.
42
CDAD - Treatment (Infect Control Hosp Epidemiol 2010) - Severe (WBC >15k or Cr >1.5x baseline or age >65y):
Vanco 125mg PO qid x 10-14d.
43
CDAD - Treatment (Infect Control Hosp Epidemiol 2010) - Complicated (ileus, malabsorption, shock, megacolon, peritonitis):
1. Vanco 500mg PO q6h AND MNZ 500mg IV q8h.
2. PR vanco if ileus, but avoid if evidence of toxic megacolon.
3. Abd CT and urgent surg consult re: colectomy.
4. ? IVIG fidaxomicin 200mg bid non inferior to vanco PO + Decr. rate of recurrence (NEJM 2011).
44
CDAD - Treatment (Infect Control Hosp Epidemiol 2010) - If Pt needs to stay on original abx ...?
Continue C.diff. Rx for >7 d post-abx cessation.
45
CDAD - Treatment (Infect Control Hosp Epidemiol 2010) - Stool carriage may persist ...?
3-6wk postcessation of sx and should NOT trigger further Rx.
46
CDAD - Treatment (Infect Control Hosp Epidemiol 2010) - Recurrent infection:
15-30% risk after d/c of abx, most w/in 2wk of stopping abx.
==> 1st relapse: if mild ==> repeat 14d course of MNZ or vanco.
==> 2nd relapse ==> PO vanco taper for 6wk.
==> >2 relapses: vanco taper and adjunctive Rx such as S.boulardii, probiotics, rifaximin, nitazoxanide, fidaxomicin or cholestyramine (binds vanco so cannot take concurrently).
47
CDAD - Treatment (Infect Control Hosp Epidemiol 2010) - Fecal transplant:
In refractory disease appears safe and effective (Clin Gas Hep 2011, NEJM 2013).
48
CDAD - Treatment (Infect Control Hosp Epidemiol 2010) - Probiotics:
May prevent CDAD by 66% in non immunosuppressed Pts (Annals 2012).
49
Chronic diarrhea (>4wk; Gastro 2004) - Medications
Cause incr. secretion + incr. motility, Δ flora, incr. cell death or inflammation.
1. PPI.
2. Colchicine.
3. Abx.
4. H2RA.
5. SSRIs.
6. ARBs.
7. NSAIDs.
8. Chemo.
9. Caffeine.
50
Chronic diarrhea (>4wk; Gastro 2004) - Osmotic:
1. Decr. diarrhea with fasting.
2. (-) fecal fat.
3. Incr. osmotic gap.
51
Chronic diarrhea (>4wk; Gastro 2004) - Lactose intolerance:
1. Seen in 75% nonwhites and in 25% whites.
| 2. Can be acquired after gastroenteritis, med illness, GI surgery.
52
Lactose intolerance - Clinical:
1. Bloating.
2. Flatulence.
3. Discomfort.
4. Diarrhea.
53
Lactose intolerance - Dx:
Hydrogen breath test or empiric lactose-free diet.
54
Lactose intolerance - Rx:
1. Lactose-free diet.
2. Use of lactose-free dairy products.
3. Lactase enzyme tablets.
55
Osmotic diarrhea - Etiology:
1. Lactose intolerance.
| 2. Other ==> Laxatives, antacids, sorbitol, fructose.
56
Malabsorption - Main features:
1. Decr. diarrhea with fasting.
2. Incr. fecal fat.
3. Incr. osmotic gap.
57
Celiac disease (NEJM 2012) - Pathogenesis:
Immune rxn in genetically predisposed Pts (1% of pop) to gliadin, a component of gluten (wheat protein)
==> Small bowel inflammatory infiltrate.
==> Crypt hyperplasia, villus atrophy.
==> Impaired intestinal absorption.
58
Celiac disease (NEJM 2012) - Other s/s:
1. Fe/Folate def anemia.
2. Osteoporosis.
3. Dermatitis herpetiformis (pruritic papulovesicular).
4. Incr. AST/ALT.
59
Celiac disease (NEJM 2012) - Dx:
IgA tissue transglutaminase or endomysial Abs ==> 90% Se and >98% Sp (JAMA 2010).
==> Small bowel bx AND clinical/serologic response to gluten-free diet definitive.
60
Celiac disease - Rx:
Gluten-free diet;
==> 7-30% do not respond to diet ==> ? wrong dx or non compliant.
61
Celiac disease - Complications:
5% refractory (sx despite strict dietary adherence).
==> Risk of T-cell lymphoma and small bowel adenocarcinoma.
62
Whipple's disease (NEJM 2007):
1. Infx w/ T.whipplei.
2. S/s ==> Fever, LAN, edema, arthritis, CNS Ds, gray-brown skin pigmentation, AI + MS, oculomasticatory myorhythmia (eye oscillations + mastication muscle contract).
63
Whipple's disease - Rx:
(PCN + Streptomycin) or 3rd-gen ceph x 10-14 d ==> Bactrim for >1y.
64
Small Intestinal Bacterial Overgrowth (SIBO; Inf Dis Clin 2010):
1. Incr. SI bacteria from incompetent/absent ileocecal valve.
2. S/p RYGB, scleroderma, diabetes, s/p vagotomy ==> Fat and CHO malabsorption.
65
Small Intestinal Bacterial Overgrowth (SIBO) - Dx:
(+) 14C-xylose and H+ breath tests.
66
SIBO - Rx:
Cycled abx (eg, MNZ, FQ, rifaximin).
67
Pancreatic insufficiency:
Most commonly from chronic pancreatitis or pancreatic cancer.
68
Other etiologies of malabsorption:
1. S/p short bowel resection (short bowel syndrome.
2. Crohn.
3. Chronic mesenteric ischemia.
4. Eosinophilic gastroenteritis.
5. Intestinal lymphoma.
6. Tropical sprue.
69
Inflammatory diarrhea - Main features:
1. (+) FOB.
2. abd pain.
3. (+) fecal WBC or lactoferrin or calprotectin.
70
Inflammatory diarrhea - Etiologies:
1. Infections ==> Parasitic (above pathogens and strongyloides), CMV, TB.
2. IBD.
3. Radiation enteritis, ischemic colitis, neoplasia (colon cancer, lymphoma).
71
Secretory diarrhea - Main clinical features:
1. Nocturnal diarrhea freq described.
2. No Δ diarrhea after NPO.
3. Normal osmotic gap.
72
Secretory diarrhea - Etiologies:
1. Hormonal.
2. Laxative abuse.
3. Neoplasm.
4. Decr. bile absorption.
5. Lymphocytic colitis, collagenous colitis (may be a/w meds, including NSAIDs).
73
Secretory diarrhea - Hormonal:
1. VIPoma (Verner-Morrison).
2. Serotonin (carcinoid).
3. Thyroxine.
4. Calcitonin (Medullary thyroid carcinoma).
5. Gastrin (Z-E).
6. Glucagon.
7. Substance P.
74
Secretory diarrhea - Neoplasm:
1. Carcinoma.
2. Lymphoma.
3. Villous adenoma.
75
Motility diarrhea - IBS:
10-15% of adults (BMJ 2012, NEJM 2012).
76
IBS (BMJ 2012, NEJM 2012) - Pathogenesis:
Due to altered intestinal motility/secretion in response to luminal or environmental stimuli w/ enhanced pain perception and dysregulation of the brain-gut axis.
77
IBS (BMJ 2012, NEJM 2012) - Rome III criteria:
Recurrent abd pain >3d/mo over last 3 mo + at least 2 of the following:
1. Improvement w/ defecation.
2. Onset w/ Δ freq of stool.
3. Onset w/ Δ in form of stool.
78
IBS (BMJ 2012, NEJM 2012) - Rx:
Sx-guided (AJG 2009):
1. Pain ==> Antispasmodics, TCA, SSRI.
2. Bloating ==> Rifaximin (NEJM 2011), probiotics.
3. Diarrhea ==> Loperamide, alosetron (5-HT3 antagonist) for women (incr. risk of ISCHEMIC COLITIS), rifaximin.
4. Constipation ==> Incr. fiber 25g/d, lubiprostone (Cl- channel activator).
79
Motility diarrhea - Other etiologies:
1. Scleroderma.
2. Diabetic autonomic neuropathy.
3. Hyperthyroidism.
4. Amyloidosis.
5. s/p vagotomy.
80
Workup for chronic diarrhea:
1. Culprit meds ==> Med-induced.
2. (+) fecal fat ==> Malabsorption ==> Based on hx check tissue transglut. Abs, stool elastase, H breath and 14C-xylose (if avail) tests, EGD w/ bx, EUS.
3. (+)FOB, (+)WBC, (+)lactoferrin, calprotectin ==> Inflammatory ==> Check stool cx, colonoscopy.
4. Stool osmotic gap <50 ==> Secretory/motility ==> CT scan, colo, hormone levels.
5. Stool osmotic gap >50 ==> Check H breath test or empiric lactose-free diet, lax abuse.
81
Stool osmotic gap = ...?
Osm/stool (usu 290) - [2x (Na Stool - K stool)].
82
Constipation (Gastro 2013) - Definition:
ROME III: At least 2 of the following during last 3mo at least 25% of time:
1. Straining.
2. Lumpy/hard stools.
3. Incomplete evacuation.
4. Sensation of anorectal obstruction.
5. Manual maneuvers to facilitate defecation.
6. Stool frequency <3 per wk.
83
Constipation (Gastro 2013) - Etiology:
1. Functional.
2. Meds.
3. Obstruction.
4. Metabolic/endo.
5. Neuro.
84
Constipation (Gastro 2013) - Functional etiology:
1. Normal transit.
2. Slow transit.
3. Pelvic floor dysfunction.
4. Constipation-predom IBS.
85
Constipation (Gastro 2013) - Etiology - Meds:
1. Opioids.
2. Anticholinergics (TCAs, antipsychotics).
3. Fe.
4. CCB.
5. Diuretics.
6. NSAIDs.
86
Constipation (Gastro 2013) - Etiology - Obstruction:
1. Cancer.
2. Stricture.
3. Rectocele.
4. Anal stenosis.
5. Extrinsic compression.
87
Constipation (Gastro 2013) - Etiology - Metabolic/endo:
1. DM.
2. Hypothyroid.
3. Uremia.
4. Preg.
5. Panhypopit.
6. Porphyria.
7. Up Ca.
8. Down Mg.
9. Down K.
88
Constipation (Gastro 2013) - Etiology - Neuro:
1. Parkinson.
2. Hirschprung.
3. Amyloid.
4. MS.
5. Spinal injury.
6. Autonomic neuropathy.
89
Constipation (Gastro 2013) - Dx:
1. H/P w/ DRE.
2. Labs: consider CBC, electrolytes w/ Ca, TSH.
3. Colono if alarm sx ==> wt loss, (+) FOBT, fever, FHx of IBD or colon cancer.
4. Sig if no alarm sx and <50y.
5. For functional constipation: Sitzmark study, anorectal manometry, defecography.
90
Constipation (Gastro 2013) - Tx - Steps:
Bulk laxatives (fiber 20g/d) ==> Osmotic laxatives ==> Stimulant laxatives.
91
Constipation (Gastro 2013) - Tx - Bulk laxatives:
1. Psyllium.
2. Methylcellulose.
3. Polycarbophil.
==> Incr. colonic residue, incr. peristalsis.
92
Constipation (Gastro 2013) - Tx - Osmotic laxatives:
1. Mg.
2. Sodium Ph [avoid if CKD].
3. Lactulose.
==> Incr. water in colon.
93
Constipation (Gastro 2013) - Tx - Stimulant laxatives:
1. Senna.
2. Castor oil.
3. Bisacodyl.
4. Docusate sodium.
==> Incr. motility and secretion.
94
Constipation (Gastro 2013) - Tx - Enema/suppository:
1. Phosphate.
2. Mineral oil.
3. Tap water.
4. Soapsuds.
5. Bicasodyl.
95
Constipation (Gastro 2013) - Tx - Other:
1. Lubiprostone (see IBS).
2. Methylnaltrexone and alvimopan for opioid-induced (AJG 2011).
3. Linaclotide ==> Incr. stool freq, decr. straining/bloating (NEJM 2011).
96
Acute pseudo-obstruction (adynamic ileus) - Definition:
Loss of intestinal peristalsis in absence of mechanical obstruction.
97
Acute pseudo-obstruction (adynamic ileus) - Ogilvie's?
Acute colonic adynamic ileus in presence of competent ileocecal valve.
98
Acute pseudo-obstruction (adynamic ileus) - Precipitants:
1. Intra-abd process (surgery, pancreatitis, peritonitis).
2. Severe medical illness (Eg, PNA, sepsis).
3. Intestinal ischemia.
4. Meds (opiates, anticholinergics).
5. Electrolyte abnl.
99
Acute pseudo-obstruction (adynamic ileus) - Clinical manifestations:
1. Abd discomfort.
2. N/V.
3. Hiccups.
4. Abd distention.
5. Decr. or absent bowel sounds.
6. No peritoneal signs (unless perforation).
==> Cecum >10-12cm ==> Incr. risk of rupture.
100
Acute pseudo-obstruction (adynamic ileus) - Dx:
Supine and upright KUB vs CT ==> Gas-filled loops of small and large intestine.
==> Must exclude mechanical obstruction (absence of gas in rectum).
101
Acute pseudo-obstruction (adynamic ileus) - Tx:
1. NPO.
2. Mobilize (walk, roll).
3. D/c Rxs that decr. intestinal motility, enemas.
4. Decompression (NGT, rectal tube, colonoscope).
5. Neostigmine (for colonic), methylnatrexone (for small bowel, ? colonic).
