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