week 3- gastro Flashcards
• GI tests:
o Gastric Analysis o Gastro Test o Heidelberg Test o H. pylori Test o Schilling Test o D-xylose Absorption Test o Intestinal Permeability Test o Lactose Intolerance o Bacterial Overgrowth Test o Celiac Tests
• Food sensitivity tests:
o IgG/IgE
o EAV
• Barrier against stomach acid:
o Mucus, protects
o Bicarbonate, neutralizes
• gastric acidity & analysis:
o Fast 12 hrs; 24 hrs abstain: drugs, acid blockers, ETOH, caffeine
o Nasogastric (NG) tube →Fasting gastric contents aspirated
o → gastric volume, presence of blood or bile, pH, total HCL: basal acid output (BAO)
o Give Histamine or other gastric stimulant
o Specimens collected at 15 min intervals over 1-2 hrs
o Measures maximal acid output (MAO)
• Normal findings of gastric analysis:
o Fluid clear or hazy, no food, blood or bile present
o pH 1.5-3.5, fasting total acidity under 2mEq/L
o BAO w/o stimulation 0-5
o MAO w/ stimulation 10-20
• Cause ↓ or ↑stomach HCl:
o ↓: Old age, Chronic Renal Failure, Pernicious anemia, Post-vagotomy, Atrophic gastritis, Thyroid toxicosis, Adrenal insufficiency, RA, Vitiligo
o ↑: Peptic/duodenal ulcer, Zollinger-Ellison syndrome, Hyperplasia/hyperfunction of antral gastric cells, SI resection
• “string/gasgtro test”
o For gastric acidity: gastro test capsules
o weighted gelatin capsule, 70 cm absorbent pH-sensitive cotton floss
o swallow w small amount of water
o Proximal end held outside mouth, floss unwinds, stays 10 min
o Remove w rapid, gentle pull; on white paper
o distal part rubbed w pH developer stick
• results of “string/gastro test”
o ambient, unchallenged, Normal pH: under 3
o Unchallenged pH mb normal in hypochlorhydria
o Achlorhydria: ↑ pH, over 3; challenge test not required
• Bicarbonate Challenge Test:
o After string/gastro test
o 10 ml saturated NaHCO3 given by mouth, swallowed with 4 oz H2O
o After 40 mins, retest pH w Gastro test capsule
o pH under / = pre-challenge pH, w normal secretory ability
• correlation of gastric analysis and string/gastro test?
o Good, 93%, by intubation
o Reliable & relatively inexpensive method to measure gastric pH
• Heidelberg test:
o For gastric acidity
o Uses radio frequency receiver next to pt
o Capsule for internal use contains a transmitter, frequency proportional to pH
o Capsule activated before swallowing, receiver calibrated to standard pH solution
o Swallow → register ambient gastric pH
o If ambient fasting pH over 3, suggests achlorhydria, no challenge test required
o NaHCO3 challenge: like Gastro Test
• Results, dis/advantages of Heidelberg test?
o pH monitored, re-acidification time recorded
o Normal re-acidification time 12-33 mins (varies with age)
o Ad: Determine pH, re-acidification time, pH of SI
o Dis: Expensive
• Absorption test: Schilling test
o help identify megaloblastic anemia dt B12 def
o Determine mechanism of malabsorption
o fast 12 hrs prior & 3 hrs after test doses of B12 given (radioactive, 57Co)
o Dx for pernicious anemia
o not in ND scope of practice
o Oral RA B12 given alone, 1 mg loading dose normal B12 IM (binds all body’s receptor sites)
o Any RA B12 absorbed is excreted in urine
o 24 hr urine analyzed for RA B12
• Schilling test results, work-up:
o Normal: 8-40% RA B12 excreted o impaired absorption: little or no RA B12 excreted (eg Pernicious Anemia) o Abn results re-tested in 10 d o RA B12 given orally w IF o If normal, dx= Pernicious Anemia o Still ↓: give abx for 1 wk, retest o If normal: malabsortion dt dysbiosis o Still ↓: repeat RA B12 w pancreatic enzymes (neede to make B12 able to bind to IF) o Retest urine, observe for ↑ RA B12
• Dx’s based on schilling test results:
o Pernicious anemia: ↓ 58Co, N w IF, ↓ w Panc Enz, ↓ after 5 d abx
o Chronic pancreatitis: ↓ 58Co, ↓ w IF, N w PE, ↓ w abx
o Bacterial overgrowth: ↓ 58Co, ↓ w IF, ↓ w PE, N w abx
o Ileal dz: ↓ 58Co, ↓ w IF, ↓ w PE, ↓ w abx
• IF blocking AB:
o =auto-Ab
o Replaces Schillign test for Pernicious Anemia.
o If serum B12 under 300 pg/ml, test for Methylmalonic Acid (MMA)
o If ↑ MMA, test for IFBA
• H. pylori:
o S or C shaped g(-) bacteria
o Major cause of active chronic gastritis
o role in development of duodenal (90%), gastric (70%) ulcers
o gastric CA: 6x risk w H pylori infx
o cultured when collected during endoscopy (bx) or by a string test. 7-10 d
o Sero test sensitive to IgA, IgM, IgG Abs to H. pylori
o Radio labeled carbon breath test
o Stool Ag test highly sensitive and specific
• Defense mechanism of h pylori:
o Covered in mucus, fights stomach acid w enzyme urease
o Urea (from saliva, gastric juice) → HCO3 & NH3 (strong bases)
o = neutralize, protect from stomach acid
o Dx w breath test
• H pylori breath test:
o drink radio labeled urea (13C)
o H. pylori metabolizes urea rapidly, labeled carbon absorbed
o measured as CO2 in pt’s expired breath
o Sensitivity and specificity 94-98%
• H pylori serum test:
o ↑ IgG (Chronic) titers may indicate active or past infx; ↑ 2 mos post exposure, peak ~ 60 d; After successful eradication, may remain ↑ up to 1 yr
o IgA ↑ 2 mos after infx, ↓ 3-4 wks after tx
o IgM (Acute) ↑ 3-4 wks after infx, gone 2-3 mos after tx (not good indicator)
• H pylori test from bx:
o During endoscopy, get bx of stomach and duodenum
o Bx urease test: rapid testing at time of bx
o Histological ID (gold standard)
o Culture → susceptibility testing.
• H pylori stool ag vs urea breath test:
o Dx: not affected by meds; off PPIs for 1 wk
o Monitor FDA cleared for therapeutic monitoring; PPI’s may interfere
o Test for cure: 1 wk, meds don’t interfere; 4 wks, no meds
o Cross reactivity: none; other urea producers may interfere
o Peds: indicated; not indicated
o Special equip: none; Mass or IR spec
o Accuracy: bot excellent
o Yuck factor: stool!; drink C13 solution
o Stability of specimen: 1-2 d at RT; 7 d
• Ssx of malabsorption:
o Weight loss (even w ↑ Cal), fatigue o Diarrhea: bulky, oily (fat), liquid (carbs) o Excess flatus o Fe/B vits: glossitis, cheilosis o Zn: acrodermatitis o EFAs: dry skin and hair o IDA: microcytic anemia o folate/B12: macrocytic anemia o Vit D/Ca: osteopenia/osteoporosis o Vit A: night blindness o Vit K: easy bruising
• Tests for Carb malabsorption:
o D-xylose:
o Lactose (in)tolerance: oral 50 g lactose, blood glucose at 0, 60, 120 mins. ↑ over 20 mg/dL plus development of symptoms is dx
o Breath tests: H2, 14CO2, 13CO2; lactose, fructose, sucrose, isomaltase and others)
• D-xylose absorption test for carb malabsorption
o overnight fast, ingests 25 g D-xylose, urine collected for next 5 hrs. blood after 1 hr.
o Normal excretion over 3.5-4 g/5 hrs (normal 25% excreted)
o ↓ Excretion or blood under 20 mg/dL (in 2 hrs) suggests abn absorption
o Absorption directly proportional to SI function (absorbed in SI)
o distinguish diarrhea dt maldigestion (pancreas/liver) & malabsorption (Sprue, Crohn’s, Whipple’s)
• intestinal permeability test (absorption tes)
o Indicated w digestive problems
o Tests both absorption & permeability
o Sensitivity & accurate method to eval Celiac dz, gluten sensitive enteropathy
o Predicts relapse in Crohn’s who are asyx & in remission
o Any irritation to gut lining ↑ permeability: Inflam, dysbiosis, Food allergies/sensitivities, Maldigestion, NSAIDS, ETOH & pro-oxidants, HIV Infx, Chemo/Radiation
o 12 hour fast, collect fasting urine, drink lactulose & mannitol (NOT metabolized in body),
o 2nd urine 6 hrs after drink
Intestinal permeability results:
o Mannitol: well absorbed by intestinal mucosa (passive diffusion), tests for malabsorption, marker for transcellular uptake, ↓ w Villous atrophy → malnutrition
o Lactulose, disacharide, not well absorbed: tests for leaky gut, marker for mucosal integrity; → ↑uptake food Ags & bacterial toxins
o Normal: lactulose recovery under 1 %, mannitol 2-25%; L:M under 0.05
o High ratio = ↑ gut permeability, ↑ antigenic molecules
o ↓ both: malabsorption
o ↑ both: ↑ permeability or leaky gut syndrome
o ↑L, ↓ M = LGS w malabsorption
• Lactose intolerance blood test:
o Diff from lactulose test; detect lactase def
o ↑ Lactose load → ↑ H and methane
o Strong cathartic effect
o Sxs: abd cramping, flatus, abd bloating & diarrhea
o Lactase def acquired (mc adults) or congenital (apparent in infant)
o Cultural: ↑ freq in Asian, African American, northern European decent
o Indicated: Adults w sxs after dairy; Infants fail to thrive, diarrhea, vomiting;↑ SI lactose load
o FBG, 100g lactose oral (ped by bw), BG at 30, 60, 120 mins after
• Lactose intolerance blood test results:
o Normal: ↑ BG over 20 mg/dl w/o cramping or diarrhea
o Lactase def: glucose not absorbed, no ↑ BG; AND have diarrhea and cramping
o Endogenous diarrhea: normal breakdown of lactose but glucose not absorbed dt malabsorption; no ↑ BG
o Recommend D-xylose and Intestinal permeability tests
• Lactose Intolerance Breath (Hydrogen) Test:
o Eval baseline breath H (14% H in GI tract enters blood, expired; normally only occurs in distal gut)
o Dose lactose same as blood test
o Eval Exhaled air for H content every 30 mins for 2-4 hrs
o Desirable: under 10 ↑H from baseline
o over 20 ppm = “lactose malabsorber”
• SIBO:
o historically : context of abn or post‐surgical anatomy
o quantitative culture of aspirated juice from PROXIMAL jejunum
o = over 105 CFU bacteria/mL of jejunal aspirate
o Normal: bacteria only distally, simple carbs completely digested in proximal SI, complex carbs only fermented in colon
o SIBO: starch, etc begins digestion/fermentation in proximal
• Normal gut flora maintenance:
o Gastric acid ↓ bacteria from food; ↓ bacterial growth in proximal SI
o Pancreatic enzymes: antimicrobial in proximal SI
o SI motility (Phase III migrating motor complex)
o Structural integrity of GI tract (intact IC valve)
o Intact gut immune system
• SIBO sequelae:
o direct and indirect effects on gut mucosa, flora
o Bacterial adherence to intestinal mucosa → direct injury, dysfunction, altered gut immunology
o Sig mucosal injury → ↓ brush border disaccharidases, altered SI permeability
o Bacteria compete with host for food → byproducts w biologic activity or alter gut function
o non‐specific sxs: Bloating, distension, abd cramping, diarrhea
o Nutritional deficiencies: B12, fat sol vits,
o ↑ or normal Vit K and folate dt bacterial synthesis
• SIBO testing gold standard test:
o jejunal aspirates via enteroscopy or nasogastric
o Abn= Bacteria over 105 cfu/mL in proximal jejunum
o Downsides: Invasive, Contamination by oral flora, ↓ sensitivity to detect distal SIBO, Expensive, need highly trained personnel
• SIBO breath test
o Record fasting breath sample
o drink 10 g lactulose, measure breath every 15 mins for 2 hrs
o normal: slow ↑ H/methane
o SIBO: ↑ peak over 12 ppm above fasting at 30 mins (usu later peak, too, dt ferm in colon)
o Note: using glucose only tests bacteria in duodenum and proximan jejunum (rapidly absorbed); but lactulose not absorbed, so tests entire gut
• Celiac disease:
o 0.5-1 % in US
o AI (unknown why) response to rxn w gluten, interact w Ag-presenting cells in lamina propria of SI
o Asx to overt malabsorption, multiple organ systems, ↑ risk some malignancies
o Usu (+) human leukocyte antigen (HLA)-DQ2 or HLA-DQ8, facilitate the response
o Twin Concordance
• Risk factors for celiac:
o Dermatitis herpetiformis, 100% o 1st degree relative, 5-22 o AI thyroid dz, 1.5-14 o Down syndrome, 5-12 o Turner's syndrome, 2-10 Type 1 DM: children, 3-8; Adults , 2-5
Ssx of celiac:
o Common: Diarrhea, Fatigue, Borborygmus, Abdominal pain, Weight loss, Abdominal distention, Flatulence
o Uncommon: Osteopenia/ osteoporosis, Abn liver function, N/V, IDA, Neuro dysfunction, Constipation
• Recommendations for celiac screening:
o If sxs, high risk, any of these conditions: AI hepatitis, Down’s, Premature onset osteoporosis, Primary biliary cirrhosis, Unexplained ↑ LFTs, Unexplained IDA
o Other: AI thyoid dz, Cerebellar ataxia, 1st or 2nd degree relative, IBS, Peripheral neuropathy, Recurrent migraine, Selective IgA def, Short stature (in children), Sjögren’s, Turner’s, Type 1 DM, Unexplained delayed puberty, Unexplained recurrent fetal loss
• Sero tests for celiac:
o Serum IgA endomysial Abs and IgA tissue transglutaminase (tTG) Abs. Sens and spec over 95%
o ↓ sens and spec for gliadin Abs
o tTG Ab test less costly because it’s ELISA; #1 for screening
o PPV 49.7%, NPV 99.9%. ↑ false (+), even w good test, dt low prevalence (in US)
o Confirm w SI bx
o Sensitivity depends on degree of mucosal involvement
o St test for HLA DQ2/8 (40% gen pop, 99% celiac)
• SI bx:
o !! all dx testing must be done while pt has been eating gluten
o Req’d to confirm celiac dx. At least 4 samples (avoid false (-), ↑ sens)
o Also do if sero (-) but high risk or suspicion of celiac
o mb partial to total villous atrophy, subtle crypt lengthening or ↑ epithelial lymphs
o very severe dz may not be recognized; or latent dz may have normal results
• Follow-up celiac pts:
o On gluten-free diet, monitor with Sero markers (IgA tTG)
o Ab levels return to normal 3-12 mos of gluten-free diet
o Bx again in 3-4 mos if not responding to tx
o Further dietary instruction (continued gluten exposure mb inadvertent)
o → consider diseases that may mimic celiac: microscopic colitis, pancreatic insufficiency, IBD, ulcerative jejunoileitis, collagenous sprue, T-cell lymphoma
• Food sensitivity types:
o Type 1- Immediate Sensitivity rxs; IgE; rashes, hives, HA, intestinal disorders
o Type IV- Delayed Sensitivity rxns: IgG (IgG4 for foods); fatigue, arthritis, eczema, hives, mood swings, depression, asthma, cardiac arrythmias, weight gain, food cravings
• Food sensitivity gold standard test:
o Elimination Diet for 6 weeks
o Remove most common food allergens then reintroduce single food groups every 3rd day
o Look for sxs 0-72 hrs later
o Cost effective, reliable indicator, difficult patient compliance
• IgG and IgE blood tests for food sensitivity:
o If sensitive, usu ↑ IgG4 against food eaten
o IgG4 has circulation ½ life of 21 d; binds Mast cells for 2-3 mos
o IgE ½ life 1-2 d, binds Mast cells 14 d
o IgG & IgE are measured via ELISA methodology w purified food Ags to detect Abs
o Panels: 96-combined foods or 100 vegetarian foods
• FST w EAV (electroacupuncture according to voll)
o Test w Bioenergetics
o galvanometer to measure skin resistance
o Pt holds (-) electrode in hand
o Dr. tests acupoints w (+) electrode on fingers of opp hand
o 10 uA current
o Meter set at 100 (acceptable)
o Sensitive value set by introducing known poison into circuit & retesting.
o Controls [vial of water (100) & Benzene (0)] put in test well & checked.
o Skin resistance ↑ (= current ↓) w poison (FS)
o high agreement w food challenge testing
• food sensitivities/intolerance/allergies:
o allergies: usu genetic, sxs every time eat the food, mb anaphylactic rxn
o Intolerance: Lack enzyme to digest food (usu Lactose)
o Sensitivities: primarily related to GI health; Maldigestion, LGS, microflora imbalance; Intensity related to frequency of Ag exposure
