Gastroenterology Flashcards
1
Q
H. pylori transmission
RFs that increases risk of transmission
A
- Fecal-oral
- Gastric cancer increases risk of transmission
- Smoking, obesity RFs; no specific recommendations for screenings
2
Q
H. pylori testing types (2)
A
- Invasive - Endoscopic - taking biopsies of gastric mucosa
- Biopsy urease testing
- Histology
- Bacterial C&S
- Non-invasive
- Stool antigen
- Urea breath testing (UBT)
- Serology
3
Q
Test & Treat H. pylori criteria
PIMND
A
- Only if < 55 and no alarm symptoms!! Do non-invasive test
- Active or hx of PUD
- Dyspepsia - indigestion
- Gastric MALT lymphoma - cancer
- NSAID induced ulcers
- Unexplained iron deficiency anemia (if can’t find source of blood loss)
4
Q
Endoscopy criteria for H. pylori
Alarm symptoms: FAJAW GORD
A
- > 55 regardless of what the symptoms are or alarm s/s
- Alarm symptoms
- Unexplained weight loss
- Progressive dysphagia
- Odynophagia
- Recurrent vomiting
- Family hx of GI cancer
- GI bleeding
- Anemia
- Jaundice
- Abd mass
- Endoscopy not indicated for sole purpose of determining H. pylori status
5
Q
Endoscopic approach testing for H. pylori
Biopsy urease testing
A
- Biopsy urease - look for presence of irease in gastric mucosa (urea and pH)
- High S + S
- Less $$ than histology
- Can only be used if no recent PPI, bismuth or abx use
6
Q
Endoscopic approach for H. Pylori testing
Histology
A
- Histology - a little more accurate than urease testing
- High S + S
- Can be done if patient has recently been on PPI, bismuth, or abx - sensitivity may be decreased
- More $$$
7
Q
Endoscopic approach testing for H. pylori
Bacterial C&S
A
- Bacterial C&S - not very common
- Performed on gastric biopsies of patients with resistance infection/treatment failure
- High false negative rate - H. pylori is difficult to culture
8
Q
Non-invasive H. Pylori Testing
Urea breath testing (UBT)
A
- Ingestion of non/radioactiveurea labeled → H. Pylori cleave urea → ammonia + CO2 which is marked w/isotope + detectable in breath samples
- Highly S + S (most of the three here)
- Cannot be used if any PPI, bismuth or abx use in the last 2 weeks
- False negatives may be seen with bleeding ulcers–Expensive
- More accurate in children > 6
9
Q
Non-invasive H. Pylori Testing
Stool antigen assay
A
- Need to return the stool sample before starting medication
- Less $$ than UBT + slightly less affected by PPI use
- Still recommend avoidance of PPIs, bismuth or abx for 2 weeks
- POC test not as sensitive but lab based testing equal to UBT
- Can be used for diagnosis and confirmation of eradication
10
Q
Non-invasive H. Pylori Testing
Serology
A
- Blood test
- ELISA test to detect H. Pylori IgG antibodies
- Inexpensive
- Not accurate (85% sensitive and 79% specific) risk for false positive and false negative
- Does not determine between active and past infection
- Not affected by PPI, bismuth, antibiotic use
- Not generally recommended
11
Q
Test & Treat recommended in children H. pylori?
A
NO
12
Q
H.pylori testing recommended for children or children w/functional abd pain?
A
NOT RECOMMENDED
13
Q
When would you do an endoscopy w/biopsy for children with possible H. pylori infection?
A
If infection is persistent or they’re experiencing severe upper abd discomfort
14
Q
When should you confirm eradication of H. pylori after antibiotic?
Which tests should you do? Which one should you not use?
A
Should be performed at least 4 weeks after completion of abx tx
Can use either UBT, stool Ag test, or endoscopy based testing
NOT SEROLOGIC TESTING
15
Q
Endoscopy procedure
Prep, during, after, risk factors
A
- Involves visualization of oropharynx, esophagus, stomach, and proximal duodenum
- Typically NPO for 4-8 hours prior to procedure
- Generally no need to stop aspirin or NSAIDs, other anticoagulants require a risk/benefit assessment
- Sedation typically accomplished with IV benzodiazepines +/- opiates
- Patient’s will require a ride home from the procedure
- Increased risk for complications relating to sedation in patients with:
- OSA – sleep apnea (aspiration)
- Significant cardiac or pulmonary disease
- Those with increased aspiration risk: morbid obesity, bowel obstruction, dysphagia, reflux
16
Q
Upper endoscopy
GI series
Barium swallow
Slide 12: perform? Visualize? When to order?
A
17
Q
When do you start screening patients for colon cancer if they have no risk factors?
A
At 50 years old
May decrease to age 45 d/t increased prevalence of colon cancer at younger age
18
Q
Gold standard screening test for colon cancer
A
COLONOSCOPY
B/c have good visualization of colon and can take biopsy during procedure if abnormal
19
Q
When do you repeat testing for colonoscopy if result is normal?
A
10 years unless symptomatic
20
Q
Two types of colon polyps
Which one is cancerous?
A
- Adenomatous: precancerous → screening repeat colonoscopy sooner than 10 yrs
- Hyperplastic: not cancerous → no need for repeat testing, just in 10 yrs (usually GI specialist will determine)
21
Q
Colon cancer screening method:
Fecal Occult Blood Test (FOBT)
A
- Guiac
- Qyearly for CRC screening - Noninvasive
- Rapid, inexpensive but POOR SPECIFICITY (high false positives)
- Can do testing at home
- Hemorrhoids can give false positives
- Dietary restrictions: avoid red meat (can interfere) 3d prior and NSAIDs 7d prior
- Requires 3 samples
- POSITIVE → COLONOSCOPY to find source of bleeding
22
Q
Colon cancer screening method:
Fecal Immunochemical Test (FIT)
A
- Qyearly - Noninvasive
- Uses abx directed against human Hgb to detect blood in stool
- Less sensitive to dietary changes than FOBT
- Requires only 1 sample vs. 3 for FOBT
- PREFERRED OVER FOBT TESTING - more accurate
- No diet prep or changes in meds
23
Q
Colon cancer screening method:
CT colonography
A
- Q5yrs - Noninvasive
- Ordered by a specialist, not commonly ordered in primary setting
- 2D → 3D views of colon and rectum
- Come back positive (dx only) → COLONOSCOPY
- Fasting + laxative
24
Q
Colon cancer screening method:
Flexible sigmoidoscopy
A
- Q3-5yrs - INVASIVE
- Not as common in primary care setting
- Examine’s entire rectum, and half of colon
- Need sedation - air put in
- Can do biopsies
- Fasting + laxative
25
Colon cancer screening method:
Colonoscopy
* Q10yrs - INVASIVE
* Rectum → entire colon
* Can get biopsies
* Fasting + laxative - drink clear liquid to empty colon
* Sedation
* GOLD STANDARD
26
Colon cancer screening method:
Stool DNA (Cologuard)
* Q3yrs for screening
* No special diet or prep
* Single stool specimen - says positive or negative
* Checks for blood in stool and colon cancer DNA
* Insurance coverage varies
27
Categories for chronic diarrhea
What lab do you also check?\*
* Watery (osmotic, secretory, functional)
* Fatty (malaborption)
* Inflammatory (blood, purulence)
thyroid!!!
28
Chronic diarrhea differentials
* IBS
* IBD (UC, Crohn's)
* Lactase deficiency
* Celiac disease
29
Chronic Diarrhea **red flags**
* New persistent changes in bowel habits/meds
* FMHx colorectal cancer, IBD, CD, age of screening younger
* Anemia
* Weight loss
* Fever
* Early satiety
30
Rome IV Criteria - for IBS
* _Recurrent abd pain_, on average, @ least 1d/wk in the last 3mos , associated w/2 or more of the following criteria
* **Defecation - pt feel better post BM**
* **Change in stool frequency**
* **Change in stool form: liquid, harder, fatty, etc**
31
Manning Criteria - for IBS
* Onset of pain linked to more frequent BMs
* Looser stools w/onset of p!
* P! relieved by passage of stool
* Abd bloating
* Incomplete evacuation of bowels sensation \> 25% of time
* Diarrhea W/MUCUS \> 25% of time
32
IBS diagnosis workup (4 steps)
1. Consistent hx: food + s/s diary
1. Fiberous foods, high fat content foods
2. Absence of alarm features (s/s)
3. Limited work-up to exclude other disease, CD + IDA
4. Trial of fiber, exercise, dietary modification
5. Stress induced
33
IBS lab work-up
* **CBC + TSH (anemia + thyroid disease differential)**
* **Diarrhea → CRP or fecal calprotectin (inflammation), celiac serology, BMP, Giardia**
* CRP - inflammation - ⇡ in IBD
* Fecal calprotectin - ⇡ in IBD
* BMP for chronic diarrhea - dehydration + Es
34
Fecal calprotectin
* Lab distinguishing IBS vs. IBD
* Non-invasive; stool collection kit
* 51-120 = borderline high → repeat in 4wks
* 120+ abnormal → IBD suspected → colonoscopy
* Less accurate in kids; high S + S
35
Celiac disease
What?
* Autoimmune disease - triggered by gluten exposure → attacking GI → inflammation + malabsorption
* Can develop at any age
* W \> M
* Both intestinal and extraintestinal manifestations
36
Celiac disease Intestinal manifestations
* Lactose intolerance
* Malabsorption syndrome
* Nutritional deficiencies
37
Celiac disease Extra intestinal manifestations
* Anemia - d/t malabsorption
* **Dermatitis herpetiformis - autoimmune rash**
* Hepatobiliary s/s
* Neuro abnormalities
* Osteoporosis
* Hematologic abnormalities
* Reproductive abnormalities
38
Gold standard for celiac testing
DUODENAL BIOPSY
Generally check serology first due to invasiveness of biopsy
39
Celiac testing - Serology types
Schematic picture
* Gliadin - not a great test w/this: poor S+S
* tTG - preferred
* EMA - more sensitive but $$
40
Celiac Antibodies
* AgA: anti-gladin antibodies
* No longer generally used
* IgA EMA: endomysial antibodies
* $$$$; mostly specific than sensitive
* **IgA tTG: tissue translutaminase - preferred**
41
(-) IgA tTG + normal IgA
Result?
NOT CD
42
(-) IgA tTG + ⇣ IgA
Result?
NOT ACCURATE
43
(+) IgA tTG + normal IgA
Result?
YES CD!!
If the IgA is normal → can trust the test result
44
False (-) CD serology when…
Deficient in IgA - SIgAD: selective immunoglobulin A deficiency
M \> F genetic immunodeficiency
45
If patient is already on gluten free diet, what will the antibody test result be?
NEGATIVE
46
HLA genotyping
Test of choice: rule out disease **if HLA is negative**
Especially If person has been on gluten free diet for a while
47
If patient has been on gluten diet for a long time, how does that affect the result of HLA test?
Doesn't effect it -\> only effects IgA
Consider reintroducing gluten diet for 2-4 weeks then test
48
Celiac disease lab workup
Screening maintenance
* CBC
* Ferritin
* Iron
* LFTs
* Vit B12
* Vit D
* Copper
* Zinc
* Calcium
Annually: These labs and tTG for adherence to GF diet
Bone density
EGD: if symptomatic; or to reassess disease within few years
49
Acute diarrhea
Criteria for acute; common etiologies
* \< 14d
* Most common: viral
* Second most common: bacterial
50
Acute diarrhea differentials
* Viral, Bacterial, Parasitic
* Non-infectious process
* Meds: Mg, metformin, abx, PPIs, NSAIDs
* Diet: lactulose, wheat, fiber
* IBS/IBD
* EtOH
* Stress
51
Inflammatory vs. non-inflammatory causing
Non-inflammatory most common
52
Acute diarrhea diagnostic testing criteria
* **Usually self-limiting**
* Fever
* Bloody stool
* Severe abd pain
* Immunosuppressed
* Recent abx tx
* Recent hospitalization
* Moderate/severe symptoms for over a week
* Age \> 70
* **Rehydration most important intervention**
53
Stool testing modalities
* Fecal Occult Blood Testing
* Leukocyte & Lactoferrin Testing
* Stool Culture
* Ova & Parasite Testing
* Clostridium Difficile Testing
54
Clues to bacterial etiology causing stool issues
* Associated with **travel, food borne illness** (raw food, everyone else you shared food with is sick)
* Often bloody diarrhea
Shiga-toxin producing e. coli (do not give abx to!!)
Salmonella, campylobacter, shigella
55
Leukocyte and lactoferrin testing
* Assess for signs of bacterial infection/inflammation
* Leukocyte - less common d/t wide variability in S + S
* Lactoferrin - protein expressed by activated neutrophils, marker for bacterial infection or IBD
* Immunoassay kits available
* More sensitive than specific
56
Stool culture
Inpatient setting indications
* Routine culture detects **salmonella, campylobacter, shigella**
* Inefficient and expensive
* Recommended w/gross blood in stool or if diarrhea lasting \> 10-14d
* Severe cases of dehydration
* s/s if Inflamm disease
* Prolonged s/s
* Immunosuppression
* Inpatient setting - use if onset \> 3d post hospital admission
* RFs: Nosocomial outbreak, HIV, neutropenia, \> 65 w/comorbidity
57
Salmonella gold standard testing
Do most pts w/this require treatment?
Stool culture
**Require no treatment - tx symptomatically**
Treat: severe disease, immunocompromised, Type A typhoid fever
58
Campylobacter
* Can look similar to salmonella and tx similar to salmonella
* Stool culture gold standard
* Fecal-oral
* From undercooked chicken
59
Shigella
* Often inflammatory
* Frequent diarrhea, tenesmus
* Fecal-oral transmission - water/food
* Stool culture gold standard
60
E. coli
* Fecal-oral
* Diarrhea, abd cramping, sometimes bloody diarrhea
* Beware of abx use!!
61
Shiga-toxin producing E. coli
* Severe stomach cramps, bloody diarrhea, vomiting, afebrile/minimal fever
* Risk for developing Hemolytic Uremic Syndrome - longer pt exposed to this bacteria
* Microangiopathic hemolytic anemia
* Thrombocytopenia
* Acute renal failure
* **Antibiotic tx should be avoided**
* Do not use until STEC ruled out
* No evidence abx beneficial tx
* **HYDRATION IS TX, SUPPORTIVE**
62
Indications for Ova & Parasite testing
* \> 7d + associated with
* Infant in daycare (giardia)
* Waterborne outbreaks (giardia)
* Travel to developing countries
* Immunocompromised (I.e. HIV)
63
Giardia infection
* Usually non-inflamm
* **(-) fever**
* Fecal-oral transmission via contaminated water
* **gold standard test: stool ova & parasite testing**
64
Traveler's diarrhea workup
* Uncomplicated cases do not require any workup and only supportive/symptomatic tx → typically resolve w/in 5d
* Do not give abx
65
C. difficile
* **Always liquid stool, NOT FORMED**
* Seen in long-term care, hospitals, community acquired
* Toxigenic vs non-toxigenic
* Asymptomatic carriers = NO TREATMENT, unless \> 3 stools in 24hrs + RFs
66
C. Difficile testing options
Lab approach to dx of C. diff (picture slide 38)
* Culture - not effective; Cannot distinguish toxin vs non-toxin
* Cell culture cytotoxicity assay
* Measures antitoxin effect - not effective
* \*Toxin Immunoassay (ELISA)
* Fast, easy to perform, inexpensive
* Lots of false (-)
* \*GDH Ag immuno assay (ELISA)
* Fast, easy to perform, inexpensive
* Cannot distinguish toxin vs non-toxin
* *Polymerase Chain reaction (PCR) (NAAT)*\*
* Fast, very sensitive, very **specific for toxigenic strains**
* $$$$
* **Doesn't measure active toxin production** → False (+) in subclinical cases, asymptomatic carriers
67
Indications for abdominal x-ray
What to check-off when looking
* Ruling in/out bowel **perforation or obstruction**
* Constipation workup - but not useful
* MAYBE RENAL STONES → U/S or CT
* Look at small vs large bowel
* Black = gas/air
* If concerned about perforation/SBO **make sure you get upright view → air rises!**
68
Abd x-ray free air interpretation
* Perforation!!!
* Caused by trauma, infection, ruptured ulcer, obstruction, foreign body
* Visible under diaphragm when upright
69
Abd x-ray obstruction interpretation
* Assess bowel gas pattern
* **Dilated loops of small bowel** (\>3cm)
* Can be seen upright or supine
* **Differential air/fluid levels**
* More than 2 air fluid levels that differ in height
* \> 2cm difference – concern for SBO
* Seen on **upright film**
