Upper GI Flashcards

Question

Methods of detecting the presence of H. pylori

Answer 1

``` Gastric mucosal biopsy (from antrum and greater curvature of the corpus) through EGD (esophagogastroduodenoscopy) Rapid urease test Stool antigen test Carbon 13 urea breath test Serology ```

Answer 2

Patients with active gastric or duodenal ulcers Patients with a documented history of peptic ulcers Patients with early gastric cancer (following resection) Patients with low-grade MALT (mucosa associated lymphoid tissue) lymphoma Current guidelines recommend treatment for H. pylori whenever it is detected – so only test if you plan to treat if positive

Answer 3

Upper EGD + biopsy is considered gold standard and reference method of diagnosis, but it is invasive.

Answer 4

Variable number of H. pylori organisms adhering to the gastric epithelium, both coating the gastric wall and lining the gastric glands

Answer 5

A small piece of gastric mucosa (obtained from gastroscopy) is inserted into testing gel containing urea and an indicator such as phenol red The urease produced by H. pylori hydrolyzes urea to ammonia, which raises the pH of the medium, and changes the color of the specimen from yellow (NEGATIVE) to red (POSITIVE) Sensitivity of 96% and specificity of 90%

Answer 6

H. pylori does not survive in the stool, but H. pylori antigens are present. ELISA using a polyclonal anti-H. pylori capture antibody detects the presence of H. pylori antigen in a fresh stool specimen Positive: presence of detectable antigen in the stool Negative: no detectable antigen in the stool Used in initial stages of infection but can also detect eradication after treatment.

Answer 7

Carbon 13 urea breath test (UBT) is based on the capability of H. pylori to metabolize urea to CO₂ because of the organism’s capability to produce urease It is expensive! False-negative results: 1. infection with coccoid forms of H pylori that do not produce as much urease 2. related to the intake of antibiotics, bismuth, H₂ blockers, or proton pump inhibitors

Answer 8

Easy to perform, non-invasive, and requires no preparation or abstinence from antacids Lab-based ELISA testing to detect immunoglobulin G (IgG) antibodies against H. pylori Lab-based ELISA testing to detect immunoglobulin G (IgG) antibodies against H. pylori Helpful for detecting a newly infected patient, but not used for follow-up because difficult to differentiate active and past infection

Answer 9

Autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward Symptoms: Abdominal discomfort, chronic constipation and diarrhea, failure to thrive (in children), anemia and fatigue

Answer 10

Celiac disease is caused by a reaction to gliadin, a gluten breakdown product found in wheat, barley, rye Upon exposure to gliadin, the enzyme tissue transglutaminase modifies the gliadin and the immune system cross-reacts with the small-bowel tissue, causing an inflammatory reaction This inflammatory reaction leads to a shortening of villi lining the small intestine (villous atrophy) which interferes with absorption Autoimmune response involves plasma cells that produce IgA and IgG

Answer 11

1. Those with GI symptoms including chronic or recurrent diarrhea, malabsorption, weight loss, and abdominal distension or bloating (including pts with symptoms suggestive for IBS or lactose intolerance) ``` 2. Individuals without other explanations for signs and symptoms of disorders of the following types: Nutritional deficiencies Elevated liver enzymes Reproductive abnormalities Nervous system abnormalities Persistent aphthous stomatitis ``` 3. Pts with type I diabetes and first-degree relatives of individuals with celiac disease if they have signs, symptoms, or lab evidence of possible celiac disease 4. Testing for celiac disease may be considered in asymptomatic first-degree relatives of patients with confirmed diagnosis of celiac disease, particularly children, and in those with Down syndrome

Answer 12

1. Patients should be tested prior to being placed on a gluten-free diet 2. Antibody testing, especially immunoglobulin A anti-tissue transglutaminase antibody (IgA tTG), is the best first test, although biopsies are needed for confirmation. In children younger than 2 years, the IgA tTG test should be combined with testing for IgG-deamidated gliadin peptides (DGP) 3. Patients diagnosed with celiac disease should be examined for deficiencies, including low bone density 4. Patients already on a gluten-free diet without prior testing need to be evaluated to assess the likelihood that celiac disease is present Genetic testing and a gluten challenge are most helpful

Answer 13

single preferred test for detection of celiac disease in individuals over the age of two years. Want to check in combination with total IgA to make sure that they do not just have IgA deficiency.

Answer 14

1. Those with certain conditions frequently associated with celiac disease: dermatitis herpetiformis, Down syndrome, selective IgA deficiency, and other conditions with autoimmune features (type 1 diabetes mellitus, thyroid disease, autoimmune liver disease) 2. Those with family history of celiac disease 3. Patients with suggestive clinical features, including: severe diarrhea, weight loss, or persistent anemia

Answer 15

1. patients with a positive serology | 2. patients with a high probability of celiac disease, regardless of the serology

Answer 16

duodenal mucosa may appear atrophic with loss of folds, contain visible fissures, have a nodular appearance or the folds may be scalloped

Answer 17

characterized only by increased intraepithelial lymphocytes (IEL)

Answer 18

flat mucosa with total mucosal atrophy, complete loss of villi, enhanced epithelial apoptosis, and crypt hyperplasia

Answer 19

Timing: evaluate 4-6 weeks following the initiation of a gluten-free diet Tests performed: 1. complete blood count 2. folate, B12, iron studies 3. liver chemistries (ALT, AST, ALP, bilirubin) 4. serologic testing Serologic testing for monitoring treatment response: IgA tTG or IgA (or IgG) DGP For any assay that is used, a pretreatment antibody level should be determined at time of diagnosis

Answer 20

Exclusion of gluten from the diet results in a gradual decline in serum IgA tTG and IgA DGP levels (half-life of 6-8 weeks). Normal baseline value is typically reached within 3-12 months depending upon pre-treatment concentrations. Normal IgA tTG levels do not reliably indicate recovery from villous atrophy Conversely, if the levels do not fall as anticipated, the patient is usually continuing to ingest gluten either intentionally or inadvertently

Upper GI Flashcards

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