LECTURE - GI Function Testing

Question 1

Dyspepsia

Answer 1

Indigestion

• upper abdominal pain related to eating
• affects up to 25-30% of Canadians

Symptoms:

• heartburn, regurgitation (reflux)
• excessive burping, belching
• fullness, bloating
• nausea

Question 2

secretion of gastric acid

Answer 2

• cephalic: stimulatory via vagus nerve and Ach
• gastric: stimulatory via gastrin and histamine
• intestinal: stimulatory via gastrin, inhibitory via enterogastrones (somatostatins, VIP = vasoactive intestinal peptide)

Question 3

endoscopy

Answer 3

visually assess tissue and collect biopsies

- via esophageal gastro duodenal scope

Question 4

common infection that colonizes gastric mucosa

Answer 4

H. pylori

>50% of worldwide population

Question 5

this causes chronic active gastritis

Answer 5

• usually asymptomatic; affects lining of stomach
• can cause pain = dyspepsia = peptic ulcer disease (PUD)
  > duodenal (90%) or lower gastric area (75%)

Question 6

this is associated with gastric cancer and MALT lymphoma

Answer 6

H. pylori

can lead to this if not treated ith antibiotics, etc.

Question 7

urea breath test

Answer 7

• detects active infection

- 13C/UBT

Question 8

serology for H. pylori

Answer 8

• detects Abs to H, pylori
• 15% false pos; only useful if negative
• cannot prove erdication

Question 9

stool Ag test

Answer 9

detects H. pylori Ag

Question 10

biopsy for H. pylori

Answer 10

• rapid urease test: a time of endoscopy
• send to pathology: histology
• send to microbiology: culture

Question 11

serum gastrin conctn may be increased due to:

Answer 11

- increased production by G cells
 > hyperplasia,hyperfunction, adenoma
- decreased acid inhibition
 > pernicious anemia, PPI therapy (goes too far)
- decreased excretion
 > renal failure

Question 12

backwash of acid enters esophagus

Answer 12

GERD

gastro esophageal reflux disease

Question 13

Celiac disease

Answer 13

significant malabsorption due to loss of microvilli
- autoimmune disease of bowel triggered by immune response to
gluten protein that cross-reacts with small bowel tissue
=> inflammation => flattening of villi => malabsorption

Question 14

symptoms of Celiac disease

Answer 14

weight loss, diarrhea, flatulence, abdominal distension, nutritional defs

Question 15

treatment of Celiac disease

Answer 15

- removal of dietary gluten 
barley
rye
oats
wheat

Question 16

serum tests for Celiac disease

Answer 16

done hwen daily diet contains gluten

• ATTG = IgA (anti-humn tissue transglutaminase)
• EMA = IgA (endomysal antibody)

Question 17

list off malabsorption diseases

Answer 17

• Celiac
• CF
• inflammatory bowel disease
  > Crohn’s
  > ulcerative colitis
• short bowel syndrome

Question 18

Cystic Fibrosis

Answer 18

• autosomal recessive

- gene mutation…

Question 19

sweat chloride test

Answer 19

• elevate [Cl-] in sweat and tears in cystic fibrosis
  > elevated dramatically in people with CF
  > done with pad; electric current to draw Cl- to pad

Question 20

IBD

Answer 20

• inflammatory bowel disease
• Crohn’s/Ulcerative Colitis
  > inflammation, unknown etiology
  > intermittent diarrhea, rectal bleeding
• string signs = diagnostic for Crohn’s

Question 21

calprotectin

Answer 21

• compromises 60% of cytosolic proteins in neuts
• neust accumulate at sites of GI inflammation; shed into stool where mucosa architecture is disrupted
• [calprotectin] directly correlates with extent of inflammation
  > evenly distributes in stool
  > distinguishes IBD from Irritable Bowel Syndrome
  > distinguishes active from inactive IBD

Question 22

short bowel syndrome

Answer 22

• decrease absorptive surface area (<2 m present)
• can be congenital
• or acquired ( some of bowel has been removed or resected bc of disease)

Question 23

irritable bowel syndrome

Answer 23

• commonest cause of chronic diarrhea in otherwise healthy persons
• overlap in syndromes
• symptoms; pain plus an altered bowel habit

Question 24

colorectal cancer

Answer 24

• 2nd leading cause of cancer death in NA
• arise from adenomatous polyps (precancerous)
• early detection = bleeding from colon
• sigmoidoscopy and colonoscopy

Question 25

colorectal cancer tests

Answer 25

fecal occult blood test (FOBT) fecal Hb > 2 mg/g stool - Guaiac FOBT: detect heme peroxidase activity - immunological FOBT; detect globin of human Hb (iFOBT = immunochemical FOBT); FIT test (fecal immunochemical test)

Question 26

xylose tolerance test

Answer 26

- sugar absorption test; rarely done; for maldigestion and/or malabsorption > give 25 g xylose orally to fasting adult > collect blood at fasting and 2h - xylose fasting should be '0' > 2 h will be 0 if malabsorbed

Question 27

lactose tolerance test

Answer 27

- lactase deficiency test; common; test for maldigestion/malabsorption - give 50g lactose orally to fasting adult - collect blood at fasting, 30, 60, 120 mins post-dose [ glucose] = a rise > 1.7 mmol/L = lactose intolerance - a rise <1.1 mmol/L = lactose intolerant; lactase deficient - a rise 1.1-1.7 mmol/L = inconclusive

Question 28

causes of dyspepsia

Answer 28

- NOT STRESS OR DIET - H. pylori - acid: stomach secretion, NSAIDs, acid reflux