LECTURE - GI Function Testing Flashcards
Dyspepsia
Indigestion
- upper abdominal pain related to eating
- affects up to 25-30% of Canadians
Symptoms:
- heartburn, regurgitation (reflux)
- excessive burping, belching
- fullness, bloating
- nausea
secretion of gastric acid
- 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)
endoscopy
visually assess tissue and collect biopsies
- via esophageal gastro duodenal scope
common infection that colonizes gastric mucosa
H. pylori
>50% of worldwide population
this causes chronic active gastritis
- usually asymptomatic; affects lining of stomach
- can cause pain = dyspepsia = peptic ulcer disease (PUD)
> duodenal (90%) or lower gastric area (75%)
this is associated with gastric cancer and MALT lymphoma
H. pylori
can lead to this if not treated ith antibiotics, etc.
urea breath test
- detects active infection
- 13C/UBT
serology for H. pylori
- detects Abs to H, pylori
- 15% false pos; only useful if negative
- cannot prove erdication
stool Ag test
detects H. pylori Ag
biopsy for H. pylori
- rapid urease test: a time of endoscopy
- send to pathology: histology
- send to microbiology: culture
serum gastrin conctn may be increased due to:
- increased production by G cells > hyperplasia,hyperfunction, adenoma - decreased acid inhibition > pernicious anemia, PPI therapy (goes too far) - decreased excretion > renal failure
backwash of acid enters esophagus
GERD
gastro esophageal reflux disease
Celiac disease
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
symptoms of Celiac disease
weight loss, diarrhea, flatulence, abdominal distension, nutritional defs
treatment of Celiac disease
- removal of dietary gluten barley rye oats wheat
serum tests for Celiac disease
done hwen daily diet contains gluten
- ATTG = IgA (anti-humn tissue transglutaminase)
- EMA = IgA (endomysal antibody)
list off malabsorption diseases
- Celiac
- CF
- inflammatory bowel disease
> Crohn’s
> ulcerative colitis - short bowel syndrome
Cystic Fibrosis
- autosomal recessive
- gene mutation…
sweat chloride test
- 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
IBD
- inflammatory bowel disease
- Crohn’s/Ulcerative Colitis
> inflammation, unknown etiology
> intermittent diarrhea, rectal bleeding - string signs = diagnostic for Crohn’s
calprotectin
- 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
short bowel syndrome
- decrease absorptive surface area (<2 m present)
- can be congenital
- or acquired ( some of bowel has been removed or resected bc of disease)
irritable bowel syndrome
- commonest cause of chronic diarrhea in otherwise healthy persons
- overlap in syndromes
- symptoms; pain plus an altered bowel habit
colorectal cancer
- 2nd leading cause of cancer death in NA
- arise from adenomatous polyps (precancerous)
- early detection = bleeding from colon
- sigmoidoscopy and colonoscopy
colorectal cancer tests
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)
xylose tolerance test
- 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
lactose tolerance test
- 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
causes of dyspepsia
- NOT STRESS OR DIET
- H. pylori
- acid: stomach secretion, NSAIDs, acid reflux
