gastric function tests and interpretation
TRANSCRIPT
Gastric function testsDr. S.Sethupathy
After overnight, 20-50- ml More than 100-120 ml – abnormal volume Causes: hypersecretion of acid Retention due to pyloric obstruction Regurgitation from duodenum Consistency- fluid No food particles Clear Red/dark red/ brown- ulcer ,bleeding Coffee ground – ca.stomach
Resting gastric juice
Bile- reflux gastritis Mucus- carcinoma stomach Free acid- 0-30 mmol/L More than 50 mmol/L – hyperacidity Total acid – 10- 40 mmol/L Organic acids- achlorhydria ,
hypochlorhydria
Gastric juice
Cancer stomach Perinicious anaemia Advanced gastritis
No acid – to investigate
Achylica gastrica
Two pieces of toast and tea or oat meal porridge
Residual content removed before meal Gastric juice collected at intervals Free acid more than 50 mmol/L –
duodenal,gastric ulcer, Zollinger Ellison syndrome, Pyloric stenosis, ch.cholecystitis
Fractional test meal
7% ethanol stimulation 100 ml Overnight fast , residual contents removed Sample every 15 mins Total and free acidity Easy to administer than oat meal Rapid and gastric emptying is better Unphysiological and free acid is more Caffeine S.Test -500mg in 200 ml - similar
to alcohol stimulation
Alcohol stimulation
Pentragastrin is a pentapeptide having the same terminal sequence of four amino acids - as gastrin
It is butyl oxy carbonyl-beta alanine-Trp-Met-Asp-Phe-CONH2
BAO, MAO, PAO are increased in Zollinger Ellison syndrome.
In atrophic gastritis, pernicious anemia and gastric carcinoma, there is achlorhydria.
Pentagastrin stimulation test
Histamine is a potent stimulus of gastric secretion
test is done by giving 0.04 mg/kg histamine s.c. Histamine fast achlorhydria is due to
pernicious anemia. Hypotension. Antihistamine to block H1 receptor effects of
histamine. Cimetidine, a H2 histamine receptor blocker is
used in peptic ulcer.
Augmented histamine test
Histamine analog – Histalog 3-beta amino ethyl pyrazole 10-50- mg No side effects
Histamine analog
Insulin stimulates HCl secretion Duodenal ulcer Hypoglycemia 15 units soluble iv
Insulin stimulation test (HOLLANDER’S)
Basal acid output (BAO) is less than 10 mmol/hour in males and less than 5.5 mmol/hour in females.
It is increased (more than 15 mmol/hour) in Zollinger Ellison syndrome.
Maximal acid output (MAO) is 7-45 mmol/hour and is after stimulation.
Peak acid output (PAO) after stimulation is 12-60 mmol/hour.
BAO MAO PAO
BAO, MAO, ratio
It is increased in gastrinoma, Zollinger Ellison syndrome.
Moderate elevation of gastrin is also seen in pernicious anemia, hyper secretion of gastrin by antral G cells and renal failure, proton pump inhibitors intake.
After secretin , serum gastrin level increases in ZES but not in other conditions.
Serum Gastrin
Condition serum gastrin (pg/ml) Normal < 500
Antral gastritis low to normal
Duodenal ulcer 300 - 500
Fundal gastritis 300 - 60,000
Z.E. syndrome 3,500 - 60,000
Serum gastrin levels
Pancreatic gastrin producing cells(Common) Gastric gastrin producing cells Peptic ulcer, diarrhea, steatorrhea Fasting serum gastrin- >1000pg/mL Secretin test- 2,5,10,15,20 mins –difference
> 200pg/mL
Zollinger syndrome
Gastric secretion is stimulated and after one hour, a dye bound to resin (Azure-A) is given orally.
Based on the surrounding pH, the resin releases the dye
It is absorbed and excreted in urine. The quantity of dye in urine indicates the
acidity of gastric juice. It rules out achlorhydria.
It is used as a screening test.
Tubeless gastric analysis
H.pylori infection is playing a role in acid peptic disease.
Urease enzyme The presence of urease- pyloric infection. Urea breath test 13 C, 14 C- urea Breath CO2 Serological tests – less reliable
Helicobacter pylori
Vitamin B12 deficiency is macrocytic anemia and c megaloblastic
Low serum vitamin B12 concentrations Pernicious anemia –intrinsic factor deficiency or to
intestinal malabsorption or dietary deficiency. The test involves - two orally administered test
doses of radioactive labelled vitamin B12 Measuring radioactivity in a urine specimen
collected for five hours. The first test dose -alone The 2nd test dose - three days later) - with intrinsic
factor.
The Schilling test
ConditionResults
1st Stage 2nd Stage
normal absorption absorptiondietary deficiency absorption absorption
intestinal disease malabsorption malabsorption
pernicious anemia malabsorption absorption
Limited but specific uses in certain conditions
Perinicious anaemia ZES Peptic ulcer Now endoscopy plays a major role Biopsy can be taken
Importance
Thank YOU