2. Case-based large group learning
Total number of slides in presentation: 22
3 case scenarios – each presenter will get 4
min
Last 10 min is for application and summary
Total duration of lecture: 40 to 45 min
Post-test at the end to conclude the chapter:
Duration 10 min
2
3. At the end of the lecture class the learner
must be able to:
List the tests done to assess gastric,
pancreatic and thyroid function
Categorise the function tests and their
importance
Apply them in clinical situations
3
4. Assessment of Gastric functions
Fractional Test Meal (FTM)
- requires aspiration of gastric contents
- aspiration: ‘Ryle’s tube’
Pentagastrin Stimulation Test
- synthetic ‘peptide’
- having biological active sequence of gastrin
Augmented Histamine test
- Most potent stimulus of gastric secretion
Serum Gastrin level
4
5. Pentagastrin Stimulation Test
Fasting gastric juice is aspirated by Ryle’s tube
→ ‘Residual juice’
Gastric juice collected for next one hour is
collected → ‘Basal secretion’
Gastric secretion is stimulated by giving
‘pentagastrin’
Dose: 6mg/Kg body weight
Gastric secretion is collected every 15 min for
next one hour
5
6. Pentagastrin Stimulation Test
Normal Response by assessment of free and
total acidity:
Trait Men Women
Basal Acid Output 0 to 10 mmol/hr 0 to 5.5 mmol/hr
Maximal Acid Output 7 to 45 mmol/hr 5 to 30 mmol/hr
Peak Acid Output 12 to 60 mmol/hr 8 to 40 mmol/hr
6
8. Classification – Thyroid Function Test
Based on Thyroid Function & Clinical Utility
Group I Primary function of Radio-iodine uptake
thyroid T3 – suppression test
TSH – stimulation test
TRH stimulation test
Group II Measurement of blood Total T3 and T4 levels
levels of thyroid Free T3 and Free T4 levels
hormones Circulating TSH level
Plasma tyrosine level
Group III Metabolic effects of Basal Metabolic Rate
Thyroid hormones Serum cholesterol level
Serum creatine level
Serum uric acid level
Serum creatine kinase level
Group IV Immunological tests for Agar gel diffusion test
auto-immune disorders Complement fixation test
8
9. Tests based on primary function of thyroid
Radioactive ‘Uptake’ studies
I131 → ‘tracer’ used for thyroid studies
Normal: 20 to 40%
TSH – stimulation test
Basal levels of thyroid hormones is measured
3 injections of TSH each of 5 USP units is given 8
hourly
Failure to produce thyroid hormones → Primary
hypothyroidism
Stimulation of gland by production of thyroid
hormones → secondary hypothyroidism
9
10. A 50 year school teacher came with the
complaints of coarse speech, dry skin, puffy face,
non-pitting pedal edema, easy fatigability and
constipation. Personal history suggested she had
noticed gaining weight despite decreased appetite
over the past few months. O/E patient had a
palpable swelling in front of the neck with brittle
nails.
What is your probable diagnosis?
Suggest the biochemical investigations to confirm
your diagnosis.
10
11. Measurement of blood levels
of thyroid hormones
Hormone Method Reference Range
Total T4 ELISA 5 to 12 µg/dl
Total T3 Chemiluminescence 120 to 190 ng/dl
Radioimmunoassay
TSH 0.5 to 4.5 mIU/ml
Free T3 Chemiluminescence 0.2 to 0.5 ng/dl
Free T4 0.7 to 1.8 ng/dl
Plasma Tyrosine 60 to 70 µ Mol/L
11
12. A 49 year old female came to the medical OPD
with complaints of intolerance to heat, loss of
weight in spite of good appetite and excessive
sweating. She also complained of excessive hair
loss. O/E patient has protruding eyes and
tremors of hands.
What is your probable diagnosis?
Suggest the biochemical investigations to confirm
your diagnosis.
12
13. Clinical Application of
Thyroid Hormone Measurement
Disorder Causes Thyroid profile Levels
Primary Congenital T3 ↓
Hypothyroidism Radiation damage T4 ↓
Surgical removal TSH ↑
Viral infection
Auto-immune
Secondary Damage to the pituitary T3 ↓
Hypothyroidism gland T4 ↓
TSH ↓
Hyperthyroidism Graves disease T3 ↑
Toxic adenoma T4 ↑
Multi-nodular goitre TSH ↓
Thyroid hormone
overdose
13
14. Tests based on metabolic effects
of thyroid gland
Parameter Measurement & Clinical Application
Normal Levels
Basal Metabolic Benedict Roth apparatus 5 to +20% → Normal
Rate (BMR) Normal: - 15 to + 20 -10 to + 10% → Euthyroid
< - 20% → Hyperthyroid
+ 50% to +75% → Hyperthyroid
Serum total Zak’s method ↑↑↑ levels → hypothyroidism
cholesterol Cholesterol oxidase method Normal or lower limit of normal
Normal: 150 to 200 mg% → Hyperthyroidism
Serum creatine HPLC > 1.6 mg% → hyperthyroidism
Normal: 0.6 to 1 mg%
Serum uric acid Uricase method ↑ levels → myxoedema
Normal: 3 to 7 mg%
Serum Creatine Enzymatic ↑ levels → hypothyroidism
kinase Normal: 38 to 300 U/L
14
15. Immunological tests for thyroid functions
Anti-thyroid antibodies
• anti-TG antibodies → attack thyroglobulin
• anti-thyroperoxidase, or anti-TPO → attack
thyroperoxidase
• TSH receptor antibodies
Antithyroid antibodies are present in ‘Hashimoto’s
disease’
Antithyroid antibodies are detected in blood by:
- hemeagglutination
- RIA
15
16. A 50 year old man who was a chronic alcoholic
was admitted to the casualty with the complaints
of severe epigastric pain & vomiting. Symptoms
started following consumption of a large meal
after alcohol intake. O/E he had mild fever with
tenderness in the upper abdominal region.
What is your probable diagnosis?
Suggest the biochemical investigations to confirm
your diagnosis.
16
17. Pancreatic Function Tests
Exocrine functions:
Secretin test
Dimethadione test (DMO test)
Triolein breath test
Pancreatic insufficiency
Para amino benzoic acid (PABA) test
Faecal fat test
Enzymes: Amylase and lipase
Endocrine function
Oral GTT
17
18. Pancreatic Enzymes
• Amylase
– only digestive enzyme secreted by the pancreas in
an active form
– functions optimally at a pH of 7
– hydrolyzes starch and glycogen to glucose, maltose,
maltotriose, and dextrins
– Reference Range: 50 to 120 U/L
• Lipase
– function optimally at a pH of 7 to 9
– emulsify & hydrolyze fat in the presence of bile salts
– Reference Range: 50 to 175 U/L
19. Gastric, Pancreatic and
Thyroid Function Test - Summary
Synthetic peptide used to stimulate gastric Pentagastrin
secretion
Primary function of thyroid assessment Radioactive iodine – I131
Decrease in T3, Decrease in T4 & Increase in Primary hypothyroidism
TSH
Increase in T3, Increase in T4 & Decrease in Hyperthyroidism
TSH
Anti-thyroid antibodies Hashimoto’s thyroiditis
Amylase and lipase levels Pancreatitis
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