Thyroid, pancreatic & gastric function test


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Thyroid, pancreatic & gastric function test

  1. 1. 1
  2. 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. 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. 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. 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. 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/hrMaximal 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
  7. 7. Clinical Application – Gastric functions Hyperacidity HypoacidityDuodenal ulcer GastritisGastric cell hyperplasia Gastric carcinomaCarcinoid tumours Partial gastrectomyZollinger-Ellison syndrome Pernecious anaemiaMultiple Endocrine Neoplasia – Type 1 Chronic iron deficiency anaemiaBasophilic leukemia 7
  8. 8. Classification – Thyroid Function Test Based on Thyroid Function & Clinical UtilityGroup I Primary function of Radio-iodine uptake thyroid T3 – suppression test TSH – stimulation test TRH stimulation testGroup II Measurement of blood Total T3 and T4 levels levels of thyroid Free T3 and Free T4 levels hormones Circulating TSH level Plasma tyrosine levelGroup III Metabolic effects of Basal Metabolic Rate Thyroid hormones Serum cholesterol level Serum creatine level Serum uric acid level Serum creatine kinase levelGroup IV Immunological tests for Agar gel diffusion test auto-immune disorders Complement fixation test 8
  9. 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. 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. 11. Measurement of blood levels of thyroid hormonesHormone Method Reference RangeTotal T4 ELISA 5 to 12 µg/dlTotal T3 Chemiluminescence 120 to 190 ng/dl RadioimmunoassayTSH 0.5 to 4.5 mIU/mlFree T3 Chemiluminescence 0.2 to 0.5 ng/dlFree T4 0.7 to 1.8 ng/dlPlasma Tyrosine 60 to 70 µ Mol/L 11
  12. 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. 13. Clinical Application of Thyroid Hormone MeasurementDisorder Causes Thyroid profile LevelsPrimary Congenital T3 ↓Hypothyroidism Radiation damage T4 ↓ Surgical removal TSH ↑ Viral infection Auto-immuneSecondary 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. 14. Tests based on metabolic effects of thyroid glandParameter Measurement & Clinical Application Normal LevelsBasal Metabolic Benedict Roth apparatus 5 to +20% → NormalRate (BMR) Normal: - 15 to + 20 -10 to + 10% → Euthyroid < - 20% → Hyperthyroid + 50% to +75% → HyperthyroidSerum total Zak’s method ↑↑↑ levels → hypothyroidismcholesterol Cholesterol oxidase method Normal or lower limit of normal Normal: 150 to 200 mg% → HyperthyroidismSerum 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 → hypothyroidismkinase Normal: 38 to 300 U/L 14
  15. 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. 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. 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. 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. 19. Gastric, Pancreatic and Thyroid Function Test - SummarySynthetic peptide used to stimulate gastric PentagastrinsecretionPrimary function of thyroid assessment Radioactive iodine – I131Decrease in T3, Decrease in T4 & Increase in Primary hypothyroidismTSHIncrease in T3, Increase in T4 & Decrease in HyperthyroidismTSHAnti-thyroid antibodies Hashimoto’s thyroiditisAmylase and lipase levels Pancreatitis 19
  20. 20. Examination Tips• Thyroid function test• Pentagastrin test• Pancreatic function test 20
  21. 21. POST TEST 21