updated (2019) Learning Unit 4 Endocrinology module slide deck

1. Principles of
Hormone Testing
All I really needed
to know I learned
in LU 3 Physiology :)
Iris Thiele Isip Tan MD, MSc
Professor, UP College of Medicine
Chief, UP Medical Informatics Unit
Baby steps by Kristina Alexanderson,
https://flic.kr/p/att5j5

2. Pathologic Mechanisms
of Endocrine Disease
By Herbert L. Fred, MD & Hendrik A. van Dijk,
http://commons.wikimedia.org/wiki/File%3AMyxedema_face.png
By Jonathan Trobe, M.D. http://commons.wikimedia.org/wiki/File
%3AProptosis_and_lid_retraction_from_Graves'_Disease.jpg
Hormone
Excess
Deficiency
Resistance

3. Explain the principle
illustrated
Answer question using
learning points given
Remember endocrine
physiology
Don’t forget by juliaf, http://www.freeimages.com/photo/729159
Question mark by 7rains,
http://www.freeimages.com/photo/1323680
Black and white by plusverde,
http://www.freeimages.com/photo/516694

4. CASE 1. A 38-year-old woman presents at your office
for evaluation of hot flashes. She has been having 6-8
hot flashes per day for the past year and often wakes
up at night drenched in sweat. She feels fatigued and
irritable most of the time. She has not had menses for
12 months. Her FSH is 85 mIU/mL.
FSH normal values
Before puberty: 0 to 4.0 mIU/ml
During puberty: 0.3 to 10.0 mIU/ml.
Women who are still menstruating: 4.7 to 21.5 mIU/ml
After menopause: 25.8 to 134.8 mIU/ml.
Which of the following is true?
A. She likely has premature ovarian failure.
B. She is menopausal.

6. The normal range for most hormone is relatively
broad, varying by a factor of two to tenfold.
The correct normative database is an essential
part of interpreting hormone tests.
FSH normal values
Before puberty: 0 to 4.0 mIU/ml
During puberty: 0.3 to 10.0 mIU/ml.
Women who are still menstruating: 4.7 to 21.5 mIU/ml
After menopause: 25.8 to 134.8 mIU/ml.

7. CASE 2
An 28 y.o. woman gains 10 kg after receiving
treatment for depression. Her psychiatrist is
alarmed and does an 8 am cortisol
Serum cortisol 26 (NV 4.3-22.4 ug/dL)
Which of the following is true?
A. She likely has Cushing’s syndrome.
B. A suppression test should be done to prove
cortisol excess.

8. http://www.endocrinesurgeon.co.uk/index.php/how-is-cushings-syndrome-diagnosed

10. Diagnostic tests take advantage of
negative feedback loops.
It is not uncommon for baseline hormone levels
associated with pathologic endocrine conditions to
overlap with the normal hormone range.
DYNAMIC testing is useful.

11. CASE 3.
A 55/M complains of loss of libido, erectile
dysfunction, depression and lethargy. You think
he has hypogonadism and order a serum
testosterone assay. Which of the following is
true? Blood draw for the testosterone assay
should be done
A. between 8-10 am
B. between 8-10 pm

13. Recognition of hormonal rhythms is
important for endocrine testing.
Laboratory tests only represent a snapshot
of endocrine function at the time that the
blood sample was obtained.

14. CASE 4.
President Eisenhower had a heart attack in 1955
and died 14 years later. The autopsy unexpectedly
revealed a 1.5 cm pheochromocytoma in the left
adrenal gland. Below is a record of his blood
pressure readings. You would have ordered a
a. 24-h urine metanephrine assay
b. plasma metanephrine test

16. There are advantages and limitations
in doing urine and blood
measurements of hormones.

17. CASE 5.
A 29-year-old pregnant woman in her 13th week of
pregnancy was admitted for frequent vomiting of more
than 10 times daily since her 11th week of pregnancy.
She complains of nausea, dizziness, lethargy, loss of
appetite and headache. She denies fever, palpitations,
agitation, diarrhea and heat intolerance. She had no eye
signs of Graves’ ophthalmopathy and no palpable goiter.
Heart rate was 89 bpm and she had no tremors. FT4 35
(NV 11-24 pmol/L) TSH 0.1 (NV 0.3-3.8 mIU/mL).
Which of the following is true?
a. She should be given antithyroid therapy.
b. She can be managed conservatively without
antithyroid therapy.

18. Juan C. Galofre, Terry F. Davies. Autoimmune Thyroid Disease in Pregnancy: A Review. Journal of women’s
health 2009;18(11):1847-1856 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2828163/pdf/jwh.2008.1234.pdf

19. Test results must be interpreted in
conjunction with a clear understanding of
the pathophysiology and natural history
of suspected disorders.
“ Fowler MJ, Pannone AF, Blevins Jr. South Med J 2002;95(5)

20. CASE 6.
A 68-year-old woman is incidentally found to have a left
adrenal mass, 2.8 cm in diameter, on abdominal
computed tomography that was ordered to evaluate
right lower abdominal discomfort (which has since
resolved). Her medical history is notable only for
hypertension that has been well controlled with
hydrochlorothiazide, at a dose of 25 mg daily. She
reports no sweating, palpitations, headache, weight
gain, or proximal muscle weakness. Her physical
examination is unremarkable. You would:
a.Order for a 24-h urine metanephrine assay and 8 am cortisol.
b.Order for 24-h urine metanephrine, plasma aldosterone and
renin

23. Biochemical confirmation of endocrine
disease precedes imaging.

26. CASE 7.
A 32-year-old pregnant woman complains of
palpitations on her 18th week of gestation. She
has a palpable goiter. Which of the following is
true?
a.A free T4 and TSH should be done to assess
thyroid function.
b.T4, T3 and TSH should be done to assess
thyroid function.

27. Juan C. Galofre, Terry F. Davies. Autoimmune Thyroid Disease in Pregnancy: A Review. Journal of women’s
health 2009;18(11):1847-1856 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2828163/pdf/jwh.2008.1234.pdf

28. Remember that many hormones
circulate in association
with serum-binding proteins.

30. CASE 8.
A dialysis patient is referred for high iPTH (intact
parathyroid hormone) results. The referring
physician did not do any other workup.
You would -
a. order a paired iPTH and serum calcium test.
b. order a serum 25(OH)D level and serum
calcium.

31. https://kleczekbiology.wikispaces.com

33. Simultaneous measurement of trophic and
target hormones may help to determine the
location of the abnormality.“ Klee G. Clinical Chemistry 1999;45(8B):1323-1330

34. Klee G. Clinical Chemistry 1999;45(8B):1323-1330

36. CASE 9.
You are working up a 40-year-old female for
Cushing’s syndrome.
Urine free cortisol 450 (NV 55-248 nmol/day)
repeat urine free cortisol 200
You will -
a. Repeat urine free cortisol a third time.
b. Request for a midnight salivary cortisol.

37. Harrison’s Principles of Internal Medicine

38. http://labtestsonline.org/understanding/features/reliability/start/1

39. http://www.med.uottawa.ca/sim/data/Images/Sen_spec.gif

41. Keep in mind the four indicators of
reliability of laboratory testing:
accuracy, precision, sensitivity, specificity

42. CASE 10.
A 58-year-old man in the ICU is referred for low T3
and TSH but low normal T4. He was admitted for
a stroke and is on dopamine and steroids. You
would -
a. give thyroid hormone replacement.
b. do nothing.

44. Always ask what drugs can interfere
with the results of hormone tests.
Test abnormalities do not always reflect
endocrine dysfunction.
Some tests may be normal in the
setting of real endocrine
dysfunction.

45. Questions to Ask
What are the key clinical issues?
What sequence of tests would be optimal?
What drugs should be discontinued before
testing?
What stabilizing, provocative or inhibitory
procedures should the patient undergo
before the specimen collection?
Klee G. Clinical Chemistry 1999;45(8B):1323-1330

46. Efficacy of endocrine tests
depends on
Choice of tests
Preparation of the patients
Integrity of the specimens
Quality of the measurements
Validity of reference data
Klee G. Clinical Chemistry 1999;45(8B):1323-1330

47. Principles of
Hormone Testing
All I really needed
to know I learned
in LU 3 Physiology :)
Iris Thiele Isip Tan MD, MSc
Professor, UP College of Medicine
Chief, UP Medical Informatics Unit
Baby steps by Kristina Alexanderson,
https://flic.kr/p/att5j5