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Flashcards in General Endocrine Deck (59):
1

what is the trajectory of thyroid hormone in thyroiditis?

Increased thyroid hormone and then steep decline of thyroid hormone due to inflammation of the thyroid gland

2

would you do a core biopsy of a thyroid mass?

NO. FNA is less traumatic, rapid result
Core biopsy- thyroid gland very vascular and can significantly bleed with a large needle

3

what are some benign causes of thyroid nodules?

follicular adenoma
colloid nodule

4

what are some malignant causes of thyroid nodules?

papillary carcinoma
follicular carcinoma
medullary carcinoma
anaplastic carcinoma

5

what is the most common type of thyroid cancer?

papillary carcinoma

6

what type of cancer arises from the C cells of the thyroid gland?

medullary carcinoma

7

what would you think if you aspirated a lot more colloid to cells via thyroid FNA?

benign nodule

8

when would you do a thyroid FNA for a thyroid nodule?

U/s features-if we see micro calcifications, hypoechogenicity, increased blood flow on the doppler
- FMH of thyroid cancer
-rapidly growing nodule
- hoarseness (recurrent laryngeal nerve)

9

what is the classification for thyroid FNA results?

bethesda classification

10

when would you do a total thyroidectomy?

thyroid cancer > 1cm, hyperthyroidism

11

what are some adjunctive therapies to thyroid surgical resection?

1. radioactive iodine
2. Thyroid hormone suppression therapy

12

when would you operate on a MNG thyroid gland?

if it is symptomatic (obstruction, hoarseness, dysphagia) or if its cancerous and increasing in size

13

what are some anti-thyroid medications for an autonomous toxic thyroid nodule?

carbimazole and PTU

14

describe generally the mechanism of production of thyroid hormones

T3, T4 hormone mechanism of production:

1. Thyroglobulin protein synthesised in follicular cell and secreted into the colloid
2. Iodide is transported to the colloid via pendrin transporter
3. Binds to thyroglobulin --> forms MIT/DIT/T3/T4 complex
4. Complex is endocytosed back into the follicular cell
5. Iodine is recycled and T3, T4 are formed.
6. T3, T4 diffuse out of cell and enter the bloodstream bound to protein

15

what proteins do T3 and T4 bind to in the bloodstream?

thyroglobulin binding protein

16

what does a toxic adenoma in the thryoid gland do?

secretes excess thyroid hormone autonomously

17

A 32 yr old woman presents with fatigue and vitiligo. Has dark pigmentation over her appendectomy scar. On ex, a postural drop in blood pressure is noted. She is also hyperkalemic. What do you think is going on and what ix will most likely confirm the diagnosis?

Addison disease

Short synacthan test

18

what must you be worry about if administrating iodinating contrast for a patient with underlying hyperthyroidism?

May precipitate thyroid storm

19

what do we check c peptide for?

c peptide is produced with proinsulin and cleaved off proinsulin. Measuring c peptide may indicate how much endogenous insulin is actually being produced.
Usually measured in the setting of ix hypoglycaemia

20

Describe Addison's disease

Insufficient CORT production from adrenal glands

21

what can cause Addison's disease

Autoimmune
Drugs
Infections
Tumour infiltration
Haemorrhage/infarction

22

key Ix of addison's disease

Electrolytes, urea
ACTH synacthan test

- so biochemical diagnosis, no imaging required

23

Symptoms of Addison's disease

• Fatigue
• Weight loss
• Anorexia
• Hyperpigmentation
Salt craving

24

What do you expect for Addison's disease when you order serum electrolytes?

hyponatremia
hyperkalemia
increased urea
acidosis

25

how do we medically manage Adrenal crisis?

dexamethasone/hydrocortisone + fluids

26

How do we medically manage addison's disease long term?

GC and MC

so dexa/hydrocortisone/pred + fludrocortisone (MC)

27

Opposite of SIADH?

diabetes insipidis

28

why do we get hyponatremia in SIADH?

Too much ADH produced. ADH acts on the distal tubule placing aquaporins in the membrane, allowing for water to be retained by the body. As a result of this, TBW increases and this leads to hyponatremia. The hyponatremia is further exacerbated by the kidnye kicking out Na+

29

why should you never give dextrose fluids if you suspect SIADH?

essentially you are making the problem worse, because water goes everywhere in dextrose fluids

30

what are the broad categories of causes for SIADH?

Drugs
Neoplasia
Neuro disorders
Pulmonary disorders
Other/idiopathic

31

how might we manage hyponatremia (in general)?

• Treat the underlying cause
• Fluid restriction- because usual suspects are SIADH and inappropriate fluid resuscitation
• However if GI losses apparent, normal saline

32

what causes hyperprolactinaemia other than a pituitary adenoma?

Hyperprolactinaemia is caused by dopamine antagonists such as:
Chlorpromazine
Haloperidol
Metoclopramide, and
Sulpiride.

Concentrations rise dramatically in pregnancy and are elevated in hypothyroidism and acromegaly and are raised in renal failure due to impaired clearance.

They are not elevated with LHRH.

33

SE of testosterone replacement therapy?

Prostate cancer,
BPH

• Sleepapnoea
• Acne
• Breast Cancer
• Reduced fertility
• Gynecomastia
• Polycythaemia!
• Mood fluctuations

34

if you get a low testosterone serum level, what do you do?

repeat the test. testosterone levels change with time of day, they peak in the morning and decrease at night. So measure at 8am

35

what do you think when you see a man with very small testes?

klinefelter's syndrome

36

how can you investigate hypogonadism?

test the following in the morning at 8am
-Serum testosterone
-LH and FSH levels
-Karyotype

37

what does low testosterone, low LH/FSH indicate?

secondary hypogonadism

38

what does low testosterone, high LH/FSH indicate?

primary hypogonadism

39

what are some causes of primary hypogonadism in a male?

congenital Kleinfelter syndrome
cryptorchidism
trauma
orchitis
spironolactone

40

what are some causes of secondary hypogonadism

High PRL
other tumours
Cushing's syndrome
acute infection
glucocorticoids

41

Name some options for androgen replacement therapy?

1. IM testosterone enantate
2. SC testosterone pellets
3. transdermal testosterone patch/gel
4.oral testosterone undecanoate

42

why might we commence androgen replacement therapy for male patients with hypogonadism?

prevent osteoporosis, restore muscle bulk and libido

43

causes of gynaecomastia?

-hypogonadism
-too much oestrogen- CLD
-drugs- spironolactone, digoxin
-androgen deficiency syndromes
-idiopathic
-physiological

44

causes of hirsutism?

CAH
PCOS
Cushing's
Anabolic steroid abuse
Androgen secreting tumour
Idiopathic

45

key characteristic symptoms of Conn's disease?

hypertension, hypokalemia, metabolic alkalosis

46

what is the main cancer change associated with Conn's disease?

aldosterone secreting adrenocortical adenoma

47

how might we ix Conn's disease?

Measure renin and aldosterone levels in the plasma
measure urinary aldosterone
24 hr urinary collection to measure excess K+ excretion

48

which clinically apparent lymph nodes does papillary thyroid cancer metastasise to?

cervical lymph nodes

49

what is the main point of the water deprivation test for DI?

to differentiate cranial vs nephrogenic causes of DI.

cranial- able to concentrate urine post desmopressin administration

nephrogenic- unable to concentrate urine post desmopressin administration

50

what is tertiary hyperparathyroidism?

autonomously functioning parathyroid glands secreting high amounts of PTH subsequent to prolonged secondary hyperparathyroidism

51

what are the causes of hypoparathyroidism?

• Inherited
• Sustained damage to the parathyroid glands during thyroid surgery
• Copper or iron infiltration from haemachromatosis or Wilson's disease
Pseudohypoparathyroidism

52

Which part of the adrenal does Conn' syndrome and pheochromocytoma originate from?

Conn's = adrenal cortex
Phaechromocytoma= adrenal medulla

53

ix for phaechromocytoma?

1. urinary 24 hr catecholamines
2. plasma catecholamines

54

Symptoms of phaechromocytoma?

Periodic episodes of:
-Palpitations
-HT
-perspiration

55

what is the mutation for MEN2

ret oncogene chromosome 10

56

3 parts of MEN 2a

hyperparathyroidism
Medullary thyroid carcinoma
phaechromocytoma

57

3 parts of MEN1

hyperparathyroidism
Pancreatic tumours
Pituitary tumours

58

What are some contraindications to testosterone replacement therapy?

desire to have a child
NYHF 3, 4
prostate cancer or breast cancer
hyper viscosity syndromes
untreated OSA

59

how frequently will you monitor testosterone replacement therapy?

every 3 months