Endocrinology

Question 1

Investigations for work up for Addison’s

Answer 1

• cortisol and ACTH serum levels (low cortisol and high ACTH)
• synacthen test (ACTH infusion) –> will show no increase in cortisol
• adrenal antibodies
• adrenal imaging

Question 2

Conn’s syndrome: too much/little of which hormone/s?

Answer 2

Too much aldosterone

Question 3

Addison’s disease: too much/little of which hormone/s?

Answer 3

Not enough aldosterone or cortisol

Question 4

Mx of Addisonian crisis

Answer 4

hydrocortisone 100mg IV

6 hourly fluid replacement - IV normal saline

glucose if hypoglycaemic

Question 5

Clinical diad of symptoms of Conn’s syndrome

Answer 5

Hypertension

Hypokalaemia

Question 6

what hormone result will you see in Conn’s syndrome?

Answer 6

High aldo/renin ratio

Question 7

what is phaeochromocytoma

Answer 7

a tumour of chromaffin cells located in the adrenal medulla that secretes catecholamines

Question 8

how do you investigate for phaeochromocytoma?

Answer 8

Urine catecholamines (24 hour collection)

Plasma catecholamines (marked variability)

Question 9

what are the clinical features of prolactinoma in men

Answer 9

hypogonadism –> decreased libido, infertility, impotence, gynaecomastia, rarely galactorrhoea

Question 10

Medications for prolactinoma

Answer 10

Cabergoline and bromocriptine (dopamine agonists)

Question 11

Main complications of corticosteroids

Answer 11

Hypertension

Diabetes/hyperglycaemia

Osteoporosis

Infections

Question 12

What electrolyte imbalances do you get in Addison’s disease?

Answer 12

hyponatraemia

hyperkalaemia

moderate acidosis

increased urea

hypoglycaemia

Question 13

What are the functions of PTH?

Answer 13

• increases bone resorption –> increased Ca and phosphate in the blood
• increases kidney Ca reabsorption and phosphate excretion
• increased kidney conversion of VitD2–>D3 –> increased Ca absorption from gut

Question 14

what is the most common thyroid cancer

Answer 14

papillary thyroid cancer

Question 15

which thyroid cancer shows “Orphan Annie Eyes” histologically

Answer 15

papillary thyroid carcinoma

Question 16

What is the gross pathology of the thyroid gland in Grave’s disease

Answer 16

Diffuse symmetrical enlargement. Soft and meaty

Question 17

Which cells secrete testosterone?

Answer 17

Leydig cells

Question 18

What is suggested by the presence of anti-thyroid peroxidase antibodies?

Answer 18

Hashimoto’s thyroiditis

Question 19

Which antibodies are generated in Hashimoto’s thyroiditis?

Answer 19

Anti-thyroglobulin and anti-thyroid peroxidase

Question 20

What are the 3 histological features of Hashimoto’s thyroiditis?

Answer 20

1. Germinal centres (lymphocytes, plasma cells)
2. Hurthle cells (thyroid cells show abundant, eospinophilic, granular cytoplasm)
3. Fibrosis (increased interstitial connective tissue from chronic inflammation)

Question 21

What is the gross pathology of the thyroid gland in Hashimoto’s thyroiditis?

Answer 21

Firm, tan-yellow, pale, somewhat nodular, enlarged initially then atrophic

Question 22

What are the 3 histological features of Grave’s disease?

Answer 22

1. Papillae (Follicular cells multiply → crowding → from papillae into colloid)
2. Scalloping of colloid
3. Lymphocytic infiltrate

Question 23

What effect does aldosterone have on potassium?

Answer 23

Increases K+ excretion

Question 24

When treating Addison’s disease, when do you need to vary the dose of cortisone?

Answer 24

Increase during times of stress eg when sick

Question 25

If a patient is hyperthyroid clinically and on biochemistry, what is the next best investigation?

Answer 25

Radioactive iodine uptake scan

Question 26

If a patient is hypothyroid clinically and on biochemistry, what is the next best investigation?

Answer 26

Thyroid ultrasound