Endocrinology

Question 1

Types of thyroid cancer?

Answer 1

• Papillary
• Follicular
• Medullary associated with raised calcitonin (an antagonist to PTH)
• Anaplastic

Question 2

 Management of thyroid cancer?

Answer 2

• Hemi-thyroidectomy (± total) + Iodine-131 given to kill all remaining thyroid cells
• Follow-up (yearly) – if +ve, then administer more I-131:
  o I-123 whole body scans
  o Thyroglobulin (TG) measurements / calcitonin (if medullary)
• Remission for 7 years  fully cured and can be discharged

Question 3

Causes of hyperthyroidism?

Answer 3

High-uptake
Grave’s disease (anti-TSH antibodies)
Toxic multinodular goitre
Single toxic adenoma

Low-uptake
Postpartum thyroiditis
Sub-acute thyroiditis
Viral thyroiditis
de Quervain’s thyroiditis

 Rare causes:
* Silent thyroiditis (AI, amiodarone) Factitious thyroiditis
* TSH-induced Thyroid cancer induced
* Trophoblastic tumour (high hCG production)

Question 4

Features of grave’s disease

Answer 4

• Diffuse goitre
• Thyroid Eye Disease (due to TSH-r on eye muscles)
  o Radioiodine  Graves’ eye disease worse
• Thyroid-associated dermopathy (pretibial myxoedema)
• Thyroid acropachy
• Hx or FHx or autoimmune disease

Question 5

Best preventative measure of grave’s disease?

Answer 5

Smoking cessation

Question 6

S/S of thyroid storm (can be precipitated by radioiodine)?

Answer 6

S/S: hyperthermia, tachycardia, jaundice, altered mental status, cardiac (AF, high-output HF)

Question 7

Mx of thryoid storm?

Answer 7

IV propranolol - thionamides (PTU), hydrocortisone - iodine (~1-4 hours after ATDs)

Question 8

Graves’ disease mx:

Answer 8

• 1st (given in primary care): propranolol (not bisoprolol)
• 1st line, likely remission with ATDs: ATDs
   1st line: Carbimazole, 40mg (then reduce)
   2nd line: PTU (pregnancy, <6m attempt for conception, pancreatitis)
  o Method:
   [1] Titration (12-18m; dose on TFTs – once euthyroid, gradually reduce)
   [2] Block and replace (6-9m; fixed high dose carbimazole, incl. thyroxine)
• 1st line, unlikely remission with ATDs: Radioiodine (I-131):
  o CI: pregnancy, <16yo, thyroid eye disease
  o SE: hypothyroidism, thyroid storm
• Surgery (in the run up to surgery… needs to be euthyroid)
  o (1) thionamides (stop 10 days pre-surgery as increases vascularity); OR propranolol
  o (2) laryngoscopy (check vocal cords)

Question 9

Causes of hypothyroidism:

Answer 9

• Hashimoto’s (most common UK; associations: IDDM, pernicious anaemia, Addison’s disease)
  o Ix: anti-TPO ABs
• Reidel’s thyroiditis
• Sub-acute thyroiditis / viral thyroiditis / de Quervain’s thyroiditis (hypothyroid phase)
• Iatrogenic:
  o Post-Graves’ disease (radioactive iodine, surgery, natural history or thionamines)
  o Drugs (amiodarone, lithium)
• Iodine deficiency (most common in the developing world)
• Sub-clinical (subclinical) hypothyroidism:
  o S/S: none
  o Ix: TSH elevated, T4 normal
  o Mx (if TSH >10; otherwise watchful waiting): levothyroxine

Question 10

Mx of hypothyroidism?

Answer 10

• Start 50-100 mcg, OD [25mcg in elderly or IHD*]  check TFTs in 8-12 weeks
• Aim for a normal TSH (0.5-2.5mU/L)
• Hypothyroid women in pregnancy  increase T4 by 25-50mcg
• Interactions (give T4 at least 4 hours before / 4 hours after interacting medications):
  o Iron
  o CaCO3

Question 11

Symptoms and management of myxoedema coma?

Answer 11

 S/S: hypothermia, hyporeflexia, bradycardia, seizures
 Mx: IV thyroxine, IV hydrocortisone, IV fluids

Question 12

Ix for addison’s disease?

Answer 12

o 1st: (9am) plasma cortisol (can be done at any time if doing a full short SynACTHen test):
 >500nmol/L = unlikely Addison’s (>276nmol/L = normal)
 <500nmol/L = short SynACTHen test (still done if suspicion as could be partial insufficiency)
o 2nd: administer SynACTHen 250ug IM
o 3rd: plasma cortisol at 30 minutes (<497nmol/L = Addison’s)

Question 13

Causes of addisonian crisis?

Answer 13

autoimmune (UK), TB (worldwide)
 Sepsis or surgery causing an acute exacerbation of chronic insufficiency (Addison’s, Hypopituitarism)
 Adrenal haemorrhage (Waterhouse-Friderichson syndrome from meningococcaemia)
 Steroid withdrawal

Question 14

Mx of addisonian crisis:

Answer 14

 Initial management:
* 1st  IM hydrocortisone (100mg, STAT)
* 2nd  IV fluid bolus (0.9% saline, >90 SBP) ± glucose
 Continuing management:
* IV fluids
* IV/IM hydrocortisone (100mg/8h)  convert to PO dexamethasone after 72 hours

Question 15

How is hydrocortisone delivered in an addisonian crisis?

Answer 15

IM

Question 16

• Signs & symptoms of pituitary adenoma?

Answer 16

o Excess hormones (e.g. Cushing’s disease acromegaly, amenorrhea & galactorrhoea)
 Men (prolactinoma)  impotence, decreased libido, galactorrhoea
 Women (prolactinoma)  infertility, decreased libido, galactorrhoea, amenorrhoea, osteoporosis
o Depletion of a hormone(s) (due to compression of the normal functioning pituitary gland)  hypopituitarism
o Headaches (stretching of the dura within/around pituitary fossa)
o Bitemporal hemianopia

Question 17

First line Ix for acromegaly?

Answer 17

serum IGF-1
2nd line is OGTT
3rdl line is MRI brain with contrast

Question 18

Mx for acromegaly?

Answer 18

 1st line (surgical) - transsphenoidal transnasal hypophysectomy
 2nd line:
* Somatostatin analogue (octreotide) > dopamine agonists (bromocriptine, cabergoline)
* Pegvisomant (GH-R antagonist)

Question 19

Mx for prolactinoma?

Answer 19

Medical mx is FIRST LINE, surgical mx is SECOND LINE
 1st line (medical)  bromocriptine, cabergoline
 2nd line (surgical)  transsphenoidal transnasal hypophysectomy