Pass medicine

Question 1

Secondary hypothyroidism is caused by pituitary failure and needs imaging

Question 3

1. C-peptide levels and diabetes-specific autoantibodies are useful to distinguish between type 1 and type 2 diabetes
2. C-peptide levels are typically low in patients with T1DM

Question 4

The PTH level in primary hyperparathyroidism may be normal

Question 5

Causes of raised prolactin - the p’s
pregnancy
prolactinoma
physiological
polycystic ovarian syndrome
primary hypothyroidism
phenothiazines, metoclopramide, domperidone

Question 6

Pioglitazone - increases the risk of bladder cancer

Question 7

Sick euthyroid syndrome = low T3/T4 and normal TSH with acute illness

Question 8

Metabolic ketoacidosis with normal or low glucose: think alcohol

Question 9

Sulfonylureas - bind to an ATP-dependent K+(KATP) channel on the cell membrane of pancreatic beta cells

Question 10

Indications for starting - Levothyroxine 25mg

Answer 10

• patients with cardiac disease,
• severe hypothyroidism
• patients over 50 years
  the initial starting dose should be 25mcg od with dose slowly titrated

Other patients should be started on a dose of 50-100mcg od

Question 11

Initiating thyroxine therapy

Answer 11

• following a change in thyroxine dose thyroid function tests should be checked after 8-12 weeks
• the therapeutic goal is ‘normalisation’ of the thyroid stimulating hormone (TSH) level.
• As the majority of unaffected people have a TSH value 0.5-2.5 mU/l it is now thought preferable to aim for a TSH in this range

Question 12

Thyroxine in pregnancy

Answer 12

women with established hypothyroidism who become pregnant should have their dose increased ‘by at least 25-50 micrograms levothyroxine’* due to the increased demands of pregnancy.

Question 13

Side-effects of thyroxine therapy

Answer 13

hyperthyroidism: due to over treatment
reduced bone mineral density
worsening of angina
atrial fibrillation

Question 14

Thyroxine - interactions

Answer 14

iron, calcium carbonate
absorption of levothyroxine reduced, give at least 4 hours apart

Question 15

Thyroxine - over replacement

Answer 15

• recent TFTs show a suppressed TSH indicating over replacement. Even though she is asymptomatic the dose should be decreased to reduce the risk of osteoporosis and atrial fibrillation. The BNF recommends adjusting the dose by 25mcg in this age group.

Question 16

Hypoglycaemia - unconscious

Answer 16

IV infusion of 50mls of 20% dextrose
The hypoglycaemic attack was most likely provoked by the lack of food and the
vomiting. IV administration of dextrose is most appropriate as the child is
described as semi-conscious. The 50% dextrose should be avoided as it can cause
skin necrosis if there is extra-vasation.