Endocrinology

Question 1

What are the various possible effects Amiodarone can have on thyroid function?

Answer 1

Amiodarone causes thyroid disturbance in 1 in 6 patients on it - can cause both hypo and hyper by increasing iodine levels

Amiodarone-induced hypothyroidism

Amiodarone-induced hyperthyroidism type I (direct result of excess iodine)-> goitre present -> treatment is Carbimazole or Potassium Perchlorate

Amiodarone-induced hyperthyroidism type 2 (a destructive thyroiditis) - NO goitre -> Tx is with steroids

Question 2

Which single antibody test is most useful in primary care to assess for Grave’s disease?

Answer 2

TRAbs - thyroid receptor antibodies
They are ~ 98% sensitive and specific to Grave’s

(whereas TPO is only present in ~ 70% of Graves cases)

Question 3

What is the typical presentation of postpartum thyroiditis and how is it usually managed?

Answer 3

Can present with biphasic picture ie initially hyper and then hypothyroid. Occurs in ~ 10% of women after birth.

Normally just treat symptomatically with a beta blocker for palpitation symptoms etc.

Question 4

What are the possible presenting symptoms of hyperprolactinaemia?

Answer 4

Presents with a hypogonadotrophic hypogonadism picture.

• Low libido
• Amenorrhoea
• Erectile dysfunction and impaired spermatogenesis
• Low energy
• Reduced muscle mass
• Anaemia
• Gynaecomastia (rarely)

Question 5

What is the most common cause of Addison’s disease (primary adrenal insufficiency) in the Western world?

Answer 5

~ 90% of Addison’s in adults in the western world is autoimmune
(40% of autoimmune Addison’s have addison’s in isolation, but ~ 60% have it as part of a poly-organ autoimmune syndrome e.g associated with vitiligo, Type I DM, autoimmune thyroiditis or pernicious anaemia)

Infections like TB and HIV can cause Addison’s - TB is an important cause in countries where it is endemic

In children, the main cause of primary adrenal insufficiency is congenital adrenal hyperplasia.

Question 6

What are Autoimmune Polyendocrine Disorders Type I and II?

Answer 6

They are syndromes linked to autoimmune Addison’s disease.

Autoimmune Polyendocrine Disorder Type I (less common) - autosomal recessive, normally presents in childhood = trial of Addison’s + hyperparathyroidism + chronic candidiasis

Autoimmune Polyendocrine Disorder Type II = more common - more complex heritabilitiy, linked to HLA = the combination of Addison’s with another major autoimmune condition, normally autoimmune thyroiditis or Type I DM.

Question 7

What would be the expected electrolyte disturbance in a patient presenting with Addison’s disease

Answer 7

HYPERkalaemia & HYPOnatraemia

(Aldosterone is responsible for excreting potassium and reabsorbing water and sodium) and so when they present in adrenal crisis they are dehydrated, with low sodium and high potassium