6: Adrenal gland disorders 2 - congenital adrenal hyperplasia, phaeochromocytomas

Question 1

What causes congenital adrenal hyperplasia?

Answer 1

Enzyme defects in steroid pathway

Question 2

What is the commonest type of congenital adrenal hyperplasia?

Answer 2

21alpha hydroxylase deficiency

Question 3

Is 21alpha hydroxylase deficiency autosomal dominant or recessive?

Answer 3

autosomal recessive

Question 4

Why is progesterone measured to diagnose 21alpha hydroxylase deficiency?

Answer 4

Metabolite at end of chain because enzyme is defective

Question 5

Which part of the adrenal gland produces catecholamines?

Answer 5

Adrenal medulla

Question 6

What are some catecholamines produced by the adrenal medulla?

Answer 6

(Nor)adrenaline

Dopamine

Question 7

Which adrenal adenoma secretes catecholamines?

Answer 7

Phaeochromocytoma

Question 8

Which genetic syndromes are associated with phaeochromocytoma?

Answer 8

MEN2a

MEN2b

Von Hippel-Lindau syndrome

Neurofibromatosis

Question 9

What percentage of phaeochromocytomas are malignant, bilateral and extra-adrenal?

Answer 9

10%

10% tumour

Question 10

What is a phaeochromocytoma called if it is found outwith the adrenal gland, e.g in the sympathetic chain?

Answer 10

Paraganglioma

Question 11

What is the classical triad of symptoms in phaeochromocytoma patients?

Answer 11

Hypertension

Headache

Sweating

Question 12

How are patients with suspected phaeochromocytomas investigated?

Answer 12

Blood catecholamines

Then 3 x 24h urine catecholamines

Question 13

Which scans can be used to investigate suspected phaeochromocytoma?

Answer 13

CT/MRI abdomen

MIBG scan (radioisotope scan)

Question 14

Patients with phaeochromocytomas may also be (hyper/hypo)glycaemic.

Answer 14

hyperglycaemic

Question 15

How are phaeochromocytomas treated?

Answer 15

α​ blocker

Then β​ blocker

Then surgical excision

Question 16

Why must patients be put on alpha blockers before beta blockers and surgery?

Answer 16

Hypertensive crisis > Cardiac arrest

Question 17

As phaeochromocytomas are associated with genetic syndromes, what else may be involved in their treatment?

Answer 17

Genetic counselling