Adrenal Medulla

Question 0

What are the two major hormones produced by the adrenal medulla?

Answer 0

1. Epinephrine (80% of output)
2. Norepinephrine (20% of output)
3. Dopamine
4. Substance P
5. Enkephalins

Question 1

What is the adrenal medulla derived from?

Answer 1

Neuroectoderm

Question 2

What is the precursor for hormones produced in the adrenal medulla?

Answer 2

Tyrosine ( this amino acid itself is formed from another amino acid phenylalanine)

Question 3

How is the adrenal medulla innervated?

Answer 3

Preganglionic sympathetic fibres synapse directly on to chromaffin cells of the adrenal medulla

Question 4

Phaeochromocytoma

Answer 4

Tumour of adrenal medulla - chromaffin cells
20-50
10% extra adrenal
10% bilateral
10% multiple
10% malignant
10% familial - MEN2a and MEN2b , von - hippel lindau, neurofibromatosis

Question 5

Clinical features of phaeochromocytoma

Answer 5

1. HTN (sustained or paroxysmal)
2. Palpitations
3. Sweating
4. Headache
5. Tachycardia
6. Anxiety
7. Weakness
8. Tremor
9. Epigastric pain
10. Stroke
11. Angina
12. Pallor
13. Nausea
14. SOB
15. Psychological disturbance
16. DM due to anti insulin effects of catecholamine’s , adrenaline causes breakdown of glycogen in liver - hyperglycaemia

Question 6

Diagnostics of phaeochromocytoma

Answer 6

1. Increase plasma adrenaline and metanephrine’s (metadrenaline, normetadrenaline)
2. 24hour urine - increase levels of metanephrine’s and Vanilyl mandelic acid