Phaechromocytoma

Question 1

Where is adrenaline produced?

Answer 1

In the chromaffin cells in the adrenal medulla of the adrenal glands

Question 2

What is a Phaeochromocytoma

Answer 2

A tumour of the chromaffin cells of the adrenal medulla which secretes excessive amount of adrenaline

Question 3

What are the different parts of the adrenal gland?

Answer 3

Medulla
Cortex - composed of:
Zona Reticularis
Zona fasciculata 
Zona Glomerulosa

Question 4

What is secreted from each section of the Adrenal Gland

Answer 4

Medulla: catcholamines - Adrenaline and Noradrenaline

Zona Reticularis: Androgens - Dehydroepiandesterone (DHEA) Oestrogen and Testosterone precursor

Zona Fasciculata: Gluccorticoids - Coritsol and cortisone

Zona Glomerulosa: Mineralocorticoids - Aldosterone

Question 5

What sort of substance is Adrenaline? What is their function?

Answer 5

Adrenaline is a catecholamine hormone and neurotransmitter

it stimulates the sympathetic nervous system and is responsible for fight or flight response

Question 6

How is adrenaline secreted in Phaeochromocytomas?

Answer 6

In bursts, giving periods of worse symptoms followed by more settles periods

Question 7

What is the genetics of Phaechromocytoma’s

Answer 7

25% are familial and associated with multiple endocrine neoplasia type 2 (MEN 2)

There is the 10% rule to describe the pattern of tumours:

Question 8

What is the 10% rule associated with Phaeochromocytomas?

Answer 8

10% bilateral
10% cancerous
10% outside the adrenal gland - most common site = organ of Zuckerkandl, adjacent to the bifurcation of the aorta

Question 9

How do you diagnose Phaeochromocytomas?

Why?

Answer 9

• 24 hour urine Metanephrines (replaced catecholamines)
• Plasma free metanephrines

serum catecholamines = unreliable as they fluctuate rapidly
24 hr urinary catecholamines gives you an idea of how much adrenaline is being secreted by tumour over 24 hours

Adrenaline has short half life but metanephrines (breakdown product) have longer half life - less prone to fluctuations = more reliable tool

Question 10

How do Phaeochromocytoma’s present?

Answer 10

• Episodic features
• pallor
• Anxiety
• Sweating
• Headache
• Hypertension
• Palpitations, tachycardia, paroxysmal atrial fibrillation

Question 11

What is the management of Phaochromocytomas?

Answer 11

• Alpha blockers - phenoxybenzamine
• Beta blockers (propanolol) once established on alpha blockers
• adrenalectomy is definitive management but symptoms need to be controlled beforehand