Phaeochromocytoma

Question 1

What type of tumour is a phaeochromocytoma?

Answer 1

A catecholamine-secreting tumour derived from chromaffin cells of the adrenal medulla

Question 2

What percentage of phaeochromocytomas are extra-adrenal, and what are they called?

Answer 2

10% (up to 30%) are extra-adrenal and are called paragangliomas

Question 3

Where are paragangliomas typically found?

Answer 3

In the sympathetic chain

= commonly in the
1. head
2. neck
3. thorax
4. pelvis
5. bladder

Question 4

What is the classical triad of symptoms in phaeochromocytoma?

Answer 4

1. Hypertension (episodic)
2. Headache
3. Sweating

Question 5

What triggers phaeochromocytoma episodes?

Answer 5

Stress, exercise, posture changes, tumour palpation

Question 6

How does a bladder paraganglioma present?

Answer 6

Episodes are triggered by micturition (urination)

Question 7

What are the main cardiovascular signs of phaeochromocytoma?

Answer 7

1. Hypertension (paroxysmal or persistent)
2. Postural hypotension
3. Tachycardia or paradoxical bradycardia

Question 8

What is the first-line biochemical test for phaeochromocytoma?

Answer 8

Plasma free metanephrines

Question 9

Why are metanephrines tested instead of catecholamines?

Answer 9

Metanephrines are the breakdown products of catecholamines, and their levels are more stable and reliable

Question 10

What is the first-line preoperative management for phaeochromocytoma?

Answer 10

Full α-blockade (e.g. phenoxybenzamine, doxazosin)

Question 11

When is β-blockade given?

Answer 11

Only after full α-blockade, and only if needed for tachycardia or palpitations

Question 12

Why should patients have a high-salt diet before surgery?

Answer 12

To prevent postural hypotension caused by α-blockade

Question 13

What is the definitive treatment for phaeochromocytoma?

Answer 13

Laparoscopic surgical excision

Question 14

What are the possible complications of phaeochromocytoma?

Answer 14

1. Cardiac failure
2. Myocardial infarction
3. Arrhythmias
4. Stroke (CVA)

Question 15

What type of tumour is a phaeochromocytoma?

Answer 15

A rare catecholamine-secreting tumour

Question 16

Which genetic conditions are associated with phaeochromocytoma?

Answer 16

MEN type II
Neurofibromatosis
Von Hippel-Lindau syndrome

Question 17

Where is the most common extra-adrenal site for phaeochromocytoma?

Answer 17

The organ of Zuckerkandl, near the aortic bifurcation

Question 18

What is the first-line test for diagnosing phaeochromocytoma?

Answer 18

Plasma free metanephrines

Question 19

Why has 24-hour urinary catecholamine testing been replaced?

Answer 19

Because urinary metanephrines have a higher sensitivity (97% vs. 86%)

Question 20

What is the definitive treatment for phaeochromocytoma?

Answer 20

Surgical removal of the tumour

Question 21

What is the preoperative medical management of phaeochromocytoma?

Answer 21

1. α-blocker first (e.g. phenoxybenzamine)
2. β-blocker second (e.g. propranolol)

Question 22

A 41-year-old man presents with recurrent headaches. These typically occur 2-3 times a day and are associated with sweating and palpitations. As he was concerned that it may be due to blood pressure he borrowed his father’s home monitor. During these episodes, his blood pressure is around 210/110 mmHg. Given the likely diagnosis, what is the most appropriate next test?

Answer 22

24 hour urinary collection of metanephrines

Question 23

A 35-year-old man has presented to his GP complaining of excessive sweating, headaches, and a feeling of his heart beating in his chest. On measurement of his blood pressure, he is found to be newly hypertensive, on three separate readings. He has a family history of MEN type II.

What is the most appropriate initial investigation for the disease you suspect this man has?

Answer 23

Urinary metanephrines

Question 24

A 31-year-old man presents with headaches, anxiety and palpitations. On examination, his BP is found to be 195/120mmHg. He is treated for essential hypertension. After failing to respond to initial medical therapy he is further investigated for secondary causes of his hypertension and is diagnosed with pheochromocytoma.

What is the best for control his blood pressure whilst awaiting definitive management of his tumour?

Answer 24

Labetalol
= Both alpha and beta blockade is required when controlling hypertension in pheochromocytoma to avoid hypertensive crises

Question 25

Phaeochromocytoma typically presents with a triad of what?

Answer 25

(1) sweating (2) headaches (3) palpitations in association with severe hypertension

Question 26

What is Phenoxybenzamine's mechanism of action?

Answer 26

Non-specific alpha blocker

Question 27

What is the medication of choice for peri-operative blood pressure management when treating a phaeochromocytoma?

Answer 27

Phenoxybenzamine

Question 28

What is the name given to extra-adrenal phaeochromocytomas?

Answer 28

Paragangliomas

Question 29

Which beta blockers are safe to use in the context of phaeochromocytoma management?

Answer 29

Labetalol = has combined alpha and beta blocker properties

Question 30

Where is phaeochromocytoma located?

Answer 30

cells of the adrenal medulla while a paraganglioma arises in sympathetic nerve tissue elsewhere in the body

Question 31

A slim 40-year-old woman with a background history of anxiety and palpitations is referred to the hypertension clinic as she has not responded to a combination of 4 anti-hypertensive agents despite good compliance. Initial blood tests are performed which show no evidence of electrolyte abnormalities. Why would the best investigation be plasma metanephrines rather than short synacthen test?

Answer 31

Plasma metanephrines have the highest sensitivity and specificity of the tests to screen for excess adrenaline metabolites plus a short synacthen test is used to check for adrenal insufficiency which would present with hypotension rather than treatment-resistant hypertension

Question 32

Tests in order

Answer 32

1. Plasma 2. If suspicion remains high after a negative serum test then 24-hour urinary

Question 33

A 54-year-old man presents to the endocrinology clinic. His GP referred him following a suspicious thyroid lump. The patient has undergone a US-guided FNAC which has demonstrated medullary thyroid cancer. A CT scan of the chest and neck reveals no further spread. The patient has a history of asthma and hypertension. as well as intermittent headaches which he finds difficult to control. He normally has ramipril, amlodipine, bendroflumethiazide and atenolol, but still has found it difficult to control his hypertension. On examination, there is a palpable neck mass, but otherwise, there are no abnormalities. What is the most likely explanation for the intermittent headaches?

Answer 33

Medullary thyroid cancer = MEN-2 = Phaeochromocytoma

Question 34

A 60-year-old woman with a background of pheochromocytoma presents with a lump in her neck. She is diagnosed with medullary thyroid cancer. What gene is associated with this malignancy?

Answer 34

RET oncogene = MEN 1 X associated with medullary cancer