Phaeochromocytoma

Question 1

What is a phaeochromocytoma?

Answer 1

Catecholamine secreting tumour of the medulla which is associated with MEN type II, neurofibromatosis and VHL syndrome.
- 10 % are bilateral, 10% are cancerous and 10% lie outside the adrenal gland

Question 2

What is the presentation of a phaeochromocytoma?

Answer 2

• Episodic symptoms such as anxiety, sweating, headaches, tremor, palpitations, fever, flushing, hypertension and tachycardia. Symptosm can be precipitated by stress, exercise, surgery or straining.
• Physical exam may revel hypertensive retinopathy

Question 3

What are the investigations for a phaeochromocytoma?

Answer 3

• Plasma free metanephrines,
• 24 hour urine catecholamines,
• CT/MRI to look for tumour,
• Genetic testing to look for cause

Question 4

What are the differential diagnoses for a phaeochromocytoma?

Answer 4

• Anxiety disorder,
• Hyperthyroidism (will also present with heat intolerance, changes in hair and skin texture)
• Essential hypertension

Question 5

What is the management of a phaeochromocytoma?

Answer 5

1. Alpha-blockade with phenoxybenzamine to prevent interaoperative hypertensive crisis
2. Once alpha blocked then you can consider beta blockade to manage tachycardia or arrhythmias.
3. Surgery to remove the tumour.

Question 6

What are the causes of acromegaly?

Answer 6

GHRH independent causes - Pituitary adenoma (most common cause), Pituitary hyperplasia
GHRH dependent causes - Hypothalamic source or ectopic GHRH

Question 7

What is the pathophysiology of Acromegaly?

Answer 7

Hypothalamus releases GHRH which stimulates the release of GH from the anterior pituitary.
Excess growth hormone results in excess Insulin-like growth factor 1 (IGF-1). This causes excess stimulation of tissue and increase gluconeogenesis and insulin release.

Question 8

What is the difference between gigantism and acromeglay?

Answer 8

Age of onset. Gigantism occurs before the fusion of epiphyseal plates thus causing excess linear growth. Acromegaly occurs after causing grown of bones and soft tissue

Question 9

What are the symptoms of acromegaly?

Answer 9

• Sudden growth of height, feet/heands, jaw, tongue, increased space between teeth and organomegaly (goitre, gynaecomastia)
• Features of pituitary tumour; hypopituitarism (due to compression from adenoma), headaches, bitemporal hemianopia,
• Raised prolactin causing galactorrhoea.
• Hypertrophic heart, hypertension, T2DM, BILATERAL carpal tunnel syndrome, arthritis, colorectal cancer

Question 10

What are the investigations for acromegaly?

Answer 10

Bedside - Fundoscopy, urine dip, perimetry, ECG
Bloods - IGF-1
Growth hormone suppression test - Administer glucose followed by testing GH.
MRI - look for pituitary adenoma

Question 11

What is the managements of acromegaly?

Answer 11

1st line - Trans-sphenoidal surgery.
2nd line - Medical management if tumour is inoperable or surgery is unsuccessful

Question 12

WHat are the medical managements options for acromegaly?

Answer 12

First line - Somatostatin analogue (octreotide)
- Pegvisomant (GH receptor antagonist)
- Dopamine agonists (Bromocriptine)

Question 13

Describe features of somatostin analogues

Answer 13

Octreotide - FIRST LINE MEDICAL MANAGEMENT
Directly inhibits release of GH

Question 14

Describe features of growth hormone antagonists

Answer 14

Pegvisomant - Very effective but doesn’t reduce size of tumour so surgery is still needed if there is mass effect.

Question 15

Describe features of dopamine agonists

Answer 15

Bromocriptine. Only effective in a minority of patients.

Question 16

What is hyperaldosteronism and Conn’s syndrome?

Answer 16

Hyperaldosteronism = High levels of aldosterone.
Conn’s syndrome = Adrenal adenoma producing excess aldosterone.
Common cause of hypertension

Question 17

What is the function of aldosterone?

Answer 17

• Increase sodium reabsoption in DCT
• Increase potassium secretion in DCT
• Increase hydrogen secretion in CD

Question 18

What are the causes of primary and secondary hyperaldosteronism?

Answer 18

Primary - Bilateral adrenal hyperplasia, adrenal adenoma, familial. Renin will be low.
Secondary - Excess renin which can be due to renal artery stenosis, heart failure or liver cirrhosis. (makes BP in kidneys low)

Question 19

What are the investigations for hyperaldosteronism

Answer 19

• Aldosterone to renin ration (ARR).
  1. High aldosterone and low renin indicated primary.
  2. High aldosterone and high renin indicates secondary
• Hypertension, hypokalaemia and alkalosis.
• CT or MRI, renal artery imaging

Question 20

What is the management of hyperaldosteronism?

Answer 20

• Aldosterone antagonists eg, eplerenone
• Surgical removal of adrenal adenoma.
• Renal artery angioplasty

Question 21

Describe features of adrenocortical carcinoma

Answer 21

Very rare and very poor survival.
First line treatment - surgery
Medical - Mitotane