Phaeochromocytoma

Question 1

Pathology

Answer 1

Catecholamine-producing tumours arising from sympathetic paraganglia
Usually found in adrenal medulla
Extra-adrenal phaeo’s found by aortic bifurcation

Question 2

Rule of 10s

Answer 2

10% malignant
10% extra-adrenal
10% bilateral
10% part of hereditary syndromes

Question 3

Associations

Answer 3

10% part of herediatary syndromes MEN2a and 2b
Neurofibrimatosis
Von Hippel-Lindau: RCC + cerebellar signs

Question 4

Presentation Triad

Answer 4

Triad: episodic headache, sweating and tachycardia

Question 5

Other adrenergic features

Answer 5

↑BP, palpitations
  Headache, tremor, dizziness   
Anxiety
  d/v, abdo pain
  Heat intolerance, flushes

Question 6

Precipitants

Answer 6

Straining, abdo palpation
Exercise, stress
β-B, IV contrast, TCAs, GA

Question 7

Ix

Answer 7

Plasma + urine metadrenaline
Also vanillylmandelic acid
Abdo CT/MRI
MIBG (mete-iodobenzylguanidine) scan

Question 8

Medical treatment

Answer 8

If malignant

Chemo or radiolabelled MIGB

Question 9

Surgical treatment

Answer 9

Adrenelectomy
α-blocker first, then β-blockade pre-op
Avoids unopposed α-adrenergic stimulation Phenoxybenzamine = α-blocker
Monitor BP post-op for ↓↓BP

Question 10

Hypertensive crisis - features

Answer 10

Pallor
Pulsating headache Feeling of impending doom ↑↑BP
↑ ST and cardiogenic shock

Question 11

Treatment

Answer 11

Phentolamine 2-5mg IV (α-blocker) or labetalol 50mg IV

Repeat to safe BP (e.g. 110 diastolic)

Phenoxybenzaime 10mg/d PO when BP controlled

Elective surgery after 4-6wks to allow full α-blockade
and volume expansion