Pheochromocytoma

OVERVIEW

• paraganglioma -> catecholamine producing tumours
• associated with: MEN, von Hippel-Lindau syndrome, neurofibromatosis and familial paraganglioma

CLINICAL FEATURES

• paroxysmal hypertension
• headaches
• palpitations
• sweating

Cardiovascular Emergencies

• hypertensive crisis: provoked by posture, exertion, certain food/beverage, emotion, urinary or drugs (histamine, ACTH, metoclopramide, phenothiazines, TCA, anaesthetics) -> use phentolamine 2.5-5mg IV, GTN or SNP
• shock: abdominal pain, APO, mydriasis, weakness, diaphoresis, cyanosis, hyperglycemia -> fluid, vasopressin, ephedrine
• arrhythmia: sinus tachycardia, SVT, broad complex, VT, AF, VF -> esmolol IV
• catecholamine induced myocarditis, cardiomyopathy, obstructive hypertrophic cardiomyopathy
• myocardial ischaemia and MI: can present as an ACS but with no troponin elevations -> normal coronaries on angiography
• acute peripheral ischaemia: sudden ischaemia, necrosis, gangrene from arterial vasoconstriction

Pulmonary Emergencies

• APO: often cardiogenic and non cardiogenic in origin

Gastrointestinal Emergencies

• severe abdominal pain and vomiting
• may be acute bleed with dumping of vast amounts of catecholamines into the circulation -> embolisation
• may require surgery if causes mesenteric vasoconstriction with distal ischaemia

Renal Emergencies

• CVA
• bleed
• SAH
• seizures

Multi-system Failure

• APO, renal failure, DIC, T > 40 C, encephalopathy, hyper/hypotension
• even if critical this syndrome is indication for emergency tumour resection.

INVESTIGATIONS

24hr Urine

• fractionated metanephrines
• fractionated catecholamines

Plasma

• fractionated metanephrines

If normal -> check during a spell

Diagnosis =

• 2 fold elevation above upper limit of normal in urine catecholamines
• increased in urine metanephrines
• significant increase in fractionated plasma metanephrines

Further Investigation

• CT – less accurate for small lesion
• MRI\CT to look @ adrenals or for paraaortic mass
• 123I-MIBG if mass > 10cm

If gland normal

• whole body MRI
• 123I-MIBG
• In-III pentetreotide scan
• PET scan

MANAGEMENT

• ICU/HDU admission
• resuscitate (A, B, C)
• alpha blockade: phentolamine (acutely), phenoxybenzamine 10mg BD -> increased to 1mg/kg/day QID (10-14 days)
• then beta blockade: atenolol 25mg OD
• other agents: phentolamine, calcium channel blockers, labetalol
• MgSO4
• screen for myocardial damage: TNT, ECG, ECHO
• surgery

Criteria for Surgery:

(1) BP < 160/90 for 24 hours
(2) postural hypotension but with a BP of 80/45 upright
(3) < 1 ventricular extrasystole Q5 min
(4) no ST changes and TWI on ECG for 1 week

COMPLICATIONS

• death
• malignancy
• MI
• arrhythmias
• seizures
• CVA (ICH)
• APO
• aortic dissection
• hypertensive encephalopathy