Pheochromocytoma Flashcards Preview

Endocrinology > Pheochromocytoma > Flashcards

Flashcards in Pheochromocytoma Deck (10):
1

Canine Pheochromocytoma

  • Rare
  • 50% benign/50% malignant
  • usually arises from adrenal medulla
  • Catecholamine secretion or postcaval obstruction

2

Clinical signs pheochromocytoma in dogs

  1. Paroxysmal anxiety, mental depression, restlessness and panting
  2. Paroxysmal blanching and flushing
  3. Tachycardia +/- VPC's, tachyarrhythmias, +/- CHF
  4. Paroxysmal weakness and/or collapse
  5. Ascites associated with postcaval invasion by tumor

3

Norepinephrine

  • pressor
    • raises BP

4

Epinephrine

  • various effects on smooth m.
    • stim heart rate
    • bronchodilitation
    • neurostimulant
  • doesn't raise BP like norepi

5

Pheo DDX

  • Hypoglycemia
  • Cardiac disease
  • Cerebral dysfunction
  • Hyperthyroidism

6

Dx of Canine Pheo

  • Imaging
  • Elevated urinary normetanephrine
  • HX
  • PE
  • Imaging
  • BP

7

sx on pheos

TEST QUESTION

  • Use alpha adrenergic antagonists for spikes in BP
    • phenoxybenzamine => lowers BP

8

Treating Pheo's

  • surgery
  • Medical
    • Phenoxybenzamine: alpha blocker PO
    • Regitine (phentolamine): alpha blocker Parenteral
    • Propranolol: beta blocker

*Always alpha block before you beta block to avoid hypertensive swing

9

Phenoxybenzamine

  • alpha adrenergic blocker
  • better surgical survival if started 2 weeks before surgery

10

Pheo take home messages

  1. Signs from episodic symphathetic surges or postcaval obstruction
  2. Abdominal rads, ultrasound, and CT scan assist diagnosis
  3. Monitor for hypertension and tachyarrhythmias
  4. Use phenoxybenzamine
  5. Alpha before Beta