Makindo Medical Notes

Related Subjects: |Adrenal Physiology |Addisons Disease |Phaeochromocytoma |Adrenal Adenomas |Adrenal Cancer |Cushing Syndrome |Cushing Disease |Congenital Adrenal hyperplasia |Primary hyperaldosteronism (Conn's syndrome) |ACTH |McCune Albright syndrome

Hypertension in phaeochromocytoma is best treated with phenoxybenzamine, a nonselective alpha-blocker.

About

• Uncommon cause of secondary hypertension, important for perioperative management.
• Tumors of chromaffin cells in the sympathetic nervous system, often located in the adrenal medulla.

Aetiology

• Chromaffin cell tumor, often in adrenal medulla or along the sympathetic chain.
• Secretes catecholamines: adrenaline, noradrenaline, and dopamine.
• Rarely, it may produce opioids, endothelin, erythropoietin, or neuropeptide Y.
• Common on the right side and may be located outside the adrenal glands, such as in the bladder or thorax.

The "10 x 10" Tumor

• 10% are malignant, lie outside the adrenals, are familial, affect children, are bilateral, or calcify.
• 10% may recur after removal, occur in the bladder, and are located in the thorax.

Pathology

• Grey tumor, potentially extra-adrenal.

Associations

• Von Hippel-Lindau syndrome, Neurofibromatosis Type 1, and MEN Type 2a and 2b.

Clinical Presentation

• Hypertension (often intermittent), headaches, sweating, and tachycardia.
• Sense of impending doom, nausea, tremor, and weight loss.
• Hyperglycemia, postural hypotension, arrhythmias, and worsening angina or ischemic heart disease.

Investigations

• Biochemical: FBC, U&E, calcium (especially if MEN suspected), and 24-hour urinary catecholamines/metanephrines (98% sensitivity).
• Imaging: CT or MRI for tumor localization, MIBG scan as an adjunct if needed.
• Clonidine suppression test: Clonidine typically reduces catecholamines in non-affected individuals but not in phaeochromocytoma.
• Note: Fine-needle aspiration is contraindicated.

Management

• Hypertension Management: Start with alpha-blockade:
  • Doxazosin 2–32 mg OD orally.
  • Phenoxybenzamine 10 mg twice daily orally.
  • Phentolamine 2–5 mg IV (short-acting).
• Beta-Blockade: Only after alpha-blockade, if needed for tachycardia, arrhythmias, or acute coronary syndrome.
• Surgical Removal: Careful preoperative preparation to manage catecholamine surges and potential hypotension post-tumor removal.
  • Preoperative alpha-blockade with phenoxybenzamine (titrated over several weeks), with later beta-blockade if indicated.
  • Experienced anesthesia management is crucial for intraoperative blood pressure control and post-removal volume replacement.

Complications

• Dilated cardiomyopathy, atrial fibrillation, SVT, ventricular tachycardia, diabetes mellitus, stroke, and hypertensive encephalopathy.