Pheochromocytoma

• • Episodic headache, excessive sweating, palpitations, and visual blurring

  • Hypertension, frequently sustained, with or without paroxysms

  • Postural tachycardia and hypotension

  • Elevated urinary catecholamines or their metabolites, hypermetabolism, hyperglycemia

Epidemiology

• • Less than < 0.1% of patients with hypertension

  • 5% of tumors discovered incidentally on CT scan

  • Most occur sporadically

  • Associated with familial syndromes, such as:

  • -Multiple endocrine neoplasia type 2A (MEN 2A)

    -MEN 2B

    -Recklinghausen disease

    -von Hippel-Lindau disease

  • Pheochromocytomas are present in 40% of patients with MEN 2

  • 90% of patients with pheochromocytoma are hypertensive

  • Rule of 10s:

  • - 10% malignant

    -10% familial

    -10% bilateral

    -10% multiple tumors

    -10% extra-adrenal

  • Hypertension less common in children

  • In children, 50% of patients have multiple or extra-adrenal tumors

  • Extra-adrenal pheochromocytomas:

  • -Abdomen (75%)

    -Bladder (10%)

    -Chest (10%)

    -Pelvis (2%)

    -Head and neck (3%)

Symptoms and Signs

• • Clinical findings are variable

  • Episodic or sustained hypertension

  • Triad of palpitation, headache, and diaphoresis

  • Anxiety, tremors

  • Weight loss

  • Dizziness, nausea, and vomiting

  • Abdominal discomfort, constipation, diarrhea

  • Visual blurring

  • Tachycardia, postural hypotension

  • Hypertensive retinopathy

Laboratory Findings

• • Hyperglycemia

  • Elevated plasma metanephrines

  • Elevated 24-hour urine metanephrines and free catecholamines

  • Elevated urinary vanillylmandelic acid (VMA)

  • Elevated plasma catecholamines

Imaging Findings

• • Adrenal mass seen on CT or MRI

  • Characteristic bright appearance on T2-weighted MRI

  • Asymmetric uptake on MIBG scan. Particularly useful for extra-adrenal, multiple, or malignant pheochromocytomas. Not useful for sporadic biochemical syndrome with unilateral mass

• • Avoid arteriography or fine-needle aspiration as they can precipitate a hypertensive crisis

  • Early recognition during pregnancy is key because if left untreated, half of fetuses and nearly half of the mothers will die

Rule Out

• • Other causes of hypertension

  • Hyperthyroidism

  • Anxiety disorder

  • Carcinoid syndrome

• • History and physical exam

  • -Suspect pheochromocytoma based on symptoms

  • CT, MRI, or other scans

  • Plasma and urine studies (metanephrines, catecholamines, VMA)

  • Begin treatment with α-blockers

  • Possible MIBG scan

  • Operative excision of tumor

When to Admit

• • Hypertensive crisis (can develop multisystem organ failure, mimicking severe sepsis)

• • α-Adrenergic blocking agents should be started as soon as the biochemical diagnosis is established to restore blood volume, to prevent a severe crisis, and to allow recovery from the cardiomyopathy

Surgery

Indications

• • All pheochromocytomas should be excised

Contraindications

• • Metastatic disease

  • Inadequate medical preparation ( blockade)

Medications

• • -Adrenergic blocking agents, such as phenoxybenzamine

  • Other agents include metyrosine, prazosin, and calcium channel blockers

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