Anaesthetic Management of Extramedullary Pheochromocytoma

Case Report

Austin Anesthesiol. 2017; 1(1).

Anaesthetic Management of Extramedullary Pheochromocytoma

Kar SK*, Ganguly T, Dasgupta CS and Goswami A

Department of Cardiac Anesthesiology, Institute of Postgraduate Medical Education & Research, India

*Corresponding author: Sandeep Kumar Kar, Department of Cardiac Anaesthesiology Institute of Postgraduate Medical Education & Research, Kolkata, India

Received: March 06, 2017; Accepted: May 18, 2017; Published: May 25, 2017

Abstract

Pheochromocytomas are catecholamine-secreting tumors of chromaffin tissue and are a rare cause of hypertension. Less than 0.1% of the hypertensive population has a pheochromocytoma. The hypertension caused by these tumors is usually curable. Surgery on a patient with an unrecognized pheochromocytoma can be fatal; similarly the administration of β-adrenergic-blocking drugs can have untoward side effects. These tumors can be associated with other potentially fatal but curable diseases.

Introduction

The high incidence of pheochromocytoma in families as a primary disease, in association with multiple endocrine neoplasia or other familial diseases such as Von Hippel Lindau syndrome and neurofibromatosis I, indicates the need for genetic counseling [1-4]. Approximately 16% of pheochromocytomas will be associated with other endocrine disorders, such as multiple endocrine syndromes [2], which is comprised of medullary thyroid carcinoma, pheochromocytoma, and parathyroid hyperplasia.

The Case:

  1. Twelve years old girl.
  2. H/O repeated attacks of dyspnoea, palpitation, headache, diaphoresis and cold clammy skin.
  3. On examination her NIBP was 182/126 mm Hg.
  4. CT of chest revealed large well defined thoracoabdominal SOL in right paravertebral region of size 50 x 64 x 87 mm.
  5. On CT abdomen the mass in right paravertebral region extended from T8-to T11
  6. Twenty four hour urinary VMA was 52.57 mg.
  7. So, it was diagnosed to be EXTRAMEDULLARY PHEOCHROMOCYTOMA

Pathophysiology

The incidence of pheochromocytoma as a benign tumor in one of the adrenal glands is 80%. Twenty percent are extra-adrenal, with half located below the diaphragm in areas such as along the aorta, near the urinary bladder, and in the organ of Zuckerkandl; the other half is located above the diaphragm in areas along the aorta, in the lungs or heart, or in the neck or carotid bodies. Ten percent occur in children. In nonfamilial disease, the classical teaching is that 10% of patients have bilateral adrenal tumors and 10% have multiple extra-adrenal tumors; however, in familial disease, more than 80% are bilateral or in multiple sites. The incidence of a malignant pheochromocytoma is 10%. The occurrence of a pheochromocytoma is evenly distributed between the sexes and can occur at any age, although the peak incidence is between the fourth and sixth decades.

Catecholamine secretion is responsible for the signs and symptoms of a pheochromocytoma [5]. It is unusual that a tumor will grow large enough or be so invasive as to interfere with the function of the surrounding organs. The manifestations of a pheochromocytoma are primarily the result of the excessive secretion of norepinephrine, epinephrine, and dopamine [6]. The most common combination is predominantly norepinehrine and epinephrine.

Some tumors secrete only norepinehrine, but <10% secrete only epinephrine. Dopamine and its metabolite are more likely to be significantly elevated in children with a pheochromocytoma.

The etiology for the increased production and secretion of catecholamines is not clear. It is conceivable that the negative feedback mechanism of norepinephrine on tyrosine hydroxylase is altered so that sensitivity to feedback is decreased, or perhaps metabolism or release is so rapid that feedback does not transpire in the usual manner. Small tumors tend to secrete high levels of circulating catecholamines. With intracellular metabolism being more prevalent in large tumors, high levels of metabolites tend to be released, and free catecholamine secretion is reduced.

Approximately 50% of patients with a pheochromocytoma have sustained hypertension, 45% are normotensive with paroxysms of hypertension, and 5% are normotensive or even hypotensive [4,6]. These differences, in part, relate to the patterns of catecholamine secretion; bursts produce hypertensive episodes. Patients with sustained hypertension and some normotensive patients can have high or normal levels of norepinephrine. How sustained levels of high norepinephrine concentrations result in persistent hypertension is not understood. However, if elevated catecholamine secretion persists, α- and β-receptors may become desensitized, or even down regulated. Homodynamic mechanisms will no longer respond to elevated levels of norepinephrine, and blood pressure will normalize.

Catecholamine levels and blood pressure do not usually correlate well, but a significant change in catecholamine concentration will elicit a blood pressure response. Patients with the rare, exclusively epinephrine producing tumors can present with normotension, or even hypotension, secondary to the vasodilating properties of epinephrine. Orthostatic hypotension is another result of the ganglionic-blocking activity of excessive amounts of catecholamines (Figure 1- 3).