Breathless after separation… from tumour

To the Editors:

It is a general property of the G-protein coupled receptor family, which includes adrenergic receptors, to attenuate their response after persistent stimulation 1. However, the airway tolerance to β₂-agonists and the phenomenon of rebound bronhoconstriction after β₂-agonist withdrawal seems not to have clinical significance 2 even though it differs between compounds 3.

Herein, we report the case of a patient who developed severe bronchial obstructive symptoms after sudden interruption of a chronic stimulation of the airway catecholamine receptors by their endogenous agonists.

The patient was an 84-yr-old, nonsmoking, healthy female with no previous history of asthma or lung disorders. She attended a gym regularly, where she observed that her resting cardiac frequency increased to 110 beats·min⁻¹. During the investigation of her tachycardia, a right-sided 48×52×55-mm adrenal tumour was found. Laboratory testing of the patient’s urine revealed highly increased levels of noradrenaline (8,780 nmol·day⁻¹; normal value <400 nmol·day⁻¹) and moderately elevated levels of adrenaline (175 nmol·day⁻¹; normal value <80 nmol·day⁻¹) confirming the diagnosis of pheochromocytoma. The patient was prepared carefully for surgery by stepwise increase of the α-blocker doxazosin to a dose of 32 mg daily at the time of surgery and diltiazem (180 mg daily), which was preferred to β-blockers for treating her tachyarrhythmia. After successful laparoscopic removal of the tumour, the patient developed severe bronchospasm and had to be treated with glucocorticoids and inhaled β₂-agonists. The obstructive symptoms lasted <1 week.

Bronchoconstriction, after removal of a catecholamine-producing tumour, is physiologically foreseeable owing to the sudden deprivation of catecholamines, as well as deprivation of other tumour-secreted bronchodilator substances, such as adrenomedullin 4, vasoactive intestinal peptide or pituitary adenylate cyclase-activating peptide 5. There are, however, few reports of respiratory problems in patients with pheochromocytoma and all, in contrast to ours, had a history of asthma and/or were being treated with β-blockers 6, 7. Our patient has, since the acute post-operative period, been feeling perfectly well. She is back in the gym on a regular basis, her cardiac frequency is normal and she has not had any further respiratory problems.

It is therefore good to keep in mind that bronchospasm, and not only cardiovascular collapse, is a possible incident that can occur after removal of a catecholamine-producing tumour.

Statement of interest

None declared.