Metastatic paraganglioma: management of orthostatic hypotension – a case report

Abstract

Paragangliomas, also referred to as extra-adrenal phaeochromocytomas, are neoplasms of extra-adrenal chromaffin tissue which synthesise cathecholamines.1 The increased production and release of catecholamines causes symptoms as a result of excess alpha- and beta-adrenoceptor stimulation. These may include headaches, palpitations and profuse sweating. On examination hypertension and tachycardia may be present, although these can be paroxysmal.2 Chromaffin cell tumours are extremely rare, and about 5–10% of these comprise paragangliomas located in the para-aortic sympathetic chains or the urinary bladder; least commonly, paragangliomas are found in the thoracic or head and neck regions.3 Although most commonly benign, they can occasionally (approximately 3% of paragangliomas) be malignant, with either local invasion (gross or microscopic), seen at the time of primary resection, or distant metastatic spread, which is usually only recognised at tumour recurrence.4 Malignant disease can often be successfully managed with high-dose radiolabelled metaiodobenzylguanidine (MIBG)5 with or without combination chemotherapy with cyclophosphamide, vincristine and dacarbazine (CVD).6 The rarity of the disease means the evidence base of management is currently relatively poor. Orthostatic hypotension can also be present with cathecholamine-secreting tumours. 7 It can be defined as more than 20mmHg fall in systolic blood pressure (BP) and/or more than 10mmHg fall in diastolic BP, over a 2 minute period after standing.8 The aetiological basis of orthostatic hypotension in this context remains unclear. For some time it has been postulated that the increase in circulating catecholamines leads to depression of sympathetic vascular response, due to alpha-adrenoceptor down-regulation; reduced blood volume is also thought to be involved, as a consequence of pressure-induced natriuresis especially when hypertension is severe and paroxysmal.9,10 It has also been proposed that sympathetic vascular modulation is involved in the aetiology.11 The existing literature contains reports of orthostatic hypotension in benign disease, where measures such as increased fluid and salt intake have been used with some success. However, in the rare cases of malignant disease, with or without distant metastases, very little has been described as regards how best to manage this debilitating and poorly understood symptom. Here we describe a case of in- and out-patient management of orthostatic hypotension in a patient with metastatic paraganglioma.