The Highs and Lows of an Unknown Pheochromocytoma in an Elderly Patient

The trace amine theory of spontaneous hypertension as induced by classic monoamine oxidase inhibitors

The classic monoamine oxidase inhibitors (MAOIs) tranylcypromine (TCP) and phenelzine (PLZ) are powerful antidepressants that come with an equally powerful stigma, and are thus rarely prescribed-despite their well-established effectiveness. Some of these preconceptions appear to stem from unclarity, as the etiology of a rare but important side effect, 'spontaneous hypertension' (SH)-a significant increase in blood pressure absent dietary tyramine ingestion-remains improperly elucidated. This paper aims at uprooting some of the stigma surrounding MAOIs by advancing the trace amine (TA) theory as the causative underpinning of SH. This theory posits that SH results from the considerable influx of TAs observed following TCP- or PLZ-administration. TAs are known, albeit at greatly supraphysiological levels, to raise blood pressure on account of their propensity to exert potent indirect sympathomimetic effects; additionally, some research posits that TAs may induce vasoconstrictive effects partly or wholly separate therefrom, which would then constitute a second hypertensive mechanism. TAs are endogenous to the human body in low quantities. Both TCP and PLZ cause marked elevations of 2-phenylethylamine (PEA), meta- and para-tyramine (m-/p-TYR), octopamine (OA), and tryptamine (TRYP), following both acute and (sub)chronic administration. This paper holds that TYR plays a pivotal role in causing SH, due to its strong pressor effect. Cautious treatment of SH is advised, given its typically self-limiting nature. The risk of hypotensive overshoots must be taken into account. For severe cases, this paper urges reconsideration, following suitable confirmation trials, of antipsychotics (notably risperidone) as these agents may reduce striatal p-TYR levels.

Recurrent Pheochromocytoma in an Elderly Patient

Pheochromocytomas are rare neuroendocrine tumors that can affect people of all ages and are commonly diagnosed in the 4th and 5th decades of life. Familial pheochromocytomas are diagnosed mostly between the 2nd and 3rd decades of life. They can be benign or metastatic and often present as isolated tumors or along with other neuroendocrine syndromes. We present a case of an elderly man who underwent laparoscopic adrenalectomy for pheochromocytoma at the age of 60 years but developed recurrence of metastatic pheochromocytoma after ten years. We also conducted a literature review to understand the epidemiology and presentation of the tumor and to emphasize that there should be a low threshold of suspicion for timely diagnosis and management of recurrent pheochromocytoma.