Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

Nandrolone administration abolishes hippocampal fEPSP-PS potentiation and passive avoidance learning of adolescent male rats

Despite the chronic effects of nandrolone decanoate (ND), the acute effects of ND on passive avoidance learning (PAL) and memory and its mechanism have not been investigated. This research examines the acute effect of ND on PAL, CA1 synaptic plasticity, testosterone and corticosterone serum levels, and the role of androgenic receptors (ARs). Adolescent male rats were treated with ND, 30 min before training and retention and after training test. AR antagonist was applied 15 min before ND. Hippocampal slices were perfused by ND. ND administration had an inverted U-shape effect on acquisition of PAL and on testosterone and corticosterone serum levels. The consolidation was only affected by high dose of ND. ND significantly decreased the retention of PAL across all doses. The magnitude of field excitatory postsynaptic potential long term potentiation was lower than that of control slices. In addition, an attenuation of field excitatory postsynaptic potential population spike coupling was also observed. Nilutamide could nullify the ND impairment effect. We concluded although a single dose of ND could affect all stages of PAL, its effects were more potent on retrieval, possibly arising from the acute effect of ND on the alterations of CA1 synaptic plasticity. In addition, ND may induce its effects directly through ARs and indirectly through plasma testosterone and corticosterone.

Liquid chromatography electrospray ionization tandem mass spectrometry study of nilutamide and its stress degradation products: in silico toxicity prediction of degradation products

Nilutamide, a nonsteroidal anti-androgen drug, widely used in the treatment of prostate cancer, was subjected to hydrolytic, photolytic, thermal and oxidative stress conditions as per International Conference on Harmonization guidelines Q1A (R2). Nilutamide showed significant degradation under basic hydrolysis and photolytic stress conditions, while it was stable to neutral, acidic and thermal stress conditions. Five degradation products were formed and the chromatographic separation of nilutamide and its degradation products was achieved on a Waters C18 column (4.6 × 250 mm, 5 µm) using a mobile phase consisting of acetonitrile and 0.1% of formic acid in an isocratic elution method. All these degradation products were characterized by LC/MS/MS in negative ion mode, combined with accurate mass measurements. To assign likely structures for the observed degradation products, the fragmentation patterns of the deprotonated drug and its degradation products were compared. The in silico toxicity of the drug and its degradation products was also assessed using TOPKAT software. The carcinogenicity probability of the degradation products, DP-I-IV, was greater than that of nilutamide.

Safety of antiandrogen therapy for treating prostate cancer

INTRODUCTION

Antiandrogens are a treatment option in patients with prostate cancer, given either in combination with androgen deprivation or, in selected cases, as monotherapy. New-generation antiandrogens have been recently introduced in clinical practice (enzalutamide) or are under evaluation in clinical trials (ARN-509).

AREAS COVERED

This review elucidates the safety profile of antiandrogens, in particular focusing on the tolerability profile of each drug either when employed in combination with castration or as monotherapy, in hormone-naive or in castration-resistant patients.

EXPERT OPINION

Non-steroidal antiandrogens are widely used in the management of hormone-sensitive disease in combination with luteinizing hormone-releasing hormone agonists or in patients failing front-line treatment with androgen-deprivative maneuvers. In selected patients, non-steroidal antiandrogen monotherapy appears to yield comparable results as castration. Novel non-steroidal antiandrogens have been investigated with promising results in castration-resistant prostate cancer. Beyond the safety profile specific to any individual compound, increased testosterone and 17β-estradiol levels are commonly observed during antiandrogen monotherapy, leading to gynecomastia and breast pain. The safety profile of old and novel antiandrogens should be taken into account by clinicians in decision making and in selecting the most suitable patients. Beyond patient selection, full clinical evaluation of patient co-morbidities that might affect the drug tolerability and clinical monitoring are anyway required.