Endocrine Abstracts

Introduction: Testosterone replacement therapy is the standard treatment for hypogonadism. However, there are also serious side effects which clinicians should be aware of. Here we present a case of unusual side effect related to testosterone therapy.

Case history: A 90 year-old gentleman attended A&E with gradually worsening confusion and dyspnoea. His breathing had deteriorated in the last week with marked decrease in exercise tolerance. Investigations for multiple osteoporotic vertebral fractures, four months ago led to the diagnosis of hypergonadotrophic hypogonadism (Testosterone 4.8 nmol/l, LH: 30.5 U/l, FSH: 20.9 U/l). 18 days before admission, he was commenced on 20 mg Tostran 2% gel. Past medical history, included GORD and mildly impaired LV systolic function. He was not on any treatment for impaired LV function. On clinical assessment, he was found to have signs of decompensated heart failure.

Investigations: Na: 113 mmol/l (was 132 mmol/l before testosterone treatment), rest of U&E, LFT and TFT were normal. Plasma osmolality: 240 mosm/kg, Urinary Na: <20 mmol/l, Urine Osmolality: 335 mosm/kg, Cortisol: 405 nmol/l, Testosterone level 17.2 nmol/l. CXR: ill-defined airspace opacification within both lower zones with cardiomegaly.

Management: Hypervolaemic Hyponatraemia secondary to heart failure was diagnosed. 1L fluid restriction and IV diuretics (for 6 days) had failed to improve sodium level. However 48 hours after discontinuation of testosterone, heart failure symptoms and signs had improved dramatically and sodium concentration increased by 11 mmol/l.

Discussion: Testosterone can cause fluid retention and could exacerbate incipient heart failure. Endocrine society recommends against testosterone therapy in men with uncontrolled heart failure. Some studies have however revealed that testosterone improves exercise capacity in hypogonadal men with heart failure.

Conclusion: Careful risk and benefit assessment should be conducted before commencing testosterone replacement in elderly patients with heart failure.