Is routine hormonal measurement necessary in initial evaluation of men with erectile dysfunction?

Prevalence of Hyperprolactinemia and Clinically Apparent Prolactinomas in Men Undergoing Fertility Evaluation

OBJECTIVE

To determine prevalence of hyperprolactinemia and prolactinoma among men presenting for initial fertility evaluation.

METHODS

We performed a retrospective review of men presenting for initial fertility evaluation at a tertiary care, academic health system between 1999 and 2018. Men with measured prolactin levels were analyzed to determine prevalence of hyperprolactinemia and prolactinoma. We compared clinical characteristics of men with and without hyperprolactinemia. Univariable and multivariable analysis were used to determine factors associated with hyperprolactinemia. We assessed effects of hyperprolactinemia and prolactinoma on testosterone levels, semen parameters and pregnancy outcomes after treatment.

RESULTS

3,101 men had serum prolactin level measured. 65 (2.1%) had hyperprolactinemia. Patients with hyperprolactinemia had lower testosterone (median 280 ng/dL vs. 313 ng/dL, p=0.038) and lower total motile sperm count (TMSC) (median 7.0 million vs. 34.7 million, p=0.001) compared to men without hyperprolactinemia. 43.1% of men with hyperprolactinemia had oligospermia versus 21.5% of men without hyperprolactinemia (p<0.001). Univariable analysis demonstrated that men with elevated luteinizing hormone (LH) (OR 1.077, p=0.001) and follicle-stimulating hormone (FSH) (OR 1.032, p=0.002) were more likely to have hyperprolactinemia. Men with oligospermia were more likely to have hyperprolactinemia (OR 2.334, p=0.004). On multivariable analysis, neither hormone parameters nor oligospermia were associated with elevated prolactin (p>0.05). Of the 65 men with hyperprolactinemia, 11 (17%) were diagnosed with a prolactinoma, resulting in an overall prevalence of 11 in 3,101 (0.35%).

CONCLUSION

The overall prevalence of prolactinoma in our cohort of men undergoing fertility evaluation was 35-fold higher than the prevalence in the general male population.

Predicting low testosterone in aging men: a systematic review

BACKGROUND

Physicians diagnose and treat suspected hypogonadism in older men by extrapolating from the defined clinical entity of hypogonadism found in younger men. We conducted a systematic review to estimate the accuracy of clinical symptoms and signs for predicting low testosterone among aging men.

METHODS

We searched the MEDLINE and Embase databases (January 1966 to July 2014) for studies that compared clinical features with a measurement of serum testosterone in men. Three of the authors independently reviewed articles for inclusion, assessed quality and extracted data.

RESULTS

Among 6053 articles identified, 40 met the inclusion criteria. The prevalence of low testosterone ranged between 2% and 77%. Threshold testosterone levels used for reference standards also varied substantially. The summary likelihood ratio associated with decreased libido was 1.6 (95% confidence interval [CI] 1.3-1.9), and the likelihood ratio for absence of this finding was 0.72 (95% CI 0.58-0.85). The likelihood ratio associated with the presence of erectile dysfunction was 1.5 (95% CI 1.3-1.8) and with absence of erectile dysfunction was 0.83 (95% CI 0.76-0.91). Of the multiple-item instruments, the ANDROTEST showed both the most favourable positive likelihood ratio (range 1.9-2.2) and the most favourable negative likelihood ratio (range 0.37-0.49).

INTERPRETATION

We found weak correlation between signs, symptoms and testosterone levels, uncertainty about what threshold testosterone levels should be considered low for aging men and wide variation in estimated prevalence of the condition. It is therefore difficult to extrapolate the method of diagnosing pathologic hypogonadism in younger men to clinical decisions regarding age-related testosterone decline in aging men.

Hyperprolactinaemia due to hypothalamic-pituitary disease or drug-induced in patients with erectile dysfunction

One hundred and sixty-five patients with erectile dysfunction were assessed at the Athens Medical Sex Institute: 60 men (36.4%) considered their condition as organic, 52 (31.5%) rated it as mostly psychogenic, 45 (27.2%) thought it could be of mixed aetiology and 8 (4.8%) could not comment at all as to the aetiology. Initial psychologic evaluation rated the condition in the majority of cases as psychogenic (130 patients, 84.8%). No psychologist considered the erectile dysfunction as purely (100%) organic. After the urological and endocrine evaluation, vascular disorder was considered in 30 patients (18.2%), endocrine dysfunction in 16 patients (9.7%) and psychogenic in 109 patients (66.1%). Sixteen of the above patients had definite hyperprolactinaemia, two had large-sized prolactinomas as revealed by magnetic resonance imaging (MRI) and pituitary function tests. Four had nonfunctioning pituitary tumours, which was also based on MRI and pituitary tests. Four had small prolactin (PRL) adenomas. Drug-induced hyperprolactinaemia was suspected in six patients who used medications affecting PRL secretion and had no evidence of tumour on radiological evaluation. In conclusion, hyperprolactinaemia in men with erectile dysfunction needs to be evaluated before considering any other treatment.

Medical causes and consequences of hyperprolactinaemia. A context for psychiatrists

Hyperprolactinaemia is the commonest endocrine disorder of the hypothalamic-pituitary axis and can lead to both short-term sexual dysfunction and galactorrhoea, and long-term loss of bone mineral density. Prolactin is secreted from the anterior pituitary gland under the influence of dopamine, which exerts a tonic inhibitory effect on prolactin secretion. Physiological regulators of prolactin secretion include many different types of 'stress' and sleep. Disruption of the normal control of prolactin secretion results in hyperprolactinaemia from pathological and pharmacological causes. The administration of antipsychotic medication is responsible for the high prevalence of hyperprolactinaemia in people with severe mental illness. Physiological hyperprolactinaemia, such as pregnancy and lactation, should be distinguished from pathological causes to prevent unnecessary investigation and treatment. The causes, consequences and management of hyperprolactinaemia are discussed in this article.

Testosterone and Sleep‐Related Erections: An Overview*

Sleep-related erections have been reported to occur from the intrauterine life to senescence. It has been speculated that the main function of nocturnal erections is to provide adequate engorgement of the corpora cavernosa, which then leads to increased tissue oxygenation. This is in turn to prevent cavernous fibrosis, the histopathological basis for corporeal venoocclusive dysfunction, which probably is the most common cause of organic erectile dysfunction. It has been suggested that sleep-related erections are triggered by the release of nitric oxide by the nitrergic nerve fibers within the cavernous nerves. Androgens regulate this mechanism as well as some other non-nitrergic processes within the corpora cavernosa and within the central nervous system. By contrast, the erectile response to tactile or visual erotic stimuli in wakefulness predominantly involves an androgen-independent system, although it may, at least to a certain degree, also be influenced by androgen-sensitive mechanisms. No doubt, androgens are key players in the physiology of nocturnal erections, and the availability of new, user-friendly testosterone preparations such as transdermal gel and intramuscularly administered testosterone undecanoate stimulates further investigations on this field. The prospect that the quality of sleep may also be improved by an androgen therapy administered to improve sleep-related erections in hypogonadal men needs further basic research and appropriate clinical studies.