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Decreased sexual function in a young man
  1. R A Fisken
  1. Friarage Hospital, Northallerton, North Yorkshire DL6 1JG, UK
  1. Dr Fisken

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A 36 year old professional man presented with an 18 month history of difficulty in achieving and maintaining an erection. He also described “lack of sex drive”, malaise, and non-specific ill health over several months. He was sometimes able to masturbate successfully but commented that his ejaculate was of small volume. Physical examination showed him to be anxious but he was otherwise normal except for the fact that the testes were smaller than expected (about 12 ml in volume) and soft.

Questions

(1)
What is the commonest cause of erectile dysfunction in a man of this age?
(2)
What features of the clinical presentation in this patient would be in favour of an organic cause for his problem.
(3)
What baseline investigations would you undertake?

Answers

Q1: What is the commonest cause of erectile dysfunction in a man of this age?

Erectile problems in young men are, on average, more likely to result from psychological than physical causes,1 though a combination of the two may be present. The older the patient at presentation, the more likely is the disorder to have a mainly physical cause.

Q2: What features of the clinical presentation in this patient would be in favour of an organic cause for his problem

The reduction in libido, small ejaculate volume, and small, soft testes are all suggestive of hypogonadism.

Q3: What baseline investigations would you undertake?

In this case there is clear evidence of the need to measure serum testosterone, prolactin, follicle stimulating hormone (FSH), and luteinising hormone. In many clinics a baseline blood glucose and renal and liver function tests would also be requested.

The patient's initial endocrine results are shown in table 1. Plain skull radiography and magnetic resonance imaging (MRI) were requested (figs 1 and 2).

Table 1

Patient's endocrine results

Figure 1

Plain skull radiograph.

The low serum testosterone and free androgen index confirm hypogonadism.

Questions

(4)
Is this patient's hypogonadism primary or secondary? Why?
(5)
What is the abnormality seen on the skull radiography (fig 1)?
(6)
What diagnosis is suggested by the MRI scan (fig 2)?
(7)
At what age does this condition typically present?
(8)
What treatment should this patient have for his primary disorder?
(9)
What treatment should he have for his hypogonadism? Why?

Answers

Q4: Is this patient's hypogonadism primary or secondary? Why?

This patient has secondary hypogonadism: his serum testosterone is very low but there is no compensatory increase in the secretion of FSH and luteinising hormone—in a man with primary testicular failure and a serum testosterone of this level one would expect the serum FSH and luteinising hormone to be greater than 30.

Q5: What is the abnormality seen on the skull radiography?

There is suprasellar calcification.

Q6: What diagnosis is suggested by the MRI (fig 2) scan?

The MRI scan shows a solid soft tissue mass in the suprasellar cistern. It does not appear to arise from the pituitary and is most likely to be a craniopharyngioma.

Q7: At what age does this condition typically present?

Craniopharyngioma is most commonly detected between the ages of 6 and 14 but may come to light in adults, even up to an advanced age.2 3

Q8: What treatment should this patient have for his primary disorder?

The patient will require a full pituitary assessment, including a combined pituitary function test. The lesion itself is compressing the optic chiasm and will require surgery followed by radiotherapy.

Q9: What treatment should he have for his hypogonadism? Why?

The patient should be offered a choice of forms of testosterone replacement, both for the sake of his sexual function and in order to preserve his muscle mass and prevent osteoporosis. Available treatments include intramuscular testosterone esters, oral testosterone undecanoate, transdermal testosterone, and testosterone implants.

Learning points

  • Erectile dysfunction in younger men is commonly caused by mainly psychological factors but organic factors should nevertheless be sought.

  • The presence of loss of libido or of small, often soft, testes favours a diagnosis of hypogonadism.

  • If the serum testosterone is low and the levels of FSH and luteinising hormone are low or normal then the patient has secondary hypogonadism due to pituitary or hypothalamic disease.

  • Craniopharyngiomas may present in adulthood.

References

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