BOF: 1
A 39-year-old married man who has 3 children (ages 10, 8
and 5) presents with a history of loss of libido and impotence.
On examination apart from obesity there are no physical
signs.
He has retained secondary sexual characteristics.
Investigations reveal normal haematology, urea and
electrolytes and liver function tests.
Fasting Blood Sugar 6.1 mmol/L
TSH 3.1 mU/L (0.5-4)
Testosterone 5.4 nmol/L (9-35)
LH 24.6 U/L (1-10)
FSH 20.4 U/L (1-7)
Prolactin 320 mU/L (< 360)
Which of the following would you arrange in this patient?
a)
MRI pituitary
b)
Testicular ultrasound
c)
Haemochromatosis genotype
d)
Insulin tolerance test
e)
CT adrenals
Answer: b)
This patient presents with secondary
hypogonadism. The high LH and FSH levels suggest that this is
hypergonadoptrophic hypogonadism. This shows that the pituitary gland is
functioning normally and there is failure of feedback inhibition suggesting a
problem with the end organ. Hence the correct answer is investigation of the
end organ; the testes. A normal prolactin level excludes hyperprolactinaemia.
Haemachromatosis would have caused pituitary insufficiency and diabetes
mellitus
Revision Tip
Revise causes of hypogonadism in the male ACES for
PACES page 342-343
