MRCP2-1250

MRCP2-1250

A 58-year-old male presents with impotence. He was diagnosed with diabetes mellitus 8 years ago and has been taking metformin for the last 2 years. He has noticed a decline in his erectile function over the last year and is now completely impotent. He is a non-smoker and drinks approximately 8 units of alcohol per week.

On examination, he is obese with a blood pressure of 150/90 mmHg. Testicular examination reveals normal testes of approximately 18 ml in volume. There are no abnormalities on cardiovascular, respiratory or abdominal examinations.

Investigations reveal:
– Haemoglobin: 140 g/L (130-180)
– White cell count: 8.5 ×109/L (4-11)
– Platelets: 190 ×109/L (150-400)
– Serum sodium: 143 mmol/L (137-144)
– Serum potassium: 4.2 mmol/L (3.5-4.9)
– Serum urea: 6.8 mmol/L (2.5-7.5)
– Serum creatinine: 105 µmol/L (60-110)
– Serum alkaline phosphatase: 90 U/L (45-105)
– Serum aspartate aminotransferase: 28 U/L (1-31)
– Serum gamma GT: 40 U/L (<50)
– HbA1c: 7.5% (3.8-6.4)
– Fasting plasma glucose: 8.0 mmol/L (3.0-6.0)
– Plasma testosterone: 6.8 nmol/L (9-33)
– Plasma FSH: 3.9 mU/L (3-12)
– Plasma luteinising hormone: 4.9 mU/L (3-10)

What further investigation would you recommend for this patient?