MRCP2-1587
A 16-year-old male patient visits the endocrine clinic for evaluation. He reports experiencing excessive urination multiple times a day for as long as he can remember. His GP prescribed him indomethacin to reduce his urine output, but it has not been effective. The patient’s older sister also suffers from a similar condition, but only during pregnancy. During the examination, his blood pressure is 122/82 mmHg, with a postural drop of 15 mmHg, and his pulse is regular at 80/min. The following are the results of his investigations:
Hb: 145 g/l (135-180)
WCC: 5.1×10(9)/l (3.8-10.8)
PLT: 221×10(9)/l (150-450)
Na: 147 mmol/l (135-145)
K: 5.1 mmol/l (3.5-5.5)
Bicarbonate: 27 mmol/l (18-28)
Cr: 125 micromol/l (60-110)
Glucose: 5.1 mmol/l (<7)
What additional intervention is most likely to benefit this patient?