A 63 year old male presents with
sudden onset breathlessness. He is a known diabetic well controlled on oral
On examination he is noted to be
breathless, orthopnoeic, sweating. He has a pulse rate of 120 beats per
minute, his BP is 170/100, his JVP is raised, heart sounds are normal with a
soft systolic murmur at the apex; on auscultation of his lungs bilateral basal
crepitations are heard.
The patient is treated with
intravenous furosemide and makes a speedy recovery.
Two days later the patient is changed
over to oral furosemide and started on an ACE inhibitor.
Urea 8.6 mmol/L
Creatinine 132 Ámol/L
Sodium 136 mmol/L
Potassium 3.8 mmol/L
One week after admission
Urea 16 mmol/L
Creatinine 240 Ámol/L
Sodium 138 mmol/L
Potassium 4.8 mmol/L
In this patient which one of the
following investigations would you arrange in order to elucidate the cause of
the deteriorating renal function?