MRCP2-4465

A 52 year-old man is referred by his GP to the respiratory outpatient clinic. He has had multiple sinusitis episodes in the past three years and is currently being referred to plastic surgery due to partial collapse of the bridge of his nose. A recent chest X-ray revealed five nodules and his blood tests showed a urea level of 11.6 mmol/l and a creatinine level of 198 µmol/l.

What is the most suitable initial treatment for this condition?