Hyperkalaemia and gynaecomastia in a 66-year-old man on ramipril and spironolactone

Mr. AB, a 66-year-old man with heart failure with reduced ejection fraction, presents to the cardiology clinic with a 10-day history of bilateral breast tenderness and swelling. He has also been feeling generally unwell and reports no other new symptoms. His regular medications include ramipril 5 mg twice daily, which he has taken for five years, and spironolactone 25 mg once daily, which was started four weeks ago for heart failure. He has chronic kidney disease stage III, with an estimated glomerular filtration rate (eGFR) of 45 mL/min/1.73 m². His serum potassium four weeks ago was 4.8 mmol/L. On examination, he is afebrile, blood pressure 132/78 mmHg, pulse 78 bpm, respiratory rate 16. The cardiovascular and respiratory examinations are unremarkable. He has bilateral breast enlargement with tenderness, no discharge or skin changes, and no lymphadenopathy. Abdominal examination is unremarkable. Laboratory investigations reveal a potassium of 6.4 mmol/L, creatinine 140 µmol/L, eGFR 45 mL/min/1.73 m², and a normal glucose, calcium, and thyroid function. An ECG shows sinus rhythm with peaked T waves, consistent with hyperkalaemia. His haemoglobin, white cell count, and platelets are normal. He is not taking any other medications, including over-the-counter or herbal products. In the absence of any other cause for gynaecomastia, such as hepatic cirrhosis, testicular tumours, or drugs like digoxin or antiandrogens, the reaction is thought to be drug-related. Spironolactone is stopped, and he is commenced on intravenous insulin with glucose for the hyperkalaemia, along with a potassium binder. Over the next five days, his potassium gradually falls to 5.0 mmol/L, and his ECG changes resolve. Over the next three weeks, his breast tenderness and swelling gradually improve. He is not rechallenged with spironolactone. His ramipril is continued. This case illustrates the importance of monitoring potassium and the potential for gynaecomastia with spironolactone in patients with renal impairment.