A CASE OF RESISTANT HYPERTENSION WITH HYPOKALAEMIA DUE TO CO-SECRETING CORTISOL AND ALDOSTERONE IN A PATIENT WITH BILATERAL ADRENAL ADENOMAS

Abstract

INTRODUCTION
Aldosterone and cortisol co-secreting adrenal tumours are rare. We report a case of subclinical Cushing’s syndrome (CS) with co-secreting aldosterone in a patient with bilateral adrenal adenomas.

CASE
A 53-year-old Indonesian lady with hypertension and diabetes for 15 years, presented to our hospital with hypertensive urgency and symptomatic hypokalaemia. Clinically there were skin-tags and acanthosis nigricans but no pathognomonic features of CS. Fundoscopy showed narrowing of retinal arteries and silver wiring. Urine microscopy showed macroalbuminuria. Her ECG showed left ventricular hypertrophy which was confirmed on echocardiogram. She was discharged with metformin, a DPP4-inhibitor, four antihypertensives and potassium supplements of 7.2 g/day. During workup for hypertension and hypokalaemia, she demonstrated a positive screening test for primary aldosteronism during which her creatinine was 112 umol/L with eGFR of 57 mls/min/1.73 m2. A 24-hour urinary cortisol was within normal. The patient underwent a 1-mg overnight dexamethasone suppression test during which her serum cortisol was elevated; 429 nmol/L. Subsequently, a low dose dexamethasone suppression test showed inability to decrease cortisol level below the cut off value to rule out CS; 290 nmol/L. Pheochromocytoma was excluded with normal 24-hour urinary catecholamine levels. A confirmation test for primary aldosteronism was not done in view of worsening renal function to stage-4 CKD. A CT scan of the adrenals revealed benign features of bilateral adrenal adenomas with rapid washout, measuring 2.6 cm and 1.5 cm by the largest diameter of the right and left adenomas respectively. The patient opted for conservative management. Her hypertension and hypokalaemia status improved while on spironolactone 75 mg BD. All potassium supplements were stopped and her BP was much easier controlled on three medications.

CONCLUSION
This interesting case illustrates that adrenal adenomas might be capable of secreting both aldosterone and cortisol without clinical features of CS.