SAT-412 - Dual Hypersensitivity to Spironolactone and Eplerenone in A Patient with an Aldosterone-Producing Adenoma

Introduction:

Primary aldosteronism (PA) is a major contributor to resistant hypertension and cardiovascular morbidity especially when left untreated. Mineralocorticoid receptor antagonists (MRAs), especially spironolactone and eplerenone, are essential for treatment when surgery is not an option. Hypersensitivity to these medications is very uncommon, and having a dual intolerance to both drugs poses a significant treatment challenge.


Case Presentation:

A 44-year-old woman with a history of resistant hypertension for eight years came in with severe muscle weakness. Previous visits to the emergency department noted severe hypokalemia, with potassium levels between 1.8 and 1.9 mmol/L. An incidental left adrenal mass was found, measuring 12×11 mm, but she was lost to follow-up. Upon her current visit, her blood pressure was 160/110 mmHg despite taking the maximum daily dose of losartan and amlodipine. Blood tests showed suppressed plasma renin activity ( < 0.07 ng/mL/hr), high plasma aldosterone (44.49 ng/dL), with a markedly high aldosterone-to-renin ratio of 635.5. A computed tomography scan of the adrenal gland showed a 1.7×1.4×1.7 cm mass on the left adrenal gland with a washout of 73.5%. All of these findings indicate an aldosterone-producing adenoma.

The patient initially opted not to have surgery. She was then given spironolactone 50mg tablet daily, but was immediately discontinued due to the development of a generalized pruritic maculopapular rash. Trial of eplerenone led to a more serious allergic reaction, causing widespread erythema, wheals, and angioedema, which resolved after discontinuation of eplerenone. Because of these, the patient's hypokalemia was treated with oral potassium supplementation, while her hypertension with losartan and amlodipine, while being reappraised about the possibility of surgery, limited by her financial status.


Conclusion:

This case highlights the rare but important situation of dual MRA hypersensitivity, which poses a serious challenge in managing PA. In such cases, alternative options like amiloride may be considered; however, the best treatment for unilateral disease remains adrenalectomy, as it can prevent further damage from excess mineralocorticoids.

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