Abstract: FR-PO269
Abiraterone-Associated Syndrome of Mineralocorticoid Excess (SAME)
Session Information
- Onconephrology: From AKI to CKD and Everything in Between
November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1700 Onconephrology
Authors
- Kodavanti, Chandra Kumar Mallick, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
- Ravender, Raja, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
- Shaffi, Saeed Kamran, Raymond G Murphy Department of Veterans Affairs Medical Center, Albuquerque, New Mexico, United States
Introduction
We present a patient with abiraterone-associated SAME and discuss its pathophysiology and treatment.
Case Description
A 77-year-old man with metastatic prostate adenocarcinoma was treated with abiraterone 1 gram daily. Prednisone 5 mg daily was added 3 months later. Soon after chemotherapy initiation, his plasma potassium declined (Figure 1), and did not improve despite potassium replacement requiring hospitalization. He was volume overloaded with signs of urinary potassium wasting (Table 1). Further investigations revealed an ACTH (adrenocorticotropic hormone) mediated SAME. Discontinuation of abiraterone with amiloride use improved serum potassium and decreased kaliuresis.
Discussion
Abiraterone acetate is a drug that irreversibly inhibits Cytochrome P450c17 with the suppression of 17 α-hydroxylase (17α-OH) and C17,20-lyase and is used for the treatment of prostate cancer. The inhibition of 17α-OH in the Zona Fasciculata causes an ACTH-mediated SAME due to accumulation of corticosterone and deoxycorticosterone. Therefore, it is co-administered with prednisone to inhibit ACTH. However, low-dose prednisone may not effectively suppress ACTH in all the patients on abiraterone. High dose steroids or spironolactone use is discouraged as they may be associated with worse outcomes. Potassium wasting can be managed effectively with amiloride and low-dose steroids. Despite prednisone use, the possibility of abiraterone inducing SAME should be entertained in patients with hypertension, volume-overload, and/or hypokalemia.
Laboratory values
| ACTH (pg/dl) (Ref 6-50) 220, Plasma Aldosterone Concentration (ng/dl) <1, Plasma Renin Activity (ng/ml/hr) 0.13, Plasma Corticosterone (ng/dl) (Ref AM 59-1293) >10,000, Deoxycorticosterone (ng/dl) 100, Plasma Total CO2 (mEq/L) 32 Arterial pH 7.46, Spot urine K/cr (mEq/gm): on day of admission - 206 and 4 days later while on amiloride- 59 |
Figure 1: A graph showing plasma K (LOESS smoothed) and total CO2 (mEq/L) since prostate-cancer diagnosis.