Abstract: TH-PO1096

A Case Report of Severe Hypokalemia Induced by Posaconazole

Session Information

Category: Fluid, Electrolytes, and Acid-Base

  • 704 Fluid, Electrolyte, Acid-Base Disorders

Authors

  • Katari, Sreelatha, Barnes Jewish Hospital, St Louis, Missouri, United States
  • Coyne, Daniel W., Washington University School of Medicine, St. Louis, Missouri, United States
Background

Hypokalemia is not a very common electrolyte abnormality that has been recognized with azole antifungals.

Methods

A 66 year old man with history of Acute Myeloid Leukemia (AML) status post stem cell transplant in 6/2016 and chemotherapy presented with weakness, loss of appetite and failure to thrive on 1/2017. His current outpatient medications are tacrolimus, atovaquone, fluconazole, valacyclovir and budesonide. His blood pressure was 137/76 mm Hg, pulse 118, and BMI 24. Serum sodium 137 mmol/L, potassium (K) 4.1 mmol/L, chloride 107 mmol/L, urea nitrogen 9 mg/dL, and creatinine 0.85mg/dL. Chest and abdominal CT showed recurrence of AML, so he was started on dasatinib. On day 3 he developed neutropenic fever so he was started on vancomycin, meropenem and posaconazole. On day#11 he developed polyuria of more than 4L and profound hypokalemia. Serum K was 2.1 mmol/L, bicarbonate of 24 mmol/L, phosphorus 1.8 mg/dl and magnesium of 1.9 mmol/L. Urine analysis showed no glycosuria with a PH of 5. Urine K 42 mmol/L, sodium 105mmol/L , osmolality of 393 mOsm/kg, serum osmolality of 297mOsm/Kg, calculated potassium deficit daily was nearly 440meq. His workup showed renal wasting of potassium with no evidence of renal tubular acidosis. Given the timeline of events the electrolyte abnormalities were attributed to posaconazole, so it was discontinued and switched with micafungin. Over next 10 days his serum potassium promptly normalized and did not require further supplementation.

Results

Posaconazole has been increasingly used in the treatment of zygomycetes and asperillus infections in hematological malignancies. It works by inhibiting enzyme lanosterol 14α-demethylase leading to defective fungal cell wall and its death. Exact mechanism of hypokalemia is not clear but animal studies have shown inhibition of 11β-hydroxysteroid dehydrogenase type 2 dependent cortisol inactivation by posaconazole leads to excessive cortisol byproducts like cortisone, leading to apparent mineralocorticoid excess causing urine potassium losses and hypokalemia.

Conclusion

Posaconazole induced profound Hypokalemia is rare complication with only two other published cases in literature. So we suggest serum potassium be closely monitored in patient treated with posaconazole and the treatment is its prompt discontinuation