Severe Electrolyte Abnormalities and Distal Renal Tubular Acidosis in the Setting of Apremilast Use for Psoriatic Arthritis: A Case Report.

Renal tubular acidosis (RTA) involves dysfunction of the renal tubular system, which leads to electrolyte abnormalities and acid-base dysregulation. The case we present here discusses a patient with a past medical history of psoriatic arthritis who presented to the emergency department with progressive generalized weakness and anorexia in the preceding four weeks. She was found to have profound hypokalemia (1.2 mmol/L), hyperchloremic metabolic acidosis, and multiple other electrolyte abnormalities. Following an extensive workup, her principle problem was deemed to be distal (type 1) RTA. She was treated with sodium bicarbonate, spironolactone, and aggressive rehydration, which eventually led to the stabilization of her electrolytes alongside clinical improvement over the course of an eight-day hospitalization. The workup did not reveal a clear etiology for the RTA. One month prior to hospitalization, she was started on apremilast, a new medication for her psoriatic arthritis. Given the limited availability of alternative explanations and the temporality of clinical manifestations, our findings raise suspicion that apremilast might be associated with her clinical presentation.