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

Abstract

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.

Keywords: apremilast; electrolyte disturbance; hypokalemia; psoriatic arthritis; renal tubular acidosis.

Figure 1. Illustration of the patient's serum potassium and bicarbonate levels during her hospitalization and the corresponding medical therapy utilized

IV: Intravenous

Figure 2. CT chest with contrast in the axial plane revealed small bilateral pleural effusions without other acute intrathoracic abnormalities

CT: Computed tomography

Figure 3. CT abdomen and pelvis with contrast in the coronal plane revealed no lesions or hyperplasia of the adrenals and no evidence of acute intra-abdominal or pelvic abnormalities

CT: Computed tomography

Figure 4. T1 weighted MRI brain in the sagittal (a) and coronal (b) planes revealed no mass, acute infarct, hemorrhage, or edema

MRI: Magnetic resonance imaging