Primary Hyperparathyroidism Due to Parathyroid Adenoma in a Post-Kidney Transplant Patient With Lupus Nephritis: A Case Report

Hyperparathyroidism is common in patients with existing chronic kidney disease (CKD), typically manifesting as secondary or tertiary hyperparathyroidism. We report a 47-year-old African American woman who initially presented with CKD secondary to lupus nephritis, as well as hyperparathyroidism, thought to be secondary to worsening kidney function. Following a kidney transplant, parathyroid hormone (PTH) was persistently elevated, at levels ranging from 370.4 to 614.9 pg/mL (reference range: 10-65 pg/mL) over the course of 12 months. Uptake on nuclear imaging demonstrated retained radionuclide along the posterior left thyroid lobe, which raised the suspicion for a diagnosis of primary hyperparathyroidism due to a parathyroid adenoma. The need for surgical intervention was supported, with the evidence obtained, and the patient was therefore treated with left inferior parathyroidectomy and has since had no complaints. This case highlights the importance of considering single-gland adenomatous pathology in post-transplant patients with persistent hyperparathyroidism, contrasted with multiple-gland hyperplasia seen in autonomous tertiary hyperparathyroidism, as expected in the usual circumstance.