Efficacy of direct injection of calcitriol into the parathyroid glands in uraemic patients with moderate to severe secondary hyperparathyroidism

Abstract

Introduction. Secondary hyperparathyroidism (2HPT) is a common complication in uraemic patients. When medical therapy, including high doses of intravenous calcitriol, fails to suppress the pathological secretion of parathyroid hormone (PTH), one of the newly developed interventional techniques, such as percutaneous ethanol injection therapy (PEIT), is an option before taking the surgical solution. A protocol for direct calcitriol injection therapy and a discussion of its effectiveness and limitations for an enlarged parathyroid gland(s) are presented. Methods. Nine patients were selected according to the Japanese Guideline for Selective PEIT. Using the same technique as PEIT, a dose of calcitriol that was ∼200-300% of the calculated volume of the selected parathyroid gland was injected directly into the gland under ultrasonographic guidance. Results. In six cases, the intact PTH concentration decreased to < 360 pg/ml. The total volume of the enlarged parathyroid gland(s) also decreased to 54.7% of the initial volume. The blood supply to the treated glands, as evaluated by colour Doppler imaging, appeared to diminish transiently after injection, probably from the volume effect of this procedure. The number of enlarged parathyroid glands was not a limiting factor for this therapy; however, a grossly enlarged parathyroid gland (> 2000 mm3) appeared to be resistant to this intervention and an intrathoracic parathyroid gland was found in a non-responsive case. None of the patients had any severe complications, such as nerve palsy or massive haemorrhage. Conclusion. This new approach to the control of 2HPT is recommended as an alternative pharmacological parathyroidectomy to surgical therapy.