Hungry bone syndrome after parathyroidectomy in end-stage renal disease patients: review of an alkaline phosphatase-based treatment protocol.

AIM: Hyperparathyroidism in chronic kidney disease-mineral and bone disorder is associated with significant morbidity and mortality. Parathyroidectomy is widely carried out as treatment despite complications such as hypocalcaemia post-surgery. Our centre has been using an ALP-based protocol to replace calcium postoperatively to prevent hypocalcaemia. We aim to describe and audit our calcium replacement protocol post-parathyroidectomy METHODS: We, retrospectively, analyse 167 end-stage kidney disease patients who had parathyroidectomy with auto-implantation in Singapore General Hospital between January 2008 and December 2013. Their calcium replacement postoperatively was initiated upon patient arrival back in ward on the same day of surgery based on their pre-op ALP prior to occurrence of hypocalcaemia. Patient demographics, surgical and laboratory parameters were reviewed from medical records. Changes in calcium postoperatively were reported to look for incidence of calcium derangement.

RESULTS: Mean calcium levels between pre-operation day and post-operation day 7 ranged from 2.31 to 2.70 mmol/L. Decline in serum calcium was common in all patients prior to starting calcium replacement. Eighteen patients (10.9%) experienced hypocalcaemia immediately post-operation prior to commencement of IV calcium replacement. Patients with immediate post-operation hypocalcaemia had lower pre-operation calcium but higher pre-operation alkaline phosphatase (ALP) and pre-operation intact parathyroid hormone. Hypercalcaemia is common likely from aggressive IV calcium replacement using the protocol. The average length of stay for patients prior to calcium stabilization and discharge was 9 days.

CONCLUSION: Implementation of an ALP-based prophylactic calcium replacement protocol with daily serum calcium monitoring can ameliorate severe hypocalcaemia post-parathyroidectomy.