Persisting Hypocalcemia After Surgical Parathyroidectomy: The Differential Effectiveness of Calcium Citrate Versus Calcium Carbonate With Acid Suppression

Assessment of Inorganic Phosphate Intake by the Measurement of the Phosphate/Urea Nitrogen Ratio in Urine

In chronic kidney disease (CKD) patients, it would be desirable to reduce the intake of inorganic phosphate (P) rather than limit the intake of P contained in proteins. Urinary excretion of P should reflect intestinal absorption of P(inorganic plus protein-derived). The aim of the present study is to determine whether the ratio of urinary P to urinary urea nitrogen (P/UUN ratio) helps identify patients with a high intake of inorganic P.A cross-sectional study was performed in 71 patients affected by metabolic syndrome with CKD (stages 2–3) with normal serum P concentration. A 3-day dietary survey was performed to estimate the average daily amount and the source of P ingested. The daily intake of P was 1086.5 ± 361.3 mg/day; 64% contained in animal proteins, 22% in vegetable proteins, and 14% as inorganic P. The total amount of P ingested did not correlate with daily phosphaturia, but it did correlate with the P/UUN ratio (p < 0.018). Patients with the highest tertile of the P/UUN ratio >71.1 mg/g presented more abundant inorganic P intake (p < 0.038).The P/UUN ratio is suggested to be a marker of inorganic P intake. This finding might be useful in clinical practices to identify the source of dietary P and to make personalized dietary recommendations directed to reduce inorganic P intake.

Targeted surgical parathyroidectomy in end-stage renal disease patients and long-term metabolic control: A single-center experience in the current era

BACKGROUND

The long-term results of surgical parathyroidectomy (PTX) in end-stage renal disease (ESRD) patients are less well known in the modern era of newer activated vitamin-D analogs, calcimimetics and intraoperative monitoring of parathyroid hormone (PTH).

METHODS

We performed a retrospective chart review of all ESRD patients undergoing PTX at the University of Mississippi Medical Center between January 2005 and August 2011, with follow-up data as available up to 4 years. All PTXs were performed with intraoperative second-generation PTH monitoring and targeted gland size reduction.

RESULTS

The cohort (N = 37) was relatively young with a mean (±SD) age of 48.4 ± 13.9. 94.6% of the subjects were African American and 59.5% female. Preoperatively, 45.9% received cinacalcet (CNC) at a mean dose of 63.5 ± 20.9 mg. The size of the largest removed glands measured 1.7 ± 0.8 cm and almost all (94.6%) glands had hyperplasia on histology. The mean length of inpatient stay was 5.5 ± 2.4 days. Preoperative calcium/phosphorus measured 9.6 ± 1.2/6.6 ± 1.7 mg/dL with PTH concentrations of 1589 ± 827 pg/mL. Postoperative PTH values measured 145.4 ± 119.2 pg/mL. Preoperative PTH strongly correlated (P < 0.0001) with both alkaline phosphatase (ALP) levels (r: 0.596) and the number of inpatient days (r: 0.545), but not with CNC administration. Independent predictors for the duration of hospitalization were preoperative ALP (beta 0.469; P = 0.001) and age (beta -0.401; P = 0.005) (R² 0.45); for postoperative hypocalcemia, age (beta: -0.321; P = 0.006) and preoperative PTH (beta: 0.431; P = 0.036) were significant in linear regression models with stepwise selection.

CONCLUSION

Gland-sparing PTX achieved acceptable control of ESRD-associated hyperparathyroidism in most patients from a socioeconomically challenged, underserved population of the United States.

Denosumab-Associated Severe Hypocalcemia in a Patient With Chronic Kidney Disease

Denosumab is a monoclonal antibody directed against the receptor activator of nuclear factor kappa B ligand (RANKL). Denosumab has been shown to reduce the risk of skeletal-related events, including spinal cord compression, pathologic fracture and hypercalcemia of malignancy in patients with bone metastases. Hypocalcemia is a known side effect of denosumab, occurring in an estimated 8-14% of the patients. Here, we present an asymptomatic patient with stage-5 chronic kidney disease and severe hypocalcemia who had received denosumab 1 month earlier.

Peritoneal dialysis: The unique features by compartmental delivery of renal replacement therapy

Despite decades of research, the clinical efficacy of peritoneal dialysis (PD) remains enigmatic. We may wonder why the modality fail in some patients but perhaps the more proper question would be, why it works in so many? We know that the contribution of residual renal function (RRF), more so than in hemodialysis, is critically important to the well-being of many of the patients. Unique features of the modality include the relatively low volume of dialysate fluid needed to provide effective uremic control and the disproportionate tendency for both hypokalemia and hypoalbuminemia, when compared to hemodialysis. It is currently believed that most uremic toxins are generated on the interface of human and bacterial structures in the gastrointestinal tract, the intestinal biota. PD offers disproportionate removal of these toxins upon "first-pass", i.e., via PD fluid exchanges before reaching the systemic circulation beyond the gastrointestinal compartment. Studies examining the net removal gradient of protein-bound uremic toxins during PD are scarce, whereas RRF receives considerably more attention without effective interventions being developed to preserve it. We propose an alternative view on PD, emphasizing the modality's compartmental nature, both for its benefits and the limitations.