1.
Reliability of calcium-phosphorus (Ca/P) ratio as a new, accurate and inexpensive tool in the diagnosis of some Ca-P disorders.
Madeo, B, De Vincentis, S, Kara, E, Vescini, F, Trenti, T, Guaraldi, G, Rochira, V
Journal of endocrinological investigation. 2019;(9):1041-1049
Abstract
PURPOSE The serum calcium/phosphorus (Ca/P) ratio is an accurate tool to differentiate patients with primary hyperparathyroidism (PHPT) from healthy subjects. However, other disorders of the Ca-P metabolism might impair the Ca/P ratio, such as hypophosphatemia (HypoP) not PHPT related. The aim of this study is to examine the diagnostic value of Ca/P ratio in the diagnosis of PHPT and HypoP not PHPT related. METHODS Single-center, retrospective, case-control study, including 150 patients with PHPT and 306 patients with HypoP, compared with 150 controls. HypoP patients were enrolled among HIV-infected patients by selecting those with Fanconi-like syndrome due to antiretroviral treatment. Parameters which were measured were serum Ca, P, parathyroid hormone (PTH), 25-OH vitamin D, albumin and creatinine). RESULTS The Ca/P ratio was significantly higher in PHPT and HypoP patients, compared to controls (p < 0.0001). At receiver operator characteristic (ROC) curve analysis, the cut-off of 3.56 (2.75 SI) for Ca/P ratio was able to identify patients with PHPT and HypoP (sensitivity 95%; specificity 93%). Among patients with Ca/P ratio above 3.56, the thresholds of 10.3 mg/dL (2.6 mmol/L) for serum Ca (sensitivity 93%; specificity 98%) and 80.5 pg/mL for PTH (sensitivity 91%; specificity 91%) were defined for the specific diagnosis of PHPT. CONCLUSIONS The Ca/P ratio above 3.56 (2.75 SI) is a highly accurate tool to identify PHPT and HypoP not PHPT-related patients. Thanks to its simplicity, this index can be proposed as a screening and first-line examination in the diagnostic work-up when a disorder of Ca-P metabolism is suspected or should be ruled out.
2.
Initial amino acid intake influences phosphorus and calcium homeostasis in preterm infants--it is time to change the composition of the early parenteral nutrition.
Bonsante, F, Iacobelli, S, Latorre, G, Rigo, J, De Felice, C, Robillard, PY, Gouyon, JB
PloS one. 2013;(8):e72880
Abstract
BACKGROUND Early aggressive parenteral nutrition (PN), consisting of caloric and nitrogen intake soon after birth, is currently proposed for the premature baby. Some electrolyte disturbances, such as hypophosphatemia and hypercalcemia, considered unusual in early life, were recently described while using this PN approach. We hypothesize that, due to its impact on cell metabolism, the initial amino acid (AA) amount may specifically influence the metabolism of phosphorus, and consequently of calcium. We aim to evaluate the influence of AA intake on calcium-phosphorus metabolism, and to create a calculation tool to estimate phosphorus needs. METHODS Prospective observational study. Phosphate and calcium plasma concentrations and calcium balance were evaluated daily during the first week of life in very preterm infants, and their relationship with nutrition was studied. For this purpose, infants were divided into three groups: high, medium and low AA intake (HAA, MAA, LAA). A calculation formula to assess phosphorus needs was elaborated, with a theoretical model based on AA and calcium intake, and the cumulative deficit of phosphate intake was estimated. RESULTS 154 infants were included. Hypophosphatemia (12.5%) and hypercalcemia (9.8%) were more frequent in the HAA than in the MAA (4.6% and 4.8%) and in the LAA group (0% and 1.9%); both p<0.001. DISCUSSION Calcium-phosphorus homeostasis was influenced by the early AA intake. We propose to consider phosphorus and calcium imbalances as being part of a syndrome, related to incomplete provision of nutrients after the abrupt discontinuation of the placental nutrition at birth (PI-ReFeeding syndrome). We provide a simple tool to calculate the optimal phosphate intake. The early introduction of AA in the PN soon after birth might be completed by an early intake of phosphorus, since AA and phosphorus are (along with potassium) the main determinants of cellular growth.
3.
Calciphylaxis: a devastating complication of derangements of calcium-phosphorus metabolism--a case report and review of the literature.
Carter, T, Ratnam, S
Nephrology nursing journal : journal of the American Nephrology Nurses' Association. 2013;(5):431-5; quiz 436
Abstract
Calciphylaxis is a rare and potentially devastating condition also referred to as uremic gangrene syndrome, calcific uremic arteriolopathy, metastatic calcification, and uremic small-vessel disease that can present in patients with end stage renal disease. This article reports a case of a 38-year-old African-American female on peritoneal dialysis for six years with a known history of non-adherence with diet, medications, and prescribed peritoneal dialysis treatment regimen. At her monthly clinic visit, the patient complained of burning sensation in the fingers of both hands with limited fine motor movement due to edema and severe pain. A presumptive diagnosis of calciphylaxis led to hospital admission with confirmation by X-ray of her hands. The patient was switched to hemodialysis with low calcium dialysate, aggressive reduction in phosphorus, diet counseling, use of cinacalcet, and six weeks of intravenous sodium thiosulfate infusion with hemodialysis treatments. The patient's condition improved with resolution of symptoms. This case was chosen based on the rarity of a calciphylaxis presentation and paucity of knowledge regarding diagnosis and treatment.
4.
Fuller Albright and our current understanding of calcium and phosphorus regulation and primary hyperparathyroidism.
Felsenfeld, AJ, Levine, BS, Kleeman, CR
Nefrologia : publicacion oficial de la Sociedad Espanola Nefrologia. 2011;(3):346-57
Abstract
The major contributions of Fuller Albright to our understanding of calcium and phosphorus regulation and primary hyperparathyroidism are highlighted. Albright was the first investigator to initiate a systematic study of mineral metabolism. With resources limited to the measurement of serum calcium and phosphorus and the infusion of parathyroid extract, Albright used balance studies to establish a framework for our understanding of calcium and phosphorus regulation and primary hyperparathyroidism. Albright was the first to show that the etiology of primary hyperparathyroidism could be from either an adenoma or hyperplasia of the parathyroid glands and stone disease was a separate manifestation of primary hyperparathyroidism. Albright also showed that: 1) a renal threshold for calcium excretion was present in hypoparathyroid patients; 2) correction of hypocalcemia in hypoparathyroid patients with vitamin D had a phosphaturic action; 3) renal failure reduced the intestinal absorption of calcium in primary hyperparathyroidism; 4) the ''hungry bone'' syndrome developed after parathyroidectomy in severe primary hyperparathyroidism; and 5) a target organ can fail to respond to a hormone. He also suggested that a malignant tumor could be responsible for ectopic hormone production. Finally, our review integrates the observations of Albright with our current knowledge of calcium regulation and disorders.
5.
Once-daily extended-release niacin lowers serum phosphorus concentrations in patients with metabolic syndrome dyslipidemia.
Hu, S, Shearer, GC, Steffes, MW, Harris, WS, Bostom, AG
American journal of kidney diseases : the official journal of the National Kidney Foundation. 2011;(1):181-2