Calcium phosphorus product

These adaptations are lost as renal failure progresses. [Ca] X [POJ calcium-phosphorus product. (From Joy MS, Kshirsagar A, Paparello J. Chronic kidney disease Progression-modifying therapies. In DiPiro JT, Talbert RL, Yee GC, et al, (eds.) Pharmacotherapy A Pathophysiologic Approach. 6th ed. New York McGraw-Hill 2005 834, with permission.)... 

TABLE 23-4. Target Levels for Calcium, Phosphorus, Calcium-Phosphorus Product, and Intact Parathyroid Hormone... 

Ca-P, calcium-phosphorus product CKD, chronic kidney disease PTH, parathyroid hormone. 

The K/DOQI guidelines provide desired ranges of calcium, phosphorus, calcium-phosphorus product, and intact PTH based on the stage of CKD (Table 76-2). Measurements should be repeated every 12 months for stage 3, every 3 months for stage 4, and more frequently for stage 5. 

Calcium phosphorus product (CPP) is generally regarded as an indicator of the likelihood of calcium phosphate precipitation in human tissues and, more specifically, the renal tubules. Based on the normal serum concentration ranges for calcium and phosphorus, the normal range for CPP is 21 to 47.3. Following the use of OSPS, serum phosphorus and CPP transiently increase and the duration and magnitude of this change are likely to be important risk factors for the development of APhN. 

Figure 6. Postulated pathogenesis of NSF (Explanation in the text). Abbreviations GFR, glomerular filtration rate CaxP, calcium-phosphorus product NSF, nephrogenic systemic fibrosis IV, intravenous GCCA, gadolinium-containing contrast agents.

Ca X P calcium phosphorus product serum calcium multiplied by serum phosphorus CKD chronic kidney disease CPK creatine phosphokinase DEO deferoxamine EPO erythropoietin ESKD end-stage kidney disease ESRD end-stage renal disease FEk fractional excretion of potassium FEn fractional excretion of sodium GFR glomerular filtration rate Hct hematocrit HDL high-density fipoprotein Hgb hemoglobin... 

Finally, intravenous phosphate may rapidly reduce ionized calcium concentrations through the formation of insoluble calcium-phosphate salts. However, intravenous phosphate is extremely hazardous because extraskeletal precipitation of calcium-phosphate may result in metastatic calcification, hypotension, acute renal failure, or death. Therefore intravenous phosphates should be reserved for the extraordinary patient with severe hypercalcemia and concomitant hypophosphatemia. Oral phosphorus is not used chronically for the treatment of hypercalcemia because calcium-phosphate crystals may precipitate in the kidneys or other major organs when the calcium-phosphorus product is > 50 to 60 mg /dL . Serum calcium, phosphorus, and creatinine should be monitored closely. Oral phosphorus treatment is only indicated when there is concomitant hypophosphatemia (<2 mg/dL). 

Severe symptomatic hyperphosphatemia manifesting as hypocalcemia and tetany should be treated by the intravenous administration of calcium salts (see the discussion of hypocalcemia). Although this may seem counterintuitive in a patient with a phosphorus of 16 mg/dL and a calcium of 7 mg/dL (the calcium-phosphorus product is 112 mg /dL ), correction of severe hypocalcemia is of primary importance because of the critical nature of this disorder. In general, the... 

Because phosphorus is excreted renally, hyperphosphatemia is common in ARF. Like potassium, large amounts of phosphorus are released into the circulation secondary to tissue breakdown during ARF. Control of hyperphosphatemia is important because as the calcium-phosphorus product (serum calcium in milligrams per deciliter multiplied by serum phosphorus in milligrams per deciliter) exceeds 55, the risk of developing metastatic calcification increases (see Chap. 44). Conversely, with initiation of dialysis, particularly CRRT, patients must be monitored for dialysis-induced hypophosphatemia. 

The increased serum phosphorus binds to calcium in the serum, which leads to deposition of hydroxyapatite crystals throughout the body. The calcium-phosphorus (Ca-P) product reflects serum solubility. A Ca-P product greater than 75 mg2/dL2 promotes crystal deposition in the joints and eye, leading to arthritis and conjunctivitis, respectively. Soft tissue deposition primarily affects the coronary arteries of the heart, lungs, and vascular tissue and is associated with a Ca-P product greater than 55 mg2/dL2.36 The Ca-P product has been associated with increased mortality37 and is a risk factor for calcification of vascular and soft tissues.35... 

Parathyroidectomy is a treatment of last resort for sHPT, but should be considered in patients with persistently elevated iPTH levels above 800 pg/mL (800 ng/L) that is refractory to medical therapy to lower serum calcium and/or phosphorus levels.39 A portion or all of the parathyroid tissue may be removed, and in some cases a portion of the parathyroid tissue may be transplanted into another site, usually the forearm. Bone turnover can be disrupted in patients undergoing parathyroidectomy whereby bone production outweighs bone resorption. The syndrome, known as hungry bone syndrome, is characterized by excessive uptake of calcium, phosphorus, and magnesium for bone production, leading to hypocalcemia, hypophosphatemia, and hypomagnesemia. Serum ionized calcium levels should be monitored frequently (every 4 to 6 hours for the first 48 to 72 hours) in patients receiving a parathyroidectomy. Calcium supplementation is usually necessary, administered IV initially, then orally (with vitamin D supplementation) once normal calcium levels are attained for several weeks to months after the procedure. 

Milk is an excellent source of calcium, phosphorus, riboflavin (vitamin B2), thiamine (vitamin Bl) and vitamin B12, and a valuable source of folate, niacin, magnesium and zinc (Food Standards Agency, 2002). In particular, dairy products are an important source of calcium, which is vital for maintaining optimal bone health in humans (Prentice, 2004). The vitamins and minerals it provides are all bioavailable (i.e. available for absorption and use by the body) and thus milk consumption in humans increases the chances of achieving nutritional recommendations for daily vitamins and mineral intake (Bellew et al., 2000). 

The importance of nutrition in the dental caries problem is reviewed in 90 pages by Shaw.22 Although we have indicated that metabolic peculiarities in the area of mineral metabolism seem "most likely to be pertinent" to the dental caries problem (p. 218), it does not follow that interest should be restricted to this field. Because teeth are organic structures produced as the result of metabolic processes, there is not a single vitamin, amino acid, or other nutrient factor which may not be implicated in the disease. Probably many different deficiencies are involved in the production of the sum total of all caries existing in all individuals. Much evidence, of course, has been found to indicate the importance of calcium, phosphorus, and vitamin D, but other items may also be very important. 

The manufacture of phosphorus-derived chemicals is almost entirely based on the production of elemental phosphorus from mined phosphate rock. Ferrophosphorus, widely used in the metallurgical industries, is a direct byproduct of the phosphorus production process. In the United States, over 85% of elemental phosphorus production is used to manufacture high-grade phosphoric acid by the furnace or dry process as opposed to the wet process that converts phosphate rock directly into low-grade phosphoric acid. The remainder of the elemental phosphorus is either marketed directly or converted into phosphoms chemicals. The furnace-grade phosphoric acid is marketed directly, mostly to the food and fertilizer industries. Finally, phosphoric acid is employed to manufacture sodium tripolyphosphate, which is used in detergents and for water treatment, and calcium phosphate, which is used in foods and animal feeds. 

Food and feed additives do not stand back with regard to the diversity of products. They extend from minerals, mainly calcium, phosphorus, and potassium, to amino acids, vitamins and natural spices. All in all, there are several hundred individual compounds used as feed and food additives. The most expensive product is saffron, made from the stigmas of the saffron crocus flower. The yearly production amounts to about 700,000 kg, and the spice is retailing for about 2500/kg. Amino acids play a big role the largest product is monosodium glutamate (MSG), with a yearly production of 1.5-2 million tons and a price of about 2.30 per kilogram, followed by L-lysine (850,000 tons/ 1.50/kg), D,L-methionine (600,000 tons/ 3/kg), L-threonine (85,000 tons, 3.40/kg), and L-tryptophane (1750 tons/ 24/kg). Major producers of... 

Milk Products Moisture (%) Protein (%> Total Fat (%> Total Carbo- hydrate (%> Ash (%) Calcium <%> Phosphorus (%) Sodium (%) Potassium (%) Lactic Acid <%)... 

Product Calcium Phosphorus Magnesium Sodium Potassium... 

The many diverse components of milk have demonstrable effects on human health. Perhaps, the most commonly associated component of dairy food is that of dietary calcium. Dairy products provide the most significant contribution to dietary calcium intake in the modem Western diet. It has been estimated that dairy products contribute to >72% of dietary calcium in the United States (Huth et al., 2006). Calcium is an important mineral for maintenance of optimal bone health (Bonjour et al., 2009) and is an integral component of key metabolic pathways relating to, for example, muscle contraction both in skeletal and smooth muscle (Cheng and Lederer, 2008). Further, dairy products contribute other essential nutrients in the diet, such as proteins, phosphorus, potassium, zinc, magnesium, selenium, folate, riboflavin, vitamin B12, and vitamin A (Haug et al., 2007 Huth et al., 2006). Low-fat milk alternatives are fortified with vitamin A and vitamin D which is added to milk and fermented milk in many countries making it an important source for vitamin D (Huth et al., 2006). 

Fluorine never occurs as a free element in nature. The most common fluorine minerals are fluorspar, fluorapatite, and cryolite. Apatite is a complex mineral containing primarily calcium, phosphorus, and oxygen, usually with fluorine. Cryolite is also known as Greenland spar. (The country of Greenland is the only commercial source of this mineral.) It consists primarily of sodium aluminum fluoride (Na3ALF6). The major sources of fluorspar are China, Mexico, Mongolia, and South Africa. In 2008 in the United States, fluorspar was produced as a by-product of limestone quarrying in Illinois. The United States imports most of the fluorspar it needs from China and Mexico. 

Derivation (1) Calcium reduction of vanadium pentoxide yields 99.8+% pure ductile vanadium (2) aluminum, cerium, etc. reduction produces a less pure product (3) solvent extraction of petroleum ash or ferrophosphorus slag from phosphorus production (4) electrolytic refining using a molten salt electrolyte containing vanadium chloride. 

A single, present-day phosphorus furnace produces from 60 to 160 tonnes of phosphorus per day, almost the same as the annual production figures of the early arc furnaces, and requires a power supply of about 90,000 kW for a single, 160 tonne/day furnace. Power consumption per tonne of phosphorus produced varies with the % calcium phosphate in the rock (% BPL level) and furnace size among other factors but ranges around 12,000-14,000 kWh/ tonne (Table 10.4). Hence, power is a major cost component of electric furnace phosphorus production. This realization has prompted a reexamination of fossil-fueled (petroleum coke-based) sources of heat for rotary kiln combustion to provide the energy of the endotherm of the reaction [15]. 

Although the commercial manufacture of the element phosphorus did not develop until the 183O s and by 1844 the total phosphorus production in Great Britain was estimated at only 0.75 tons per year already in 1845 Thenard synthesized the first organophosphorus compounds by the interaction of calcium phosphide (or phosphorus and calcium) and methyl chloride. Today elemental phosphorus is readily and cheaply available. Its high reactivity makes it an excellent starting material for the synthesis of organic phosphorus compounds. 

Ca3(P04)2. This compound is treated with carbon to reduce phosphorus from P(V) in PO4 to P(0) in P4 and with silica, Si02, to keep the calcium-containing products molten for easy removal from the furnace. TTie impure P4 is purified by sublimation and then oxidized with O2 to form P4O10, which is hydrated to form pure H3PO4. 

Parenteral phosphorus supplementation is associated with risks of hyperphosphatemia, metastatic soft tissue deposition of calcium-phosphate product, hypomagnesemia, hypocalcemia, and hyperkalemia or hypernatremia (caused by intravenous phosphorus salt) (Table 49-9). Inappropriate administration of large doses of parenteral phosphorus over relatively short time periods has resulted in symptomatic hypocalcemia and soft-tissue calcification. The rate of infusion and choice of initial dosage should therefore be based on severity of hypophosphatemia, presence of symptoms, and coexistent medical conditions. Patients should be closely monitored with frequent (every 6 hours) serum phosphorus determinations for 48 to 72 hours after starting intravenous therapy. It may be necessary to continue administration of intravenous phosphorus for several days in some patients, while other patients may be able to tolerate an... 

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