Hyperphosphatemia

Jas hyperphosphatemia we refer to plasma phosphate levels > 2.3 mmol / l in infants, 1.6 mmol / l in older children.

Etiology
It occurs as a result of increased exogenous intake or endogenous translocation (eg tumorolysis), increased intestinal absorption, decreased renal excretion or as pseudohyperphosphataemia (analytical causes).
 * Hypoparathyroidism
 * Pseudohypoparathyroidism
 * Hypervitaminosis D
 * Hyperthyroidism
 * Excessive P dietary intake - dairy products
 * Cell lysis syndrome
 * Osteoblastic metastases

Clinical manifestations
Elevated inorganic phosphate in plasma leads to hypocalcemia and further to tetany. Increased Ca x P product in plasma induces precipitation of calcium salts in soft tissues, hypocalcemia occurs (inorganic phosphate also inhibits 1α-hydroxylation and thus reduces the production of 1,25-dihydroxyvitamin D3 → reduced absorption in the intestine). Ectopic calcification is a common complication in patients with chronic renal failure receiving vitamin D supplementation when correction for hyperphosphataemia is inadequate.

Therapy
The initial treatment is, as in the case of acute hypercalcemia, a 1/1 saline infusion of 20 ml / kg i.v. as a bolus. Our goal is hyperhydration, where we calculate the physiological daily fluid requirement as twice the norm. We co-administer  furosemide 1 mg / kg i.v. and we try to keep diuresis 3-5 ml / kg / hour. We reduce the intake of protein in the diet. In the extreme case, the indication is hemodialysis.

Related Articles

 * Phosphate
 * Hypophosphataemia
 * Disorders of calcium-phosphate metabolism
 * Pathophysiology of bone, calcium and phosphates

Source

 * HAVRÁNEK, J .: Dysbalance of other ions.
 * MASOPUST, Jaroslav and Richard PRŮŠA. Pathobiochemistry of metabolic pathways. 2nd edition. Charles University, 2004. 208 p.