Hiperkalcemija pri bolniku z rakom Hypercalcemia in cancer patients

Abstract

Hiperkalcemija je najpogostejša presnovna motnja, ki ogroža bolnika z rakom. Najpogostejša je pri solidnih rakih (rak pljuč, dojke), pogosta pa je tudi pri hematoloških malignomih (zlasti pri multiplem mielomu). Glavni vzrok hiperkalcemije zaradi rakave bolezni je povečana resorpcija kosti in nezadostno izločanje kalcija prek ledvic. Najpogostejši sta osteolitična in humoralna hiperkalcemija. Osteolitična je posledica večje kostne resorpcije, njeni mediatorji pa so različni citokini na mestu zasevka. Humoralna hiperkalcemija je posledica izločanja paratiroidnemu hormonu podobnega peptida (PTH-rP). Prvi znaki hiperkalcemije so žeja, poliurija, slabost, splošna utrujenost in zaprtje. Pri vrednosti serumskega kalcija nad 3,0 mmol/l se začnejo pojavljati znaki prizadetosti osrednjega živčevja, poveča se nevarnost za srčne aritmije, pri dalj časa trajajoči hiperkalcemiji lahko pride do okvare ledvic. Uspešno zdravljenje temelji na intenzivni hidraciji s fiziološko raztopino, vzpodbujanju izločanja kalcija z diuretiki po doseženi normovolemiji in zaviranju kostne resorpcije z bisfosfonati (zolendronatom, pamiodronatom ali ibandronatom). Vendar pa bomo hiperkalcemijo dolgotrajno uspešno obvladovali le, če bomo sočasno zdravili rakavo bolezen, ki je privedla do nje. Če zdravljenje maligne bolezni ni bilo uspešno, tudi zdravljenje hiperkalcemije ni smiselno.

Abstract (Eng)

Hypercalcemia is the most common life-threatening metabolic disorder in cancer patients. Solid tumors (such as lung or breast cancer) as well as certain hematologic malignancies (particularly multiple myeloma) are most frequently associated with hypercalcemia. The fundamental cause of cancer–induced hypercalcemia is increased bone resorbtion and inadequate renal clearance. The most common types of hypercalcemia are osteolytic and humoral. The osteolytic hypercalcemia results in increased local osteoclastic bone resorbtion mediated by different cytokines. Humoral hypercalcemia is caused by secretion of parathyroid hormone-related protein (PTH-rP). Early symptoms of hypercalcemia are thirst, polyuria, nausea, vomiting, fatigue and constipation. Signs and symptoms of central nerve system impairment and a higher risk of cardiac arrhythmias appear when serum calcium level rises beyond 3,0 mmol/l. Renal function deterioration could evolve in long-lasting hypercalcemia. The cornerstones of successful antihypercalcemic therapy are rehydration with normal saline, calciuresis with the use of loop diuretics after normovolemia has been restored and inhibition of bone resorbtion with the use of intravenous bisphosphonates (zolendronate, pamiodronate or ibandronate). However, long-term efficacy of cancer-induced hypercalcemia will be successful only if it is accompanied with the effective treatment of underlying malignant disease. When all available cancer therapies have failed, also treatment of hypercalcemia is of no sense.