Avaliação do cálcio sérico ionizado em gatos sadios e em gatos com insuficiência renal crônica / Serum ionized calcium evaluation in healthy cats and in cats with chronic renal failure

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Chronic renal failure (CRF) can cause many metabolic abnormalities in the body, and one of these is represented by alteration in calcium metabolism, and the animal can develop demineralization and calcification of soft tissues, including renal parenchyma, which can facilitate the progression of renal damage. In routine, calcium is usually evaluated by measurement of total serum calcium, however, the biologically active fraction is represented by ionized calcium. Thus, the aim of the present study was to evaluate serum ionized calcium in healthy cats and in cats with chronic renal failure. Twenty-five clinically normal cats (control group) and nineteen cats with CRF were evaluated, and serum ionized calcium, total calcium, sodium, potassium, chloride, phosphorus, albumin, as well as blood pH and blood gases parameters were measured. No difference between normal cats and cats with CRF concerning total calcium (control = 9.52 ± 0.96; CRF = 9.48 ± 0.96) and ionized calcium (control = 5.24 ± 0.18; CRF = 5.29 ± 0.53) were observed. In both groups, the fraction of ionized calcium represented more than 50% of total calcium value, and the data were different from those reported in the literature, mainly concerning dogs. In cats with CRF, when the data were evaluated individually, serum ionized calcium was increased in 31.6% of the animals and decreased in 15.8%; however considering serum total calcium, hypercalcemia was not detected in any of those cats and hypocalcemia was observed in 5.3%. In addition, from the cats with CRF that presented normocalcemia related to ionized calcium, only 50% of those animals showed normocalcemia when total calcium was determined. Difference between control group and the group of cats with CRF concerning phosphorus and some parameters of blood gases were detected, observing slight phosphatemia and metabolic acidosis. The presence of acidosis can possible result in decrease of albumin bound to calcium and in consequence justify the hypercalcemia related to ionized calcium observed in cats with CRF, but normocalcemia and hypocalcemia were also observed, showing the importance of the measurement of ionized calcium, because total serum calcium did not reflect the real status of calcium that is considered the biologically active form; in addition, other mechanisms that can compromise the ionized calcium fraction should be investigated.

ASSUNTO(S)

chronic renal failure calcium cálcio gatos cats insuficiência renal

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