The importance of measurement of ionised calcium in characterisation of diseases in a referral population of dogs with polyuria and polydipsia [chapter]

Sophie Broughton, Jessica Adamany, Alenka Hrovat
2020 BSAVA Congress Proceedings 2020  
OBJECTIVES To examine the utility of measuring the serum total calcium (tCa) and blood ionised calcium (iCa) concentration in a referral population of dogs presenting with polyuria and polydipsia (PUPD). METHODS Medical records of dogs presenting with PUPD and measured tCa and iCa were searched retrospectively between 2016 and 2019. RESULTS Forty five dogs met the inclusion criteria. The median serum tCa and blood iCa concentrations were 2.55 (range, 1.94-3.74 mmol/l) and 1.4 (range, 0.79-2.08
more » ... (range, 0.79-2.08 mmol/l), respectively. Hypercalcaemia was documented in 23/45 dogs. Nine dogs had increased both, tCa and iCa, with median values of 3.42 (range, 3.11-3.74; RI 2.1-3 mmol/l) and 1.88 (range, 1.46-2.08; RI 1.12-1.4 mmol/l)), respectively. Discordance between iCa and tCa in classifying calcium status occurred in 14/23 dogs; thirteen dogs had isolated ionised hypercalcaemia (iCa 1.49 (range, 1.42-1.73 mmol/l)); normal iCa with increased tCa was documented in one dog. Reliance on tCa alone would miss 41% of dogs with ionised hypercalcaemia. Diseases associated with increased tCa and iCa were neoplasia (5/9), CKD (1/9) and primary hyperparathyroidism (PHPTH) (3/9); diseases associated with isolated ionised hypercalcaemia were congenital portosystemic shunt (3/13), CKD (3/13), neoplasia (3/13), pyogranulomatous and immune mediated conditions (2/13) and PHPTH (2/13). Measurement of iCa was only paramount to the final diagnosis in two dogs diagnosed with PHPTH.
doi:10.22233/9781910443774.57.1 fatcat:tv7mfrrtgbc3jpnbeyislupwlm