Ionized hypercalcemia in 238 cats from a referral hospital population (2009‐2019)

Broughton, Sophie E.; O'Neill, Dan G.; Syme, Harriet M.; Geddes, Rebecca F.

Abstract

Background
Ionized calcium concentration ([iCa]) is more sensitive for detecting calcium disturbances than serum total calcium concentration but literature on ionized hypercalcemia in cats is limited. Urolithiasis is a possible adverse consequence of hypercalcemia.

Hypothesis/Objectives
To describe clinical details of diagnoses associated with ionized hypercalcemia in cats and association with urolithiasis.

Animals
Cats (238) seen between 2009 and 2019 at a referral hospital with [iCa] above the normal reference interval.

Methods
Observational cross-sectional study. Signalment, serum biochemical and imaging findings were reviewed for cats with ionized hypercalcemia considered to be clinically relevant (>1.41 mmol/L). Data were summarized by cause of hypercalcemia (i.e., diagnosis).

Results
Diagnoses for the 238 cats with [iCa] >1.41 mmol/L included: acute kidney injury (AKI; 13%), malignancy-associated (10.1%), idiopathic hypercalcemia (IHC; 10.1%), chronic kidney disease/renal diet-associated (8.4%), iatrogenic (5.5%), primary hyperparathyroidism (2.1%), vitamin D toxicity (2.1%) and granulomatous disease (1.7%). In 112 cases (47.1%), no cause for ionized hypercalcemia could be determined (n = 95), hypercalcemia was transient (n = 12), or the cat was juvenile (<1 year; n = 5). Urolithiasis was identified in 83.3% of AKI, 72.7% of iatrogenic, 61.1% of CKD/renal diet-associated and 50% of IHC cases that were imaged (<50% for other diagnoses). Diagnoses with a high proportion of concurrent total hypercalcemia included primary hyperparathyroidism (100%), vitamin D toxicity (100%), malignancy-associated (71.4%), granulomatous disease (66.7%) and IHC (65.2%).

Conclusions and Clinical Importance
Ionized hypercalcemia was most commonly associated with kidney diseases, neoplasia or IHC. The proportion of urolithiasis cases varied by diagnosis.

Citation

Broughton, S. E., O'Neill, D. G., Syme, H. M., & Geddes, R. F. (in press). Ionized hypercalcemia in 238 cats from a referral hospital population (2009‐2019). Journal of Veterinary Internal Medicine, https://doi.org/10.1111/jvim.16627

• Journal Article Type: Article
• Acceptance Date: Dec 15, 2022
• Online Publication Date: Jan 16, 2023
• Deposit Date: Jan 19, 2023
• Publicly Available Date: Jan 19, 2023
• Journal: Journal of Veterinary Internal Medicine
• Print ISSN: 0891-6640
• Electronic ISSN: 1939-1676
• Publisher: Wiley Open Access
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1111/jvim.16627
• Keywords: General Veterinary
• Additional Information: Received: 2022-07-29; Accepted: 2022-12-15; Published: 2023-01-16