Veterinary Medicine - July 2008 - (Page 402)

Feline hypercalcemia PEER-REVIEWED This protein is called parathyroid hormonerelated protein (PTH-rP), and it binds with PTH receptors in bone and kidney. In normal animals, PTH-rP concentrations are essentially undetectable, but one of the mechanisms for paraneoplastic hypercalcemia is the release of PTH-rP by malignant tissues.12 In dogs, PTH-rP production has also been documented in association with in ammatory disorders, but that is not the case in cats.13 Although PTH-rP is not a highly sensitive marker for cancer in cats, it is regarded as speci c. Consequently, an elevated concentration strongly suggests malignancy. Various types of carcinoma (e.g. squamous cell, bronchogenic, renal, thyroid) and lymphoma are most often associated with PTH-rP secretion in cats.2,12 12. Vitamin D concentration Vitamin D metabolism is complex, as dietary sources require hepatic and renal activation to become metabolically active. Elevated serum vitamin D concentrations indicate excessive dietary supplementation or accidental ingestion of a cholecalciferol rodenticide. However, the standard vitamin D assay only measures 25-hydroxycholecalciferol; some potent vitamin D CE You can earn two hours of Continuing Education credit from Kansas State University by answering the following questions on feline hypercalcemia. Circle only the best answer for each question, and transfer your answers to the form on page 404 or take the test online at https://outreach.ksu.edu/ce/. This test expires August 1, 2009. a. Total calcium concentrations are decreased. b. Ionized calcium concentrations are normal. c. PTH-rP concentrations are increased. d. The PTH concentration is normal or increased. e. Vitamin D concentrations are usually increased. PTH-rP concentrations in cats. e. The assay for PTH-rP cross-reacts with the feline PTH assay. 1. Which of the following is an accurate deﬁnition of true hypercalcemia? a. Elevated tCa concentration b. Elevated corrected serum calcium concentration c. Elevated iCa concentration d. Elevated iCa and complexed serum calcium concentrations e. Normal corrected serum calcium concentration but elevated tCa concentration 8. Thoracic radiography should be considered in a hypercalcemic cat for which reason? a. To screen for neoplastic and granulomatous disease b. To screen for heartworm disease c. To evaluate cardiac status d. To look for evidence of tissue mineralization e. To identify ectopic parathyroid tissue 6. In cats with chronic kidney disease: a. An increased total serum calcium concentration indicates true hypercalcemia. b. Mild hypercalcemia (tCa < 13 mg/ dl) is probably secondary to renal compromise. c. Elevated serum creatinine concentrations affect the measurement of iCa concentrations. d. PTH-rP concentrations are usually elevated. e. Calcitriol overdose can be identiﬁed by using standard vitamin D assays. 2. Which of these clinical signs is not associated with hypercalcemia? a. Facial pruritus and hair loss b. Anorexia c. Polyuria and polydipsia d. Vomiting e. Twitching 9. Cats with hyperthyroidism: a. Commonly exhibit hypercalcemia b. May also have increased PTH concentrations c. Commonly have concurrent primary hyperparathyroidism d. Usually exhibit decreased PTH concentrations e. Have thyroid carcinomas if their PTH concentration is increased 3. Which of these disorders is associated with hypercalcemia in cats? a. Calcium oxalate urolithiasis b. Bacterial cholangitis c. Heartworm infection d. Feline asthma e. Hyperadrenocorticism 7. When measuring PTH-rP concentrations in cats, keep in mind that: a. PTH-rP concentrations are always elevated in cats with renal compromise. b. A low PTH-rP concentration rules out neoplasia in hypercalcemic cats. c. Lymphoma and various carcinomas are commonly associated with elevated PTH-rP concentrations. d. Inﬂammatory diseases are commonly associated with increased 4. Which of the following is a common cause of feline hypercalcemia? a. Neoplasia b. Osteolytic disease c. Granulomatous disease d. Hypoadrenocorticism e. Nutritional imbalance 5. In cats with primary hyperparathyroidism, which test results are expected? 10. Immediate therapy for hypercalcemia should be considered if: a. The calcium-phosphorus product is 70 c. The serum calcium concentration is 13 mg/dl d. Serum PTH concentrations are elevated e. Serum phosphorus concentrations are subnormal 402 July 2008 VETERINARY MEDICINE https://outreach.ksu.edu/ce/

Table of Contents Feed for the Digital Edition of Veterinary Medicine - July 2008

Veterinary Medicine - July 2008 Contents Leading Off Practical Matters Idea Exchange Clarification Dental Corner The Diagnostic Approach to Hematuria Guidelines for Evaluating Hypercalcemic Cats CE Form Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - July 2008

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