Page 953 - Small Animal Internal Medicine, 6th Edition
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CHAPTER 53 Electrolyte Imbalances 925
Severe
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Mild
SERUM CALCIUM Normal range
Mild
Severe
Primary Hyper- Renal Vitamin D Nutritional Addison
HP calcemia failure toxicity 2 ° HP disease
of malignancy
Severe
SERUM PHOSPHORUS Normal range
Mild
Mild
Severe
Primary Hyper- Renal Vitamin D Nutritional Addison
HP calcemia failure toxicity 2 ° HP disease
of malignancy
FIG 53.1
The range in serum calcium and phosphorus concentrations for the more common causes
of hypercalcemia and/or hyperparathyroidism in the dog. HP, Hyperparathyroidism; 2°
HP, secondary hyperparathyroidism. (From Feldman EC, Nelson RW: Canine and feline
endocrinology and reproduction, ed 4, St Louis, 2015, Saunders Elsevier.)
can cause progressive mineralization of the kidney and and normal to low serum phosphorus concentrations are
eventual chronic kidney disease. Measurement of the serum identified. The most common malignancy is lymphoma. A
ionized calcium concentration may help identify dogs and careful review of the history and physical examination find-
cats with kidney disease–induced hypercalcemia; serum ings may provide clues to the diagnosis. Systemic signs of
ionized calcium concentrations are typically normal or illness suggest hypercalcemia of malignancy. Dogs and cats
decreased in kidney disease and increased in hypercalcemia with primary hyperparathyroidism are usually healthy, and
caused by other disorders. However, autonomous hyperse- clinical signs are mild. The appendicular skeleton, peripheral
cretion of PTH by the parathyroid gland and an increase lymph nodes, abdominal cavity, and rectum should be care-
in serum ionized calcium (i.e., tertiary hyperparathyroid- fully palpated for masses, lymphadenopathy, hepatomegaly,
ism) may occur albeit uncommonly in dogs and cats with splenomegaly, or pain on digital palpation of the long bones.
chronic kidney disease and long-standing renal secondary Diagnostic tests helpful in identifying an underlying malig-
hyperparathyroidism. nancy include thoracic and abdominal radiographs; abdomi-
Hypercalcemia of malignancy and primary hyperpara- nal ultrasound; cytologic evaluation of aspirates of the liver,
thyroidism are the primary differentials when hypercalcemia spleen, lymph nodes, and bone marrow; determination of
