1. Hypercalcemia Hypocalcemia
Calcium
Hypercalcemia
Hypocalcemia

2. Calcium
99% of the bodies calcium is in the bone in calcium phosphate compounds

3. Calcium Calcium ions serve many important roles in the body.
Components of bone and teeth
Responsible for the excitation and contraction of muscle cells
Important is regulating cardiac function
Required for nerve function
Activates metabolic enzymes
Serves as a cofactor for several blood-clotting proteins

4. Calcium Regulation Calcium homeostasis
Total blood calcium is usually 10 mg/dl

5. Ionized Calcium
Ionized calcium is considered the biologically active form of calcium and is the component that regulates the secretion of PTH.
Total calcium is made up of three components :protein bound calcium, ionized calcium and calcium that is complexed with other anions such as phosphate, citrate, bicarbonate and lactate

6. Thyroid Parathyroid

7. Parathyroid Hormone PTH
Parathyroid glands are found in all air-breathing vertebrates
The parathyroid glands act to increase serum calcium via production of parathyroid hormone (PTH).
Parathyroid gland cells have receptors for ionized Calcium that regulate secretion of PTH in a tight negative-feedback relation.
Small increases in ionized calcium inhibit secretion of PTH and small decreases of ionized calcium prompt the release of PTH

8. PTH Parathyroid Hormone
The primary function of PTH is to elevate the serum ionized Ca++ concentration.
This is accomplished by
1. Stimulating bone resorption (dissolution)
2. Increase the Reabsorption of Ca++ in the kidneys
3. Decrease renal Phosphate reabsorbtion
4. Stimulate activation of Vit D in the kidneys
Vit D increases the efficiency of Ca absorption in the small intestine

9. Hypercalcemia
Calcium is intimately involved with muscle and nerve function
The biologically active form of calcium is the ionized portion
Ionized calcium has a negative feedback on parathyroid hormone (PTH) production
Normal total blood calcium levels are 10mg/dl
Clinical signs appear around 15mg/dl

10. Hypercalcemia Symptoms
Often related to underlying disease
Lethargy
Weakness
PU/PD
Cardiac irregularities
Anorexia
+/- seizures and muscle twitching

11. Hypercalcemia Etiology
Laboratory error
Hypercalcemia of malignancy
Addison’s disease (30-40%)
Primary hyperparathyroidism
Granulomatous disease (Blasto, Cocci)
Cholecalciferol rodenticide poisoning
Bone cancer
Bone infection (osteomyelitis)

12. Parathyroid Hormone Analysis
Measurement of PTH currently is accomplished using commercially available immunoradiometric assays (IRMAs) for human PTH.
PTH degrades quickly . Samples are usually frozen. Large commercial labs and the University of Michigan can run the analysis

13. Hypercalcemia Diagnosis
Total Calcium is routinely measured on chemistry panels.

14. Hypercalcemia Malignant Causes
>40% of all cases of hypercalcemia in dogs and <30% in cats are caused by malignant tumors.
Humoral Hypercalcemia of Malignancy (HHM)-Parathyroid hormone related protein. (PTHrP)
1. Lymphosarcoma (especially medianstinal forms)
2. Adenocarcinoma of the anal sacs
3. Multiple Myeloma

15. Hypercalcemia Hyperparathyroidism
Usually caused by adenomas of one of the parathyroid glands
Moans, groans, stones and bones

16. Hyperparathyroidism Treatment
Treat and lower the hypercalcemia
Surgically remove all enlarged thyroid glands
Hypocalcaemia commonly occurs after surgery

17. Hypercalcemia Treatment
1. Detecting and treating the underlying cause
2. Fluid therapy preferably with .9%NaCl
3. Furosemide (lasix) diuretic
4. Prednislone reduces calcium reabsorbtion
5. Calcitonin (thyroid)

18. Hypercalcemia Prognosis
1. Primary Hyperparathyroidism
2. Malignant Hypercalcemia
3. Assorted diseases

19. Hypocalcemia
A common biochemical abnormality in dogs and cats caused by numerous conditions. Common conditions associated with Hypocalcemia are puerperal tetany, iatrogenic hypoparathyroidism and primary hypoparathyroidism

20. Hypocalcemia 1. Puerperal tetany-Eclampsia 2. Hypoparathyroidism
3. Renal failure
4. Pancreatitis
5. Antifreeze, ethylene glycol toxicity

21. Hypocalcemia Symptoms
Tetany, Stiff gait, muscle fasciculations and generalized tremors
Facial rubbing and pawing
Generalized seizures
Drooling (cats)
Hyperthermia**
Panting and Hyperventilation**
Puerperal tetany usually occurs postpartum but can occur near the end of pregnancy

22. Laboratory Findings Physical Examination
Medical History-Recent Thyroid surgery
Low Total blood calcium