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Calcium

Calcium. Hypercalcemia Hypocalcemia. Calcium. 99% of the bodies calcium is in the bone in calcium phosphate compounds. Calcium. Calcium ions serve many important roles in the body. Components of bone and teeth Responsible for the excitation and contraction of muscle cells

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Calcium

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  1. 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 HormonePTH • 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. PTHParathyroid 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. HypercalcemiaSymptoms • Often related to underlying disease • Lethargy • Weakness • PU/PD • Cardiac irregularities • Anorexia • +/- seizures and muscle twitching

  11. HypercalcemiaEtiology • 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 HormoneAnalysis • 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. HypercalcemiaDiagnosis • Total Calcium is routinely measured on chemistry panels.

  14. HypercalcemiaMalignant 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. HypercalcemiaHyperparathyroidism • Usually caused by adenomas of one of the parathyroid glands • Moans, groans, stones and bones

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

  17. HypercalcemiaTreatment • 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. HypercalcemiaPrognosis • 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. HypocalcemiaSymptoms • 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

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