RENAL OSTEODYSTROPHY

A CHRONIC RENAL DISORDER DUE TO DEFECIENCY OF 25-OHCHOLECALCIFEROL

1. RENAL OSTEODYSTROPHY BY HARSHAD KHAN SIRAJ GROUP 16 TBILISI STATE MEDICAL UNIVERSITY

2. IN CHRONIC RENAL FAILURE, A CHAIN OF EVENTS LEADS TO RENAL OSTEODYSTROPHY THE RENAL FAILURE RESULTS IN THE INABILITY TO PRODUCE 1,25- DIHYDROXYCHOLECALCIFEROL (CALCITROL) WHAT IS OSTEODYSTROPHY

3. VITAMIN D IS CONSIDERED AS A PROVITAMIN THAN VITAMIN CHOLECALCIFEROL (D30 IS PRODUCED FROM SUNLIGHT IN SKIN THUS A LONG EXPOSURE OF SKIN IN SUNLIGHT DOESNOT REQUIRE DIETARY INTAKE CHOLECALCIFEROL IS MAINLY METABOLIZED IN LIVER WHERE 25-HYDROXYCHOLECALCIFEROL IS FORMED BIOCHEMISTRY

4. METABOLISM OF CHOLECALCIFEROL 25-HYDROXYCHOLECALCIFEROL IS CONVERTED TO BIOLOGICALLY ACTIVE 1- α ,25DIHYDROXYCHOLECALCIFEROL THIS IS CALLED CALCITROL THIS IS USUALLY DONE BY AN ENZYME 25-HYDROXYVITAMIN D-1- α HYDROXYLASE

5. KIDNEYS APPEAR AS A MAJOR SOURCE OF 1- α 25 DIHYDROXYCHOLECALCIFEROL ALSO SOME OF THE MAJOR TISSUES INCLUDING BREAST,PROSTRATE,COLON SYNTHESIS

6. THE REDUCTION IN LEVEL OF CALCIUM IN SERUM RESULTS IN THE INCREASED LEVEL OF PHOSPHATE RESULTING IN THE CONDITION OF HYPERPHOSPHATEMIA THE SERUM PHOSPHATE LEVELS ARE OFTEN HIGH ENOUGH TO METASTISE CALCIUM i.e CALCIFICATION OF SOFT TISSUES IT TENDS TO LOWER SERUM CALCIUM LEVELS DISEASE

7. PARATHYROID HORMONE FURTHER HYPERPHOSPHATEMIA AND HYPOCALCEMIA STIMULATE PARATHYROID HORMONE SECRETION THIS CONDITION LEADS TO DEMINERALIZATION OF BONES

8. TREATMENT ADMINISTRATION OF VITAMIN D IS NOT SUFFICIENT BECAUSE OF COMBINATION OF HYPERPHOSPHATEMIA AND HYPOCALCEMIA IT LEADS TO EXTENSIVE METASTASTIC CALCIFICATION THE HIGH DOSES OF VITAMIN D MUST BE ACCOMPANIED BY PHOSPHATE REDUCTION BUT IT IS DIFFICULT TO TEDUCE DIRECTLY PHOSPHATE BECAUSE MOST PROTEIN SOURCES ARE HIGH IN CALCIUM

9. IN THIS REGARD VEGETABLE PROTEINS IS BETTER CHOICE THAN ANIMAL PROTEIN THIS IS BECAUSE VEGETABLE PROTEINS IS IN THE FORM OF PHYTATES AND ARE UNAVAILABLE FOR ABSORPTION IT IS NECESSARY TO AVOID PROCESSED FAT BECAUSE OF ADDING OF PHOSPHATES CALCIUM ACETATE AND A CATIONIC POLYMER CALLED SEVELAMER HYDROCHLORIDE ARE MOST COMMONLY USED PHOSPHATE BINDER AT PRESENT TREATMENT

10. ORALLY ADMINISTERED 1,25-(OH)2 D IS EFFECTIVE AT STIMULATING CALCIUM ABSORPTION IN THE MUCOSA BUT IT DOESNOT SIGNIFICANTLY ENTER PERIPHERAL CIRCULATION THUS IN SEVERE HYPERPARATHYROIDISM INTRAVENOUS 1,25(OH)2 D IS REQUIRED DRUGS

11. DEFICIENCY OF VITAMIN D ALSO LEADS TO RICKETS-IN GROWING CHILDREN OSTEOMALACIA-IN ADULTS OTHER RELATED DISEASE