Osteomalacia by T.Pem.

In osteomalacia
                   -Demineralization of bone. 
                                                    -i.e hydroxyapatite which forms 90% of bone mineral is reduced.
In rickets-undermineralization.
causes:
         vit D deficiency.
                              - a hormone
                                   7-dehydrocholesterol----->cholecalciferol----->25OHD3(liver)---->1,25OH calciferol--rate limiting step(controled by PTH.(active-calcitriol) or 1 24-OH calciferol(inactive)

Functions.--maintain calcium level in the body.

1.calcium absorption from GIT.
2.reduces calcium excretion in kidney.
3.increases bone mineralization.(90% of calcium in bone.
)

Investigation-
                -serum calcium level(reduced or normal)
                -serum phosphate is reduced.(because PTH increases its excretion)
                -ALP-marker of bone formation-released by osteoblast.---->increased

Clinical features:
                    bone pain
                    pathological fracture.
                    in rickets, epiphyseal plates--abnormal changes, bowed leg, costochondral ricketial rosaries, harisson's sulcus

Why?
          -reduced intake. (400-800-- IU intake normal)
          -reduced absorption(ADEK vit deficiency)
          -Defective 25 hydroxylation like in chronic cholestsasis, drugs(anticonvulsants-phenytoin)--in liver
          -defective 1,25 hydroxylation(kidney)
          -Tubular disorders, e.g. renal tubular acidosis
          -Others:
                       -inhibition of bone mineraliztion, eg excessive fluoride, bisphosphonide, Al, etc.
                       -inhereditary disease-X-linked hypophosphataemia(Dents' disease)
                     

Management:
                    Find and Treat the cause,
                                                        eg muslim ---less sun exposure--->sun exposure
                                       -Vit D tablets,
                                                           -calcitrio given directly.
                                                           - calciferol tablets tpp given.