WEEK: LECTURE: METABOLIC BONE DISORDERS 2 RICKETS S OSTEOMALACIA CLASSIFICATION: Fundamental defect From an impairment of mineralisation CAUSES: Deficiency of vitamin D Abnormal metabolism of vitamin D May occur in renal osteodystrophy A result of an accumulation of an mineralised matrix Rickets CLINICAL MANIFESTATIONS occurs in children Rickets Reduce the position of bone in the growth plates Delayed grow Bowed legs or knock knees osteomalacia Thickened wrists and ankles Under-mineralised bone during bone remodelling, resulting in predisposition to Fractures MANAGEMENT Adequate exposure to sunlight osteomalacia Pain in the bones and hips Bone Fractures Muscle weakness Difficulty walking Vitamin D, calcium or phosphate supplements Wearing braces to reduce or prevent bone irregularities Surgery to correct bone deformities (severe cases) CLASSIFICATION: Dysfunctional kidney which impairs activation of vitamin D RENAL OSTEODYSTROPHY NORMAL VITAMIN D METABOLISM CAUSES: Lack of activated vitamin D: Reduced (or no) absorption of calcium From gut Chronic kidney disease ( CKD) Ultraviolet irradiation of 7-dehydrocholesterol in skin Small intestine absorption of dietary sources D-25-hydroxylase in blood 25-OH-D Loss of calcium through kidneys Increase of phosphorous in blood Ca Bone mineralization + Ca and P absorption w-1-hythoxylase 1,25 [OH},D Normal serun levels of Ca (normocalcemia) and P A Decreased secretion into urine Activation of parathyroid hormone (PTH) to stimulate bone resorption Figure 1: Normal vitamin D metabolism PATHOLOGIC FRACTURES CLASSIFICATION: Fractures that occur due to some type of phone abnormality Pathological CAUSES Oblique Spiral -4 Troraversa Osteoporosis osteomalacia osteomyelitis Bone tumours