Bone Metabolism In this segment we are going to be talking about problems with bone metabolism that can be read identified and evaluated by imaging.

Rickets Rickets (children) – failure of mineralization of the epiphyseal plate Related to lack of Vitamin D Dietary Poverty Third world countries Sunlight exposure Northern latitudes Sun screen Metabolic failure Ricketts is a disease primarily identified in children as a result of failure to mineralized epiphyseal plate. Ricketts is related to vitamin D metabolism and can be either dietary, and if dietary is the result of poverty, poor nutrition or individuals living in third world countries. It can also be related to limited sunlight exposure which is seen in northern latitudes and can as well be identified in individuals who are overly protected by sunscreen; preventing the normal conversion of vitamin D. Metabolic failure can also lead to Ricketts development.

Renal Osteodystrophy Osteomalacia (low bone density) – failure of mineralization of osteoid Osteosclerosis (high bone density) – dense bones Abnormal resorption of mineral Abnormal deposition of mineral Metabolically, renal osteodystrophy can lead to all ostemalacia or low bone density, this as result of a failure to mineralize the osteiod. Osteoid is laid down in a normal fashion but there is insufficient mineralization of the osteiod. You can also identify osteosclerosis or high bone density or resulting dense bones for variety of reasons. This can be as result of an abnormal resorption of the minerals and more mineral remains within the bone or in abnormal deposition of the mineral where too much mineral is deposited.

Renal Rickets Child Zone of provisional calcification is deficient Metaphyses irregularly mineralized, widened and cupped Fracture of distal fibula The next few slides will document the appearances of renal rickets. In these images courtesy of Nancy Fitzgerald of the Texas Children's Hospital, we see a child who is suffering from the results of rickets. There is a deficiency in the zone of provisional calcification. Note the relatively flared metaphysis which are somewhat irregular in their nature, somewhat widened and cuffed, this is a typical appearance in rickets. Also with his child an unrelated fracture of the distal fibula perhaps related to a general loss of mineralization throughout. Images courtesy Nancy Fitzgerald, MD, Texas Children’s Hospital

Rickets Widening of the ribs at the costal-chondral junction Known clinically as Rachitic Rosary When a child has rickets, there will be at times the development of widening of the ribs at the costochondral junction. This widening is referred to as rachitic rosary as these bumps will typically be identified on the child's chest. They are accentuated because in most cases rickets as a result of malnutrition the child is also very thin as well. Arrows point to the rachitic rosary.

Rickets The lateral view in the same individual demonstrates the rachitic rosary as the sclerotic zones at the distal ends of the ribs, but also note the changes within the hand for this individual with a broadening, widening of the metaphyseal surfaces with cupping noted at these locations. Images courtesy Nancy Fitzgerald, MD, Texas Children’s Hospital

Rickets Widened metaphysis with fraying In another individual we see widening of the distal metaphysis with some fraying of the margins. We also note some mixed sclerosis of the jointing bony structures.

Rickets Wrist film Another patient Cupping and fraying of metaphyses On this wrist film in another patient we see similar findings with cupping and fraying of metaphysis in the broadening or widening of the metaphysis as well.

Treated Rickets Same patient after 3 months of Vitamin D Improved appearance with well defined slightly undulating metaphysis Looking at the same child sometimes later after 3 months of vitamin D therapy, note that the metaphysis distally now is smooth without the fraying that was noted previously, less cupping is seen, it remains widened but that will remodel over time.