Descriptions
Vitamin D deficiency causes rickets in children and osteomalacia in adults. The body needs 710 micrograms of vitamin D per day to maintain healthy bones. The body makes its own vitamin D when sunlight falls on the skin in the summer months, but a diet with adequate vitamin D is needed to maintain the supply in the winter, especially for people who do not get out or, for cultural or religious reasons are completely shielded from the sun by their clothing.
Clinical features of rickets
– Bone pain/tenderness: arms, legs, spine, pelvis
– Skeletal deformity: bow legs, pigeon chest (forward projection of the sternum), rachitic rosary (enlarged ends of ribs), asymmetrical/odd-shaped skull due to bones, spinal kyphosis, scoliosis & pelvic deformities
– Pathological fracture
– Dental deformities: delayed formation of teeth, holes in enamel, cavities
– Muscular problems: progressive weakness, decreased muscle tone, muscle cramps
– Impaired growth leading to short stature (can be permanent)
Clinical
– features of osteomalacia: Bone pain—diffuse, particularly in the hips
– Muscle weakness
– Pathological fractures
– Low calcium leading to perioral numbness, numbness of extremities, hand and feet spasms, and/or arrhythmias
Causes and management
– Dietary deficiency (<30nmol/L): Particularly in children with pigmented skin in Northern climes. Give vitamin D and Ca 2+ supplements.
– Age-related deficiency (<30nmol/L): Vitamin D metabolism deteriorates with age and many >80y are deficient. Consider giving vitamin D (800IU/d) to all elderly >80y.
– Secondary rickets/osteomalacia: Due to other diseases, e.g. malabsorption, liver disease, or renal tubular disorders, chronic renal failure. Treat the underlying cause and supplement Ca 2+ and vitamin D as needed.
– Vitamin D-dependent rickets: Rare, autosomal recessive inherited disorder resulting in an enzyme deficit in the metabolism of vitamin D. Refer care to a specialist. Treated with vitamin D and Ca 2+ supplements.
– Hypophosphatemic rickets (vitamin D-resistant rickets): X-linked dominant trait resulting in decreased proximal renal tubular resorption of phosphate. Parathyroid hormone and vitamin D levels are normal. Specialist management is needed. Treatment is with phosphate replacement ± calcitriol.