Plasma phosphatase in rickets and other disorders of growth.

Investigations carried out in 1931-32 revealed that the plasma phosphatase is increased in active rickets', the degree of increase corresponding to the severity of the disease. They also showed that, whereas the serum calcium and phosphorus rapidly returned to the normal amount under treatment, the decline in the figures for phosphatase was much more gradual, normal values not being regained until the healing process was complete. It has long been recognized that radiological proof of the presence of rickets is only obtained at a fairly advanced stage of the disease, and the present investigations were undertaken to ascertain what changes, if any, take place in the plasma phosphatase in children taking a rachitogenic diet before such radiological evidence is forthcoming, and the effect of anti-rachitic treatment in such cases. The method used was a modification of Kay's method as described in an earlier paper'. The infants on whom these investigations were carried out were classed in the following groups: Group 1. 10 healthy breast-fed infants. Group 2. 13 infants on artificial food with added fat-soluble vitamins. Group 3. 16 infants with radiological evidence of rickets. Group 4. 10 infants on rachitogenic diets. Group 5. 15 infants with various conditions associated with cessation of growth. All the children were seen at frequent intervals, weekly or fortnightly, and were examined for the usual signs of rickets (sweating, flabbiness, antemia, delay in dentition, closure of fontanelle and sitting up). They were also radiographed at frequent intervals to detect any changes at the epiphyses or costochondral junctions. Group 1.-The ages of the 10 healthy breast-fed infants in this group varied from 6 to 8 months. The average plasma phosphatase was 0-248 units, with a range of 0-2 to 03 units. Group 2.-The 13 infants in this group were fed on artificial foods, but with the addition of cod-liver oil (or preparations containing vitamins A and D), and orange juice. With two exceptions who were 12 and 11 months old respectively, the ages of these infants were between 4 and 81 months, the average being approximately 71 months. The average plasma phosphatase in this group was 0 3 units, with a range of 0-2 to 0-36 units: that is, practically the same as in the healthy breast-fed infants