Occurrence of macrocephaly (MC) in infants with nutritional rickets (NR) is described sporadically and rarely with hydrocephalus. Craniosomatic dysproportion is studied here in a large series at diagnosis of various forms of rickets. The 73 cases included: NR, Vitamin D Dependent Rickets

Type I (VDDR-I), Vitamin D Dependent Rickets Type II (VDDR-II) and Familial Hypophosphatemic Rickets (FHR). Head circumference (HC), length (L) and weight(W) were expressed as standard deviation scores (Z) for age and sex. Relative MC was defined as (HC.Z - W.Z) with (HC.Z - L.Z)≥2.Table

Table 1
Full size table

Four cases (3 NR, 1 VDDR-I), evaluated by Neurology for MC, had hydrocephalus which resolved with healing of rickets in 2. Comparison of NR with (n=22) and without (n=42) MC, showed association of MC with lower age(14.2 ± 4.8 vs 20.3 ± 8.3 mo; p<0.01), larger HC.Z (1.34± 0.81 vs 0.4±0.76; p<0.001), lower W.Z (-1.65 ± 0.84 vs -0.35 ± 1.09; p<0.001), lower L.Z (-2.32 ± 0.79 vs -1.0± 0.86; p<0.001), and higher alkaline phosphatase (1553 ± 466 vs 1110 ± 439 U/L; p<0.001).

Summary: MC with low W as well as L occurs commonly in both NR and other forms of rickets in infants. In NR, younger age, growth delay in W and L, and biochemical severity of rickets are associated with MC. Cause of MC remains unclear, with abnormal skull bone formation and hypophosphatemia common to the various forms of rickets. MC in rickets may be associated with hydrocephalus.