Reply regarding rickets vs. abuse: the evidence

Abstract

Jenny [1], Chesney [2], Slovis and Chapman [3], and Feldman [4] seem to acknowledge the evidence that the highest rates of vitamin D deficiency (DD) are now being reported in undersupplemented breastfed infants younger than 6 months of age (including those born to mothers with DD). What is the evidence that DD can be congenital rickets? Greer [5] has concluded that “good evidence” exists that these infants are at increased risk of rickets. Jenny’s article, referenced in Slovis and Chapman [3], on evaluating infants with multiple fractures states that a 25OH-vitamin D level can be obtained “if rickets is suspected because of radiographic findings or history.” We agree with her call for a careful correlation of radiographs and biomechanical parameters in infant DD as a valid research project. Chesney [2] states that he has witnessed DD in an infant who was also “abused.” This is not surprising since the age range of infant DD overlaps the peak age range for infant abuse [6]. In the face of this epidemic, why aren’t there more reports of radiographic evidence of rickets in infants <6 months of age? Shouldn’t these infants be at increased risk for fractures? Are there really no radiographic findings until the classic metaphyseal “cupping and fraying” occurs at 6 months or older? And do these classic changes develop so rapidly that no one has ever identified them in their earlier stages? Yorifuji et al. [7], Gordon et al. [8], and Ward et al. [9] all report radiographic abnormalities of rickets in infants with DD but provide no illustrations. In his recent review, Kleinman et al. [10] lists rickets at the top of the differential diagnosis for the classic metaphyseal lesion (CML). He states, “on occasion discrete osseous fragments resembling corner fractures may be identified in the absence of more dramatic signs of rickets.” Is he not describing the early signs of “CML-like lesions” in rickets? In both his book, as referenced in Slovis and Chapman [3], and his recent review [10], Kleinman clearly identifies rickets (along with other conditions) as a mimic of abuse, including the metaphyseal lesions, skull fractures, subperiosteal new bone formation, insufficiency fractures (e.g., Looser zones), and osteopenia. In our case series, the radiologists originally described the bone findings as characteristic of abuse, often calling the bone mineralization normal, and provided no differential diagnosis to include bone fragility disorders. Yet, all these infants were asymptomatic and fit the classic demographic profile placing them in the highest-risk category for severe DD. This discrepancy between the radiographic findings and the clinical findings should not be ignored, particularly when the psychosocial evaluation of the caretaker shows no risk factors for abuse. Ruling out abnormal bone mineralization on radiography is An associated editorial can be found at doi 10.1007/s00247-009-1377-4.