Paul K. Kleinman

Prevalence of Vitamin D Deficiency Among Healthy Infants and Toddlers

OBJECTIVES To determine the prevalence of vitamin D deficiency and to examine whether 25-hydroxyvitamin D (25OHD) concentration varies as a function of skin pigmentation, season, sun exposure, breastfeeding, and vitamin D supplementation. DESIGN Cross-sectional sample. SETTING Urban primary care clinic. PARTICIPANTS Healthy infants and toddlers (N = 380) who were seen for a routine health visit. OUTCOME MEASURES Primary outcomes were serum 25OHD and parathyroid hormone levels; secondary measures included data on sun exposure, nutrition, skin pigmentation, and parental health habits. Wrist and knee radiographs were obtained for vitamin D-deficient participants. RESULTS The prevalence of vitamin D deficiency (< or =20 ng/mL) was 12.1% (44 of 365 participants), and 146 participants (40.0%) had levels below an accepted optimal threshold (< or =30 ng/mL). The prevalence did not vary between infants and toddlers or by skin pigmentation. There was an inverse correlation between serum 25OHD and parathyroid hormone levels (infants: r = -0.27, P < .001; toddlers: r = -0.20, P = .02). In multivariable models, breastfeeding without supplementation among infants and lower milk intake among toddlers were significant predictors of vitamin D deficiency. In vitamin D-deficient participants, 3 participants (7.5%) exhibited rachitic changes on radiographs, whereas 13 (32.5%) had evidence of demineralization. CONCLUSIONS Suboptimal vitamin D status is common among otherwise healthy young children. Predictors of vitamin D status vary in infants vs toddlers, information that is important to consider in the care of these young patients. One-third of vitamin D-deficient participants exhibited demineralization, highlighting the deleterious skeletal effects of this condition.

Mechanical factors associated with posterior rib fractures: laboratory and case studies.

Objective. The objective of this study was to explore the mechanical factors associated with posterior rib fractures. Materials and methods. Radiographs were reviewed in ten cadavers where rib fractures were produced by opening a median sternotomy with a sternal retractor. A second study used CT to evaluate for rib fractures following digital sternal depression and anteroposterior bimanual thoracic compression in three rabbits. Lastly, two cases of accidental posterior rib fractures in children were reviewed. Results. In the cadaver studies, ten rib fractures were noted, all at or medial to the costotransverse process articulations. In the rabbit study, 13 posterior rib fractures were noted, all occurring with excessive posterior levering of the ribs during bimanual compression. The accidental posterior rib fractures occurred with severe anteroposterior thoracic compression as children were decelerated into a car dashboard or struck by a car. Conclusion. Posterior rib fractures require excessive levering of the posterior ribs at the costotransverse process articulation. When these fractures occur in accidental situations, they require massive forces that entail similar mechanics to those occurring in abusive settings.

Bone marrow changes in adolescent girls with anorexia nervosa

Early osteoporosis is common among adolescent girls with anorexia nervosa (AN) and may result from premature conversion of red (RM) to yellow bone marrow. We performed right knee magnetic resonance imaging (MRI) on a 1.0 T extremity scanner in 20 patients and 20 healthy controls, aged 16.2 ± 1.6 years (mean ± SD). Coronal T1‐weighted (T1W) images and T1 maps were generated from T1 relaxometry images. Blinded radiologists visually assessed RM in the distal femoral and proximal tibial metaphyses in T1W images using a scale of signal intensity from 0 (homogeneous hyperintensity, no RM) to 4 (all dark, complete RM). Subjects with AN exhibited nearly twofold lower metaphyseal RM scores in both the femur (0.64 versus 1.22, p = .03) and tibia (0.54 versus 0.96, p = .08). In relaxometric measurements of four selected regions (femur and tibia amd epiphysis and metaphysis), subjects with AN showed higher mean epiphyseal but lower metaphyseal T1. The net AN‐control difference between epiphysis and metaphysis was 70 ms in the femur (+31 versus −35 ms, p = .02) and of smaller magnitude in the tibia. In relaxometry data from the full width of the femur adjacent to the growth plate, AN subjects showed mean T1 consistently lower than in controls by 30 to 50 ms in virtually every part of the sampling region. These findings suggest that adolescents with AN exhibit premature conversion of hematopoietic to fat cells in the marrow of the peripheral skeleton potentially owing to adipocyte over osteoblast differentiation in the mesenchymal stem cell pool.

Radiologic contributions to the investigation and prosecution of cases of fatal infant abuse.

In 1984 we started a two-year program in Worcester (Mass.) and Boston to provide additional radiologic data for the medical investigation of suspected fatal infant abuse. During that period the investigation of 12 cases of unexplained infant death included the review of complete radiographic skeletal surveys by a pediatric radiologist. Autopsies were supplemented with resection, high-detail radiography, and histologic study of all non-cranial sites of suspected osseous injury. Thirty-four bony injuries were noted, including 12 acute and 16 healing fractures of the long-bone metaphyses and posterior-rib arcs in patterns indicative of infant abuse. The investigations determined that there were eight cases of abuse, two accidental deaths, and two natural deaths (sudden infant death syndrome). At this writing, the radiologic and osseous histologic studies appear to have influenced the determination of the manner of death in six of the eight cases of abuse and the criminal prosecution in four of the five convictions. These findings suggest that a thorough postmortem radiologic evaluation followed by selected histologic studies can have an impact on the investigation and prosecution of cases of fatal infant abuse.

Skeletal Trauma in Child Abuse: Detection with 18F-NaF PET

PURPOSE To evaluate the sensitivity of fluorine 18-labeled sodium fluoride ((18)F-NaF) positron emission tomography (PET) for assessment of skeletal trauma in pediatric patients suspected of having been abused and to compare the diagnostic performance of this examination with that of high-detail skeletal survey. MATERIALS AND METHODS The institutional review board approved this retrospective study and determined that it was in accordance with regulations of HIPAA privacy rule 45, Code of Federal Regulations parts 160 and 164, and that the criteria for waived patient authorization were met. The baseline skeletal survey and PET images obtained in 22 patients younger than 2 years between September 2007 and January 2009 were reviewed. Fourteen patients also underwent follow-up skeletal survey. The PET images were interpreted by two pediatric nuclear medicine physicians. The initially obtained skeletal survey images were interpreted blindly by a pediatric radiologist. A second pediatric radiologist interpreted the follow-up skeletal survey images in conjunction with the baseline survey images and rendered a final interpretation for the 14 patients in whom both baseline and follow-up skeletal survey data were available, which served as the reference standard. RESULTS A total of 156 fractures were detected at baseline skeletal survey, and 200 fractures were detected at PET. Compared with the reference standard (findings in the 14 patients who underwent baseline and follow-up skeletal survey), PET had sensitivities of 85% for the detection of all fractures, 92% for the detection of thoracic fractures (ribs, sternum, clavicle, and scapula), 93% for the detection of posterior rib fractures, and 67% for the detection of classic metaphyseal lesions (CMLs), defined as a series of microfractures across the metaphysis. Compared with the reference standard, baseline skeletal survey had sensitivities of 72% for the detection of all fractures, 68% for the detection of thoracic fractures, 73% for the detection of posterior rib fractures, and 80% for the detection of CMLs. CONCLUSION (18)F-NaF PET had greater sensitivity in the overall detection of fractures related to child abuse than did baseline skeletal survey. (18)F-NaF PET was superior in the detection of rib fractures in particular. Thus, (18)F-NaF PET is an attractive choice for evaluation of suspected child abuse, an application in which high sensitivity is desirable. Because of the lower sensitivity of PET in the detection of CMLs, a characteristic fracture in child abuse, initial radiographic evaluation remains necessary.

Skeletal imaging of child abuse (non-accidental injury)

In recent years there has been a worldwide increased awareness that children are physically abused by their carers. Radiologists play a vital role in the detection of inflicted injuries. This article reviews the skeletal imaging findings seen in child abuse.

Distinct chromosomal rearrangements in subungual (Dupuytren) exostosis and bizarre parosteal osteochondromatous proliferation (Nora lesion)

Background:Proliferative lesions of the bone surface, such as subungual (Dupuytren) exostosis and bizarre parosteal osteochondromatous proliferation (BPOP, Nora lesion) are currently classified as reactive, proliferative processes that mimic primary neoplasms of bone. Methods:Cytogenetic analysis was performed on 3 subungual exostoses of the great toe and 2 BPOP lesions of the radius and ulna. Results:A balanced translocation t(X;6) was identified in all cases of subungual exostoses. The chromosomal rearrangements observed in 1 case of BPOP differed from those seen in subungual exostosis. Conclusions:The presence of chromosomal abnormalities in subungual exostosis and BPOP suggests that these lesions are neoplastic, with a different molecular pathogenesis, and that each is a distinct clinicopathologic entity.

Imaging of child abuse.

Skeletal imaging plays a critical role in the diagnosis of abuse. High-detail radiographs of the entire skeleton, at times supplemented with nuclear imaging, CT, US, and MR imaging, elucidate the variety of findings with this entity. The radiologists role includes careful analysis of clinical history, familiarity with typical osseous findings in abuse, and awareness of potential normal variants and pitfalls. An accurate diagnosis of abuse can then lead to appropriate measures to protect all family members at risk of serious injury.

Problems in the diagnosis of metaphyseal fractures

The classic metaphyseal lesion (CML) is a high-specificity indicator of inflicted injury, and is the most frequently encountered long bone injury in infants dying with evidence of abuse. [1] The fractures are most common in the distal femur (Fig. 1), proximal and distal tibia (Fig. 2) and proximal humeri. They are much less frequent at the elbow, wrist and proximal femur. The injury carries a high predictive value for abuse in infants (<1 year of age). The CML has been the subject of much clinical and laboratory study and it is not only a common topic among medical professionals dealing with child abuse, but it has come under considerable scrutiny in courtrooms on both sides of the Atlantic. A recent internet query employing a popular search engine yielded over 150 links for the ‘classic metaphyseal lesion’—despite the fact that the specific terminology appeared in the literature only as recently as 1996 [2].

Prevalence of the classic metaphyseal lesion in infants at low versus high risk for abuse.

OBJECTIVE The purpose of this article is to determine the relative likelihood of encountering a classic metaphyseal lesion in infants at low and high risk for abuse. MATERIALS AND METHODS This 10-year retrospective study compared the prevalence of the classic metaphyseal lesion on high-detail American College of Radiology-standardized skeletal surveys in infants at low and high risk for abuse. Low-risk infants met all of the following criteria: skull fracture without significant intracranial injury on CT, history of a fall, and no other social risk factors for abuse. High-risk infants met all of the following criteria: significant intracranial injury, retinal hemorrhages, and skeletal injuries (excluding classic metaphyseal lesions and skull fractures). Differences between the two groups were calculated using the Fisher exact test. RESULTS There were 42 low-risk infants (age range, 0.4-12 months; mean age, 4.4 months) and 18 high-risk infants (age range, 0.8-10.3 months; mean age, 4.6 months). At least one classic metaphyseal lesion was identified in nine infants (50%) in the high-risk category. No classic metaphyseal lesions were identified in the low-risk group. The relative prevalence of classic metaphyseal lesions in the low-risk group (0/42) versus that in the high-risk group (9/18) was statistically significant (p < 0.0001; 95% CI, 0-8% to 29-76%). CONCLUSION Classic metaphyseal lesions are commonly encountered in infants at high risk for abuse and are rare in infants with skull fractures associated with falls, but no other risk factors. The findings support the view that the classic metaphyseal lesion is a high-specificity indicator of infant abuse.