Introduction

The differential diagnosis of the skeletal lesions of child abuse includes a variety of naturally occurring diseases, dysplasias, and syndromes. They may be characterized by fractures, subperiosteal new bone formation (SPNBF), irregular metaphyses, and miscellaneous osseous alterations that suggest a traumatic etiology (Table 7.1). The findings can occur in isolation or in combination, creating complex imaging patterns. In many entities, associated radiologic features allow differentiation from abuse. In most others, proper diagnosis is established by a systematic analysis of the history, clinical, and laboratory findings, in conjunction with the imaging alterations. This chapter discusses a variety of diseases in which the skeletal abnormalities may be a source of potential confusion with child abuse. Rickets, including osteopenia of prematurity (see Chapter 8), osteogenesis imperfecta (see Chapter 9), accidental injuries (see Chapter 10), obstetric injuries (see Chapter 11), and normal variants (see Chapter 12) are covered separately.

Inherited bone dysplasias

The diagnosis of child abuse is sometimes entertained at the initial presentation of infants with inherited bone dysplasias, which are extensively catalogued in the On Line Mendelian Inheritance in Man (OMIM®) with unique phenotype MIM numbers (1, 2). The conditions which can potentially lead to the mistaken diagnosis of child abuse are those with metaphyseal irregularity and fragmentation. Langer and colleagues described a form of spondylometaphyseal dysplasia (SMD) with metaphyseal fragmentation similar to that noted with abuse, and termed this condition SMD, Sutcliffe/corner fracture type (MIM 184255) (3–5). Patients with this disorder are short, with progressive coxa vara. The condition is genetically transmitted, with either autosomal or X-linked dominant inheritance. Although the radiographic features are strikingly similar to those in child abuse, the long bones are short and dysplastic and the spine is abnormal (Fig. 7.1). With weightbearing, remodeling, and evolution of the dysplastic features, conspicuous medial metaphyseal fragments may be associated with tibia vara (Fig. 7.2).