One week ago, a 4-month-old infant had received a vaccination in herleft thigh. Four days after the immunization, the child’s mother phonedthe pediatrician’s office to report that the child’s left thigh had beenswollen after the injection and that the child was fussy, especially duringdiaper changes. The pediatrician’s nurse advised the mother toplace an ice pack on the child’s swollen leg.
Case 1:Spiral Fracture Post-Immunization
One week ago, a 4-month-old infant had received a vaccination in her left thigh. Four days after the immunization, the child’s mother phoned the pediatrician’s office to report that the child’s left thigh had been swollen after the injection and that the child was fussy, especially during diaper changes. The pediatrician’s nurse advised the mother to place an ice pack on the child’s swollen leg. Swelling and discomfort persisted for 4 days after the mother started applying ice packs. The mother again called the pediatrician, who sent the child for radiographic evaluation. X-ray films reveal a spiral femur fracture (Figure 1). A skeletal survey reveals 5 left-sided healing posterior rib fractures and 4 lateral rib fractures (Figure 2). The films also suggest a possible old left tibial fracture, as evidenced by a layer of subperiosteal new bone formation. The child shows no evidence of osteopenia or blue sclera on physical examination, and there is no family history of easy fracturability.DISCUSSION: These cases illustrate different scenarios in which 3 children present with a spiral femur fracture. It has been suggested that spiral femur fractures are more likely to result from abuse than other types of femur fractures, such as transverse or buckle fractures. However, “spiral” merely reflects the mechanism of the fracture (ie, a torsional or twisting force applied across the bone). Fractures in non-mobile infants often result from abuse; however, the same is not necessarily true for toddlers. Thus, analysis of the type of fracture alone is not generally sufficient to determine whether a child has been abused. Case 1 There is significant evidence of abuse here. The fracture alone in such a young (4-month-old) infant is highly suggestive-if not diagnostic-of abuse. The mother’s delay in seeking care is also worrisome. A skeletal survey demonstrated multiple fractures incurred at 2 different points in the child’s brief life. Posterior rib fractures are highly suggestive of abuse. The mechanism is usually forceful squeezing accompanied by torsion of the posterior rib head over the transverse process of the vertebra. Such forces are often applied during shaking. In this setting, an evaluation for evidence of intracranial and retinal injury is indicated. This includes a CT or MRI scan of the head and a dilated indirect retinal examination by an ophthalmologist with pediatric experience.1Case 2:Femur Fracture After a Fall
An 18-month-old girl presents with a spiral femur fracture. Her father reports that the child was sitting next to him on the arm of a chair when she fell; he grabbed her leg to break the fall, heard a “loud snap,” and knew her leg had broken. He immediately sought care for the child at a local emergency department. A skeletal survey revealed a spiral femur fracture (Figure 3), generalized osteopenia, no wormian bones of the skull, and bilateral healed humeral supracondylar fractures. Four months earlier, this child had fallen off a bed and sustained a transverse radial and ulnar fracture. These are healing, but more slowly than expected (Figure 4). The child is under the fifth percentile for height and weight, has abnormally erupting teeth, and gray sclera.Case 2 This case is suspicious because the mechanism of injury did not seem sufficient to cause such a serious fracture- if the bones were normal. However, the patient’s medical history, physical examination, and skeletal survey suggest a diagnosis of osteogenesis imperfecta. Further review of an old chest film indicated osteomalacia of both proximal humeri. The patient was seen by a pediatric dentist who diagnosed amelogenesis imperfecta-a defect of enamel often associated with osteogenesis imperfecta. A geneticist and endocrinologist were also consulted. The child had triangular facies and blue sclera-conditions consistent with osteogenesis imperfecta. Osteogenesis imperfecta is rare: it is caused by a defect in the synthesis of type I collagen. Typically there are 4 major variants (Table).2 Patients with types II and III present with very severe disease in utero or at birth; fractures in affected children would be so severe and present so early in life that they would not be mistaken for abuse. Collagen studies involve a skin biopsy to evaluate the growth of fibroblasts and to analyze the quantity and quality of the type I collagen molecule. (Type I collagen is the major constituent of skin, bone, tendon, and blood vessels.) This analysis is 80% sensitive for detection of osteogenesis imperfecta. However, this diagnosis can usually be based on clinical suspicion and typical features.3 In most cases of abusive or accidental injury, the lack of clinical manifestations of osteogenesis imperfecta and typical fractures exclude this diagnosis. Fractures from osteogenesis imperfecta typically can occur in any bone; however, posterior rib fractures have not been described in children with this condition. Children with osteogenesis imperfecta who have been abused will have fractures or other typical indicators of abuse, such as bruising.Case 3:Head and Femur Trauma After a Fall From a Bunk Bed
A 2-year-old girl presents with a spiral femur fracture (Figure 5). The mother reports that the child was in the next room when she fell from the top bunk of her bed approximately 5 ft onto a carpeted floor. The mother was initially concerned because the child complained of head pain. The mother carried her to the next room where the child began to calm down; the mother then noticed that the child’s leg looked distorted. The girl was taken immediately to a local emergency department. At the hospital, a skeletal survey showed only the femur fracture. Child Protective Services was called to help investigate. Have the children in these 3 cases been intentionally harmed-or is there a medical explanation in each case for the spiral femur fracture?Case 3 In this case, the investigator from Child Protective Services went to the child’s home and described a scene exactly as the mother had revealed it. The bunk bed measured 5 ft with a railing across the top. The child would have had to fall over 5 ft if she had climbed over the rail. A ladder leading up to the bed could have provided an area on which the child’s leg “caught” during the fall: the child’s weight and velocity could have caused torsion across the femur. An interview with the patient’s 5-yearold brother, who was in the room but who did not actually see the fall, revealed that his sister was on the top bunk one minute and then on the floor crying the next. As children become mobile and place themselves in situations where they can accidentally fracture long bones, the clinician’s knowledge of injury mechanics is extremely helpful. The mechanism must be consistent with the severity of the injury. (For example, if a parent insists that he or she broke their child’s leg while putting on a shoe, this is clearly an inconsistent mechanism.) If an accidental mechanism seems likely, but a review of the scene or interview of siblings does not support the parent’s history, then abuse must be strongly considered. Different Mechanisms for the 3 Fractures All 3 cases presented here have elements that suggest possible abuse. All involve spiral femoral fractures, yet the mechanisms of injury are different.
American Academy of Pediatrics Policy Statement. Diagnostic imaging ofchild abuse.
Diagnostic Imaging of Child Abuse.
2nd ed. St Louis: MosbyCompany; 1998.
Steiner RD, Pepin M, Byers PH. Studies of collagen synthesis and structurein the differentiation of child abuse from osteogenesis imperfecta.
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