periods of vigorous activity, usually worse at night, suggest benign hypermobility syndrome or benign nocturnal limb pain of childhood (growing pains) A painless, poorly localized limp may occur with metabolic bone disease (e.g., rickets) Limping in the absence of localized limb findings may also suggest a nonlimb source such as the spine or the abdomen Spinal problems that can cause leg pain, weakness, or limp include dysraphism, vertebral infection, spondylolisthesis, and herniated disc Spinal dysraphism refers to a spectrum of abnormalities in the development of the spinal cord and vertebrae ranging from obvious (myelomeningocele) to occult (tethered cord) Associated neurologic and musculoskeletal findings, including pain, atrophy, high arches, and tight heel cords, may develop in early childhood Vertebral infection typically presents with fever and back pain Spondylolisthesis and herniated disc are rare in young children but may be seen in adolescents who complain of back pain or radicular pain Limp may rarely present as an early symptom of a peripheral neuropathy, either hereditary (e.g., Charcot–Marie–Tooth disease) or acquired (Guillain–Barré syndrome, vitamin or medication related) Intra-abdominal pathology that can result in limp includes appendicitis, ovarian cyst, inflammatory bowel disease, pelvic or psoas abscess, and renal disease Solid tumors, most commonly neuroblastoma, can cause limp through retroperitoneal irritation or extension into the spinal canal Likewise, a sacral teratoma may affect the nerves of the cauda equina or sacral plexus Testicular pain may present with limping in a boy who is reluctant or embarrassed to admit the true source of his discomfort EVALUATION AND DECISION The conditions that lead to a presentation of limp range from mundane (poorly fitting shoes) to life threatening (leukemia) The role of the pediatric acute care clinician is to rule out the possibility of life- and limb-threatening pathologic conditions The serious conditions include bacterial infection of the bone or joint space, malignancy, and disorders that threaten the blood supply to the bone, such as avascular necrosis and SCFE Often, a definitive diagnosis will not be reached in the emergency department, and the patient will require follow-up with the primary care physician or specialist Figure 46.1 provides an algorithmic approach to the child with a limp History The history in a limping child should include information about the onset and duration of the limp, the family’s perception of the origin of the problem, and associated symptoms such as pain, fever, and systemic illness When pain is