myalgias due to influenza), infections with referred pain to the back (e.g., pneumonia, pelvic inflammatory disease, cholecystitis, and pancreatitis), and herpes zoster Neoplasms, both benign and malignant, may present with back pain Osteoid osteoma, the most common tumor that presents with back pain, is benign and can present with nocturnal pain that is relieved with anti-inflammatory medications Localized back pain can also result from primary bony malignancies (e.g., Ewing sarcoma, osteosarcoma, and osteoblastoma), as well as bony metastases from other sites Other nonbony solid tumors (e.g., neuroblastoma, Wilms tumor) can lead to regional pain Leukemia, lymphoma, and other marrow infiltrative processes can also cause back pain Inflammatory arthritides may present with back pain in children These include ankylosing spondylitis, inflammatory bowel disease–associated arthritis, reactive sacroiliitis, and psoriatic arthritis Arthritides typically have pain that is worse in the morning and improves as the day progresses Finally, there are other causes of back pain that present in children Children with sickle cell disease can have vaso-occlusive crises of the spine and are also at increased risk of infectious causes of back pain, especially osteomyelitis Nephrolithiasis and urinary tract obstruction, can cause severe back pain Aortic dissection is exceedingly rare in children but should be considered in patients with Marfan syndrome or other connective tissue disorders An imperforate hymen can lead to recurrent back pain in an adolescent female Chronic pain syndromes also present with back pain, though they are unlikely to have isolated back pain Psychogenic back pain is a diagnosis of exclusion Table 54.1 lists the differential diagnosis for back pain EVALUATION AND DECISION History Evaluation of back pain begins with further characterization of the pain Where exactly is the pain? Localization of pain to a specific vertebra is more suggestive of pathology at that location, such as a fracture or infection, as opposed to the more generalized musculoskeletal lower back pain What was the onset of the pain like? Did it occur after trauma, raising suspicion for fracture, or was it more insidious in onset? Does the pain radiate down the buttock and the back of the leg suggesting a radiculopathy from a herniated lumbar disc? What does it feel like? Is it dull and achy like muscular pain? How severe is the pain? Does anything make the pain better or worse? Pain that improves as the day progresses may be suggestive of a rheumatologic etiology, pain that worsens with activity is typically musculoskeletal, and pain at night may be indicative of more