A PREVIOUSLY healthy 8-year-old boy with no history of trauma was seen during influenza season with a temperature of 100° to 104°F and lower back pain of 4 days' duration, which woke him at night. On examination, he had tense paraspinal muscles with absence of normal lumbar lordosis and normal findings from neurological examination. Possible diagnoses included myositis or possible discitis. Findings from laboratory tests included white blood cell count, 9.9 × 109/L; neutrophils, 0.83; lymphocytes, 0.09; monocytes, 0.06; basophils, 0.02; erythrocyte sedimentation rate, 50 mm/h; aldolase, 5.8 U/L (reference range, 1.2-8.8 U/L); and creatine phosphokinase, 56 U/L. Because of the elevated erythrocyte sedimentation rate and lack of muscle enzyme elevation, a lumbar spine magnetic resonance imaging (MRI) scan was obtained (Figure 1) and showed enhancement and an increased T2-weighted signal in the paraspinal muscles, with normal findings in the vertebral bodies and discs.
The following day the pain persisted, and findings from examination were unchanged. Findings from urinalysis and complete blood cell count were normal. A computed tomographic scan of the abdomen showed paraspinous muscle enhancement (Figure 2). A possible parenchymal infiltrate was identified in the left lung base. Treatment with cefuroxime sodium was begun. The pain persisted, and erythrocyte sedimentation rate on the second day of admission was 81 mm/h. Creatine phosphokinase levels were 24 U/L. Antinuclear antibodies and rheumatoid factor titers were both below 1:20. A blood culture did not grow organisms. Gradually, the paraspinal tenderness decreased and localized point tenderness was established over lumbar vertebra 3. Another MRI of the spine was obtained (Figure 3).
Seidman D. Radiological Case of the Month. Arch Pediatr Adolesc Med. 2000;154(4):415-416. doi:10.1001/archpedi.154.4.415