Case 1: Unilateral Leg Pain and Difficulty Walking

Presentation

A 5-year-old boy presents with unilateral leg pain and difficulty walking for 6 days. During that time, the patient developed a fever and an upper respiratory tract infection. Physical examination shows no edema, erythema, or warmth in the lower extremities. There is tenderness to palpation of the right lower extremity (RLE). There is also pain on passive and active range of motion (ROM) testing as well as decreased muscle strength in the RLE. The right patellar and Achilles reflexes are absent. The left lower extremity, however, shows unaffected ROM and muscle strength testing, with the patellar and Achilles reflexes diminished to 1/4+. When prompted to walk, the patient limps and is unable to bear weight on his RLE. Findings on radiographs of the hips and RLE and magnetic resonance images (MRIs) of the hips are all normal. Lumbar puncture shows a normal white blood cell count with an increased protein level, as well as elevated immunoglobulin G (IgG) levels. The MRI of the thoracic and lumbar spine shows abnormal enhancement of ventral and dorsal nerve roots extending off the conus and filum terminale into the cauda equina (Fig 1). In addition, there is particularly asymmetrical enhancement of the right dorsal nerve roots versus the left in the lumbar spine (Fig 2). Nerve conduction studies show axonal polyneuropathy in the bilateral lower extremity nerves tested and borderline decreased conduction velocity (abnormal findings summarized in Tables 1-3). Electromyography testing finds positive waves and fibrillations and decreased recruitment. All …