Longitudinal extensive anti-AMPA-GluR3-related transverse myelitis and favorable therapeutic response: A case report and review of literature

BACKGROUND Longitudinally extensive transverse myelitis (LETM) is defined as a spinal cord lesion that extends over three or more consecutive vertebral segments. It is a key manifestation of various inflammatory and demyelinating disorders of the central nervous system. We have described a rare case of a probable association between LETM and the presence of high serum and cerebrospinal fluid levels of metabotropic glutamate receptor 3 antibodies (mGluR3abs) in a 5-year-old girl. LETM is a neurological disorder characterized by a spinal cord lesion extending over three or more vertebral segments. CASE SUMMARY We report a case of a 5-year-old Caucasian girl affected by LETM, along with a review of the literature. The patient presented with lower back pain, varying degrees of bilateral sensory and motor deficits, and autonomic dysfunction. Magnetic resonance imaging showed hyperintense signals involving the spinal cord from C3 to the conus medullaris, suggesting a diagnosis of LETM. Laboratory analysis revealed high levels of mGluR3abs in both serum and cerebrospinal fluid. The patient responded favorably to treatment with high doses of intravenous methylprednisolone and immunoglobulin therapy, which has been shown to be particularly effective in children. CONCLUSION The frequency of LETM associated with mGluR3abs is unknown; this report may contribute to expanding the understanding of it.