Pediatric Encephalomyeloradiculoneuropathy With High Lactate in Cerebrospinal Fluid and Magnetic Resonance Spectroscopy: A Case Report.

We report a pediatric case of encephalomyeloradiculoneuropathy (EMRN) presenting with elevated lactate levels in cerebrospinal fluid (CSF) and magnetic resonance spectroscopy (MRS), indicating astrocytic metabolic dysfunction. A 7-year-old girl developed fever, headache, and altered consciousness, initially diagnosed as acute disseminated encephalomyelitis (ADEM). Brain and spinal magnetic resonance imaging revealed multifocal lesions in the cerebral white matter and cervical spinal cord. CSF lactate was markedly elevated (4.06 mmol/L), and MRS demonstrated a lactate peak (7.95 mM). Nerve conduction studies revealed absent F waves and decreased reflexes, indicating peripheral nerve involvement. Anti-lactosylceramide antibodies were detected. The patient showed limited response to corticosteroids and IVIG but improved after plasma exchange. Follow-up MRS confirmed lactate normalization. This case underscores the relevance of astrocytic inflammation in EMRN pathogenesis and utility of MRS in identifying astrocytic metabolic impairment. MRS may differentiate EMRN from ADEM, especially in atypical or treatment-refractory presentations, allowing earlier diagnosis and targeted therapeutic strategies.