Abstract
BACKGROUND: Acute lithium toxicity can cause cerebellar impairment, but long-term follow-up data are limited. We describe a case of acute lithium intoxication followed by progressive cerebellar atrophy and permanent cerebellar dysfunction. CASE PRESENTATION: Five years ago, a previously healthy 38-year-old man developed a clinical syndrome consistent with neuroleptic malignant syndrome (NMS)-like syndrome in the setting of acute lithium and quetiapine toxicity. On admission, the serum lithium concentration was 4.07 mmol/L and the cerebrospinal fluid lithium concentration was 2.45 mmol/L. Continuous renal replacement therapy (CRRT) was initiated, and cerebrospinal fluid lavage was also performed as documented in the outside hospital records. Serum lithium levels subsequently decreased to below 0.2 mmol/L. After treatment, consciousness improved. However, he developed a persistent cerebellar syndrome, characterized by ataxia, gait instability, and dysarthria. Brain magnetic resonance imaging one year later revealed cerebellar atrophy. Over five years of follow-up, severe ataxia persisted, and serial MRI showed progressive isolated cerebellar atrophy without supratentorial structural abnormalities. CONCLUSIONS: This case suggests that severe acute lithium toxicity may be associated with progressive cerebellar degeneration, even after normalization of serum lithium levels. Clinicians should consider long-term follow-up for neurological sequelae in individuals suffering from acute lithium intoxication. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12883-026-04788-7.