A reappraisal of the role of fever in the occurrence of neurological sequelae following lithium intoxication: a systematic review

Introduction: We aimed to review cases of Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT) characterized by neurological sequelae following acute lithium toxicity and to explore whether cerebellar sequelae are more frequent in cases presenting with fever and/or infection. Areas covered: Case reports were identified from: (i) 6 reviews published up to 2005; (ii) MEDLINE, Web of Sciences, Cochrane Library and PsycINFO search. Expert opinion: We identified 123 SILENT cases published from 1965 to 2019, in which cerebellar sequelae were observed in an overwhelming proportion (79%). SILENT may occur at any time during lithium treatment. This complication is most frequently observed during routine lithium treatment, with fewer than 10% of cases occurring after accidental or intentional overdoses. SILENT may occur even when lithium plasma levels are within the therapeutic range: 63% of cases had lithium plasma level <2.5 mEq/l (low/mild toxicity). Fever and/or infection were reported in nearly half of the patients (48%). The likelihood of presenting with cerebellar vs. other neurological sequelae was independently increased by elevated plasma lithium level (≥ 2.5 mEq/l) and by a history of fever and/or infection. Lithium users should be warned of the need to consult in case of fever to adjust their lithium dosage.