Cerebellar syndrome in lithium poisoning: a case of partial recovery

Lithium-associated movement disorder: A literature review

In 1949, Cade described “sedative effects” after injecting guinea pigs intraperitoneally with lithium (LTM) carbonate. Based on his experiments, he began treating psychiatric patients with LTM. This literature review aims to evaluate the clinical epidemiological profile, pathological mechanisms, and management of LTM-associated movement disorder (MD). Relevant reports in six databases (Excerpta Medica, Google Scholar, Latin American and Caribbean Health Sciences Literature, Medline, Scientific Electronic Library Online, and ScienceDirect) were identified and assessed by two reviewers without language restriction from 1949 to 2021. A total of 250 reports containing 1100 individuals who developed MD associated with LTM were identified. The MDs encountered 148 parkinsonism (PKN), 114 dyskinesia (DKN), 97 myoclonus, 22 dystonia (DTN), 20 Creutzfeldt–Jakob-like syndrome, 11 akathisia, 10 restless legs syndrome (RLS) symptoms, 6 tics, 5 cerebellar syndromes, and 3 stuttering. In the subgroup of cases not clearly defined, there were 320 individuals with extrapyramidal symptoms, 135 with DTN, 37 with DKN, 24 with PKN, and 7 with RLS. Other 141 individuals were only described as presenting an abnormal involuntary movement without further explanation. The mean age was 53.06 years (standard deviation [SD]: 15.64) and the predominant sex was female, i.e., 56.20% (154/274). The mean LTM dose was 963.03 mg/day (SD: 392.03). The mean serum LTM level was 1.53 mEq/L (SD: 1.08). The median onset time was 3 months (1 day to 40 years). The mean recovery time was 0.94 months (SD: 0.87). 45.94% had a full recovery. LTM-induced MD was extensively reported in the literature. Only general terms were used in the majority of the reports. LTM polytherapy probably affected the identification of the MD cause.

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.

Lithium Poisoning

Lithium is a commonly prescribed treatment for bipolar affective disorder. However, treatment is complicated by lithium’s narrow therapeutic index and the influence of kidney function, both of which increase the risk of toxicity. Therefore, careful attention to dosing, monitoring, and titration is required. The cause of lithium poisoning influences treatment and 3 patterns are described: acute, acute-on-chronic, and chronic. Chronic poisoning is the most common etiology, is usually unintentional, and results from lithium intake exceeding elimination. This is most commonly due to impaired kidney function caused by volume depletion from lithium-induced nephrogenic diabetes insipidus or intercurrent illnesses and is also drug-induced. Lithium poisoning can affect multiple organs; however, the primary site of toxicity is the central nervous system and clinical manifestations vary from asymptomatic supratherapeutic drug concentrations to clinical toxicity such as confusion, ataxia, or seizures. Lithium poisoning has a low mortality rate; however, chronic lithium poisoning can require a prolonged hospital length of stay from impaired mobility and cognition and associated nosocomial complications. Persistent neurological deficits, in particular cerebellar, are described and the incidence and risk factors for its development are poorly understood, but it appears to be uncommon in uncomplicated acute poisoning. Lithium is readily dialyzable, and rationale support extracorporeal treatments to reduce the risk or the duration of toxicity in high-risk exposures. There is disagreement in the literature regarding factors that define patients most likely to benefit from treatments that enhance lithium elimination, including specific plasma lithium concentration thresholds. In the case of extracorporeal treatments, there are observational data in its favor, without evidence from randomized controlled trials (none have been performed), which may lead to conservative practices and potentially unnecessary interventions in some circumstances. More data are required to define the risk–benefit of extracorporeal treatments and their use (modality, duration) in the management of lithium poisoning.

Long-term lithium treatment reduces glucose metabolism in the cerebellum and hippocampus of nondemented older adults: an [¹⁸F]FDG-PET study

Lithium modulates several intracellular pathways related to neuroplasticity and resilience against neuronal injury. These properties have been consistently reported in experimental models, and involve the up-regulation of neurotrophic response and autophagy, and down-regulation of apoptosis, oxidative stress, and inflammation. Clinical and epidemiological studies in bipolar disorder show that acute treatment with lithium increases plasma concentrations of brain-derived neurotrophic factor, and long-term treatment lowers the risk of dementia. Neuroimaging studies indicate that lithium use is further associated with increased cortical thickness and larger hippocampal volumes. The objective of the present study was to evaluate whether these neurobiological properties of lithium reflect in increased regional brain glucose metabolism, as shown by [(18)F]FDG-PET. Participants (n = 19) were nondemented older adults recruited at the end point of a controlled trial addressing clinical and biological effects of lithium in a sample of patients with amnestic mild cognitive impairment. Twelve patients who had received low-dose lithium carbonate for 4 years were compared to seven matched controls. Chronic lithium treatment was not associated with any significant increase in brain glucose metabolism in the studied areas. Conversely, we found a significant reduction in glucose uptake in several clusters of the cerebellum and in both hippocampi. These findings were not associated with any clinical evidence of toxicity. The clinical implications of the present findings need to be clarified by future controlled studies, particularly in the light of the potential use of lithium as a disease-modifying treatment approach for certain neurodegenerative disorders, namely, Alzheimer's disease and amyotrophic lateral sclerosis.

The Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT): one-year follow-up of a single case

In this article, we report the case history of a 44-year-old female patient with bipolar disorder who developed the so-called Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT). A detailed description of our patient's neurologic status is provided at baseline (i.e. during lithium intoxication) and after one year of follow-up, confirming the persistency of cerebellar signs and symptoms. Although rare, our report - which shows a severe and disabling form of SILENT - underscores the need to perform a strict control of the putative risk factors argued to be associated with the development of this syndrome. In our case, the presence of fever and the administration of multiple doses of antipsychotics may have contributed to the poor outcome exhibited by the patient.

The Syndrome of Irreversible Lithium-Effectuated Neurotoxicity

OBJECTIVES

Persistent sequelae of lithium intoxication gained clinical attention in the 1980s and were named Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT). The authors review the published cases of SILENT reported in the literature and discuss various clinical manifestations.

METHODS

The authors' inclusion criteria included persistence of sequelae for at least 2 months after the cessation of lithium administration. They conducted a MEDLINE and Pub Med search for journal articles from the year 1965 to 2004. They also cross-referenced available papers.

RESULTS

The authors identified 90 cases of SILENT in peer-reviewed publications. Persistent cerebellar dysfunction was the most commonly reported sequela. Other atypical presentations have also been reported.

CONCLUSION

Although the biologic mechanism remains unclear, the authors hypothesize that the putative cause of SILENT is demyelination caused by lithium at multiple sites in the nervous system, including the cerebellum. Recent advances in the understanding of the molecular basis of lithium-induced neurotoxicity may be able to provide a means of defining a pathway associated with the long-term prophylactic properties of lithium, distinct from its toxicity profile. This identification of differential gene expression patterns that distinguish between therapeutic and toxic actions of lithium may help in the discovery of new drugs for mood stabilization. Clinically and heuristically, it is important to raise the awareness of this syndrome so that clinicians are able to avoid it. A precise definition, operational diagnostic criteria, and a descriptive name will aid in the early identification and prevention of SILENT.

[Neurologic sequelae secondary to acute lithium poisoning]

OBJECTIVE

To review the literature on the permanent neurological sequelae resulting from acute lithium poisoning.

METHOD

Sixty-six articles were reviewed in English and in French. They were accessed through Medline and cover the period from 1968 to 1997.

RESULTS

Fifty-nine case studies were broken down into 3 groups: lithium intoxications without a neuroleptic that has provoked a cerebellar syndrome; those in which there was a neuroleptic; and those with diverse neurological consequences, with or without a neuroleptic.

CONCLUSIONS

Lithium has an intrinsic toxicity for the central nervous system and provokes a tropism specific to the cerebellum. The association with neuroleptics appears to increase toxicity as well as some associated factors, including infections and the rapid correction of the lithium level in the blood. We discuss the psychopathological mechanisms invoked to explain lithium's neurotoxicity.

Cerebellar syndrome in lithium poisoning

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