Acute lithium-induced tremor

A Unique Case of the Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT) Presenting With Multiple Neurological Sequelae

Lithium can have toxic effects on the central nervous system (CNS) that can be both acute and chronic. The syndrome of irreversible lithium-effectuated neurotoxicity (SILENT) was suggested in the 1980s to describe lithium intoxication-induced persistent neurological sequelae. In this article, we report a 61-year-old patient with bipolar disorder who had developed expressive aphasia, ataxia, cogwheel rigidity, and fine tremors after acute on chronic lithium toxicity. These neurological symptoms remained for four months after discontinuation of lithium, confirming the persistence of CNS signs and symptoms, which makes this case meets the SILENT syndrome criteria. Although rare, our report - which shows a severe and disabling form of SILENT syndrome - highlights the need for additional caution when treating patients with lithium and the need to perform strict control of the putative risk factors argued to be associated with the development of this syndrome.

Tremor after long term lithium treatment; is it cortical myoclonus?

Introduction

Tremor is a common side effect of treatment with lithium. Its characteristics can vary and when less rhythmical, distinction from myoclonus can be difficult.

Methods

We identified 8 patients on long-term treatment with lithium that developed upper limb tremor. All patients were assessed clinically and electrophysiologically, with jerk-locked averaging (JLA) and cross-correlation (CC) analysis, and five of them underwent brain MRI examination including spectroscopy (MRS) of the cerebellum.

Results

Seven patients (6 female) had action and postural myoclonus and one a regular postural and kinetic tremor that persisted at rest. Mean age at presentation was 58 years (range 42-77) after lengthy exposure to lithium (range 7-40 years). During routine monitoring all patients had lithium levels within the recommended therapeutic range (0.4-1 mmol/l). There was clinical and/or radiological evidence (on cerebellar MRS) of cerebellar dysfunction in 6 patients. JLA and/or CC suggested a cortical generator of the myoclonus in seven patients. All seven were on antidepressants and three additionally on neuroleptics, four of them had gluten sensitivity and two reported alcohol abuse.

Conclusions

A synergistic effect of different factors appears to be contributing to the development of cortical myoclonus after chronic exposure to lithium. We hypothesise that the cerebellum is involved in the generation of cortical myoclonus in these cases and factors aetiologically linked to cerebellar pathology like gluten sensitivity and alcohol abuse may play a role in the development of myoclonus. Despite the very limited evidence in the literature, lithium induced cortical myoclonus may not be so rare.

Tremor: clinical phenomenology and assessment techniques

BACKGROUND

Tremors are among the most common movement disorders. As there can be considerable variability in the manner in which clinicians assess tremor, objective quantitative tools such as electromyography, accelerometry, and computerized, spiral analysis can be very useful in establishing a clinical diagnosis and in research settings.

METHODS

In this review, we discuss the various methods of quantitative tremor analysis and the classification and pathogenesis of tremor. The most common pathologic tremors and an approach to the diagnosis of tremor etiology are described.

CONCLUSIONS

Pathologic tremors are common, and the diagnosis of underlying etiology is not always straightforward. Computerized quantitative tremor analysis is a valuable adjunct to careful clinical evaluation in distinguishing tremulous diseases from physiologic tremors, and can also help shed light on their pathogenesis.

Lithium and valproate-induced tremors

Lithium and valproate are mood stabilizers known to cause tremor. This article concisely addresses etiological questions, expected time frame of tremor onset, and treatment options for this medication-induced side effect. Along with dosage modifications of the tremor-inducing medication, authors review evidence from small trials of adjunctive treatment modalities.

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.