SILENT Irreversible Lithium-Induced Neurotoxicity

In 1987, Adityanjee discussed so-called lithium poisoning and made an observation that remains true today There is a general lack of awareness about irreversible and unbeatable complications of lithium treatment despite evidence to the contrary.  

Originally, it was thought that, except in extreme cases, lithium-induced neurotoxicity was reversible. However, it eventually became apparent that many patients develop irreversible brain damage and dysfunction, often involving the cerebellum (Grignon et al., 1996). In the last two decades, researchers have defined a syndrome of irreversible lithium-effectuated neurotoxicity (SILENT). Adityanjee et al. (2005) reviewed the literature from 1965 to 2004 for cases of lithium neurotoxicity with the persistence of sequelae for at least 2 months after cessation of treatment. They found 90 cases of SILENT, with persistent cerebellar dysfunction as the most commonly reported persistent aftereffect. These 

Irreversible neurotoxicity can occur at relatively low serum doses. Lang and Davis (2002) described the case of a 44 year old man who presented with a two-month history of dysarthria, ataxia and leg weakness whilst on maintenance lithium for bipolar disorder. He had significant cerebellar and pyramidal dysfunction. His serum lithium was 1.5 mmol/L, a moderate elevation for this patient. His recovery was only partial, leaving him mainly with cerebellar ataxia. The authors warned about the insidious onset of persistent neurotoxicity during routine treatment. 

Branchey et al. (1976) published a follow-up of patients on long-term lithium maintenance (6 months to 7 years). Only 10 of 36 were free of neurologic symptoms, even with the low maintenance doses employed. Four of 36 patients had parkinsonian symptoms at a low level of severity.  

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In a review of published cases of the syndrome of irreversible lithium-induced neurotoxicity (SILENT), cerebellar dysfunction was the most commonly reported long-lived outcome (183). 

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