Lithium-induced bilateral flapping tremors (asterixis) in geriatric mania

Abstract

Asterixis (flapping tremors) is a movement disorder due to cortical or subcortical pathology that usually indicates serious underlying disease processes such as encephalopathy secondary to severe hepatic dysfunction, metabolic derangements, toxic agents, or serious adverse drug events. Mood stabilizers such as valproate and carbamazepine with or without concomitant administration of antipsychotics such as clozapine and risperidone have been implicated to induce asterixis. Lithium, a first-line mood stabilizer drug for geriatric mania, with its unique profile of side-effects due to narrow therapeutic window, is very rarely implicated to induce asterixis, especially when used as a monotherapy. We report a case of lithium-induced asterixis, ataxia, acute cognitive impairment, and altered sensorium in an elderly male with first-episode of mania, both during toxic and therapeutic serum levels of lithium. This case highlights the association between asterixis, ataxia, delirium, and lithium, substantiating the dictum “start low and go slow” in geriatric psychopharmacology.

Keywords

• asterixis
• ataxia
• bipolar disorder
• delirium
• flapping tremors
• lithium