A Case Report on an Atypical Presentation of the Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT) in a War Veteran with Bipolar Disorder and PTSD

Abstract

Background: Lithium is still the first-line agent for bipolar disorder. Despite common knowledge on monitoring lithium levels to prevent toxicity, it still occurs at varying degrees. Here we present a rare sequela of lithium toxicity, the Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT). Case Presentation. A 56-year-old male war veteran who is fully functional despite being on chronic lithium therapy for Posttraumatic Stress Disorder (PTSD) and bipolar disorder presented at the emergency room with altered mental status and seizures associated with elevated lithium levels and renal insufficiency. Antiepileptic drugs were given for seizure control, and intermittent hemodialysis was done to clear the lithium. Despite clearance of the offending agent, the patient remained to have a generalized slowing on repeated EEG with only eye opening and nonpurposeful limb movements regained even after more than 2 months of lithium cessation.

Conclusion: SILENT has been coined after reports of persistent neurologic deficits were seen in patients who experienced lithium toxicity more than 2 months after cessation of lithium. Chronic lithium therapy predisposes to gradual accumulation of lithium in the brain. Demyelination is the typically reported feature of SILENT. It can also leave the patient in a persistent encephalopathic state. Chronic lithium toxicity from failure of monitoring puts patients on lithium therapy at risk.

Figure 1

Timeline of the patient's neurologic status and serum lithium and urine benzodiazepine levels. HD: hospitalization day; Li: lithium; EEG: electroencephalogram; hz: Hertz.