Lithium Toxicity or Alcohol Withdrawal?

Lithium has a narrow therapeutic index and remains the first-line treatment for bipolar I and II disorders. Dosing this medication requires careful monitoring, and there is a risk of toxicity. This case follows a 43-year-old male with a medical history of alcohol use and bipolar I disorder, admitted to the hospital three days after an intentional lithium overdose. Initial management involved treating alcohol withdrawal with scheduled phenobarbital, lorazepam, and intravenous fluids. In the following days, he demonstrated a neurologic decline in the setting of subtherapeutic serum lithium levels. As the patient continued to worsen, hemodialysis was eventually initiated due to concern for lithium neurotoxicity. After completing three rounds of hemodialysis, the patient subsequently returned to a normal neurologic baseline. This case highlights the significance of clinical manifestations of lithium toxicity in the setting of subtherapeutic and down-trending serum lithium to manage lithium toxicity. Pre-existing tissue stores and rate of elimination contribute to the discrepancy between the severity of symptoms and serum levels in those with chronic lithium use.