The law of unintended consequences: An unusual case of posterior reversible encephalopathy syndrome during lithium therapy and hypernatremia

Background

We present the case of a 70-year-old woman who experienced an episode of posterior reversible encephalopathy syndrome (PRES) triggered by hyperlithiemia and hypernatremia.

Case repor

t: This case report describes a 70-year-old woman with bipolar disorder who presented at the Emergency Department (ED) with posterior reversible encephalopathy syndrome (PRES) triggered by hyperlithiemia and hypernatremia. Although lithium treatment is commonly prescribed for bipolar disorder, the exact mechanisms underlying lithium-induced PRES are still under investigation. The patient's altered consciousness prompted toxicological consultation, leading to a diagnosis of PRES associated with lithium toxicity. The patient required intensive care and received hydration therapy, resulting in a gradual reduction of sodium and lithium levels. After a period of rehabilitation, she was discharged with minimal neurological deficits.

"Why should an emergency physician be aware of this?"

Hyperlithiemia is an extremely rare cause of PRES (Posterior Reversible Encephalopathy Syndrome), which, if unrecognized, can have serious consequences and long-term effects on the patient.