Persistent lithium-induced neurotoxicity: direct effect of lithium and/or hypernatremia?

Persistent lithium-induced neurotoxicity: direct effect of lithium and/or hypernatremia? 7.3.2008 Case report A 54-year-old African-American woman was brought to the emergency department of a university medical center with increased confusion. Over several days prior to presentation, she had become drowsy and disoriented. On the day of her admission she had her clothes on inside out. She did not have any nausea, vomiting or diarrhea, and there were no recent changes in her medications. She was previously diagnosed with bipolar disorder type I, and her medications were lithium carbonate extended-release 450 mg at nighttime, valproic acid 500 mg bid, fluphenazine 30 mg bid, and benztropine 2 mg bid. She had had prior episodes of lithium toxicity. The patient was followed in a community mental health center and, unfortunately, no information was available about how her previous episodes of lithium toxicity were characterized, and more importantly why the lithium was reinstated by her outpatient psychiatrist following these episodes. Physical examination showed a fine resting tremor. The patient was afebrile, with blood pressure of 124/73 mm Hg and pulse of 104 BPM. Initial serum electrolytes were unremarkable (including Na+ of 143 mmol/L), but the creatinine was 2.3 mg/dL. Creatine kinase, ammonia, TSH, folate, vitamin B12 were unremarkable, and WBC count was 12.7 (cells x 1000/microliter). Serum lithium level was 2.4 mEq/L, and valproic acid level was 48 mEq/L.