P3C028: Living with Lethal Lithium Levels

Introduction: Lithium is a medication that is used primarily as a mood stabilizer, most notably as a treatment for bipolar disorder. It has long been known that lithium has a narrow therapeutic window; small changes in blood concentration can lead to toxic effects. This case highlights several effects of severe lithium intoxication.

Case Description: Methods
This is a single patient case report. A 16-year-old female with history of autism spectrum disorder, bipolar disorder, and schizophrenia presented to the pediatric emergency department for altered mental status. Symptoms at the time included a sudden onset of tremors, inability to walk, nonverbal, hypertonicity, tachycardia, and incontinence of stool and urine. Initial screening labs showed an elevated free T4 to 4.45, T3 to 2.81, and creatinine to 3.2, with transaminitis and leukocytosis. Given her elevated thyroid levels and clinical exam, there were concerns for thyroid storm. But upon further review of the medication history, it was noted that she was taking lithium, atomoxetine, and benztropine. At this point, there was a high level of suspicion for drug overdose, and lithium level was obtained and found to be 5.27.
Results
Patient was admitted to the Pediatric ICU for emergent dialysis and management of thyroid storm, altered mental status, and renal failure. She was intubated in the pediatric intensive care unit for 8 days. After 4 treatments of hemodialysis, her lithium decreased to < 1.
This patient had major complications for lithium toxicity. She was noted to have increased tone and tremors, for which neurology started a video EEG and found her to have metabolic encephalopathy secondary to her lithium toxicity. She developed renal failure consistent with acute tubular necrosis. Hyperthyroidism was treated with propranolol and her symptoms resolved after hemodialysis treatment. This patient eventually recovered and was able to be discharged with outpatient physical therapy.

Discussion: This case is notable because many of the major complications from lithium toxicity were observed in a single patient. If not addressed quickly and assertively, lithium toxicity and complications can lead to coma and possible death. It is imperative that patients using lithium are educated about side effects, particularly the importance of monthly serum level monitoring.

Conclusion: This is a case of severe lithium toxicity requiring emergent dialysis. Many complications were noted. With dialysis and treatment of each complication, the patient fully recovered.