Lithium-induced cortical atrophy and cognitive dysfunction
Ceylan, Mehmet Emin
Unsalver, Baris Onen
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A 50 year-old female patient presented to the psychiatry clinic with complaints of forgetfulness, distractibility and difficulty in learning new information. She was started on lithium after a manic episode 10 years ago, and she had been on lithium 900 mg/day for the past 10 years. During this period, her mood had remained stable, and she was euthymic. However, her occupational and social functioning was impaired significantly in the last year. She had no family history of bipolar disorder and dementia. No medical condition was detected as an explanation of forgetfulness. Cranial magnetic resonance imaging (MRI) and quantitative electroencephalography (QEEG) were done. Bilateral temporoparietal cortical atrophy and lateral ventricular asymmetry were detected in her MRI (Figure 1). Increase in theta and delta frequency was detected in her QEEG without any paroxysmal activity (Figure 2). Lithium was stopped, and 6 weeks after lithium withdrawal neuropsychological tests demonstrated significant improvement in the patient's cognitive functions. Mini Mental State Examination scores increased from 25 to 30. Theta and delta waves disappeared and QEEG was normalized (Figure 3). Neuroprotective effects of lithium have been reported.1 In these reports, the duration of lifetime exposure to lithium was not known. In the prospective studies lithium was used short-term (several weeks).1 Unlike these studies, impairment in cognitive function due to long-term use of lithium have been found.2,3 It is not known how chronic use of lithium makes changes in the brain and hippocampus volume. Lithium has toxic effects on the thyroid gland and kidney. Although it has neuroprotective effect in a short time, it might also have neurotoxic effect in a long time. In this case, cortical atrophy and cognitive dysfunction are thought to be due to long-term lithium use. It should be monitored in the patients who used long term lithium not just their thyroid and kidney functions also their cognitive functions and changes in their brain volume.