Lithium (Li) is a highly efficient therapy in bipolar disorder, but its therapeutic index is extremely narrow. The vast majority of patients receiving maintenance Li therapy become toxic at some point during their course of treatment. Due to its pharmacokinetics, the clinical effects of Li toxicity vary according to the type of intoxication; and diagnosis may be difficult. We present a case of lithium intoxication in whom, despite very high serum Li levels, the clinical presentation was very subtle and we discuss treatment strategies in line with literature. A 37 year old female bipolar patient with a serum Li concentration of 5.4 mmol/L had insomnia, nausea and fine tremor which developed in the last three days. She had been on Li carbonate 1200 mg/day for the last 10 days. She recovered and her Li level returned to normal in 24 hours with forced alkaline diuresis and supportive measures. Lithium carbonate is applied in psychiatry in doses close to the maximum intake level. In some cases of Li intoxication, serum Li levels may be normal. Conversely, in acute overdoses because of Li?s delayed serum equilibrium concentration may be very high, but because of normal intracellular concentrations, the patient may be asymptomatic. Clinical symptoms correlate best with severity of intoxication. Our case supports the approach that decisions regarding treatment in Li toxicity should be based on clinical parameters rather than Li levels.
Key words: Lithium, acute intoxication, adverse effects
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