Which of the following is a toxic sign of lithium toxicity?

• A. Headache
• B. Tremors
• C. Rash
• D. Weight gain

Answer: (B)

Lithium has a narrow therapeutic window, so signs of toxicity often show up as the levels rise and affect the nervous system. Tremors are a classic early warning sign of lithium toxicity because they reflect central nervous system involvement from elevated lithium. The other options—headache, rash, and weight gain—are common side effects of lithium at therapeutic doses or nonspecific symptoms, not specific indicators of acute toxicity. If tremors appear, especially if accompanied by confusion, nausea, vomiting, or ataxia, it’s important to evaluate lithium levels and adjust the treatment to prevent progression to more serious toxicity.