A client diagnosed with bipolar disorder, who has taken lithium carbonate (Eskalith) for 1 year, presents in an emergency department with severe diarrhea, blurred vision, and tinnitus. How should the nurse interpret these symptoms?

Choice A reason: Discontinuation syndrome is not associated with lithium. It is more common with antidepressants and involves symptoms like flu-like feelings, insomnia, and mood changes—not the physical symptoms listed here. Choice B reason: Tyramine reactions are linked to MAOIs, not lithium. They cause hypertensive crises, not diarrhea, blurred vision, or tinnitus. Choice C reason: Tolerance implies reduced therapeutic effect over time, not acute toxicity symptoms. The listed symptoms are signs of overdose or impaired excretion, not tolerance. Choice D reason: Diarrhea, blurred vision, and tinnitus are classic signs of lithium toxicity. Lithium has a narrow therapeutic index, and toxicity can occur due to dehydration, renal impairment, or drug interactions. Immediate intervention is required.