The nurse is admitting a male client who takes lithium carbonate twice a day. Which information should the nurse report to the healthcare provider immediately?

A. Nausea and vomiting could indicate potential lithium toxicity, which requires immediate medical attention to prevent serious complications. B. Short-term memory loss is a known side effect of lithium therapy but may not require immediate medical attention unless severe or persistent. C. Weight gain is a common side effect of lithium, but a five-pound (2.3 kg) gain may not be considered significant enough to warrant immediate medical attention unless it occurs rapidly or is accompanied by other symptoms. D. Depressed affect is a symptom of depression and may be related to the client's underlying condition but may not require immediate medical attention unless it poses a risk to the client's safety.