Which clinical observation indicates potential lithium toxicity in a patient?

Blurred vision and muscle twitching are clinical observations that can indicate potential lithium toxicity in a patient. Lithium is a mood-stabilizing medication frequently used to treat bipolar disorder, and its therapeutic range is quite narrow. When the levels of lithium in the blood exceed the therapeutic range, individuals may begin to experience signs of toxicity.

Blurred vision can occur due to effects on the central nervous system, and muscle twitching indicates neuromuscular irritability, both of which are associated with higher lithium levels. Such symptoms signal the need for immediate assessment and possible intervention, as prolonged toxicity can lead to more serious complications.

The other symptoms listed, while they can be discomforting or concerning, are more commonly associated with the side effects of lithium at therapeutic levels or with other conditions and do not specifically indicate acute lithium toxicity. Therefore, the combination of blurred vision and muscle twitching is a more specific red flag for clinicians to consider.