Which clinical sign should the nurse expect in a client with Cushing syndrome?

In a client with Cushing syndrome, lability of mood is a common clinical sign due to the effects of elevated cortisol levels on the central nervous system. Cushing syndrome is characterized by excessive cortisol production, which can result in psychological symptoms including mood swings, irritability, and mood lability. This emotional instability is often a direct consequence of the hormonal imbalances present in the disorder.

The other signs listed, while they may hold some relevance in different contexts, do not align as closely with the primary symptoms of Cushing syndrome. Rapid weight gain is indeed associated with the condition; however, it often reflects the accumulation of fat, particularly in specific areas of the body, rather than simply being a direct symptom. Decreased heart rate does not typically occur, as elevated cortisol often leads to increased heart rate and blood pressure due to its stimulating effects on the cardiovascular system. Increased appetite can also occur as a result of stress and hormonal changes, but it is not as definitive or prevalent as the mood-related symptoms seen in patients with Cushing syndrome. Hence, lability of mood emerges as a standout clinical sign in this scenario.