In a scenario where a client has received rapid-acting insulin but has not completed their meal, which symptom is likely to occur?

When a client has received rapid-acting insulin but has not completed their meal, it creates a situation where the insulin lowers blood glucose levels without sufficient carbohydrates entering the bloodstream to counterbalance that effect. This mismatch can lead to hypoglycemia, a condition characterized by low blood sugar levels.

Lethargy is a common symptom of hypoglycemia. As blood glucose levels fall, the brain and body may not receive enough glucose, which is their primary source of energy, resulting in a feeling of extreme tiredness or sluggishness. This lack of energy can impede cognitive functions and physical performance, making lethargy a prominent symptom during such an episode.

Other symptoms of hypoglycemia can include sweating, shakiness, irritability, and confusion. Drowsiness can occur as well, but lethargy is more specific to the overwhelming fatigue and lack of energy someone might experience due to rapidly dropping glucose levels after insulin administration without food intake. The other options—polyuria (increased urination) and polydipsia (increased thirst)—are more closely related to hyperglycemia (high blood sugar) rather than the immediate effects of insufficient food intake following rapid-acting insulin administration.