Final answer:
The nurse should suspect that the older adult client is experiencing atrophy, more specifically, sarcopenia, an age-related and irreversible reduction in skeletal muscle mass and strength.
Step-by-step explanation:
When a nurse in a long-term facility observes that an older adult client is experiencing decreased muscle size and weakness, the condition they should suspect is atrophy. Specifically, this is likely a case of sarcopenia, which is a normal aspect of aging characterized by the gradual decrease in the ability to maintain skeletal muscle mass. Sarcopenia results from the dying off of muscle fibers, which are replaced by connective and adipose tissues, leading to a decline in muscle strength needed for posture and mobility.
Age-related muscle atrophy is generally irreversible, although its effects can be mitigated to some extent through regular exercise, which helps maintain muscle function and mass.
As a result of sarcopenia, older adults may experience functional impairments in locomotion, balance, and posture, which can decrease quality of life and lead to medical problems.