Final answer:
The priority nursing diagnosis for a bipolar client with an episode of acute mania is Risk for injury.
Step-by-step explanation:
The nursing diagnosis that is a priority for a bipolar client with an episode of acute mania is Risk for injury. During an episode of mania, individuals often engage in reckless behaviors, which can put them at risk for accidents, falls, or self-harm. Therefore, it is important for healthcare professionals to closely monitor the client for any signs of potential harm and implement measures to prevent injuries.