Which initial nursing action should be prioritized for a client with anorexia nervosa reporting weakness and abdominal distention?

In a client with anorexia nervosa presenting with weakness and abdominal distention, the priority nursing action is to perform a 12-lead electrocardiogram (ECG). This is important because clients with anorexia nervosa are at significant risk for electrolyte imbalances, particularly hypokalemia, which can lead to serious cardiovascular complications, including arrhythmias. Weakness may be a sign of electrolyte disturbances, and abdominal distention could indicate gastrointestinal issues often related to malnutrition. Conducting an ECG allows for the identification of any cardiac abnormalities, enabling timely intervention if needed.

While the other options are also relevant in the long-term management of a client with anorexia nervosa, none take precedence over immediate cardiovascular monitoring. Administering olanzapine, while it may help with treatment, does not address the acute risks posed by cardiac issues. Consulting nutritional services is crucial for addressing the underlying eating disorder, but that step comes after assessing the immediate health status. Weighing the client can provide information about their current nutritional status but would not take priority over ensuring their cardiovascular safety through an ECG, given the client's symptoms.