Final answer:
The nurse should consider heart failure as the likely cause of the bilateral pedal edema in the casted patient, given the age and systemic presence of the condition. Compartment syndrome and localized infection are less probable due to the bilateral nature of the edema, whereas thrombophlebitis can't be ruled out completely, although less typical when edema is bilateral.
Step-by-step explanation:
When assessing a 72-year-old client with bilateral pedal edema and a full-leg cast on the left leg three days after cast application, the nurse needs to consider various conditions that can cause such symptoms. While the provided options are all potential concerns, the presence of edema on both sides (“bilateral”) suggests a systemic issue rather than one localized to the leg with the cast. As compartment syndrome typically affects only the injured limb, and the infection is usually localized, we can rule those out. Heart failure could be a more likely cause because it can cause fluid to accumulate in both legs, leading to edema. On the other hand, thrombophlebitis usually affects one leg, but it can't be entirely dismissed if there's a clot in both legs.
Considering factors like the patient's age and lack of mobility due to the cast, heart failure becomes a significant consideration for bilateral pedal edema. If the patient has a history of heart problems or the symptoms align with heart failure (like fatigue, shortness of breath, etc.), the nurse should promptly refer the patient for a more definitive assessment to rule in or out of heart failure or other systemic causes of the edema. Quick and accurate diagnosis is essential to address the underlying cause and initiate appropriate treatment.