Which of the following symptoms indicates a possible electrolyte imbalance in a patient?

Muscle cramps or spasms are commonly associated with electrolyte imbalances, particularly with disturbances in levels of sodium, potassium, calcium, and magnesium. Electrolytes are crucial for muscle function, and when there is an imbalance, it can disrupt normal muscle contraction and relaxation processes. For instance, low potassium levels (hypokalemia) and low calcium levels (hypocalcemia) can lead to increased excitability of muscle tissues, resulting in cramps or spasms.

In contrast, while other symptoms such as rapid weight gain, feeling excessively cold, and chest pain can indicate various health issues, they are not as directly linked to electrolytic disturbances as muscle cramps or spasms are. Thus, the presence of muscle cramps is a strong indicator of potential electrolyte imbalance, making it the correct choice in this context.