Which of the following describes a patient with hyponatremia?

Hyponatremia, or low sodium levels in the blood, can lead to a variety of clinical symptoms due to the important role sodium plays in maintaining fluid balance, nerve function, and muscle contraction. Muscle weakness is a common manifestation of this condition, as low sodium levels can disrupt the normal function of nerve and muscle cells, impairing their ability to conduct electrical impulses properly.

When sodium levels drop, it can cause an imbalance in the osmotic pressure across cell membranes, leading to cellular swelling and dysfunction. This can particularly affect skeletal muscle, resulting in the sensation of weakness. Thus, a patient experiencing muscle weakness is indeed consistent with the effects of hyponatremia.

In addition, while confusion and agitation (often seen in cases of more severe hyponatremia) can also occur, the description of muscle weakness directly relates to the physiological impact of low sodium levels. Increased thirst is generally more associated with dehydration or conditions that raise thirst as a regulatory mechanism rather than directly indicating hyponatremia. Abnormal heartbeat is more commonly linked with other electrolyte imbalances rather than specifically with low sodium levels. Therefore, muscle weakness stands out as a direct reflection of the symptoms seen in hyponatremia.