Which of the following is NOT a symptom of hypocalcemia?

Hypocalcemia, which is a condition characterized by low levels of calcium in the blood, often presents with several noticeable symptoms. One of the key indicators of hypocalcemia is hyperactivity of the nervous system, which can lead to symptoms such as numbness, muscle spasms (also referred to as tetany), and abnormal heart rhythms due to the role calcium plays in muscle contraction and nerve transmission.

Numbness can occur as neuromuscular excitability increases, causing alterations in sensation. Muscle spasms are a direct consequence of this increased excitability and can manifest as cramps or twitching. Abnormal heart rhythms may arise from the heart muscle's dependency on calcium for proper electrical conduction, leading to arrhythmias if calcium levels are not maintained.

In contrast, hyperactivity in this context refers to an increased nervous system response or increased muscle tension rather than a lack or deficiency. It is generally not regarded as a direct symptom of hypocalcemia when compared to the other symptoms listed. Thus, identifying hyperactivity as not being representative of hypocalcemia helps to clarify its relationship with the condition and emphasizes the connection between calcium levels and neuromuscular function.