Which of these conditions may lead to tetany, convulsions, and ECG changes?

Hypocalcemia, or low levels of calcium in the blood, can indeed lead to a range of serious symptoms, including tetany (involuntary muscle contractions), convulsions (seizures), and notable changes in the electrocardiogram (ECG). Calcium plays a critical role in neuromuscular excitability, muscle contraction, and cardiac function. When calcium levels are low, the nervous system becomes more excitable, which can manifest as muscle spasms or cramps. Additionally, the heart's electrical activity can be affected, leading to characteristic changes on an ECG, such as a prolonged QT interval.

Understanding this is crucial because it highlights the importance of maintaining proper calcium levels for both muscle and cardiac health. While other conditions listed can cause various symptoms, none directly relate to the specific triad of tetany, convulsions, and ECG changes as for hypocalcemia.