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What symptoms can occur in severe calcium deficiency or hypocalcemia?

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A labeled diagram of the periodic table entry for calcium, showing its atomic number 20, symbol Ca, atomic weight 40.078, electron configuration, and classification as an alkaline-earth metal. Icons indicate calcium is a solid with a face-centered cubic crystal structure and strongly basic oxides at room temperature. — calcium The chemical element calcium is the most abundant metallic element in the human body.

Severe calcium deficiency, or hypocalcemia, occurs when calcium levels in the bloodstream fall below the normal range. Because calcium is essential for muscle contraction and nerve impulse transmission, its deficiency primarily manifests through neuromuscular excitability.12

The primary clinical syndrome associated with severe hypocalcemia is tetany, which is characterized by the following symptoms:

Sensations: Numbness and tingling, particularly around the mouth and in the hands and feet.21
Muscular symptoms: Rhythmic cramping, twitching, and painful muscle spasms. A classic presentation is carpopedal spasm, where the arms and hands contract rigidly with the fingers extended and the thumb pressed against the palm.321
Severe complications: In extreme cases, neuromuscular excitability can progress to generalized convulsions or spasms of the larynx, which may cause difficulty breathing.32
Chronic effects: Patients with long-term, chronic hypocalcemia may develop cataracts and calcification in the basal ganglia of the brain, potentially leading to symptoms of parkinsonism.2

These symptoms are typically treated by restoring metabolic balance through the administration of calcium.321