Hypocalcemia

Epidemiology

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Etiology

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Pathophysiology

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Clinical features

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Neurological manifestations

• Tetany: increased neuromuscular excitability (when caused by respiratory alkalosis = hyperventilation-induced tetany)
  • Paresthesias: typically tingling or pins-and-needles sensation in extremities and/or in the perioral area
  • Spasms (e.g., carpopedal spasm, bronchospasm or laryngospasm), and cramps (possible in any muscle)
  • Stiffness, myalgia
  • Maneuvers to elicit latent tetany on physical exam
    • Chvostek sign: short contractions (twitching) of the facial muscles elicited by tapping the facial nerve below and in front of the ear (∼ 2 cm ventral to the ear lobe)
    • Trousseau sign: ipsilateral carpopedal spasm occurring several minutes after inflation of a blood pressure cuff to pressures above the systolic blood pressure
• Seizure: may be the initial or only symptom

Diagnostics

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• Acute Symptomatic/Severe Hypocalcemia (tetany, seizures, arrhythmias):
  • IV calcium gluconate is preferred (less risk of tissue necrosis than CaCl2 if extravasated).
  • Correct concurrent hypomagnesemia if present.
• Chronic/Asymptomatic Hypocalcemia:
  • Oral calcium (carbonate or citrate) and vitamin D supplements (e.g., calcitriol in CKD or hypoparathyroidism).
  • For hypoparathyroidism, may add thiazide diuretics to decrease urinary Ca2+ excretion.

Treatment

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