Define Hypocalcemia.
Hypocalcemia: total serum calcium concentration < 8.5 mg/dL (< 2.12 mmol/L), or ionized (free) calcium concentration < 4.65 mg/dL (< 1.16 mmol/L) [1]
Severe hypocalcemia: total serum calcium concentration ≤ 7.5 mg/dL (< 1.9 mmol/L), or ionized (free) calcium concentration < 3.6 mg/dL (< 0.9 mmol/L) [2]
Factitious hypocalcemia: an asymptomatic decrease in total calcium with a normal ionized Ca2+ level (typically occurs due to low serum protein levels)
Which medications can cause hypocalcemia?
Loop diuretics increase renal calcium excretion.
Calcitonin
Bisphosphonates
List 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) [1]
Trousseau sign: ipsilateral carpopedal spasm occurring several minutes after inflation of a blood pressure cuff to pressures above the systolic blood pressure [1]
Seizure: may be the initial or only symptom [14]
List cardiovascular manifestations
Congestive heart failure —> Hypocalcemia may lead to myocardial dysfunction
Hypotension
Cardiac arrhythmias (symptoms may include palpitations, irregular pulse, syncope)
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