Medical Care
Symptomatic hypocalcemia (eg, seizure, tetany, laryngospasm) in patients with hypoparathyroidism requires intravenous calcium and continuous monitoring for cardiac arrhythmias.
Oral calcium and active vitamin D (calcitriol) should be initiated as soon as possible (eg, when the patient is tolerating oral feeds).
Once serum calcium concentrations are in a safe range (>7.5 mg/dL), intravenous calcium can be stopped. Prolonged intravenous calcium therapy with existing high serum phosphate will increase further precipitation of calcium-phosphate compound. However, rebound hypocalcemia can occur and requires that a patient be monitored for therapeutic success on oral agents for at least 24 hours after intravenous calcium is withdrawn. In patients with hungry bone syndrome, prolonged intravenous calcium therapy may be needed.
The active form of vitamin D, 1,25-dihydroxyvitamin D (calcitriol), is preferred in the treatment of hypoparathyroidism because both the parathyroid hormone (PTH) deficiency/resistance and the hyperphosphatemia impair the activation of 25-hydroxyvitamin D by 1-alpha-hydroxylase.
General recent guidelines on chronic hypoparathyroidism by the European Society of Endocrinology are below: [5]
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Consider a diagnosis of chronic hypoparathyroidism (HypoPT) in a patient with hypocalcemia and inappropriately low parathyroid hormone (PTH) levels.
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Consider genetic testing and/or family screening in a patient with HypoPT of unknown etiology.
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Treatment targeted to maintain serum calcium level (albumin adjusted total calcium or ionized calcium) in the lower part or slightly below the lower limit of the reference range (target range) is suggested, with patients being free of symptoms or signs of hypocalcemia.
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Treat patients with chronic HypoPT with symptoms of hypocalcemia and/or an albumin adjusted serum calcium level < 2.0 mmol/L (< 8.0 mg/dL/ionized serum calcium levels [S-Ca 2] < 1.00 mmol/L).
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Offer treatment to asymptomatic patients with chronic HypoPT and an albumin adjusted calcium level between 2.0 mmol/L (8.0 mg/dL/S-Ca 2+ 1.00 mmol/L) and the lower limit of the reference range in order to assess whether this may improve their well-being.
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Use activated vitamin D analogues plus calcium supplements in divided doses as the primary therapy.
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If activated vitamin D analogues are not available, treat with calciferol (preferentially cholecalciferol).
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Titrate activated vitamin D analogues or cholecalciferol in such a manner that patients are without symptoms of hypocalcaemia and serum calcium levels are maintained within the target range.
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Provide vitamin D supplementations in a daily dose of 400–800 IU to patients treated with activated vitamin D analogues.
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In a patient with hypercalciuria, consider a reduction in calcium intake, a sodium-restricted diet, and/or treatment with a thiazide diuretic.
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In a patient with renal stones, evaluate renal stone risk factors and management according to relevant international guidelines.
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In a patient with hyperphosphatemia and/or an elevated calcium-phosphate product, consider dietary interventions and/or adjustment of treatment with calcium and vitamin D analogues.
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In a patient with hypomagnesemia, consider measures that may increase serum magnesium levels.
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The routine use of replacement therapy with PTH or PTH analogues is not recommended.
Diet
No special diet is required, but adequate calcium and vitamin D intake is recommended.
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Electrocardiogram (ECG) findings in severe hypocalcemia.
