Guidelines Summary
Following the First International Conference on the Management of Hypoparathyroidism in Florence, Italy in 2015, guidelines on the diagnosis and treatment hypoparathyroidism were released. Diagnosis is based on the following findings [48] :
-
Hypocalcemia confirmed twice, at least 2 weeks apart.
-
Parathyroid hormone (PTH) concentration, by second- or third-generation immunoassay, that is undetectable or inappropriately low (ie, < 20 pg/mL) in the presence of hypocalcemia on at least two occasions.
Phosphate levels in the upper normal or frankly elevated range supports diagnosis but is not mandatory. After neck surgery, chronic hypoparathyroidism can only be diagnosed after 6 months.
Urgent management of acute hypoparathyroidism requires intravenous calcium over 10 to 20 minutes followed by a slower infusion of calcium gluconate over an 8- to 10-hour period.
Management of chronic hypocalcemia in patients with hypoparathyroidism include the following [48] :
-
Dietary calcium and oral calcium supplements
-
Active vitamin D or analogs
-
Magnesium
-
Thiazide diuretics when necessary to help manage hypercalciuria and low salt diet
-
Phosphate binders and low phosphate diet, if necessary to control hyperphosphatemia
Indications for consideration of rhPTH (1-84) therapy include the following [48] :
-
Inadequate control of the serum calcium concentration
-
Excessive amounts of oral calcium and active vitamin D required to control symptoms
-
Hypercalciuria, renal stones, nephrocalcinosis, stone risk, or reduced creatinine clearance or eGFR (< 60 mL/min)
-
Hyperphosphatemia and/or calcium-phosphate product that exceeds 55 mgb/dLb (4.4 mmolb/Lb)
-
A gastrointestinal tract disorder that is associated with malabsorption
-
Reduced quality of life
Chronic Hypoparathyroidism
Guidelines on chronic hypoparathyroidism by the European Society of Endocrinology include the following [49] :
-
Consider a diagnosis of chronic hypoparathyroidism (HypoPT) in a patient with hypocalcemia and inappropriately low parathyroid hormone (PTH) levels.
-
Consider genetic testing and/or family screening in a patient with HypoPT of unknown etiology.
-
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.
-
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-Ca2] < 1.00 mmol/L).
-
Offer treatment to asymptomatic patients with chronic HypoPT and an albumin adjusted calcium level between 2.0 mmol/L (8.0 mg/dL/S-Ca2+ 1.00 mmol/L) and the lower limit of the reference range in order to assess whether this may improve their well-being.
-
Use activated vitamin D analogues plus calcium supplements in divided doses as the primary therapy.
-
If activated vitamin D analogues are not available, treat with calciferol (preferentially cholecalciferol).
-
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.
-
Provide vitamin D supplementation in a daily dose of 400–800 IU to patients treated with activated vitamin D analogues.
-
In a patient with hypercalciuria, consider a reduction in calcium intake, a sodium-restricted diet, and/or treatment with a thiazide diuretic.
-
In a patient with renal stones, evaluate renal stone risk factors and management according to relevant international guidelines.
-
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.
-
In a patient with hypomagnesemia, consider measures that may increase serum magnesium levels.
-
The routine use of replacement therapy with PTH or PTH analogues is not recommended.
Emergency Management of Hypocalcemia
The Society for Endocrinology guidelines for the emergency management of hypocalcemia in adults includes the following recommendations for postoperative hypocalcemia and hypoparathyroidism [50] :
-
Administer intravenous (IV) calcium gluconate over 10 minutes with electrocardiographic (ECG) monitoring; repeat until patient is asymptomatic. Titrate the rate of infusion to achieve normocalcemia and continue until treatment of the underlying cause has taken effect.
-
Treat hypoparathyroidism with alfacalcidol or calcitriol therapy. If there are concerns about absorbtion or difficulties with oral administration, alfacalcidol can be given intravenously.
The guidelines note that adverse effects of calcium administration include local thrombophlebitis, cardiotoxicity, hypotension, calcium taste, flushing, nausea, vomiting and sweating. Patients with cardiac arrhythmias or on digoxin therapy need continuous ECG monitoring during IV calcium replacement. Large volume calcium infusions should not be used in patients with end stage renal failure or who are on dialysis.
