Disorders of Calcium Metabolism: Hypocalcemia and Hypercalcemia

The clinical presentation includes severe hypocalcemia, hypophosphatemia, and resultant secondary hyperparathyroidism with elevated alkaline phosphatase and rickets. In this disorder, however, the constant stimulation of renal 1-alpha-hydroxylase from the chronic hypocalcemia, hypophosphatemia, and increased PTH levels results in elevated serum levels of 1,25-(OH)2 vitamin D (15,16). These factors should be considered in deciding postoperative prevention and/or management of hypocalcemia. Further studies are suggested in this domain to include these parameters with greater sample size, biochemical analysis and obtaining data from multiple centers. We recommend that female patients undergoing total thyroidectomy should be considered for hypocalcemia testing. Hypoparathyroidism, a condition where the parathyroid glands do not produce enough parathyroid hormone, is prevalent in about 75% of hypocalcemia patients.

Patient Publications

Also, we modify our empiric replacement protocol based on intraoperative findings, such as the viability of the parathyroid glands during the thyroidectomy, or the number of parathyroid glands removed during the parathyroidectomy. We also decrease the dose of calcium in patients with impaired renal function and in elderly patients. Primary hypoparathyroidism can be due to antibodies against the parathyroid glands or activating antibodies against the CaSR. Transient or permanent hypoparathyroidism can occur post thyroidectomy20.

Treatment algorithm for postoperative hypocalcemia

If PTH levels are abnormal, it could signify a problem with the parathyroid glands or other related issues that could lead to hypocalcemia. The symptom-based treatment algorithm included a protocolized attempt to phase out supplementation with the aim to reduce unwarranted long-term supplementation. Previously, we have shown the discrepancy in the incidence of hypoparathyroidism in patients with and without a dedicated effort to phase out supplementation (15).

• This sequence is critical for the movement of newly formed prepro-PTH through the endoplastic reticulum.
• An alternative to calcium carbonate is calcium citrate (2000 to 6000 mg per day) administered orally in divided doses for those patients on proton pump inhibitors, elderly patients with achlorhydria, and those who had a gastric bypass.
• Hypercalcemia is fairly common with a prevalence of approximately 1-4% in the general population and 0.17-3% in hospitalized populations 4.

Finally, malabsorption, for example, secondary to celiac disease, can also cause hypercalcemia, as can chronic kidney disease secondary to reduced vitamin D activation. And certain medications, including bisphosphonates or denosumab, can also cause hypocalcemia. Calcitonin is released by the thyroid C cells in response to increased calcium levels.

Post-Thyroidectomy Hypocalcemia: A Single-Center Experience

• Between April 7, 2017, and September 17, 2019, a total of 134 patients were included in the prospective cohort.
• Temporary hypocalcemia is defined as a decrease in calcium levels following thyroidectomy that lasts for six to 12 months 11.
• A common complication of thyroid surgery is low calcium levels (hypocalcemia) after surgery, which may be more common after more extensive surgery.
• With hospital stays after surgery typically short, it is important to know how long to monitor a postoperative thyroid or parathyroid surgical patient for hypocalcemia.
• In cultures where traditional dress includes long garments, hoods or veils, this may result in reduced sun exposure and vitamin D deficiency (19,20).

Another strategy is more objective and based on immediate postoperative PTH levels, within 1 hour of the surgery. If the PTH level is above 15 pg/mL (detected but at the lower limit of normal), the patient can be discharged home on prophylactic oral dose of 500 to 1000 mg of calcium three times a day. If the PTH level is less than 15 pg/mL, calcitriol at a dose of 0.5 to 1.0 μg per day should be started in addition to calcium.

Results

The use of PTH as a predictor has several limitations caused by biological variation, the influence of vitamin D status and between-method variation due to a lack of standardization of PTH assays (22). Forty different PTH cutoffs have been identified as the most reliable threshold to detect hypoparathyroidism, as reported in a recent meta-analysis (37). To account for between-method variation, we calculated the proportional difference in pre- to postoperative PTH and confirmed the higher sensitivity compared to a single postoperative PTH value (38). The high negative predictive value for synthroid acb calcium and/or alfacalcidol supplementation enables its use as a rule-out test.

A balanced diet with calcium-rich foods and vitamin D supplements is key. Vitamin D deficiency, affecting calcium absorption, is a common cause of hypocalcemia. Medical issues like kidney failure and hypomagnesemia disrupt calcium regulation, leading to hypocalcemia. Disorders of calcium metabolism are encountered relatively frequently in routine clinical practice. Hypocalcemia is not seen as frequently as hypercalcemia is, but it can be potentially life-threatening if not appropriately recognized and promptly treated. Clinical presentations can vary from asymptomatic to life-threatening arrhythmias or seizures.

The prepro-PTH gene mutation resulted in a substitution of G to C in the first nucleotide position of the prepro-PTH intron 2. This mutation resulted in an aberrant prepro-PTH mRNA so that the entire signal sequence would be absent preventing PTH secretion. The patients were homozygous for the mutant allele and were the product of a consanguineous marriage.

Magnesium supplementation should be considered if the serum magnesium level is below normal. The patient can be observed in the hospital overnight, or, if reliable, compliant, and close by, they can be sent home with clear instructions on symptoms and when to call the doctor. Oral calcium carbonate is often the most commonly administered salt, although many different calcium salts exist.

Hypocalcemia is a common biochemical abnormality in sepsis, seen in up to 60-80% of critically ill septic patients. It can occur due to multiple mechanisms, including reduced intake, increased loss, and redistribution of calcium. It is important to take your medication as prescribed and to contact your doctor if you develop any signs of low or high calcium, as described in the “Signs and Symptoms” section. If you develop any of the symptoms of low calcium listed below, take an additional dose of calcium. If symptoms persist, particularly hand cramping, please contact your doctor or go to the nearest hospital emergency center to assess your calcium levels.