Hypocalcemia following total and subtotal thyroidectomy and associated factors

Renal function tests may identify underlying conditions contributing to hypocalcemia. Low calcium levels over time can lead to diseases like osteoporosis and osteopenia. These conditions, resulting from insufficient calcium, cause weak bones and increased fracture risks. Factors like genetics, hormonal changes, and certain medications also play roles. Calcium homeostasis in the body is a complex interplay between different hormones, regulatory proteins, receptors, and serum chemistries. Thyroidectomy is one of the common endocrinological surgeries for the treatment of thyroid disorders.

The process of post-operative management of thyroidectomy patients and the QI plan is summarised in Figure 1. It represents the post-operative pathway for patients undergoing thyroid surgery. All thyroidectomies performed at a single tertiary center between 2012 and 2017 were retrospectively analyzed. As chronic hypoparathyroidism is a life-long disorder, the long-term use of rhPTH(1-84) is of particular importance both with regard to efficacy and safety. Over time, but not in the near term, urinary calcium declined by 38%, an observation also confirmed in the 5-year follow-up study of the REPLACE trial.

Measuring calcium levels postoperatively has been used to predict who can be safely discharged and who will require post-thyroidectomy calcium and vitamin D supplementation. If the serum calcium level is less than 8.5 mg/dL, or the ionized calcium level is less than 1.1 mmol/L, replacement should be considered. The pitfall with this protocol is in the timing of the measurement as studies have failed to demonstrate the reliability of the immediate postoperative calcium measurements to predict the development of hypoparathyroidism. Postoperatively, the decrease in serum calcium level can be delayed by as much as 48 to 72 hours and only materialize after the patient is home. Inherited disorders can result from the deficiency in the renal production of 1,25-(OH)2 vitamin D (vitamin D-dependent rickets type 1) or a defect in the vitamin D receptor (VDR) (vitamin D-dependent rickets type 2).

DATA AVAILABILITY STATEMENT

Intraoperative PTH monitoring has also been shown to reduce the rate of complications (including hypoparathyroidism) in patients undergoing reoperations for primary hyperparathyroidism (29). A normal calcium range is around 2.15 to 2.60 mmol/L, but reference ranges and units will vary globally. In the blood, around 40% of calcium is bound to proteins such as albumin. Abnormal albumin levels can make total calcium levels appear too high or too low. Corrected calcium levels are a better indicator of the amount of calcium that is free in the blood for its physiologic functions.

Magnesium Deficiency

• On the other hand, calcium supplementation is not without risks, patients are exposed to adverse effects related to calcium supplementation, including kidney stones, constipation, heartburn, and hypercalcemia (8).
• Finally, malabsorption, for example, secondary to celiac disease, can also cause hypercalcemia, as can chronic kidney disease secondary to reduced vitamin D activation.
• 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.
• Hypocalcemia is a medical condition characterized by abnormally low levels of calcium in the blood.
• In two other studies examining a symptom-based treatment approach the mean hospital stay was either significantly longer or not reported (16, 26).

As a primary care practice, we are committed to supporting our patients in their health journey. Through our telemedicine services, we strive to provide quality care that is accessible, convenient, and responsive to your needs. If you’re experiencing symptoms of Hypocalcemia or have been diagnosed with this condition, we are here to help.

Hypoparathyroidism

• These studies did not consistently demonstrate a reduction in urinary calcium excretion.
• Acidosis reduces calcium binding to albumin, causing increased ionized calcium levels, while an alkaline environment has the opposite effect.
• Through our telemedicine services, we strive to provide quality care that is accessible, convenient, and responsive to your needs.

This test is important because magnesium is necessary for the proper function of the parathyroid glands, which regulate calcium levels. If the results show low magnesium levels, this could indicate hypocalcemia, as magnesium deficiency can lead to low calcium levels. Hyperparathyroidism is a condition where the parathyroid glands produce excessive amounts of parathyroid hormone (PTH). The overproduction of PTH causes excessive removal of calcium from bones, leading to bone weakening and high calcium levels in the blood, thereby causing hypocalcemia.

Post-Thyroidectomy Hypocalcemia: A Single-Center Experience

Moreover, PTH stimulates bone resorption by the osteoclasts and increases the secretion of calcitriol, which in turn stimulates intestinal Ca+2 and phosphate absorption by activating the VDR. Conversely, hypercalcemia decreases PTH secretion by activating the CaSR and the above actions are reversed. The hormonal response keeps serum Ca+2 in a narrow physiologic range 1. Therefore, the function of the CaSR in the parathyroid glands is to change PTH secretion depending on serum ionized Ca+2 level. Both Mg+2 and Ca+2 bind to the CaSR in the parathyroid glands and the kidney; however, each has a distinct binding site.

Other safety indices, such as the incidence of hypercalcemia and hypercalciuria, are favorable. The fortification of milk, cereals, breads, and other foods with vitamin D and the use of supplements are why there are so few cases of vitamin D deficiency in children in the United States. Vitamin D deficiency has been recognized in the synthroid uso United States in children who have restricted diets or specialized diets (18).

These patients were mildly hypoestrogenemic with normal to slightly elevated serum gonadotropin levels. It was proposed that the reproductive dysfunction was due to partial resistance to gonadotropins since administration of the synthetic GnRH analogue produced normal FSH and LH responses (85). In patients with radiographic evidence of osteitis fibrosis cystica, there is clearly skeletal sensitivity to PTH. In such individuals, serum alkaline phosphatase levels and biochemical markers of bone turnover, especially of bone resorption, may be increased. Especially in those with skeletal sensitivity to PTH, there may be decreased BMD, especially at cortical sites.

The etiology of postoperative hypocalcemia following thyroidectomy is due to “stunning” or ischemia to all four parathyroid glands or inadvertent removal or devascularization, or failed autotransplantation of parathyroid glands. With specific reference to thyroid surgery, transient hypoparathyroidism occurs in approximately 23% to 38% of patients undergoing total thyroidectomy, with about 7% to 14% requiring a long-term calcium supplementation. Studies by Sosa et al. and Aspinall et al. demonstrated that a high-volume surgeon is the one who performs more than 50 parathyroidectomies and thyroidectomies per year. The impaired parathyroid function is characterized by a decline in PTH and calcium concentrations during and shortly after thyroidectomy (3). In most patients parathyroid function fully recovers over time, but in 5–16% hypoparathyroidism will persist (4, 5).