Hypoparathyroidism after thyroidectomy: prevention, assessment and management

The role of carbon nanoparticle in lymph node detection and parathyroid gland protection during thyroidectomy for non-anaplastic thyroid carcinoma- a meta-analysis

OBJECTIVE

To assess the efficiency of the carbon nanoparticles (CNs) in lymph node identification and parathyroid gland (PG) protection during thyroidectomy for non-anaplastic thyroid carcinoma (N-ATC).

METHODS

A systematic literature search for relevant literatures published up to December 2018 in PubMed, EMBASE, Web of Science and Cochrane Library was performed. Both English and Chinese literatures were retrieved and analyzed. Randomized controlled trials or nonrandomized controlled trials comparing the use of CNs with the use of methylene blue or a blank control in patients undergoing thyroidectomy for N-ATC were enrolled in this study. The primary outcomes included the number of lymph nodes harvested, the rate of lymph nodes involved, and the rates of accidental parathyroidectomy, hypoparathyroidism, and hypocalcemia. Weighted mean differences (WMDs), odds ratios (ORs) and risk differences (RDs) were calculated for the dichotomous outcome variables. Between study heterogeneity was tested using the Q tests and the I2 statistics. All analyses were performed using Review Manager (version 5.3.5).

RESULTS

25 studies comprising 3266 patients were included in this analysis. The total number of lymph nodes harvested in the CNs groups was significantly higher than that in the control groups (WMD, 2.36; 95% CI, 1.40 to 3.32; P <0.01). Administrating CNs was associated with a lower incidence of accidental PG removal (OR = 0.28, 95% CI = 0.21 to 0.37, P<0.01) and lower rates of both postoperative transient hypoparathyroidism (OR = 0.46, 95% CI = 0.33 to 0.64, P <0.01) and transient hypocalcemia (OR = 0.46, 95% CI = 0.33 to 0.65, P <0.01). No significant difference was found concerning lymph node metastatic rates between CNs group and control group. Subgroup analysis indicated that the application of CNs in reoperation thyroidectomy reduced both the rate of transient hypoparathyroidism (OR = 0.21, 95% CI = 0.06 to 0.75, P = 0.02) and the possibility of accidental PGs removal (OR = 0.21, 95% CI = 0.07 to 0.62, P = 0.004, P<0.05).

CONCLUSIONS

The application of CNs in thyroidectomy for N-ATC results in higher number of lymph node harvested and better PG protection during both initial and reoperation thyroidectomy.

Vitamin D Deficiency as a Predictive Factor of Transient Hypocalcemia after Total Thyroidectomy

BACKGROUND

Total thyroidectomy (TT) is recommended in the treatment of malignant and benignant thyroid diseases, and, to date, transient hypocalcemia is the most frequent complication after the procedure. We prospectively evaluated the role of vitamin D deficiency as a predictor of postoperative hypocalcemia.

METHODS

This is a prospective cohort study which was conducted between January 2016 and April 2019. A total of 177 consecutive patients (141 (79.7%) women and 36 (20.3%) men) who underwent TT were included in the current study. Hypocalcemia occurred when serum calcium levels were below 8.0 mg/dL or 1.10 mmol/L. Patients were divided into two groups (Group 1, normocalcemic; Group 2, hypocalcemic) and were assessed taking into consideration preoperative serum 25-hydroxy vitamin D (25-OHD) levels, preoperative serum calcium levels, thyroid hormone levels, sex, body mass index (BMI), and smoking habits. Vitamin D deficiency was defined as 25-OHD levels <25 ng/mL.

RESULTS

The incidence of postoperative asymptomatic and symptomatic hypocalcemia in the two groups was 19.8% and 15.8%, respectively. Preoperative 25-OHD level was significantly different between Group 1 and Group 2 (31.5 ± 15.0 ng/mL vs 18.7 ± 9.8 ng/mL,p=0.017). Logistic regression analysis revealed that preoperative vitamin D deficiency was a significant predictive factor of postoperative hypocalcemia (p=0.012), and, specifically, the risk of hypocalcemia increased 15-fold in patients with a preoperative vitamin D level <25 ng/mL (odds ratio [OR], 14.8).

CONCLUSIONS

Postoperative hypocalcemia is significantly associated with low preoperative levels of serum 25-OHD. Our studies demonstrate that vitamin D deficiency (<25 ng/mL) is an independent predictive factor of postoperative hypocalcemia.

Discharging a Patient Treated With Parathyroid Allotransplantation After Having Been Hospitalized for 3.5 Years With Permanent Hypoparathyroidism: A Case Report

INTRODUCTION

Parathyroid allotransplantation is one of the methods used in the treatment of permanent hypoparathyroidism. We present a patient who underwent continuous intravenous (IV) calcium replacement therapy because of permanent hypoparathyroidism after total thyroidectomy.

CASE PRESENTATION

A 47-year-old woman who underwent a total thyroidectomy with a multinodular goiter developed hypoparathyroidism and hypocalcemia 1 week after discharge. The patient was started on daily oral calcitriol, magnesium effervescent, vitamin D, and IV calcium gluconate and was unable to be discharged because the IV calcium could not be stopped. After 3.5 years, 50×10⁶ parathyroid cells were transplanted by injecting the cells into the left deltoid muscle of the patient. The immunosuppression of the patient, who used 20-mg methylprednisolone for the first month, was completely discontinued.

RESULTS

No complications were observed in the patient after transplantation. The parenteral calcium replacement of the patient was progressively interrupted after transplantation. The patient's serum calcium level was 7.8 mg/dL and the PTH level was 6.9 pg/mL without IV calcium replacement at 12 weeks after transplantation, and the patient was discharged using oral ionized calcium. In the 10-week follow-up after discharge, the need for IV calcium was not observed in the patient.

CONCLUSION

Parathyroid allotransplantation is a simple, fast, and cost-effective method that should be tried in patients with persistent hypoparathyroidism, especially those who have to take IV calcium replacement, because its cost is much cheaper than standard medical care, its morbidity is much more limited, and it increases the patient's quality of life.

Study of the Ultrasound Appearance of the Normal Parathyroid Using an Intraoperative Procedure

OBJECTIVES

This study was designed to confirm the echogenicity of normal parathyroid glands using intraoperative ultrasound (US).

METHODS

Between October 2015 and January 2016, normal parathyroid glands were examined with an intraoperative US transducer during thyroidectomy procedures in 13 patients with thyroid disease. According to the findings from intraoperative US, routine percutaneous US of normal parathyroid glands was performed in a group of adults. On the basis of previous information on normal parathyroid echogenicity, a series of parathyroid diseases that were proved by surgery and histopathologic analyses were retrospectively reviewed. The presence of residual normal parathyroid in the lesion on US imaging, which was defined as the residual parathyroid sign in this study, was reviewed and correlated with histopathologic results.

RESULTS

In the intraoperative US group, 23 parathyroid glands were scanned intraoperatively, and 21 (91.3%) were hyperechoic, homogeneous in texture, and oval. In the routine percutaneous US group, 106 parathyroid glands were found in total, and 96 (90.5%) of the glands had hyperechoic and homogeneous echogenicity, with 75 (70.8%) being oval. In the review of parathyroid diseases, 33 parathyroid glands in 30 cases were reviewed, with a positive residual parathyroid sign in 7 (21.2%) parathyroid glands, presenting with a hyperechoic rim in the margin, and 4 of them (12.1%) were confirmed by histopathologic results.

CONCLUSIONS

The normal parathyroid had hyperechoic echogenicity on both intraoperative and percutaneous US imaging. Residual tissue of parathyroid glands can also be observed in some parathyroid abnormalities with an echogenic appearance on US imaging and confirmed by histopathologic results.

Hypocalcemic disorders

Calcium is vital for life, and extracellular calcium concentrations must constantly be maintained within a precise concentration range. Low serum calcium (hypocalcemia) occurs in conjunction with multiple disorders and can be life-threatening if severe. Symptoms of acute hypocalcemia include neuromuscular irritability, tetany, and seizures, which are rapidly resolved with intravenous administration of calcium gluconate. However, disorders that lead to chronic hypocalcemia often have more subtle manifestations. Hypoparathyroidism, characterized by impaired secretion of parathyroid hormone (PTH), a key regulatory hormone for maintaining calcium homeostasis, is a classic cause of chronic hypocalcemia. Disorders that disrupt the metabolism of vitamin D can also lead to chronic hypocalcemia, as vitamin D is responsible for increasing the gut absorption of dietary calcium. Treatment and management options for chronic hypocalcemia vary depending on the underlying disorder. For example, in patients with hypoparathyroidism, calcium and vitamin D supplementation must be carefully titrated to avoid symptoms of hypocalcemia while keeping serum calcium in the low-normal range to minimize hypercalciuria, which can lead to renal dysfunction. Management of chronic hypocalcemia requires knowledge of the factors that influence the complex regulatory axes of calcium homeostasis in a given disorder. This chapter discusses common and rare disorders of hypocalcemia, symptoms and workup, and management options including replacement of PTH in hypoparathyroidism.

Hypoparathyroidism: what is the best calcium carbonate supplementation intake form?

INTRODUCTION

In hypoparathyroidism, calcium supplementation using calcium carbonate is necessary for the hypocalcemia control. The best calcium carbonate intake form is unknown, be it associated with feeding, juice or in fasting.

OBJECTIVE

The objective was to evaluate the calcium, phosphorus and calcium×phosphorus product serum levels of hypoparathyroidism women after total thyroidectomy, following calcium carbonate intake in three different forms.

METHODS

A crossover study was carried out with patients presenting definitive hypoparathyroidism, assessed in different situations (fasting, with water, orange juice, breakfast with a one-week washout). Through the review of clinical data records of tertiary hospital patients from 1994 to 2010, 12 adult women (18-50 years old) were identified and diagnosed with definitive post-thyroidectomy hypoparathyroidism. The laboratory results of calcium and phosphorus serum levels dosed before and every 30min were assessed, for 5h, after calcium carbonate intake (elementary calcium 500mg).

RESULTS

The maximum peak average values for calcium, phosphorus and calcium×phosphorus product were 8.63mg/dL (water), 8.77mg/dL (orange juice) and 8.95mg/dL (breakfast); 4.04mg/dL (water), 4.03mg/dL (orange juice) and 4.12mg/dL (breakfast); 34.3mg²/dL² (water), 35.8mg²/dL² (orange juice) and 34.5mg²/dL² (breakfast), respectively, and the area under the curve 2433mg/dLmin (water), 2577mg/dLmin (orange juice) and 2506mg/dLmin (breakfast), 1203mg/dLmin (water), 1052mg/dLmin (orange juice) and 1128mg/dLmin (breakfast), respectively. There was no significant difference among the three different tests (p>0.05).

CONCLUSION

The calcium, phosphorus and calcium×phosphorus product serum levels evolved in a similar fashion in the three calcium carbonate intake forms.