Histopathology, pathophysiology, and indications for surgical treatment of renal hyperparathyroidism

[Diagnosis and treatment of osteoporosis in patients with chronic kidney disease : Joint guidelines of the Austrian Society for Bone and Mineral Research (ÖGKM), the Austrian Society of Physical and Rehabilitation Medicine (ÖGPMR) and the Austrian Society of Nephrology (ÖGN)]

DEFINITION AND EPIDEMIOLOGY

Chronic kidney disease (CKD): abnormalities of kidney structure or function, present for over 3 months. Staging of CKD is based on GFR and albuminuria (not graded). Osteoporosis: compromised bone strength (low bone mass, disturbance of microarchitecture) predisposing to fracture. By definition, osteoporosis is diagnosed if the bone mineral density T‑score is ≤ -2.5. Furthermore, osteoporosis is diagnosed if a low-trauma (inadequate trauma) fracture occurs, irrespective of the measured T‑score (not graded). The prevalence of osteoporosis, osteoporotic fractures and CKD is increasing worldwide (not graded). PATHOPHYSIOLOGY, DIAGNOSIS AND TREATMENT OF CHRONIC KIDNEY DISEASE-MINERAL AND BONE DISORDER (CKD-MBD): Definition of CKD-MBD: a systemic disorder of mineral and bone metabolism due to CKD manifested by either one or a combination of the following: abnormalities of calcium, phosphorus, PTH, or vitamin D metabolism; renal osteodystrophy; vascular calcification (not graded). Increased, normal or decreased bone turnover can be found in renal osteodystrophy (not graded). Depending on CKD stage, routine monitoring of calcium, phosphorus, alkaline phosphatase, PTH and 25-OH-vitamin D is recommended (2C). Recommendations for treatment of CKD-MBD: Avoid hypercalcemia (1C). In cases of hyperphosphatemia, lower phosphorus towards normal range (2C). Keep PTH within or slightly above normal range (2D). Vitamin D deficiency should be avoided and treated when diagnosed (1C).

DIAGNOSIS AND RISK STRATIFICATION OF OSTEOPOROSIS IN CKD

Densitometry (using dual X‑ray absorptiometry, DXA): low T‑score correlates with increased fracture risk across all stages of CKD (not graded). A decrease of the T‑score by 1 unit approximately doubles the risk for osteoporotic fracture (not graded). A T-score ≥ -2.5 does not exclude osteoporosis (not graded). Bone mineral density of the lumbar spine measured by DXA can be increased and therefore should not be used for the diagnosis or monitoring of osteoporosis in the presence of aortic calcification, osteophytes or vertebral fracture (not graded). FRAX can be used to aid fracture risk estimation in all stages of CKD (1C). Bone turnover markers can be measured in individual cases to monitor treatment (2D). Bone biopsy may be considered in individual cases, especially in patients with CKD G5 (eGFR < 15 ml/min/1.73 m2) or CKD 5D (dialysis).

SPECIFIC TREATMENT OF OSTEOPOROSIS IN PATIENTS WITH CKD

Hypocalcemia should be treated and serum calcium normalized before initiating osteoporosis therapy (1C). CKD G1-G2 (eGFR ≥ 60 ml/min/1.73 m2): treat osteoporosis as recommended for the general population (1A). CKD G3-G5D (eGFR < 60 ml/min/1.73 m2 to dialysis): treat CKD-MBD first before initiating osteoporosis treatment (2C). CKD G3 (eGFR 30-59 ml/min/1.73 m2) with PTH within normal limits and osteoporotic fracture and/or high fracture risk according to FRAX: treat osteoporosis as recommended for the general population (2B). CKD G4-5 (eGFR < 30 ml/min/1.73 m2) with osteoporotic fracture (secondary prevention): Individualized treatment of osteoporosis is recommended (2C). CKD G4-5 (eGFR < 30 ml/min/1.73 m2) and high fracture risk (e.g. FRAX score > 20% for a major osteoporotic fracture or > 5% for hip fracture) but without prevalent osteoporotic fracture (primary prevention): treatment of osteoporosis may be considered and initiated individually (2D). CKD G4-5D (eGFR < 30 ml/min/1.73 m2 to dialysis): Calcium should be measured 1-2 weeks after initiation of antiresorptive therapy (1C).

PHYSICAL MEDICINE AND REHABILITATION

Resistance training prioritizing major muscle groups thrice weekly (1B). Aerobic exercise training for 40 min four times per week (1B). Coordination and balance exercises thrice weekly (1B). Flexibility exercise 3-7 times per week (1B).

Incremental value of 99m Tc-MIBI single-photon emission computed tomography/computed tomography fusion imaging for the diagnosis of secondary hyperparathyroidism

PURPOSE

To assess the added value of 99m Tc-MIBI single-photon emission computed tomography/computed tomography (SPECT/CT) fusion imaging over dual-phase scintigraphy in the diagnosis of secondary hyperparathyroidism (SHPT).

METHODS

This retrospective study included 23 patients with SHPT. The diagnostic efficacy of 99m Tc-MIBI dual-phase scintigraphy and SPECT/CT fusion imaging was analyzed and compared based on the result of postoperative pathology and follow-up. To evaluate the diagnostic ability of 99m Tc-MIBI dual-phase scintigraphy, the volume and radioactive count of parathyroid lesions were assessed using the region of interest method.

RESULTS

A total of 79 hyperplastic parathyroid glands and two thyroid tissues were surgically removed from 23 SHPT patients and 13 normal parathyroid glands were preserved. 99m Tc-MIBI SPECT/CT fusion imaging showed higher sensitivity and accuracy than 99m Tc-MIBI dual-phase scintigraphy [sensitivity, 77.2% (61/79) vs 46.8% (37/79); accuracy, 80.4% (74/92) vs 54.3% (50/92), respectively], but comparable specificity [100% (13/13)). Among 61 positive lesions detected by 99m Tc-MIBI SPECT/CT fusion imaging, 37 were dual-phase scintigraphy positive and 24 were dual-phase scintigraphy false negative. The radioactivity counts and radioactivity per unit volume in dual-phase scintigraphy positive were higher than that in dual-phase scintigraphy false negative ( P  < 0.05), but the volume of parathyroid lesions between the two groups had no significant difference ( P  > 0.05).

CONCLUSION

Compared with 99m Tc-MIBI dual-phase scintigraphy, 99m Tc-MIBI SPECT/CT fusion imaging has incremental value in the diagnosis of SHPT. The low uptake of MIBI in the whole gland and low MIBI uptake per unit volume are easy to cause dual-phase scintigraphy false negative.

Treatment for secondary hyperparathyroidism focusing on parathyroidectomy

Secondary hyperparathyroidism (SHPT) is a major problem for patients with chronic kidney disease and can cause many complications, including osteodystrophy, fractures, and cardiovascular diseases. Treatment for SHPT has changed radically with the advent of calcimimetics; however, parathyroidectomy (PTx) remains one of the most important treatments. For successful PTx, removing all parathyroid glands (PTGs) without complications is essential to prevent persistent or recurrent SHPT. Preoperative imaging studies for the localization of PTGs, such as ultrasonography, computed tomography, and 99mTc-Sestamibi scintigraphy, and intraoperative evaluation methods to confirm the removal of all PTGs, including, intraoperative intact parathyroid hormone monitoring and frozen section diagnosis, are useful. Functional and anatomical preservation of the recurrent laryngeal nerves can be confirmed via intraoperative nerve monitoring. Total or subtotal PTx with or without transcervical thymectomy and autotransplantation can also be performed. Appropriate operative methods for PTx should be selected according to the patients' need for kidney transplantation. In the case of persistent or recurrent SHPT after the initial PTx, localization of the causative PTGs with autotransplantation is challenging as causative PTGs can exist in the neck, mediastinum, or autotransplanted areas. Additionally, the efficacy and cost-effectiveness of calcimimetics and PTx are increasingly being discussed. In this review, medical and surgical treatments for SHPT are described.

Localization Strategy Prior to Radiofrequency Ablation for Primary and Secondary Hyperparathyroidism

Objective: Preoperative localization in patients with primary or secondary hyperparathyroidism before radiofrequency ablation (RFA) is crucial. There is currently a lack of consensus regarding imaging protocol. Evaluating the diagnostic performance of ultrasound, four-dimensional computed tomography (4D-CT), and technetium 99m-sestamibi single-photon-emission-computed tomography/computed tomography (SPECT/CT) is necessary for RFA of hyperparathyroidism. Methods: This retrospective study recruited patients with primary or secondary hyperparathyroidism who underwent ultrasound, 4D-CT, and SPECT/CT before RFA at a single institution. The sensitivity, accuracy, and receiver operating characteristic curve analysis were used to evaluate the diagnostic performance of the imaging modalities. Results: A total of 33 patients underwent RFA for hyperparathyroidism (8 patients with primary hyperparathyroidism, 25 patients with secondary hyperparathyroidism). Ultrasound had the highest sensitivity (0.953) and accuracy (0.943), while 4D-CT had higher sensitivity and accuracy than SPECT/CT (sensitivity/accuracy, 4D-CT vs. SPECT/CT: 0.929/0.920 vs. 0.741/0.716). Combined ultrasound with 4D-CT and the three combined modalities achieved equivalent, and the highest, diagnostic performance (sensitivity 1.000, accuracy 0.989). The lesion length and volume were important predictors of the diagnostic performance of 4D-CT and SPECT/CT (area under curve of length in 4D-CT/volume in 4D-CT/length in SPECT/volume in SPECT: 0.895/0.834/0.767/0.761). Conclusion: Combined ultrasound with 4D-CT provides optimal preoperative localization prior to RFA in patients with primary or secondary hyperparathyroidism. The length and volume of parathyroid lesions are determinative of the diagnostic performance of 4D-CT and SPECT/CT.

Timing of parathyroidectomy for kidney transplant patients with secondary hyperparathyroidism: A practical overview

Kidney transplantation remains the best treatment for patients with end-stage kidney disease, and it could partially mitigate systemic disorders of mineral and bone metabolism caused by secondary hyperparathyroidism. However, persistent hyperparathyroidism is still observed in 30-60% of patients 1 year after kidney transplantation, leading to impairment of allograft function and a disturbance of mineral metabolism. The timing of parathyroidectomy varies among transplant centers because the possible negative effects of parathyroidectomy on allograft outcomes are still unclear. This review provides a comprehensive and detailed overview of the natural course of hyperparathyroidism following kidney transplantation and the effects of the timing and extent of parathyroidectomy on allograft function. It aims to provide useful information for surgeons to propose an appropriate intervention strategy to break the vicious cycle of post-kidney transplantation hyperparathyroidism and deterioration of allograft function.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Secondary and Tertiary Renal Hyperparathyroidism

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate treatment of secondary (SHPT) and tertiary (THPT) renal hyperparathyroidism.

BACKGROUND

Hyperparathyroidism is common among patients with chronic kidney disease, end-stage kidney disease, and kidney transplant. The surgical management of SHPT and THPT is nuanced and requires a multidisciplinary approach. There are currently no clinical practice guidelines that address the surgical treatment of SHPT and THPT.

METHODS

Medical literature was reviewed from January 1, 1985 to present January 1, 2021 by a panel of 10 experts in SHPT and THPT. Recommendations using the best available evidence was constructed. The American College of Physicians grading system was used to determine levels of evidence. Recommendations were discussed to consensus. The American Association of Endocrine Surgeons membership reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines present the epidemiology and pathophysiology of SHPT and THPT and provide recommendations for work-up and management of SHPT and THPT for all involved clinicians. It outlines the preoperative, intraoperative, and postoperative management of SHPT and THPT, as well as related definitions, operative techniques, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Preoperative and Perioperative Care, Surgical Planning and Parathyroidectomy, Adjuncts and Approaches, Outcomes, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal management of secondary and tertiary renal hyperparathyroidism.

OUP accepted manuscript

Chronic kidney disease mineral and bone disorder may persist after successful kidney transplantation. Persistent hyperparathyroidism has been identified in up to 80% of patients throughout the first year after kidney transplantation. International guidelines lack strict recommendations about the management of persistent hyperparathyroidism. However, it is associated with adverse graft and patient outcomes, including higher fracture risk and an increased risk of all-cause mortality and allograft loss. Secondary hyperparathyroidism may be treated medically (vitamin D, phosphate binders and calcimimetics) or surgically (parathyroidectomy). Guideline recommendations suggest medical therapy first but do not clarify optimal parathyroid hormone targets or indications and timing of parathyroidectomy. There are no clear guidelines or long-term studies about the impact of hyperparathyroidism therapy. Parathyroidectomy is more effective than medical treatment, although it is associated with increased short-term risks. Ideally parathyroidectomy should be performed before kidney transplantation to prevent persistent hyperparathyroidism and improve graft outcomes. We now propose a roadmap for the management of secondary hyperparathyroidism in patients eligible for kidney transplantation that includes the indications and timing (pre- or post-kidney transplantation) of parathyroidectomy, the evaluation of parathyroid gland size and the integration of parathyroid gland size in the decision-making process by a multidisciplinary team of nephrologists, radiologists and surgeons.

Use of 99mTc-sestamibi SPECT/CT imaging in predicting the degree of pathological hyperplasia of the parathyroid gland: semi-quantitative analysis

Background

Previous studies have demonstrated that ^99mTc-sestamibi (^99mTc-MIBI) Single-Photon Emission Computed Tomography/ Computed Tomography (SPECT/CT) imaging is an effective isotopic technique for locating the parathyroid in secondary hyperparathyroidism (SHPT). This study aimed to explore further the correlation between ^99mTc-MIBI SPECT/CT imaging and SHPT to demonstrate the value of ^99mTc-MIBI SPECT/CT in evaluating the degree of pathological hyperplasia of the parathyroid gland (PG).

Methods

The demographics, surgical records, and follow-up information of 91 patients were recorded and analyzed. A total of 216 paraffin-embedded PGs of 54 patients were obtained and analyzed.

Results

Patients with ^99mTc-MIBI negative PG(s) had significantly lower preoperative serum phosphorus and higher serum calcium levels at 6 months postoperatively compared to those with ^99mTc-MIBI positive PG(s) (P<0.05). We also found a higher total uptake ratio of the region of interest (URRI) and higher URRI max in the hypocalcemia group than in the non-hypocalcemia group. Both URRI total (P=0.003) and URRI max (P=0.028) were independent risk factors for hypocalcemia 6 months postoperatively. The URRI values of the PGs were significantly positively correlated with glandular weight (R²=0.343, P<0.001), glandular volume (R²=0.240, P<0.001), and degree of pathological hyperplasia (P<0.001). However, the URRI value of the PGs exhibited a notably weak correlation with proliferating cell nuclear antigen (PCNA) (R²=0.035, P=0.006). The area under the receiver operating characteristic curve showed a URRI evaluative value of 0.771 for diffuse and nodular types in 216 PGs (P<0.001). We further evaluated 167 nodular-type PGs, distinguishing between nodular hyperplasia and a single nodule; the URRI evaluative value reached 0.819, which was higher than the volume or weight (P<0.001).

Conclusions

The ^99mTc-MIBI SPECT/CT scintigraphy results were related to serum calcium levels at 6 months after total parathyroidectomy with autotransplantation (TPTX+AT), suggesting the occurrence of hypocalcemia (6 months after TPTX+AT). More importantly, this technique effectively evaluated the pathological hyperplasia of PGs preoperatively, and therefore, could assist surgeons in selecting the PGs with the lowest degree of hyperplasia intraoperatively.

Chronic Kidney Disease-Mineral and Bone Disorders: Pathogenesis and Management

The key players of the chronic kidney disease-mineral and bone disorders (CKD-MBD) are calcium, phosphate, PTH, FGF23, and the vitamin D hormonal system. The progressive reduction of kidney function greatly modifies the tightly interrelated mechanisms that control these parameters. As a result, important changes occur in the bone and mineral hormonal axis, leading to changes in bone turnover with relevant consequences in clinical outcomes, such as decrease in bone mass with increased bone fragility and bone fractures and increased vascular and valvular calcification, also with great impact in the cardiovascular outcomes. So far, the knowledge of the mineral and bone disorders in CKD and the increased variety of efficacious therapies should lead to a better prevention and management of CKD-MBD.

Relationship between intraoperative measured parameters of parathyroid gland and pathological patterns in patients with secondary hyperparathyroidism

Background

The hyperplastic patterns of parathyroid glands (PTGs) in secondary hyperparathyroidism (SHPT) are critical for surgical indication and deciding on the approach. Earlier histopathological investigations have suggested the occurrence of an initial increase in the parathyroid cells, with a normal lobular structure (diffuse hyperplasia, DH). After this, the PTGs become hyperplastic with some nodules (nodular hyperplasia, NH). The current study aimed to explore the relationship between the intraoperative measurements of weight, volume, and maximal diameter of dissected PTGs and the histopathological diagnosis of SHPT patients with end-stage renal disease.

Methods

A total of 182 SHPT patients who received parathyroidectomy (PTX) were retrospectively enrolled. Altogether 21 patients were selected as having at least one diffuse polyclonal hyperplasia PTG. Intraoperative measurements of weight, volume, and maximal diameter of dissected PTGs were compared between tissues with DH and NH.

Results

Intraoperative dissected PTGs were verified histologically. The differences in the intraoperative measurements of weight, volume, maximal diameter, and the combination of the three measurements between the DH and the NH PTGs groups were significant (P=0.000), and the values of area under the ROC curve (AUCs) were 0.824 (95% CI: 0.731–0.918), 0.812 (95% CI: 0.716–0.908), 0.746 (95% CI: 0.633–0.860), and 0.851 (95% CI: 0.768–0.935), respectively, with cut-off values of the three parameters being 0.19 g, 206.3 mm³, and 10.5 mm, respectively.

Conclusions

The measurement of weight, volume, and maximal diameter of dissected PTGs is a possible alternative to assess the hyperplasia patterns of the dissected PTGs. It is a promising reference for the ultrasound prediction of pathological patterns of PTGs.

Parathyroidectomy for tertiary hyperparathyroidism after second kidney transplantation: a case report

Successful kidney transplantation usually resolves secondary hyperparathyroidism (SHPT). However, some patients fail to normalize, and their condition is often referred to as tertiary hyperparathyroidism (THPT). Surgical consensus on the timing of post-transplant parathyroidectomy (PTX) for THPT has not been reached. Herein, we report a case of a 58-year-old post-transplant woman, considering the concrete timing of PTX for both SHPT and THPT. She initiated hemodialysis with end-stage renal disease at the age of 24, and underwent first kidney transplantation at the age of 28. When peritoneal dialysis (PD) was induced due to the worsening kidney function at the age of 50, the serum intact parathyroid hormone (iPTH) level remarkably increased (2332 pg/mL). Although cinacalcet was administered, the patient's iPTH levels were not sufficiently suppressed for seven years. Diagnostic images including ultrasound, computed tomography, and ^99mTc-methoxyisobutylisonitrile scintigraphy indicated THPT as the reason for prolonged post-transplant hypercalcemia. Therefore, PTX was performed 14 months after the second transplantation. Histology showed nodular hyperplasia of all parathyroid glands, indicating autonomous secretion of parathyroid hormone. In general, patients with more severe THPT are recognized with more severe SHPT prior to transplantation during the dialysis period. We should consider a referral for surgery based on the individual risk factors. We recommend to perform parathyroidectomy earlier, before the kidney transplantation in the clinical suspicion of severe SHPT.

Calcium-mediated parathyroid hormone suppression test in uraemic secondary hyperparathyroidism

AIM

The present study aimed to investigate the value of calcium-mediated parathyroid hormone (PTH) suppression test in evaluating the autonomic secretory function of parathyroid, and the management of uraemic secondary hyperparathyroidism (SHPT).

METHODS

Calcium-mediated PTH suppression test was performed in dialysis with SHPT, who were candidates for parathyroidectomy from June 2017 to December 2019 in our hospital. The PTH inhibition rate (PTH-IR) was calculated, and the correlation between PTH-IR and clinical indicators was explored.

RESULTS

Fifty-one subjects were included. PTH-IR was negatively correlated with baseline PTH (r = -0.35, P = .012), it was also correlated with dialysis years, coronary artery calcification score (CACS) and parathyroid mass (r = -0.397, P = .004; r = -0.327, P = .028; r = -0.363, P = .015), which were not found for baseline PTH. Forty-four patients underwent surgical treatment. According to the histological results, 26 patients presented with parathyroid non-nodular hyperplasia, and 18 patients presented with parathyroid nodular hyperplasia. The mass of parathyroid of patients with nodular hyperplasia was higher than that of patients with non-nodular hyperplasia (ρ = 0.01). The difference of the PTH-IR was not found between the two groups (ρ = 0.296). During the test, the highest serum calcium was 2.9 ± 0.4 mmol/L, which dropped to normal at the end of the test.

CONCLUSION

Parathyroid hormone inhibition rate might be a useful indicator in evaluating the autonomic secretory function of parathyroid and the progression of SHPT on top of intact PTH. Calcium-mediated PTH suppression test was safe in uraemic SHPT patients, but need to monitor for transient hypercalcaemia.

Critical analysis of the intraoperative parathyroid hormone decrease during parathyroidectomy for secondary and tertiary hyperparathyroidism

BACKGROUND

This study aims to determine whether intraoperative parathyroid hormone monitoring helps to predict early surgical outcomes in patients with renal hyperparathyroidism and evaluate the impact on decision making during surgery.

METHODS

A prospective study was conducted. Serial samples of the intraoperative parathyroid hormone were collected; 2 of these were taken before the excision, and 2 were taken after the planned parathyroid resection (10 minutes and 15 minutes). We tested the criterion of an intraoperative parathyroid hormone percentage decay ≥80% of the highest value of the basal samples as a predictor of success.

RESULTS

Of the 228 patients, parathyroidectomy achieved success in 92.1%. In patients with secondary hyperparathyroidism, the failure group showed a tendency to stabilize or even increase the intraoperative parathyroid hormone values from the 10-minute measure (577 pg/mL) to the 15-minute measure (535 pg/mL) (P = .903). Conversely, intraoperative parathyroid hormone continued to drop in those with a successful outcome: 245 pg/mL (10 minutes) and 206 pg/mL (15 minutes) (P < .001). The failure group had a significantly lower percentage decay (P < .001) from baseline when compared with the success group. The intraoperative parathyroid hormone influenced the surgical management in up to 7% of the cases. The intraoperative parathyroid hormone dosage method showed an accuracy of 86%, a sensitivity of 88%, and specificity of 67%.

CONCLUSION

In patients with renal hyperparathyroidism undergoing parathyroidectomy, the use of intraoperative parathyroid hormone may help to predict an early therapeutic outcome with high sensitivity and accuracy by indicating the operation's success when there is an 80% reduction of baseline intraoperative parathyroid hormone 15 minutes after removal of the enlarged glands, an associated continuous decrease in serum intraoperative parathyroid hormone levels between 10 and 15 minutes, and achievement of plasma target values <500 pg/mL.

Diagnostic performance of ultrasonography, dual-phase 99mTc-MIBI scintigraphy, early and delayed 99mTc-MIBI SPECT/CT in preoperative parathyroid gland localization in secondary hyperparathyroidism

BACKGROUND

Secondary hyperparathyroidism (SHPT) usually requires parathyroidectomy when drug regimens fail. However, obtaining an exact preoperative map of the locations of the parathyroid glands is a challenge. The purpose of this study was to compare the diagnostic performance of US, dual-phase ^99mTc-MIBI scintigraphy, early and delayed ^99mTc-MIBI SPECT/CT in patients with SHPT.

METHODS

Sixty patients with SHPT who were undergoing dialysis were evaluated preoperatively by US, dual-phase ^99mTc-MIBI scintigraphy, early and delayed ^99mTc-MIBI SPECT/CT. Postoperative pathology served as the gold standard. The sensitivity, specificity, and accuracy were determined for each method. Spearman correlation analysis was used to analyse the correlation of hyperplastic parathyroid calcification with serum alkaline phosphatase (ALP) and parathyroid hormone (PTH).

RESULTS

A total of 229 lesions in 60 patients were pathologically confirmed to be parathyroid hyperplasia, with 209 lesions in typical sites, 15 lesions in the upper mediastinum and 5 lesions in the thyroid. A total of 88.33% (53/60) of patients had four lesions. US, early and delayed ^99mTc-MIBI SPECT/CT had significantly higher sensitivity and accuracy than dual-phase ^99mTc-MIBI scintigraphy (P < 0.001). Furthermore, early ^99mTc-MIBI SPECT/CT had significantly higher sensitivity (P < 0.001) and accuracy (P = 0.001 and P < 0.001) than US and delayed ^99mTc-MIBI SPECT/CT. In patients with ectopic hyperplastic parathyroid glands, the sensitivity of early ^99mTc-MIBI SPECT/CT (90%) was significantly higher than that of US (55%) and dual-phase ^99mTc-MIBI scintigraphy (50%) (P < 0.05). The Spearman correlation results showed a significant albeit weak association between calcification and both serum PTH and ALP (P = 0.002).

CONCLUSION

The ability of early ^99mTc-MIBI SPECT/CT to detect hyperplastic parathyroid glands in patients with SHPT is superior to that of US, dual-phase ^99mTc-MIBI scintigraphy and delayed ^99mTc-MIBI SPECT/CT; furthermore, dual-phase ^99mTc-MIBI SPECT/CT is not essential.

Parathyroid carcinoma arising from auto-transplanted parathyroid tissue after Total Parathyroidectomy in chronic kidney disease patient: a case report

BACKGROUND

Secondary hyperparathyroidism is a common complication in patients with chronic kidney disease that requires vigilant treatment due to its high mortality rate. Pharmacologic therapy is recommended as an initial treatment; if there is no response, a total parathyroidectomy is performed. In some cases, surgery is accompanied by auto-transplantation of parathyroid tissue.

CASE PRESENTATION

The patient was diagnosed with chronic kidney disease and received a kidney transplant. However, due to rejection of the transplanted kidney, medical nephrectomy was carried out and routine hemodialysis was initiated and observed. At this time, secondary hyperparathyroidism with elevated parathyroid hormone and hyperphosphatemia developed and pharmacologic treatment was applied. However, there was no response to pharmacologic treatment; therefore, total parathyroidectomy with auto-transplantation was performed. Eight years after surgery, a growing mass was observed in the transplantation site, accompanied by an elevation of parathyroid hormone. A complete resection of the mass was performed, and the patient was diagnosed with parathyroid carcinoma. Additional adjuvant radiation therapy was ordered, and the patient is being monitored.

CONCLUSIONS

This is a rare but remarkable case of parathyroid carcinoma arising from auto-transplanted parathyroid tissue after total parathyroidectomy in a patient with secondary hyperparathyroidism. We suggest caution should be taken when choosing to auto- transplant parathyroid tissue and that careful postoperative observation should be performed.

The Emerging Role of Nutritional Vitamin D in Secondary Hyperparathyroidism in CKD

In chronic kidney disease (CKD), hyperphosphatemia induces fibroblast growth factor-23 (FGF-23) expression that disturbs renal 1,25-dihydroxy vitamin D (1,25D) synthesis; thereby increasing parathyroid hormone (PTH) production. FGF-23 acts on the parathyroid gland (PTG) to increase 1α-hydroxylase activity and results in increase intra-gland 1,25D production that attenuates PTH secretion efficiently if sufficient 25D are available. Interesting, calcimimetics can further increase PTG 1α-hydroxylase activity that emphasizes the demand for nutritional vitamin D (NVD) under high PTH status. In addition, the changes in hydroxylase enzyme activity highlight the greater parathyroid 25-hydroxyvitmain D (25D) requirement in secondary hyperparathyroidism (SHPT); the higher proportion of oxyphil cells as hyperplastic parathyroid progression; lower cytosolic vitamin D binding protein (DBP) content in the oxyphil cell; and calcitriol promote vitamin D degradation are all possible reasons supports nutritional vitamin D (NVD; e.g., Cholecalciferol) supplement is crucial in SHPT. Clinically, NVD can effectively restore serum 25D concentration and prevent the further increase in PTH level. Therefore, NVD might have the benefit of alleviating the development of SHPT in early CKD and further lowering PTH in moderate to severe SHPT in dialysis patients.

Subtotal Parathyroidectomy and Relocation of the Parathyroid Remnant for Renal Hyperparathyroidism: modification of a traditional operation

Background

We describe a modification of the conventional subtotal parathyroidectomy operation where the parathyroid gland(s) remnant is repositioned with intact vascular supply to a plane superficial to the infrahyoid strap muscles and immediately under the skin incision. This technique called Subtotal Parathyroidectomy and Remnant Relocation (SPARE) retains all the metabolic advantages of the conventional operation with the added advantage of easier identification of a recurrent hyperplastic remnant if re-exploration becomes necessary.

Methods

In the SPARE technique, four parathyroid glands were identified and the quality of each gland and the length of each vascular pedicle to the parathyroid glands were assessed. The optimal parathyroid gland was relocated to a plane superficial to the strap muscles. The remainder of the glands were removed.

Results

In total, 30 patients with hyperparathyroidism secondary to renal failure (HSRF) underwent parathyroidectomy with the SPARE technique. The mean age was 53.1±12.5 years and median follow-up was 17.1 months (range 1-78.9 months). There were no recurrent laryngeal nerve (RLN) injuries or hematomas. The pre- and post-operative value for corrected calcium and PTH were 158.4±109.4 pmol/L and 11.4±12.1 pmol/L, respectively (p < 0.05). Three recurrences were noted (10.0%), with a mean time to recurrence of 15.3±6.6 months. One patient had excision of the remnant parathyroid glands performed under local anaesthetic (29 min); one had re-exploration performed under general anaesthetic (81 min), and one was managed medically.

Conclusion

We described a novel parathyroidectomy technique for patients with HSRF, which provides the advantages of conventional subtotal parathyroidectomy while mitigating the challenges of thyroid bed re-exploration when recurrences arise.

Risk-factors for nodular hyperplasia of parathyroid glands in sHPT patients

Introduction

Nodular hyperplasia of parathyroid glands (PG) is the most probable cause of medical treatment failure in secondary hyperparathyroidism (sHPT). This prospective cohort study is located at the interface of medical and surgical consideration of sHPT treatment options and identifies risk-factors for nodular hyperplasia of PG.

Material and methods

One-hundred-eight resected PG of 27 patients with a broad spectrum of sHPT severity were classified according to the degree of hyperplasia by histopathology. Twenty routinely gathered parameters from medical history, ultrasound findings of PG and laboratory results were analyzed for their influence on nodular hyperplasia of PG by risk-adjusted multivariable binary regression. A prognostic model for non-invasive assessment of PG was developed and used to weight the individual impact of identified risk-factors on the probability of nodular hyperplasia of single PG.

Results

Independent risk-factors for nodular hyperplasia of single PG were duration of dialysis in years, PG volume in mm³ determined by ultrasound and serum level of parathyroid hormone in pg/mL. Multivariable analyses computed a model with an Area Under the Receiver Operative Curve of 0.857 (95%-CI:0.773–0.941) when predicting nodular hyperplasia of PG. Theoretical assessment of risk-factor interaction revealed that the duration of dialysis had the strongest influence on the probability of nodular hyperplasia of single PG.

Conclusions

The three identified risk-factors (duration of dialysis, PG volume determined by ultrasound and serum level of parathyroid hormone) can be easily gathered in daily routine and could be used to non-invasively assess the probability of nodular hyperplasia of PG. This assessment would benefit from periodically collected data sets of PG changes during the course of sHPT, so that the choice of medical or surgical sHPT treatment could be adjusted more to the naturally changing type of histological PG lesion on an individually adopted basis in the future.

Parathyroid Nodular Hyperplasia and Responsiveness to Drug Therapy in Renal Secondary Hyperparathyroidism: An Open Question

The goal of the pharmacological therapy in secondary hyperparathyroidism (SHPT) is to reduce serum levels of parathyroid hormone and phosphorus, to correct those of calcium and vitamin D, to arrest or reverse the parathyroid hyperplasia. However, when nodular hyperplasia or an autonomous adenoma develops, surgery may be indicated. We reviewed the literature with the aim of defining if the echographic criteria predictive of unresponsiveness of SHPT to calcitriol therapy are valid also in the cinacalcet era and if drug therapy may reverse nodular hyperplasia of parathyroid gland (PTG). The responsiveness to therapy and regression of the nodular hyperplasia of PTG remains an open question in the calcimimetic era as well as the cutoff between medical and surgical therapy. Prospective studies are needed in order to clarify if an earlier use of cinacalcet in moderate SHPT might arrest the progression of parathyroid growth and stabilize SHPT.

Ultrasound-based scores as predictors for nodular hyperplasia in patients with secondary hyperparathyroidism: a prospective validation study

PURPOSE

Former studies evaluated echostructural and vascular patterns in ultrasound of the parathyroid gland to identify nodular hyperplasia in patients with secondary hyperparathyroidism due to chronic kidney disease. This prospective study aims to externally validate suggested ultrasound classifications.

METHODS

Parathyroid glands of 27 patients with secondary hyperparathyroidism undergoing parathyroidectomy were prospectively analyzed. Ultrasound including Doppler imaging was performed 1 day prior to surgery. Ultrasound data were available for 70 parathyroid glands. Echostructural and vascular scores according to previous studies were applied calculating the area under the receiver operating characteristic curve (AUROC). Overall correctness, sensitivity, and specificity of the investigated scores were assessed with the Youden index method.

RESULTS

The Doppler score introduced by Vulpio and colleagues based on characteristic blood flow patterns in parathyroid glands showed an AUROC of 0.749 for the prediction of nodular hyperplasia with an overall correctness of 72.8%. Other ultrasound classifications based on blood flow patterns, as well as echostructure of the parathyroid gland displayed AUROCs of <0.700, thus, lacking sufficient capability as a prognostic model. Overall correctness of prediction varied from 53.8 to 55.9%.

CONCLUSIONS

The Vulpio Doppler score for the prediction of nodular hyperplasia in patients with secondary hyperparathyroidism was externally validated for the first time. Other ultrasound scores fail as prognostic models in this study population. Doppler sonography of the parathyroid gland has prognostic capability to identify nodular hyperplasia as surrogate marker for patients with secondary hyperparathyroidism indicating the need for ablative or surgical treatment when failing conservative therapy.

Pathologic Features of Parathyroid Glands Associated With the Pathogenesis of Long-lasting Persistent Hyperparathyroidism After Kidney Transplantation in Long-term Dialysis Patients

BACKGROUND

Persistent hyperparathyroidism in kidney transplant recipients may be prolonged for a few years, and in these cases, parathyroidectomy is indicated even if graft function is satisfactory. The aim of this study was to characterize the parathyroid glands in long-term dialysis recipients and determine the pathogenesis of persistent hyperparathyroidism.

METHODS

We analyzed 44 parathyroid glands resected from 11 patients who underwent parathyroidectomy after kidney transplantation. The histopathologic types and weights of all the parathyroid glands were evaluated.

RESULTS

The mean dialysis period was 15.8 years, and the time from kidney transplantation to parathyroidectomy ranged from 3.5 to 89 months. Nodular hyperplasia was present in parathyroid glands in all cases. The mean glandular weight was 396.0 ± 299.0 mg, and the maximum glandular weight was 3200 mg. Seven patients who underwent parathyroidectomy >1 year after kidney transplantation (late PT) were compared with 4 patients who underwent parathyroidectomy within 10 months after transplantation (early PT). The maximum (442.9 vs 1503 mg; P = .018) and mean (312.5 ± 177.4 mg vs 1135.6 ± 977.7 mg; P = .001) glandular weights were significantly lower in patients who underwent late PT compared with those who received early PT. Based on the histopathologic type and glandular weight of each parathyroid gland, nodular hyperplasia in glands ≤150 mg was common in patients who underwent late PT.

CONCLUSIONS

The presence of nodular hyperplasia in parathyroid glands with a low weight may be involved in long-lasting persistent hyperparathyroidism in patients undergoing long-term dialysis.

Hyperparathyroidism of Renal Disease

Renal hyperparathyroidism (rHPT) is a common complication of chronic kidney disease characterized by elevated parathyroid hormone levels secondary to derangements in the homeostasis of calcium, phosphate, and vitamin D. Patients with rHPT experience increased rates of cardiovascular problems and bone disease. The Kidney Disease: Improving Global Outcomes guidelines recommend that screening and management of rHPT be initiated for all patients with chronic kidney disease stage 3 (estimated glomerular filtration rate, < 60 mL/min/1.73 m(2)). Since the 1990s, improving medical management with vitamin D analogs, phosphate binders, and calcimimetic drugs has expanded the treatment options for patients with rHPT, but some patients still require a parathyroidectomy to mitigate the sequelae of this challenging disease.

Parathyroid Ultrasonography in Renal Secondary Hyperparathyroidism: An Overlooked and Useful Procedure

In secondary hyperparathyroidism (SHPT), ultrasonography (US) can accurately define the size and structure of parathyroid glands as well as differentiate diffuse and nodular hyperplasia. US may be also useful to predict the response of SHPT to vitamin D analogs and cinacalcet and to assess for regression of parathyroid glands hyperplasia by measurement of parathyroid gland volume. There is increasing evidence that US can potentially identify patients who will benefit from prompt surgical intervention. Therefore, US should be part of the diagnostic armamentarium in the treatment of SHPT in the daily clinical practice.

Surgical management of secondary hyperparathyroidism: how to effectively reduce recurrence at the time of primary surgery

BACKGROUND

Successful parathyroidectomy (PTX) often results in a dramatic drop in the parathyroid hormone (PTH) levels, relieves the patient from clinical symptoms, and reduces mortality. Although PTX is generally a successful treatment for progressive secondary hyperparathyroidism (SHPT) patients subjected to surgery, a significant proportion develops recurrent SHPT following PTX.

KEY MESSAGE

SHPT requiring PTX occurs more commonly in progressive chronic kidney disease and in long-term lithium therapy. Operative approaches include subtotal PTX, total PTX with or without autotransplantation, and possible thymectomy. Each approach has its proponents, advantages, and disadvantages. Although PTX offers the highest percentage cure for SHPT, compared to all other medical and surgical treatment, recurrent hyperparathyroidism can be observed in some patients dependent on follow-up time. A literature review and analysis of recent data regarding how to reduce recurrence of SHPT at the time of primary surgery was performed. The current literature and our own experience in the field have confirmed that pre-operative imaging, thymectomy, stereo magnifier, and surgical procedure may effectively reduce recurrence of SHPT at the time of primary surgery.

[Management of secondary hyperparathyroidism-current impact of parathyroidectomy]

Parathyroidectomy still presents an adequate and efficient therapeutic option for the management of refractory secondary hyperparathyroidism (sHPT). Dependent on the selected surgical technique it allows the highest rate of "laboratory cure" of sHPT. The question remains as to whether these improvements translate into clinical long-term benefits regarding the sHPT-associated vascular calcification and the increased risk for cardiovascular morbidity and mortality as well as overall mortality. Recent large observational studies point in this direction but definite evidence through prospective randomized controlled trials is still lacking.

The role of preoperative ultrasonography, computed tomography, and sestamibi scintigraphy localization in secondary hyperparathyroidism

PURPOSE

The role of preoperative localization studies is controversial in surgery of secondary hyperparathyroidism (sHPT). The aim of study was to evaluate the accuracy of preoperative ultrasonography (USG), CT, and (99m)Tc sestamibi scintigraphy (MIBI) in localizing enlarged parathyroid glands and to find the impact of correct localization in successful parathyroidectomy.

METHODS

We compared operative findings with the preoperative localization of ultrasonography, computerized tomography and sestamibi scintigraphy in 109 patients with sHPT and identified well-visualized locations of abnormal parathyroid glands by evaluating the sensitivity of each imaging study with regard to typical locations of glands. We investigated the effect of preoperative imaging localization on the surgical outcomes by measuring the intraoperative parathyroid hormone (ioPTH) decrement for positive or negative imaging localization.

RESULTS

USG (91.5%) had the highest sensitivity and MIBI (56.1%) had the lowest among 3 modalities. The sensitivity of combined USG and CT (95.0%) was the highest among combined 2 modalities. The combination of all 3 modalities (95.4%) had the highest sensitivity among the combinations of modalities. The reduction of ioPTH in patients with positive imaging localization (86.6%) was greater than negative imaging localization (84.2%), with no significant difference (P = 0.586). The recurrence or persistence of sHPT was not correlated with preoperative imaging localization (19 patients in negative, 16 in positive; P = 0.14).

CONCLUSION

Preoperative imaging localization contributed to surgical success but not to surgical outcomes. The combination of ioPTH measurement with imaging localization might be valuable for better surgical results in sHPT.

Surgical management of secondary hyperparathyroidism in chronic kidney disease--a consensus report of the European Society of Endocrine Surgeons

BACKGROUND

Despite advances in the medical management of secondary hyperparathyroidism due to chronic renal failure and dialysis (renal hyperparathyroidism), parathyroid surgery remains an important treatment option in the spectrum of the disease. Patients with severe and complicated renal hyperparathyroidism (HPT), refractory or intolerant to medical therapy and patients with specific requirements in prospect of or excluded from renal transplantation may require parathyroidectomy for renal hyperparathyroidism.

METHODS

Present standard and actual controversial issues regarding surgical treatment of patients with hyperparathyroidism due to chronic renal failure were identified, and pertinent literature was searched and reviewed. Whenever applicable, evaluation of the level of evidence concerning diagnosis and management of renal hyperparathyroidism according to standard criteria and recommendation grading were employed. Results were discussed at the 6th Workshop of the European Society of Endocrine Surgeons entitled Hyperparathyroidism due to multiple gland disease: An evidence-based perspective.

RESULTS

Presently, literature reveals scant data, especially, no prospective randomized studies to provide sufficient levels of evidence to substantiate recommendations for surgery in renal hyperparathyroidism. Appropriate surgical management of renal hyperparathyroidism involves standard bilateral exploration with bilateral cervical thymectomy and a spectrum of four standardized types of parathyroid resection that reveal comparable outcome results with regard to levels of evidence and recommendation. Specific patient requirements may favour one over the other procedure according to individualized demands.

CONCLUSIONS

Surgery for patients with renal hyperparathyroidism in the era of calcimimetics continues to play an important role in selected patients and achieves efficient control of hyperparathyroidism. The overall success rate and long-term control of renal hyperparathyroidism and optimal handling of postoperative metabolic effects also depend on the timely indication, individually suitable type of parathyroid resection and specialized endocrine surgery.

Association between long-term efficacy of cinacalcet and parathyroid gland volume in haemodialysis patients with secondary hyperparathyroidism

Purpose. Secondary hyperparathyroidism with nodular hyperplasia is resistant to medical therapies. Cinacalcet is an effective treatment for severe secondary hyperparathyroidism. This multicentre retrospective study was designed to determine the long-term efficacy of cinacalcet in patients with nodular hyperplasia, the advanced type of parathyroid hyperplasia. Subjects and methods. The study subjects were 20 haemodialysis patients with secondary hyperparathyroidism. Patients with ultrasonographically confirmed large parathyroid glands (volume >0.5 cm(3)) were considered to have nodular hyperplasia (n = 8). Cinacalcet was started at the dose of 25 mg/day and titrated up to 100 mg/day to achieve the target intact-parathyroid hormone (iPTH) level of <250 pg/ml. Serum iPTH, corrected calcium, serum phosphorus, calcium × phosphorus product were measured and compared over the 48-week period of treatment with cinacalcet in all 20 patients and over 120 weeks in 6 of the patients (2 with nodular hyperplasia and 4 with non-nodular hyperplasia). We also examined the achievement rate of K/DOQI guideline treatment targets. The dosages of vitamin D preparation, sevelamer hydrochloride and calcium- containing phosphate binder were adjusted for the above target values. Results. iPTH levels were significantly lower at 48 weeks in both groups. However, corrected calcium levels, serum phosphorus levels and calcium phosphorus products were within the target values in the non-nodular hyperplasia group (n = 12), while the target value could not be achieved in the nodular hyperplasia group. In the long-term follow-up group, the levels of iPTH, corrected calcium, serum phosphorus and calcium × phosphorus products were significantly higher in nodular hyperplasia than in non-nodular hyperplasia. Conclusion. Our study suggests that cinacalcet lacks long-term efficacy in nodular hyperplasia, especially for controlling serum calcium and phosphorus levels.

The whole-PTH/intact-PTH ratio is a useful predictor of severity of secondary hyperparathyroidism

Background. The newer parathyroid hormone (PTH) assay, whole-PTH, uses an antibody that binds the region harbouring the first amino acid, making it specific for the complete molecule, 1–84-PTH. Especially among dialysis patients, it has been reported that the level of whole-PTH can be calculated as ∼60% of their intact-PTH value. In addition, since 1–84-PTH is part of intact-PTH, the whole-PTH/intact-PTH ratio should not theoretically exceed 1. However, an abnormally high 1–84-PTH/intact-PTH ratio is reported in a few patients with parathyroid carcinoma, primary hyperparathyroidism and secondary hyperparathyroidism. In this study, we examined the correlation between the 1–84-PTH/intact-PTH ratio and the severity of hyperparathyroidism in patients on haemodialysis (HD).

Patients and methods. The study population comprised 196 HD patients (males 113, females 83, age 67.4 ± 13.6 years, HD period 8.1 ± 7.3 years; mean ± SD). The whole-PTH/intact-PTH ratio was compared in patients with high PTH levels (intact-PTH ≥300 pg/ ml; high PTH group, n = 32), moderate PTH levels (intact-PTH >150–<300 pg/ml; moderate PTH group, n = 50) and low PTH levels (intact-PTH <150 pg/ml; low PTH group, n = 114). The ratio was also compared in 25 patients with at least one enlarged gland >0.5 cm³ suggesting nodular hyperplasia, as determined by power Doppler ultrasonography (hyperplasia group) with seven patients without enlarged gland (non-hyperplasia group) and six patients who had undergone total parathyroidectomy (post-PTx group).

Results. The whole-PTH/intact-PTH ratio of the high PTH group (0.68 ± 0.1) was significantly higher than those of the moderate (0.61 ± 0.1, P < 0.001) and low (0.52 ± 0.1, P < 0.001) groups. Moreover, the ratio was significantly higher in the hyperplasia group (0.70 ± 0.1) than those in the non-hyperplasia group (0.59 ± 0.1, P < 0.05) and post-PTx group (0.456 ± 0.12, P < 0.001).

Conclusions. The whole-PTH/intact-PTH ratio correlated with the severity of hyperparathyroidism. Our results suggest that the ratio might be a useful predictor of severity of secondary hyperparathyroidism in HD patients.

Indication and efficacy of PEIT in the management of secondary hyperparathyroidism

Control of secondary hyperparathyroidism (SHPT) using active vitamin D analogues becomes difficult in advanced SHPT, because the enlarged parathyroid glands (PTGs) are resistant to medical therapy. Percutaneous ethanol injection therapy (PEIT) has been widely used in Japan since the 1990s as a surgical intervention for advanced SHPT, by selectively destroying only the enlarged glands with nodular hyperplasia (i.e. >0.5 cm(3), measured by ultrasonography). If there is only one PTG with nodular hyperplasia, PEIT will be successful with a small number of injections, and it then becomes possible to maintain target levels of parathyroid hormone by treatment with active vitamin D analogues. Recent studies have demonstrated that in the advanced phase of SHPT, it is desirable to perform PEIT when it is restricted to patients with not more than one PTG larger than 0.5 cm(3) in terms of superior prognosis can be obtained including efficacy, low recurrence, and long-term remission period.

Long-term prognosis of parathyroid function in chronic dialysis patients after PEIT-a single-centre trial

Background. Secondary hyperparathyroidism (SHPT) is a common complication observed in long-term dialysis patients. Percutaneous ethanol injection therapy (PEIT) of parathyroid glands (PTGs) is now established in Japan as a treatment option for SHPT. In this study, to elucidate the factors influencing efficacy in 1 year and relapse following PEIT, we analysed the long-term prognosis of parathyroid function that is known to have the greatest effect on therapeutic results.

Methods. The study design was a retrospective cohort study. We studied 104 patients with SHPT, who underwent PEIT at Tokai University Hospital between January 1993 and December 2002, and we followed them up until January 2008. The effective group reached intact parathyroid hormone of 200 pg/ml or less, corrected calcium (Ca) of 10.5 mg/dl or less and phosphate (P) of 6.0 mg/dl or less. The ineffective group failed to achieve these criteria.

Results. Among the 104 patients, 66 patients (63%) fulfilled the criteria for the effective group within the first year of PEIT. Using the multivariate logistic regression analysis, the number of PTGs before PEIT was a significant risk factor to deviate from the criteria. At the end of the surveillance period, 31 patients (30%) fulfilled the criteria, and their SHPT was controlled with PEIT. Using the multivariate logistic regression analysis, more than three PTGs at the beginning, and the increase in PTGs during the observation period were significant risk factors to deviate from the criteria. In conclusion, superior results with PEIT are obtained in terms of efficacy, remission period and risk of relapse, regardless of the size of the gland.

Clinical significance of parathyroid intervention on CKD-MBD management

Recently published ‘Guidelines for the management of secondary hyperparathyroidism in chronic dialysis patients’ by the Japanese Society for Dialysis Therapy advocate that percutaneous ethanol injection into enlarged glands, which has been considered as the only alternative to parathyroidectomy (PTx), should be indicated in patients with a single enlarged parathyroid gland (estimated volume >500 mm³, or estimated major axis >10 mm), and that PTx should be recommended in patients with multiple enlarged glands. Cinacalcet cannot achieve optimal control of chronic kidney disease–mineral bone disorder in all patients, and parathyroid intervention will be required in a considerable number of patients with refractory secondary hyperparathyroidism.

New clinical guidelines for selective direct injection therapy of the parathyroid glands in chronic dialysis patients

In 2000, the Japanese Society for Parathyroid Intervention issued the 'Guidelines for percutaneous ethanol injection therapy of the parathyroid glands in chronic dialysis patients'. Since then, the concept of 'selective PEIT' has been well accepted and the number of patients treated by this method in Japan has increased. Recently, it has been reported that the effect of PEIT differs depending on the degree of nodular hyperplasia. Several new drugs have become available since 2000, and active vitamin D and its analogue have also been used for direct injection into the parathyroids. We present the new 'Guidelines for selective direct injection therapy of the parathyroid glands in chronic dialysis patients', a revised version of the 2000 Guidelines. We believe that these new guidelines are useful for selecting direct injection therapy in patients with advanced secondary hyperparathyroidism.

Pathophysiology of parathyroid hyperplasia in chronic kidney disease: preclinical and clinical basis for parathyroid intervention

Secondary hyperparathyroidism is characterised by excessive secretion of parathyroid hormone and parathyroid hyperplasia, resulting in both skeletal and extraskeletal consequences. Recent basic and clinical studies have brought considerable advances in our understanding of the pathophysiology of parathyroid hyperplasia and have also provided practical therapeutic approaches, especially with regard to indications for parathyroid intervention. In this context, it is quite important to recognize the development of nodular hyperplasia, because the cells in nodular hyperplasia are usually resistant to calcitriol treatment. Patients with nodular hyperplasia should undergo parathyroid intervention including percutaneous ethanol injection therapy (PEIT). Selective PEIT of the parathyroid gland is an effective approach in which the enlarged parathyroid gland with nodular hyperplasia is 'selectively' destroyed by ethanol injection, and other glands with diffuse hyperplasia are then managed by medical therapy. With a more focused attention to applying parathyroid intervention, we can expect significant improvement in the management of secondary hyperparathyroidism in dialysis patients.

Two Years of Cinacalcet Hydrochloride Treatment Decreased Parathyroid Gland Volume and Serum Parathyroid Hormone Level in Hemodialysis Patients With Advanced Secondary Hyperparathyroidism

The long-term effect of cinacalcet hydrochloride treatment on parathyroid gland (PTG) volume has been scarcely investigated in patients with moderate to advanced secondary hyperparathyroidism (SHPT). The present study was a prospective observational study to determine the effect of cinacalcet treatment on PTG volume and serum biochemical parameters in 60 patients with renal SHPT, already treated with intravenous vitamin D receptor activator (VDRA). Measurement of biochemical parameters and PTG volumes were performed periodically, which were analyzed by stratification into tertiles across the baseline parathyroid hormone (PTH) level or PTG volume. We also determined the factors that can estimate the changes in PTG volume and the achievement of the target PTH range by multivariable analyses. Two years of cinacalcet treatment significantly decreased the serum levels of PTH, calcium, and phosphate, followed by the improvement of achieving the target ranges for these parameters recommended by the Japanese Society for Dialysis Therapy. Cinacalcet decreased the maximal and total PTG volume by about 30%, and also decreased the serum PTH level independent of the baseline serum PTH level and PTG volume. Ten out of 60 patients showed 30% increase in maximal PTG after 2 years. Multivariable analysis showed that patients with nodular PTG at baseline and patients with higher serum calcium and PTH levels at 1 year were likely to exceed the target range of PTH at two years. In conclusion, cinacalcet treatment with intravenous VDRA therapy decreased both PTG volume and serum intact PTH level, irrespective of the pretreatment PTG status and past treatment history.

Soluble Klotho and intact fibroblast growth factor 23 in long-term kidney transplant patients

BACKGROUND

Controversies exist whether disturbances in mineral and bone disorder (MBD) normalise or persist after kidney transplantation. We assessed markers of MBD in patients with well-functioning kidney transplants to minimise confounding by reduced transplant function.

METHODS

In this cross-sectional study, 40 patients aged ≥18 years who received a first kidney transplant more than 10 years ago were included. A well-functioning transplant was defined as an estimated glomerular filtration rate (eGFR) ≥45 ml/min per 1.73 m(2).

RESULTS

Median time since transplantation was 18.3 years (inter quartile range (IQR) 12.2-26.2). Albumin-corrected serum calcium levels were above upper limit of normal in 15% of the transplanted patients, and serum phosphate levels below lower limit of normal in 31%. The median levels of intact parathyroid hormone (iPTH) and intact fibroblast growth factor 23 (iFGF23) were significantly higher than that in a group of healthy volunteers (11.3 pmol/l (IQR: 8.7-16.2) vs 4.4 pmol/l (IQR: 3.8-5.9), P<0.001 and 75.0 pg/ml (IQR: 53.3-108.0) vs 51.3 pg/ml (IQR: 36.3-67.6), P=0.004 respectively). There was a non-significant reduction in soluble Klotho (sKlotho) levels (605 pg/ml (IQR: 506-784) vs 692 pg/ml (IQR: 618-866)). When compared with a control group matched for eGFR, levels of iPTH were significantly higher (P<0.001), iFGF23 had a non-significant trend towards higher levels and sKlotho towards lower levels.

CONCLUSIONS

In long-term kidney transplant patients with well-functioning kidney transplants, we found inappropriately high levels of iPTH and iFGF23 consistent with a state of persistent hyperparathyroidism. We speculate that the primary defect, FGF23 resistance, has evolved in the parathyroid gland before transplantation, and persists due to long half-life of the parathyroid cells.

Presence of small parathyroid glands in renal transplant patients supports less-than-total parathyroidectomy to treat hypercalcemic hyperparathyroidism

BACKGROUND

Parathyroid glands (PG) are rarely analyzed in renal transplant (RTX) patients. This study analyzes comparatively PG of RTX and end-stage renal disease (ESRD) patients. The clinical part of the study evaluates if total parathyroidectomy with autotransplantation (TPT+AT) treats appropriately hypercalcemic hyperparathyroidism in RTX patients.

METHODS

TPT+AT was performed in 15 of 23 RTX and 21 of 27 ESRD patients. Remaining patients underwent less-than-total PT. Volume and stage of hyperplasia were determined from 86 PG of RTX and 109 PG of ESRD patients. Patients were categorized according to the presence of small PG (volume < 100 mm(3)). Calcium homeostasis and hyperparathyroidism were evaluated 2 years after PT in RTX patients.

RESULTS

PG of RTX patients were significantly smaller, but similar hyperplastic in comparison to PG of ESRD patients. Small PG were more frequent in RTX than in ESRD patients (19% vs 6%) and mainly graded normal or diffuse hyperplastic (94%). Forty-seven percent of RTX, but only 14% of ESRD, patients receiving a total PT possessed ≥1 small PG (P < .05). Overall, PT treated successfully hypercalcemic hyperparathyroidism. However, TPT+AT caused permanent hypocalcemia in 50% of RTX patients without small PG and even in 83% of RTX patients with small PG. All RTX patients receiving less-than-total PT were normocalcemic at 2-year follow-up. Logistic regression revealed a 10.7 times greater risk of permanent hypocalcemia in RTX patients with small PG receiving TPT+AT compared with RTX patients without small PG receiving TPT+AT or RTX patients undergoing less-than-total PT.

CONCLUSION

Surgeons performing PT should be aware of the high frequency of small and less diseased PG in RTX patients. In this context, TPT+AT might overtreat hypercalcemic hyperparathyroidism in RTX patients, especially when small PG are present.

4D-CT for preoperative localization of abnormal parathyroid glands in patients with hyperparathyroidism: accuracy and ability to stratify patients by unilateral versus bilateral disease in surgery-naive and re-exploration patients

BACKGROUND AND PURPOSE

4D-CT is an emerging technique that uses high-resolution images, multiplanar reformats, and perfusion characteristics to identify abnormal parathyroid glands in patients with hyperparathyroidism. This study evaluates the accuracy of 4D-CT for localization and lateralization of abnormal parathyroid glands in preoperative planning for minimally invasive parathyroidectomy vs bilateral neck exploration at a tertiary referral center.

MATERIALS AND METHODS

Radiology, pathology, and operative reports were retrospectively reviewed for 208 patients with hyperparathyroidism who underwent 4D-CT and parathyroid surgery between May 2008 and January 2012. 4D-CT performance in localizing side and site was determined by use of surgical and pathologic findings as a reference.

RESULTS

Of 208 patients, 155 underwent initial surgery and 53 underwent re-exploration parathyroid surgery. No lesions were found in 8 patients (3.8%). A total of 284 lesions were found in 200 patients; 233 were correctly localized by 4D-CT (82.0%). Of the 200 patients with parathyroid lesions, 146 underwent unilateral and 54 bilateral neck exploration. 4D-CT correctly identified unilateral vs bilateral disease in 179 (89.5%) of 200. 4D-CT correctly localized parathyroid lesions in 126 of the unilateral cases (86.3%). In the re-exploration cohort, 4D-CT correctly identified unilateral vs bilateral disease in 46 (95.8%) of 48. There was no statistically significant difference in subgroups stratified by surgery type (primary or subsequent) and number of scan phases (3 or 4) (P > .56).

CONCLUSIONS

4D-CT leverages modern high-resolution CT scanning and dynamic contrast enhancement to localize abnormal parathyroid glands in patients with hyperparathyroidism of any cause and can be used for planning minimally invasive parathyroidectomy vs bilateral neck exploration.

Histology and immunohistochemistry of the parathyroid glands in renal secondary hyperparathyroidism refractory to vitamin D or cinacalcet therapy

BACKGROUND

Cinacalcet is a new effective treatment of secondary hyperparathyroidism (SHPT) in hemodialysis patients (HP), but the alterations of parathyroid gland (PTG) hyperplasia determined by cinacalcet and vitamin D have not been extensively investigated in humans.

METHODS

We performed histological analyses of 94 PTGs removed from 25 HP who underwent parathyroidectomy (PTx) because of SHPT refractory to therapy with vitamin D alone (group A=13 HP and 46 PTGs) or associated with cinacalcet (group B=12 HP and 48 PTGs). The number, weight, the macroscopic cystic/hemorrhagic changes, and type of hyperplasia of PTG (nodular=NH, diffuse=DH) were assessed. In randomly selected HP of group A (4 HP and 14 PTGs) and group B (4 HP and 15 PTGs), the labeling index of cells positive to Ki-67 and TUNEL and the semiquantitative score of immunohistochemistry staining of vitamin D receptor, calcium-sensing receptor, and vascular endothelial growth factor-α (VEGF-α) were measured in the entire PTGs and in the areas with DH or NH.

RESULTS

The number and weight of single and total PTG of each HP were similar in the two groups as well as the number of PTG with macroscopic cystic/hemorrhagic areas. TUNEL, Ki-67, and VEGF-α scores were higher in NH than in DH areas.

CONCLUSION

This observational study of a highly selected population of HP, submitted to PTx because SHPT refractory to therapy, shows that the macroscopic, microscopic, and immunochemistry characteristics of PTG in HP who received or did not receive cinacalcet before PTx did not differ significantly.

A prospective randomized pilot study on intermittent post-dialysis dosing of cinacalcet

BACKGROUND

Treatment of secondary hyperparathyroidism (SHPT) is important in management of patients with end-stage renal disease on hemodialysis (HD). Calcimimetic agent, cinacalcet provides an option for control of SHPT in patients who fail traditional therapy. It may not have optimal results in non-compliant patients. To enhance compliance, we evaluated effectiveness of post-dialysis dosing of cinacalcet (group AD) as compared to daily home administration (group D) in a prospective randomized trial of HD patients with refractory SHPT.

METHODS

After 2-week run-in phase, patients were randomly assigned to two treatment groups. In group AD (N = 12), patients were administered cinacalcet on the day of dialysis (3 times/week) by dialysis staff, while in control group D (N = 11), cinacalcet was prescribed daily to be taken by patients at home. Intact parathyroid hormone (i-PTH), serum calcium, phosphorus, and alkaline phosphatase were followed for 16 weeks and compared to baseline in both groups. Data were analyzed using between-groups linear regression for repeated measures.

RESULTS

No significant decline in i-PTH occurred in group AD at 16 weeks as compared to a significant drop in group D (p = 0.006). However, subgroup analysis showed effectiveness of post-dialysis dosing in patients with less severe SHPT (p = 0.04).

CONCLUSION

Although daily dosing overall was more effective for treatment of SHPT, dialysis dosing was effective in patients with less severe SHPT. This warrants a larger study considering the limitations of this pilot trial. In the meantime, dialysis dosing can be considered in non-compliant patients with less severe SHPT.

Clinicopathological analysis of persistent hypercalcemia and hyperparathyroidism after kidney transplantation in long-term dialysis patients

Deceased donor kidney transplantation in long-term dialysis patients in Japan has been increasing because of a severe lack of donors. Parathyroid glands of long-term dialysis patients often show qualitative morphological changes from diffuse to nodular hyperplasia. Only a few studies have reported the clinicopathological analysis of persistent hyperparathyroidism after kidney transplantation in long-term (>10 years) dialysis patients. This study on consecutive deceased donor kidney transplantation performed from 2002 to 2010 measured biochemical parameters related to bone and mineral disorders and examined parathyroid tissues in parathyroidectomy cases. Thirty-four subjects (22 males; mean age, 53.8 ± 7.9 years; mean dialysis period, 14.4 ± 4.3 years) were enrolled. Multivariate analysis of potential predictors for the hypercalcemia group at 12 months after transplantation showed that pre-transplantation and early post-transplantation calcium and parathyroid hormone levels were significant determinants. Pathological examination showed that a number of glands showed nodular hyperplasia, even in small glands weighing < 100 mg. In long-term dialysis patients, hyperparathyroidism and hypercalcemia developed at an early stage after transplantation and persisted for a long period (>4 years), with nodular hyperplasia being found even in low-weight parathyroid glands. Pre-transplant high calcium and parathyroid hormone levels were the predictors for the prolonged hypercalcemia. Persistent hyperparathyroidism was considered to be caused by remaining nodular hyperplasia, even if the glands were small. Although the best treatment option is to perform a parathyroidectomy in the waiting period before transplantation, we suggest that it be performed in cases with prolonged hypercalcemia of >6 months after transplantation.

Dialysis vintage and parathyroid hormone level, not fibroblast growth factor-23, determines chronic-phase phosphate wasting after renal transplantation

PURPOSE

Fibroblast growth factor 23 (FGF23), rather than parathyroid hormone (PTH), has been shown to be the major factor behind hypophosphatemia in the early period after renal transplantation. However, it is not clear whether phosphate wasting persists in the chronic phase. Purpose of our study is to elucidate whether FGF23 can also explain phosphate wasting, if any, in the chronic phase.

METHODS

In this cross-sectional observational study, we enrolled 247 recipients who had received a graft more than 1 year prior to this study. We compared the phosphate metabolism of recipients and predialysis chronic kidney disease (CKD) patients who are matched on age and estimated glomerular filtration rate (eGFR). We also investigated the determinants of tubular reabsorption of phosphate normalized for glomerular filtration rate (TmP/GFR), as an index of renal threshold for phosphate.

RESULTS

Recipients had a median dialysis vintage of 27.0 months and eGFR 41.2 mL/min/1.73 m(2). Whereas hypophosphatemia (<2.4 mg/dL) was observed in 6.1% of the recipients, 55.2% had TmP/GFR lower than 2.4 mg/dL. Recipients showed significantly lower TmP/GFR in all CKD stages than their predialysis counterparts, indicating that phosphate wasting persists in the chronic phase. Compared to predialysis patients, the recipients in stages 2T and 3T showed lower phosphate and higher intact PTH levels, despite a higher percentage being active vitamin D users. However, in stage 4T, phosphate retention masked relative hypophosphatemia. FGF23 was higher in the recipients across all CKD stages, but adjustment for vitamin D prescription revealed that transplantation had no effect on FGF23. Multiple regression analysis in the recipients showed significant negative associations of intact PTH and dialysis vintage with TmP/GFR.

CONCLUSIONS

Renal phosphate wasting persists in the chronic-phase renal transplantation recipients even with normophosphatemia. Persistent hyperparathyroidism and longer dialysis vintage, not FGF23, was associated with renal phosphate wasting in the chronic phase. Such an impact on phosphate metabolism of the factors determined in dialysis period could be called as "uremic memory". This novel finding in the chronic phase is in sharp contrast to the previous finding in the early phase that FGF23 levels are determinants of phosphate wasting.

Postoperative hungry bone syndrome in patients with secondary hyperparathyroidism of renal origin

BACKGROUND

Hungry bone syndrome (HBS) is a postoperative condition of severe hypocalcemia that can be seen in patients who have undergone parathyroidectomy (PTX) for secondary hyperparathyroidism (2HPT) of renal origin. This study examines HBS in patients after PTX for 2HPT.

METHODS

Prospectively collected data was retrospectively reviewed in patients who underwent PTX for 2HPT of renal origin at a single institution. HBS was defined as the need for additional days of hospitalization or readmission for intravenous calcium supplementation due to clinical symptoms of hypocalcemia, including tingling, muscle spasms, and bone pain and/or immediate postoperative low serum calcium ≤7.5 mg/dl.

RESULTS

Of 79 patients who underwent PTX for 2HPT, 27.8% (n = 22) experienced HBS. Young age (≤45 years, p = 0.02) was the only preoperative variable that predicted HBS. Most patients developed HBS within 18 h after surgery and required a prolonged hospital stay (19/22) compared to those requiring hospital readmission within the first 7 days (3/22). Initial postoperative serum calcium levels within 18 h of surgery were significantly lower in those patients who developed HBS (7.1 vs. 8.3 mg/dl, p = 0.001), and those patients also had a greater absolute decrease in serum calcium (2.8 vs. 3.5 mg/dl, p = 0.04).

CONCLUSION

HBS develops in a significant proportion of patients generally within the first 18 h after subtotal PTX for 2HPT. The only identifiable preoperative risk factor for HBS was young age. Additionally, low initial calcium levels and greater absolute decrease in serum calcium may help identify those patients that will develop HBS requiring judicious calcium supplementation.

Efficacy of intraoperative parathyroid hormone monitoring to predict success of parathyroidectomy for secondary hyperparathyroidism

Purpose

In secondary hyperparathyroidism (sHPT), it is unclear which criterion for intraoperative parathyroid hormone (ioPTH) decline performs best and whether ioPTH monitoring is sufficiently efficacious in predicting postoperative surgical cure by retrospective review.

Methods

In 80 parathyroidectomies for sHPT, patients with ioPTH monitoring and follow-up PTH assay were categorized into physiologically accepted and failed groups. Receiver operating characteristic (ROC) curves were used to identify the criterion with the best performance and to determine the regression equation for prediction of surgical success.

Results

There was a statistically significant difference in the percentage reduction of ioPTHs between the two groups (P < 0.05). With our criterion, cure was predicted with a sensitivity of 86% and specificity that could be improved to 60% using an 85% ioPTH decrease as cut-off level when this value was compared to the Miami Criterion. There was a slightly negative correlation between the natural logarithm of percentage reduction of ioPTH and percentage reduction of PTH at follow-up (R² = 0.109, P = 0.003).

Conclusion

ioPTH measurements are a useful tool for improvement of the cure rate of operations for sHPT. Because this study aimed at 40 minutes (ioPTH3) as an optimal process in the operation, we recommend using a criterion of more than 85% ioPTH decline at 40 minutes by use of the ROC curve, and the use of the presently calculated regression equation may enable prediction of success.