Management of disturbed calcium metabolism in uraemic patients: 2. Indications for parathyroidectomy

Retro-tracheal parathyroid adenoma: A rare location of a common pathology

Ectopic parathyroid adenoma in the mediastinum has been reported in several publications; however, its location in the posterior mediastinum, especially a retro-tracheal location, has been rarely reported. We report a case of a 61-year-old patient who presented with clinical symptoms of malignant hypercalcemia due to a retro-tracheal mediastinal parathyroid adenoma. The surgical excision normalized the phosphocalcic balance with improvement in the patient's clinical symptoms. An ectopic hypersecreting parathyroid adenoma with life-threatening hypercalcemia should prompt radiological assessment and appropriate surgical management to prevent significant clinical complications.

Increasing Age Hinders the Decline in B-Type Natriuretic Peptide Following Parathyroidectomy in Dialysis Patients

BACKGROUND/AIM

Parathyroidectomy has beneficial effects on all-cause and cardiovascular mortality in patients with uncontrolled hyperparathyroidism. B-Type natriuretic peptide (BNP) correlates with the severity of heart failure. We aimed to investigate whether parathyroidectomy modulates the BNP levels in dialysis patients.

PATIENTS AND METHODS

Patients who underwent surgical intervention for hyperparathyroidism were included. The serum BNP levels were determined before parathyroidectomy and during follow-up.

RESULTS

The preoperative and postoperative BNP levels were 499±561 and 453±442 pg/ml, respectively (p=0.82). The baseline BNP level was positively correlated with weakness and headache, but not biochemical parameters. In multivariate analysis, age (odds ratio=0.837) and preoperative symptom score (odds ratio=0.935) were independent predictors for the postoperative decline in BNP levels Conclusion: The serum BNP levels may increase or decrease after parathyroidectomy. Younger age and lower symptom burden are associated with decline in BNP levels.

The value of intraoperative parathyroid hormone assay in the surgery of mediastinal ectopic parathyroid adenoma (A case series)

Background and aims

Ectopic parathyroid adenoma is a rare entity. Its clinical management is challenging due to varying locations in the mediastinum. The aim of our study is to report our experience about the preoperative localization of the ectopic parathyroid adenoma and to emphasize the major role of the intraoperative parathyroid hormone assay in such circumstances.

Methods

It is a monocentric, retrospective study about patients diagnosed with EPA (ectopic parathyroid adenoma) from January 2015 to December 2016. Clinical aspects, preoperative management as well as the surgical procedures have been analyzed.

Results

There were 7 women, with an average age of 59.14 years. Six patients presented with biological disorders of the phosphocalcic metabolism such as spontaneous bone fracture and recurrent renal lithiasis. In one case, EPA was discovered in the setting of malignant hypercalcemia. The topographic preoperative assessment with a cervicothoracic CT (computed tomography) showed spontaneously hyperdense tissular masses of variable localizations in the mediastinum. A Tc-99 m (99mTc - MIBI) scintigraphy was performed in 5 patients and showed uptake in all cases. We performed cervicotomy in 1 case, manubriotomy in 2 patients, neck manubriotomy in 2 cases, total vertical sternotomy in 1 case, and posterolateral thoracotomy in 1 patient. The lesion was localized in the mediastinum in 1 patient in the perithymic fat in 1 case; EPA was laterotracheal in 1 case, retro tracheal in 1 case, intra-thymic in 2 cases, inter-jugulo-carotidian with contact with the left subclavial artery in 1 case, and anterior mediastinal in 1 patient. The 1-h after-parathormonemia following removal of the surgical specimens showed a decrease value of 45 and 80% of the baseline value. No surgical morbidity was noted after an average follow-up of 7.9 months (range of 5–18 months).

Conclusion

The preoperative topographic diagnosis of ectopic parathyroid adenoma is challenging for the surgeon despite progress in the morphological assessment. The intraoperative parathyroid hormone assay is a valuable tool for an appropriate surgical management.

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Thoracic surgeons faced difficulties in the management of ectopic parathyroid adenomas in the mediastinal location.

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The intraoperative assay of parathormonemia helps guide the surgeon in his strategy of complete excision of the ectopic parathyroid adenom

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Hypocalcemia is a constant postoperative complication and its absence may make questionnable the quality of the tumor resection.

Parathyroid Tissue Cryopreservation: Does the Storage Time Affect Viability and Functionality?

Parathyroidectomy is a standard practice to treat recurrent or persistent hyperparathyroidism. However, this can lead to the onset of hypoparathyroidism, treatable with the autotransplantation of parathyroid tissue (PT). Tissue can be transplanted immediately after parathyroidectomy or cryopreserved and transplanted only in case of necessity. Since 2011, the Cord Blood Bank and Cardiovascular Tissue Bank of Emilia-Romagna has been storing PT for potential autologous transplantation. To date, there are highly variable data about the viability and function of PT after thawing. However, it is not clear if the PT quality is affected by different cryopreservation protocols and/or by the storage time. The aim of this study was to assess the ex vivo function and viability of the PTs of ten patients stored in the Bank. Tissue morphology was evaluated before and after cryopreservation through histological investigations. PT function was analyzed by assessing the ability of cryopreserved PT to synthesize and secrete parathyroid hormone (PTH) in response to different calcium concentrations. Moreover, viability and function were also investigated on tissue-isolated cells in culture. These data show that tested tissues appear to be viable and able to produce PTH even after 5 years of storage, and the histological architecture is well preserved.

An Unusual Mass of Posterior Mediastinum: A Case of Retrotracheal Parathyroid Adenoma Presenting With Primary Hyperparathyroidism

Although parathyroid ectopy in the mediastinum has been the subject of several publications, its location in the posterior mediastinum is very rarely reported. We report a case of a 69-year-old patient who presented with clinical symptoms of malignant hypercalcemia due to a retrotracheal mediastinal parathyroid adenoma. The surgical excision leads to a quick normalisation of the phosphocalcic balance with improvement of the clinical symptoms. Ectopic hypersecreting parathyroid adenoma with life-threatening hypercalcemia should prompt radiological assessment and appropriate surgical management to prevent further clinical complications.

Parathyroid ultrasonography and bone metabolic profile of patients on dialysis with hyperparathyroidism

AIM

To evaluate the parathyroid ultrasonography and define parameters that can predict poor response to treatment in patients with secondary hyperparathyroidism due to renal failure.

METHODS

This cohort study evaluated 85 patients with chronic kidney disease stage V with parathyroid hormone levels above 800 pg/mL. All patients underwent ultrasonography of the parathyroids and the following parameters were analyzed: Demographic characteristics (etiology of chronic kidney disease, gender, age, dialysis vintage, vascular access, use of vitamin D), laboratory (calcium, phosphorus, parathyroid hormone, alkaline phosphatase, bone alkaline phosphatase), and the occurrence of bone changes, cardiovascular events and death. The χ² test were used to compare proportions or the Fisher exact test for small sample frequencies. Student t-test was used to detect differences between the two groups regarding continuous variables.

RESULTS

Fifty-three patients (66.4%) had parathyroid nodules with higher levels of parathyroid hormone, calcium and phosphorus. Sixteen patients underwent parathyroidectomy and had higher levels of phosphorus and calcium × phosphorus product (P = 0.03 and P = 0.006, respectively). They also had lower mortality (32% vs 68%, P = 0.01) and lower incidence of cardiovascular or cerebrovascular events (27% vs 73%, P = 0.02). Calcium × phosphorus product above 55 mg²/dL² [RR 1.48 (1.06, 2.08), P = 0.03], presence of vascular calcification [1.33 (1.01, 1.76), P = 0.015] and previous occurrence of vascular events [RR 2.25 (1.27, 3.98), P < 0.001] were risk factors for mortality in this population. There was no association between the occurrence of nodules and mortality.

CONCLUSION

The identification of nodules at ultrasonography strengthens the indication for parathyroidectomy in patients with secondary hyperparathyroidism due to renal failure.

Bone disease in post-transplant patients

PURPOSE OF REVIEW

Mineral and bone disorders are common problems in organ transplant recipients. Successful transplantation solves many aspects of abnormal mineral and bone metabolism, but the degree of improvement is frequently incomplete. Posttransplant bone disease can affect long-term outcomes as well as increase the likelihood of fracture. In this article, we reviewed the major posttransplant bone diseases and recent advances in treatment strategies.

RECENT FINDINGS

Pretransplant bone disease and immunosuppressants are important risk factors for posttransplant bone disease. Corticosteroid withdrawal may result in minimal or no protection against fractures, with increased risk for acute rejection. Vitamin D analogue and bisphosphonate are frequently used to prevent and treat posttransplant osteoporosis. Posttransplant hyperparathyroidism increases the risk for all-cause mortality and graft loss, but not major cardiovascular events. Cinacalcet was well tolerated and effectively controlled hypercalcemic hyperparathyroidism; however, it did not improve bone mineral density and discontinuation led to parathyroid hormone rebound. Six-month paricalcitol supplementation reduced parathyroid hormone levels and attenuated bone remodeling and mineral loss in case of posttransplant hyperparathyroidism.

SUMMARY

Posttransplant bone diseases present in various forms, including osteoporosis, hyperparathyroidism, adynamic bone disease, and osteonecrosis. Prophylactic and therapeutic approaches to both pretransplant and posttransplant periods should be considered.

Impact of parathyroidectomy on allograft outcomes in kidney transplantation

We performed retrospective, multi-center study of the impacts of parathyroidectomy (PTX) after or before kidney transplantation on allograft outcomes. A total of 63 patients who underwent PTX after kidney transplantation were identified. Deterioration in eGFR by more than 25% at 1 month after PTX occurred in 20% of the patients. The baseline eGFR was significantly lower in impairment group than nonimpairment group [adjusted odds ratio (OR) 0.87, 95% confidence interval (CI) 0.77-0.99, P = 0.033]. Low iPTH concentration after PTX was also a significant risk factor for the renal impairment (OR 0.96, CI 0.94-0.99, P = 0.009). A total of 37 patients who underwent PTX before transplantation were identified. Thirty-six percent of the patients had persistent hyperparathyroidism by 1 year after transplantation. A high iPTH level before PTX was a significant risk factor for persistent post-transplant hyperparathyroidism (adjusted OR 1.002, CI 1.000-1.005, P = 0.039). Finally, eGFR values during the first 5 years after transplantation were significantly lower in the patients who underwent PTX at less than 1 year after transplantation, than the pretransplant PTX patients (P = 0.032). As PTX after kidney transplantation has a risk of deterioration of allograft function, pretransplant PTX should be considered for patients with severe hyperparathyroidism, who could undergo post-transplant PTX.

Use of ultrasound to assess the response to therapy for secondary hyperparathyroidism

Secondary hyperparathyroidism (SHPT) is a common complication in patients with chronic kidney disease. In SHPT, the biology of parathyroid cells changes significantly toward diffuse nodular hyperplasia. Currently, diagnosis of SHPT is based on intact parathyroid hormone serum levels and parameters of mineral metabolism. The morphologic diagnosis of SHPT relies on high-resolution ultrasonography with color Doppler imaging. This report describes a maintenance hemodialysis patient with severe SHPT treated using conventional therapy (phosphate binders and oral/intravenous vitamin D or analogues) and the subsequent addition of a calcimimetic. The role of color Doppler ultrasonography in the diagnosis, clinical follow-up, and assessment of therapeutic response of SHPT is discussed. This case suggests that the availability of calcimimetics has changed the natural history of clinical SHPT and may change the therapeutic utility of parathyroidectomy. Use of color Doppler ultrasonography further supports these therapeutic advances, allowing evaluation of the morphologic and vascular changes in hyperplastic parathyroid glands and aiding clinical, pharmacologic, and surgical strategies.

Prevention and treatment of renal osteodystrophy in children on chronic renal failure: European guidelines

Childhood renal osteodystrophy (ROD) is the consequence of disturbances of the calcium-regulating hormones vitamin D and parathyroid hormone (PTH) as well as of the somatotroph hormone axis associated with local modulation of bone and growth cartilage function. The resulting growth retardation and the potentially rapid onset of ROD in children are different from ROD in adults. The biochemical changes of ROD as well as its prevention and treatment affect calcium and phosphorus homeostasis and are directly associated with the development of cardiovascular disease in pediatric renal patients. The aims of the clinical and biochemical surveillance of pediatric patients with CRF or on dialysis are prevention of hyperphosphatemia, avoidance of hypercalcemia and keeping the calcium phosphorus product below 5 mmol(2)/l(2). The PTH levels should be within the normal range in chronic renal failure (CRF) and up to 2-3 times the upper limit of normal levels in dialysed children. Prevention of ROD is expected to result in improved growth and less vascular calcification.

Viewpoint: How Do Calcimimetics Fit Into the Management of Parathyroid Hormone, Calcium, and Phosphate Disturbances in Dialysis Patients?

As suggested by its American brand name (Sensipar), the calcimimetic cinacalcet sensitizes the parathyroid cells to the extracellular calcium signal, suppressing parathyroid hormone (PTH) release and synthesis and preventing parathyroid cell proliferation. This primary PTH suppression decreases the release of calcium and phosphate from bone without increasing intestinal absorption of calcium and phosphate. Therefore cinacalcet decreases the risk of hypercalcemia and hyperphosphatemia in contrast to 1alpha-OH vitamin D derivatives. Compared with calcium-containing oral phosphate binder (OPB), it increases the risk of hypocalcemia and may decrease the PTH-mediated phosphaturia in predialysis patients. This justifies its combined use with calcium-containing OPB in order to prevent hypocalcemia and enhance the hypophosphatemic effect of the latter, while improving PTH suppression. The National Kidney Foundation (NKF) Kidney Disease Outcomes Quality Initiative (K/DOQI) has recommended restriction of supplemental elemental calcium to 1.5 g/day, a recommendation that we believe should be revised. No pathophysiologic or randomized trial data have yet evidenced the absolute necessity for systematically using 1alpha-OH vitamin D derivatives and noncalcium-containing OPB rather than higher doses of calcium-containing OPB alone in uremic patients without vitamin D insufficiency. In patients with hyperparathyroidism as severe as in the "Treat to Goal Study," the Durham study showed that a calcium carbonate dose more than three times the K/DOQI limit could decrease PTH into the recommended range, with the advantage of a lower calcium-phosphate product compared with the combination of calcitriol and noncalcium OPB. Besides the efficient PTH suppression associated with lower calcium-phosphate product and a good gastrointestinal tolerance, long-term data suggest that cinacalcet may decrease the risk of parathyroidectomy and fracture, while high bone turnover lesions are improved. However, no long-term data on bone mineral density and cardiovascular calcification and complications are yet available. Such studies, along with those comparing cinacalcet and 1alpha-OH vitamin D-based approaches to hyperparathyroidism, are needed.

Effect of Parathyroidectomy on Renal Graft Function

Some authors have reported acute impairment of renal transplant function after parathyroidectomy (PTx). Since 1996 PTx has been performed in 22 renal transplant recipients (follow-up, 24.2 +/- 15 months; serum creatinine concentration (SCr) pre-PTx, 1.26 +/- 0.4 mg/dL). We analyzed the serum levels of immunoreactive parathyroid hormone, calcitriol, calcium, phosphate, alkaline phosphatase, SCr, and hemoglobin, as well as proteinuria, blood pressure, and immunosuppressive treatment at several times: before PTx and at 7 days, 1 month, and then every 3 months post-PTx. After PTx we observed acute renal function deterioration until the third post-PTx month, when SCr levels returned to baseline values. We found no changes in blood pressure, although there was a trend toward a reduced dosage of antihypertensive drugs. We compared the patients who showed more significant increases (>30% from baseline) in SCr (group A, n = 7) with those who did not (group B, n = 15). Group A had higher SCr levels pre-PTx. We observed no other significant differences, either pre-PTx or post-PTx. In 2 patients in group A, SCr returned to baseline at the third month after PTx, but in the other 5 the renal function impairment persisted. Taking into account this risk and that severe hyperparathyroidism does not revert after transplantation, it would seem more appropriate in such cases to perform PTx while the patient is on the waiting list. The causes of this renal functional impairment are not clear, but the patients who showed worse deterioration also had a worse renal function pre-PTx.

Parathyroidectomy: whom and when?

Hyperparathyroidism (HPT) is common in patients on dialysis, and parathyroidectomy (PTx) is often required. We present a retrospective, descriptive analysis of data corresponding to 148 patients on dialysis undergoing PTx due to severe refractory HPT (PTH 1401 +/- 497 pg/mL, Ca 10.6 +/- 0.8 mg/dL, P 6.9 +/- 1.7 mg/dL). Demographic data were compared with those recorded in 309 patients on dialysis not subjected to PTx who were managed at the same hospital. In the PTx group, the factors age (49.3 +/- 14 years), male gender (48.6%), and diabetes (0.7%) were significantly lower than in the non-PTx group (61.5 +/- 14.9 years, male gender 59%, diabetes 19.4%), while time on dialysis was longer (8.6 +/- 5.8 vs. 5.5 +/- 5.4 years). In 129 of the study patients (87.4%), four or more glands were identified, and total PTx plus autotransplantation (AT) in the forearm was performed. In the remaining 19 patients, two to three glands were identified, and AT was not undertaken. Four of the 19 patients were successfully operated on again for persistent HPT, seven showed PTH levels <250 pg/mL, and eight maintained severe HPT. Perioperative complications included one death due to cardiac insufficiency, two repeat operations due to bleeding, and one patient with chronic hoarseness. Hospital stay was prolonged in 20% of patients due to a hungry bone syndrome. Among those patients with PTx and AT, HPT recurred in 21 patients (16.2%) at 3.1 +/- 2.3 years. In 13 of these patients, autograft was removed at 7.5 +/- 2.9 years. Serum calcium and phosphate levels improved after PTx, and these results were maintained for 5 years (9.6 +/- 0.8 and 4.2 +/- 1.2 mg/dL, respectively). In conclusion, PTx with AT is a safe option for the treatment of severe HPT that is accompanied by low morbidity and mortality and a good outcome. Medical treatment should not be prolonged at the expense of long repeated bouts of hypercalcemia and/or hyperphosphatemia with their irreversible consequences.

Resolution of massive uremic tumoral calcinosis with daily nocturnal home hemodialysis

BACKGROUND

Derangements in bone mineral metabolism are an invariable consequence of end-stage renal disease (ESRD). Extraosseous tumoral calcification is a relatively uncommon complication that can be associated with substantial morbidity.

METHODS

The authors report a case of an ESRD patient who had severe tumoral calcification of his shoulder, hands, and feet despite daily conventional hemodialysis. Conversion to daily nocturnal hemodialysis (DNHD) led to a dramatic resolution of his calcific deposits within only 9 months of initiating this form of renal replacement therapy.

RESULTS

After initiating DNHD, the patient's serum phosphate level, which had been exceedingly difficult to control, normalized within the first week. Despite maintaining a high dialysate calcium (Ca) bath up to 4.2 mEq/L (2.1 mmol/L; to maintain calcium balance and suppress parathyroid hormone [PTH]), there was ongoing dissolution of the calcific deposits. This occurred with relatively preserved bone mineral density. The Ca x phosphorus (PO4) product decreased from 85 mg2/dL2 (6.80 mmol2/L2) and remained less than 55 mg2/dL2 (4.4 mmol2/L2) throughout the patient's course on DNHD. PTH levels fell precipitously early on but then rose again several months after starting DNHD. This PTH rebound as well as the possible mechanisms underlying the dissolution of this patient's extraosseous calcifications are explored further.

CONCLUSION

Extraosseous tumoral calcification associated with ESRD is an uncommon but potentially serious complication in this patient population. DNHD, by offering superior phosphate clearance, can facilitate the dissolution of these calcific deposits over a relatively short period. This effect can be seen despite using high calcium concentration dialysate to maintain calcium balance and mitigate hyperparathyroidism.

Surgical management of secondary hyperparathyroidism

Most patients with renal failure maintained on chronic dialysis have elevated parathyroid hormone (PTH) levels and PTH-mediated bone disease (secondary hyperparathyroidism [sHPT]). Elevated PTH production in this setting represents a progressive, exaggerated physiologic response to hypocalcemia by the parathyroid glands, and generalized growth of the parathyroids is an adaptive response to chronic stimulation. Effective medical strategies to reduce PTH secretion and PTH-mediated bone turnover in sHPT (eg, controlling hyperphosphatemia, normalizing serum calcium, and administering vitamin D analogs) has decreased the need for parathyroidectomy in recent years. However, failure of medical therapy because of inadequate treatment, persistent hyperphosphatemia, or acquired parathyroid neoplasia still leads to recommendations for parathyroidectomy in select patients. Furthermore, increased awareness of potential long-term, irreversible cardiovascular effects of uncorrected hyperparathyroidism has led some to advocate parathyroidectomy earlier in the course of this disease. This monograph will review parathyroidectomy for secondary and tertiary hyperparathyroidism.

Parathyroidectomy in dialysis patients

Subtotal parathyroidectomy or total parathyroidectomy (PTx) with autotransplantation are surgical procedures considered while the patient is included on the waiting list for renal transplantation. Total PTx alone is based in the possibility that a fragment of tissue (nodular hyperplasia in particular) left in the same pathophysiological environment of long term dialysis would show the same behavior and reproduce in time the same clinicopathological picture. The persistence of uremia induces a continued growth stimulus developing residual hyperplasia and consequently a very high risk of recurrence. We performed total PTx alone in 15 uremic patients excluded for renal transplantation 10 patients with undetectable iPTH serum concentration and were followed up for 37 to 144 months. There was no evidence of clinical bone disease (bone pain or fractures). Bone mineral lumbar spine and hip density was measured at the end of follow-up. The z score data showed that all patients had a bone mass similar than that expected for their age. Bone biopsies performed in four patients showed a uniform picture of low turnover without aluminium staining. Calcification of small arteries (digital and arcade vessels in hands and feet) were evaluated pre and post total PTx alone in nine out of the 10 patients with undetectable PTH levels. The small vessel calcification was present in five patients at the moment of PTx. At the end of the long term follow-up only one patient showed progression. In conclusion, total PTx without autotransplantation is a very effective and adequate treatment for refractory severe hyperparathyroidism in patients excluded for renal transplantation. Aluminium related osteopathy post PTx is a risk to be controlled with aluminium "free" dialysis water and avoiding aluminium containing phosphate binders.

Total parathyroidectomy with autotransplantation in renal hyperparathyroidism: low recurrence after intra-operative tissue selection

BACKGROUND

Total parathyroidectomy with simultaneous autotransplantation (AT) is a well-established surgical modality in the treatment of severe drug-resistant renal hyperparathyroidism. In literature, the high rate of graft-dependent recurrence seems a serious disadvantage. This complication can possibly be avoided by parathyroid tissue selection prior to AT.

METHODS

Total parathyroidectomy with simultaneous AT was performed in 37 patients on intermittent haemodialysis treatment. Parathyroid tissue with a low proliferative potential ('A-regions') was selected for AT intra-operatively with a stereomagnifier. The mean post-operative follow-up was 37+/-24 months.

RESULTS

Plasma levels of intact parathyroid hormone decreased from 1211+/-541 to 69+/-32 pg/ml, calcium from 2.49+/-0.27 to 2.17+/-0.30 mmol/l, phosphorus from 2.28+/-0.63 to 2.11+/-0.69 mmol/l, and total alkaline phosphatases from 272+/-210 to 117+/-70 U/l. Graft-dependent recurrent hyperparathyroidism occurred in one patient after 32 months and was cured by the selective removal of five enlarged autografts.

CONCLUSIONS

Simply discriminating between diffuse and nodular hyperplastic parathyroid tissue appears to be inadequate. Intra-operative tissue selection with a stereomagnifier may facilitate the identification and AT of tissue with optimal functional characteristics and a low proliferative potential, thus minimizing the rate of recurrent hyperparathyroidism.