Secondary Hyperparathyroidism in Chronic Kidney Disease: Pathophysiology and Management

Chronic Kidney Disease and Charcot Neuro-Osteoarthropathy of Foot in Diabetes

INTRODUCTION

Charcot neuro-osteoarthropathy (CNO) occurs late in diabetes and may cause fracture, deformity, and higher mortality. Diabetic kidney disease (DKD) affects bone metabolism and contributes to mortality. However, there is no data on prevalence of CNO and its outcomes with coexisting DKD (or chronic kidney disease [CKD]).

METHODS

To ascertain the prevalence of CKD (pick CKD or DKD) among patients with CNO and delineate the remission of active CNO and subsequent lower extremity amputation and all-cause mortality during prospective follow-up. Consecutive patients with diabetic CNO (active or inactive) were enrolled and subsequently divided into those with and without CKD (pick CKD or DKD) (Group A and Group B, respectively). A preestablished timeframe of 36 weeks was utilized to evaluate the remission proportion of active CNO.

RESULTS

A total of 493 CNO patients were observed and 449 subjects (150 patients had active CNO) were further evaluated. The overall prevalence of diabetic nephropathy (DKD or CKD?) CNO was 43.7%. The proportion of patients achieving remission was significantly lower in Group A compared to Group B (OR 0.468, CI [0.239-0.934], P = .025), however, the median time for achieving remission was similar between the 2 groups (14 weeks vs 16 weeks, P = .885). Overall, all-cause mortality was notably higher Group A compared to Group B (OR 2.23, 95% CI [1.474-3.368]) over a median follow-up of 4 years. No significant differences were observed in rates of diabetic foot ulcers (58.2% vs 54.9%; P = .584) and amputations (17.4% vs 15.12%; P = .889) between Group A and Group B.

CONCLUSION

Patients of CNO with coexisting CKD have poor prognosis both in terms of likelihood of active CNO remission and higher mortality.

A practical approach to nutritional intervention for people with chronic kidney disease in Vietnam

BACKGROUND AND OBJECTIVES

A comprehensive nutritional management is necessary for favourable outcomes in patients with chronic kidney disease (CKD). We aimed to assess the changes in nutritional status and disease progression with nutritional management where renal replacement therapy (RRT) was not in place.

METHODS AND STUDY DESIGN

A quasi-experiment intervention was conducted on 70 CKD patients at stages 3-5 from July to December 2022. Participants were excluded if they underwent RRT, including dialy-sis (hemodialysis or peritoneal dialysis), or kidney transplantation. The nutritional regimen covered nutrition-al counseling, samples of the dietary menu, and supplement products. We evaluated nutritional status using Subjective Global Assessment (SGA) scale and sub-clinical blood test at T0 (hospital admission) and T1 (two weeks after the admission or 24 hours before the discharge).

RESULTS

After the intervention, the number of patients classified as malnutrition or at risk of malnourished reduced significantly (65.7% to 54.3% and 25.7% and 5.7%, respectively). The serum concentration of urea, creatinine and parathyroid hormone decreased remarkably, especially in patients receiving nutritional management. In the intervention group, the dietary pattern provided increased intakes of calcium and iron at T1, while phosphorus, sodium and potassium decreased after follow-up. Nausea/vomiting, loss of appetite, tiredness and sleep disorders were improved in the intervention compared to the control group.

CONCLUSIONS

Nutritional therapy enhanced the nutritional sta-tus, and quality of dietary and renal function in CKD patients without RRT. Applying nutrition education and treatment at an early stage can slow CKD progression, which should be applicable elsewhere in Vietnam.

Hyperparathyroidism and Peripheral Arterial Disease

Primary hyperparathyroidism (PHPT) is presented in various forms, including classic PHPT, characterised by increased parathyroid hormone (PTH) secretion, normohormonal PHPT, and normocalcaemic PHPT. Secondary hyperparathyroidism is characterised by increased PTH secretion triggered by factors such as vitamin D deficiency and kidney failure. This review aims to discuss the involvement of hyperparathyroidism (HPT) in atherosclerosis, including peripheral arterial disease (PAD). The increased level of PTH is involved in developing subclinical and overt vascular diseases, encompassing endothelial dysfunction, vascular stiffness, hypertension, and coronary and peripheral arterial diseases. It has been consistently associated with an augmented risk of cardiovascular morbidity and mortality, independent of classical risk factors for atherosclerosis. Chronic hypercalcemia associated with increased levels of PTH contributes to the development of calcification of vessel walls and atherosclerotic plaques. Vascular calcification can occur in the intima or media of the arterial wall and is associated with stiffness of peripheral arteries, which the formation of atherosclerotic plaques and narrowing of the vessel lumen can follow. For treating hyperparathyroidism, particularly SHPT, calcimimetics, novel phosphorus binders and novel vitamin D receptor activators are used. However, they are ineffective in severe PHPT. Therefore, parathyroidectomy remains the primary therapeutic option of PHPT.

Osteoporosis: Investigations and Monitoring

Background

Osteoporosis is characterized by microarchitectural disruption of the bone, decrease in bone mineral density, and increased skeletal fragility and risk of fracture. Osteoporosis occurs due to the decoupling of bone formation and bone resorption, with a significant increase in resorption. This review article focuses on the role of laboratory investigations in the diagnosis and monitoring of treatment in patients with osteoporosis.

Methods

This review article collected literature from various databases using keywords such as 'Laboratory investigations', 'Osteoporosis', 'Diagnosis', 'Monitoring', and 'Bone turnover markers'.

Results and Discussion

Laboratory investigations, including serum calcium, alkaline phosphatase, vitamin D, and parathormone, are commonly performed tests to exclude secondary causes of osteoporosis and monitor the response to therapy. The biochemical markers of bone turnover are newly emerged tests for monitoring individual patients with osteoporosis. These markers are classified as bone formation and resorption markers, measurable in both serum and urine. The use of these markers is limited by biological and analytical variability. The International Federation of Clinical Chemistry and Laboratory Medicine and the International Osteoporosis Foundation recommend serum procollagen type 1 amino-terminal propeptide as the bone formation marker and β-form of C-terminal cross-linked telopeptide of type I collagen (β-CTx-1/β-CrossLaps) as the marker of choice, using standardized procedures. However, in specific cases, such as patients with chronic renal disease, CTx-1 is replaced by the resorption marker tartrate-resistant acid phosphatase 5b, as its levels are not affected by renal excretion.

Conclusion

Bone turnover markers have emerged as tools for the assessment of osteoporosis, using standardized procedures, and are useful in monitoring therapy and treatment compliance.

Mini review: A reevaluation of nutritional vitamin D in the treatment of chronic kidney disease

Chronic kidney disease-mineral and bone disorder is a syndrome of mineral and bone metabolism abnormalities caused by chronic kidney disease. Osteoporosis is a systemic metabolic bone disease characterized by low bone mass, disruption of bone microstructure, increased brittleness, and a higher propensity for fractures. Both of these conditions significantly affect bone metabolism and substantially increase the risk of fractures. Nutritional vitamin D is an essential trace element in the human body and an important fat-soluble vitamin. One crucial physiological role of nutritional vitamin D is to achieve mineral-bone metabolism balance by regulating calcium homeostasis. This review summarized the metabolism of vitamin in normal population and its specificity in chronic kidney disease. Over the years, the understanding and application of vitamin D in patients with chronic renal failure is changing. As people pay more attention to hypercalcemia, vascular calcification, osteoporosis, nutritional vitamin D has come into people's attention again. More and more studies are discussing how to prescribe vitamin D supplementation in hemodialysis patients.

Hungry bone syndrome in peritoneal dialysis patients after parathyroid surgery

Secondary hyperparathyroidism (SHPT) is a common complication of end-stage kidney disease (ESKD). Hungry bone syndrome (HBS) occurs frequently in patients on maintenance dialysis receiving parathyroidectomy for refractory SHPT. However, there is scanty study investigating the clinical risk factors that predict postoperative HBS, and its outcome in peritoneal dialysis (PD) patients. We conducted a single-center retrospective study to analyze 66 PD patients who had undergone parathyroidectomy for secondary hyperparathyroidism at Chang Gung Memorial Hospital between 2009 and 2019. The patients were stratified into two groups based on the presence (n=47) or absence (n=19) of HBS after parathyroidectomy. Subtotal parathyroidectomy was the most common surgery performed (74.2%), followed by total parathyroidectomy with autoimplantation (25.8%). Pathological examination of all surgical specimens revealed parathyroid hyperplasia (100%). Patients with HBS had lower levels of postoperative nadir corrected calcium, higher alkaline phosphate (ALP), and higher potassium levels compared with patients without HBS (all P<0.05). A multivariate logistic regression model confirmed that lower preoperative serum calcium level (OR 0.354, 95% CI 0.133-0.940, P=0.037), higher ALP (OR 1.026, 95% CI 1.008-1.044, P=0.004), and higher potassium level (OR 6.894, 95% CI 1.806-26.317, P=0.005) were associated with HBS after parathyroidectomy. Patients were followed for 58.2±30.8 months after the surgery. There was no significant difference between HBS and non-HBS groups in persistence (P=0.496) or recurrence (P=1.000) of hyperparathyroidism. The overall mortality rate was 10.6% with no significant difference found between both groups (P=0.099). We concluded that HBS is a common complication (71.2%) of parathyroidectomy for SHPT and should be managed appropriately.

Risk Factor Analysis and Prediction of Severe Hypocalcemia after Total Parathyroidectomy without Auto-Transplantation in Patients with Secondary Hyperparathyroidism

OBJECTIVE

Our study aimed to develop and validate a nomogram to predict severe hypocalcemia (SH) before total parathyroidectomy (TPTX) without auto-transplantation in patients with secondary hyperparathyroidism.

METHODS

A total of 299 consecutive patients who underwent TPTX without transplantation for secondary hyperparathyroidism were selected from the General Hospital of Northern Theater Command between January 2013 and December 2021. Of these, patients who underwent surgery between January 2013 and December 2020 formed the training cohort (n = 208) to develop a nomogram, and those who underwent surgery thereafter formed the validation cohort (n = 91) to validate the performance of this nomogram. Univariate and multivariate logistic regression analyses were used to identify the risk factors associated with SH, and then, a nomogram was constructed.

RESULTS

The incidence of postoperative SH was 27.9% and 35.2% in the training and validation cohorts, respectively. The preoperative factors associated with SH were younger age, lower serum calcium (Ca) level, higher intact parathyroid hormone (iPTH) level, and higher serum alkaline phosphatase (ALP) level. Incorporating these 4 factors, the nomogram achieved good concordance indexes of 0.866 (95%CI, 0.816-0.916) and 0.867 (95% CI, 0.793-0.941) in predicting SH in the training and validation cohorts, respectively, and had well-fitted calibration curves. The positive predictive values of the nomogram were 64.7% (54.1%-78.4%) and 75.0% (58.6%-88.5%), and negative predictive values of the nomogram were 90.0% (82.9%-93.6%) and 86.4% (73.5%-94.0%) for the training and validation cohorts, respectively.

CONCLUSIONS

We developed and validated a nomogram for the prediction of SH in patients who underwent TPTX without auto-transplantation for secondary hyperparathyroidism. Our nomogram may facilitate the identification of high-risk SH in patients after TPTX and optimization of preoperative decision-making.

Evaluation of malnutrition and inflammation after total parathyroidectomy in patients on maintenance dialysis

PURPOSE

To evaluate the effect of total parathyroidectomy (tPTx) on malnutrition and inflammation in patients on maintenance dialysis (MHD) having secondary hyperparathyroidism (SHPT).

METHODS

Twenty-five patients on MHD having SHPT who were being treated with tPTx were selected, and changes in their general condition (dry body mass), parathyroid hormone (PTH) and calcium levels, nutrition state (hemoglobin, hematocrit, serum albumin, and total iron binding capacity), and inflammatory status [serum C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor (TNF-α), and the malnutrition-inflammation score (MIS)] were observed at 12, 24, and 36 months postoperatively.

RESULTS

Compared with the preoperative period, the dry body mass increased at 12, 24, and 36 months postoperatively (P < 0.01), hemoglobin, hematocrit, and serum albumin increased significantly (P < 0.01), whereas calcium, phosphorus, and PTH levels decreased significantly (P < 0.01). Serum CRP, IL-6, and TNF-α levels were significantly decreased at 12, 24, and 36 months after surgery (P < 0.01). Furthermore, MIS was reduced as well but to a lesser extent (P < 0.01).

CONCLUSION

tPTx effectively reduced MIS in maintenance dialysis patients, and the alleviated malnutrition and improved inflammatory status may contributed to improving the quality of life of patients on MHD with SHPT.

Secondary hyperparathyroidism due to multiple parathyroid carcinomas in a patient with chronic hemodialysis: a case report

Parathyroid carcinoma (PC) in cases of secondary or tertiary hyperparathyroidism is relatively uncommon, and only a few case reports have described this entity. Although some papers have reported patients with one or two parathyroid malignancies, multiple PC–especially three or more–have been even more rarely reported. Herein, we report a case of secondary hyperparathyroidism due to multiple PCs in a chronic hemodialysis patient. A 54-year-old man with end-stage kidney disease was referred for hyperparathyroidism. He had been diagnosed with chronic kidney disease in 2001 and had begun hemodialysis in 2009. In laboratory tests, intact parathyroid hormone (iPTH) was markedly elevated to 1,144.1 pg/mL (normal range: 15.0–68.3 pg/mL) and serum calcium was mildly elevated to 10.56 mg/dL (normal range: 8.5–10.3 mg/dL). Ultrasonography showed hypoechoic nodules in the posterior part of both thyroid glands. All three nodules showed increased uptake on a 99mTc sestamibi scan. The patient underwent total parathyroidectomy with autotransplantation to the right forearm. Histopathology findings showed three PCs with capsular invasion and one parathyroid hyperplasia. In the immediate postoperative period, the iPTH level dropped from 1,446.8 to 82.4 pg/dL and, after 1 month, to 4.0 pg/dL. This patient needed oral calcium carbonate and active vitamin D to maintain appropriate serum calcium levels. Although multiple PCs are rare, they can cause secondary hyperparathyroidism. Therefore, clinicians should suspect multiple PCs when patients’ serum iPTH levels are exceptionally high. Additionally, since PCs could occur in multiple glands, autotransplantation of the parathyroid gland after parathyroidectomy should be done carefully.

Applications of Metabolomics in Calcium Metabolism Disorders in Humans

The pathogenesis of the disorders of calcium metabolism is not fully understood. This review discusses the studies in which metabolomics was applied in this area. Indeed, metabolomics could play an essential role in discovering biomarkers and elucidating pathological mechanisms. Despite the limited bibliography, the present review highlights the potential of metabolomics in identifying the biomarkers of some of the most common endocrine disorders, such as primary hyperparathyroidism (PHPT), secondary hyperparathyroidism (SHPT), calcium deficiency, osteoporosis and vitamin D supplementation. Metabolites related to above-mentioned diseorders were grouped into specific classes and mapped into metabolic pathways. Furthermore, disturbed metabolic pathways can open up new directions for the in-depth exploration of the basic mechanisms of these diseases at the molecular level.

Case report: Reoperative parathyroidectomy for large ectopic hyperplastic parathyroid in the mediastinum of a patient with recurrent secondary hyperparathyroidism

Introduction

Secondary hyperparathyroidism (SHPT) is a common complication in hemodialysis patients with chronic renal failure uremia. For severe SHPT, parathyroidectomy is effective. Owing to the variability in parathyroid anatomy, surgical parathyroidectomy can be complex and many patients experience recurrent SHPT, which may require repeated surgery. These cases pose significant challenges to surgeons.

Case description

An elderly woman with recurrent severe SHPT was admitted to our hospital. Preoperative methoxyisobutylisonitrile (MIBI) examination found a large ectopic parathyroid gland in the superior mediastinum, and she underwent reoperative parathyroidectomy. A large parathyroid gland in the right anterior mediastinum and another parathyroid gland in the left lingual lobe of the thymus were removed. The patient had postoperative hypocalcemia that was successfully corrected with calcium supplementation via femoral vein catheterization. During the 1-year postoperative follow-up, the patient's iPTH was well controlled and her blood calcium was within the normal range.

Conclusion

We report a case of parathyroidectomy to remove multifocal ectopic hyperplastic parathyroid tissue in the mediastinum. Preoperative MIBI accurately detected the lesions. Calcium supplementation via femoral vein catheterization successfully corrected postoperative hypocalcemia. Postoperative follow-up for 1 year indicated that the surgery was successful.

Interpretation of Parathyroid Hormone Levels in Renal Impairment

Distinguishing between acute kidney injury and chronic kidney disease (CKD) in an emergency setting may pose a conundrum for physicians, especially when a patient’s medical history and records are unknown. Parathyroid hormone (PTH) has proved valuable as a marker of CKD and is frequently assayed for this reason. The use of PTH as a sole marker of CKD may be misleading in certain conditions, and for this reason, physicians need to interpret PTH values with caution. In patients with no existing medical records, it is vital to consider their overall clinical picture, an accurate interpretation of urinalysis and urine microscopy, and the PTH values when making the initial management decisions.

Bone Marrow Findings in Renal Patients: A Single Renal Specialist Center Experience

Objective

This study evaluated the importance of bone marrow aspiration and trephine biopsy (BM) for the diagnosis of underlying hematological abnormalities in renal patients.

Methods

This cross-sectional study on BM was carried out between August 2010 and April 2019, in our specialist renal center for various unexplained hematological abnormalities in patients with renal diseases [chronic kidney disease (CKD), end-stage renal disease (ESRD) requiring maintenance hemodialysis (MHD), patients with normal renal function but other nephrology and urology issues like stone disease and nephrotic syndrome].

Results

Out of 176 reported BM examinations, 48 (27.3%) were done on ESRD patients on MHD (CKD-D), and 69 (39.2%) on CKD patients not on MHD (CKD-nD). Fifty-nine (33.5%) BM were done on patients with normal renal function (n-CKD). The indication for BM was pancytopenia 50 (28.4%), unexplained anemia 39 (22.2%), and unexplained thrombocytopenia 43 (24.4%). In 91 (51.7%) patients BM was normal. In 30 (17%) patients multiple myeloma (MM) was diagnosed on BM, out of which 18 (26.1%), nine (18%), three (5.3%) were CKD-nD, CKD-D, and n-CKD patients, respectively. In 11 (6.3%) patients BM was suggestive of myelodysplasia (MD), out of these 11 patients, five (10%) were CKD-D patients.

Conclusion

BM is an underutilized method of diagnosis of hematological abnormalities in renal patients. Our study revealed the importance of BM examination, especially in patients with CKD.