Specific Bone and Mineral Disorders in Patients with Chronic Kidney Disease

Management of calciphylaxis in a burn center: A case series and review of the literature

Calciphylaxis is a rare, necrotizing skin disorder usually associated with kidney disease, but also caused by many other systemic illnesses. This disease is associated with mortality rates as high as 80% at 1year. We present the demographic and clinical data of nine patients with calciphylaxis treated at our burn center over a 10year period. We review the literature on the clinical presentation, pathophysiology, diagnosis and treatment of this rare disease. We propose that these patients be treated similar to patients with thermal burn injury; meaning intensive wound care, surgical management, critical care and physical therapy. Burn centers are uniquely capable of caring for these incredibly complex patients due to their experience in managing patients with extensive skin and soft tissue defects, wounds and diseases.

The utility of whole body vibration exercise in haemodialysis patients: a pilot study

Background

Exercise improves physical capacity in patients with end-stage renal disease on haemodialysis (HD), but few patients engage in it. Whole-body vibration exercise (WBVE) is a novel protocol that has been shown to benefit frail elderly patients’ rehabilitation. We assessed the utility of WBVE before HD sessions and tested methods to inform the design of a randomized controlled trial (RCT).

Methods

Physical condition and quality of life were assessed at enrolment and repeated 2 weeks later in a pilot study of 49 patients undergoing regular HD. All patients then undertook 8 weeks of WBVE, thrice weekly for 3 min, after which the assessments were repeated and results compared (paired t-tests). Further assessments were made after a 4-week layoff. Patients completed a post-study questionnaire about their experiences of using WBVE. The reproducibility of WBVE and effects on measures of functionality, muscle strength, indirect exercise capacity, nutritional status, bone health and quality of life were recorded to undertake a power calculation for an RCT.

Results

Of 49 patients enrolled, 25 completed all assessments. The dropout rate was high at 49%, but overall, WBVE was an acceptable form of exercise. Functionality as assessed by the 60-s sit-to-stand test (STS-60) improved significantly by 11% (P = 0.002). Some quality of life domains also improved significantly. All improvements were maintained 4 weeks after discontinuing WBVE.

Conclusions

WBVE was acceptable, safe, easily incorporated into the routine of HD and was associated with useful improvements in physical function sufficient to justify a RCT.

Severe maxillofacial renal osteodystrophy in two patients with chronic kidney disease

Renal osteodystrophy (ROD) is the bone pathology that occurs as an uncommon complication related to the several alterations in mineral metabolism present in patients with chronic kidney disease (CKD). This paper describes two cases of severe ROD affecting the maxilla and mandible and causing facial disfigurement of a young and a middle-aged female patient with CKD. Both patients had a history of secondary hyperparathyroidism, previously treated by surgery. The pathogenesis of the disease, as well as its clinical, imaging, and histopathological features, and management of the patient are discussed.

Adynamic bone disease: from bone to vessels in chronic kidney disease

Adynamic bone disease (ABD) is a well-recognized clinical entity in the complex chronic kidney disease (CKD)-mineral and bone disorder. Although the combination of low intact parathyroid hormone (PTH) and low bone alkaline phosphatase levels may be suggestive of ABD, the gold standard for precise diagnosis is histomorphometric analysis of tetracycline double-labeled bone biopsies. ABD essentially is characterized by low bone turnover, low bone volume, normal mineralization, and markedly decreased cellularity with minimal or no fibrosis. ABD is increasing in prevalence relative to other forms of renal osteodystrophy, and is becoming the most frequent type of bone lesion in some series. ABD develops in situations with reduced osteoanabolic stimulation caused by oversuppression of PTH, multifactorial skeletal resistance to PTH actions in uremia, and/or dysregulation of Wnt signaling. All may contribute not only to bone disease but also to the early vascular calcification processes observed in CKD. Various risk factors have been linked to ABD, including calcium loading, ageing, diabetes, hypogonadism, parathyroidectomy, peritoneal dialysis, and antiresorptive therapies, among others. The relationship between low PTH level, ABD, increased risk fracture, and vascular calcifications may at least partially explain the association of ABD with increased mortality rates. To achieve optimal bone and cardiovascular health, attention should be focused not only on classic control of secondary hyperparathyroidism but also on prevention of ABD, especially in the steadily growing proportions of diabetic, white, and elderly patients. Overcoming the insufficient osteoanabolic stimulation in ABD is the ultimate treatment goal.

Histomorphometric diagnostics of renal osteopathy in chronic dialysis patients at high risk of cardiovascular disease

Chronic kidney disease-mineral and bone disorder (CKD-MBD) ranks among clinically and pathogenetically significant complications in patients with CKD. Numerous factors are involved in its development, and histomorphometric analysis of the bone tissue is still necessary for accurate diagnosis.

METHODS

The open, pilot, prospective study aimed at performing a comprehensive histomorphometric bone analysis in 26 dialysis patients and assessing the relationships of different types of CKD-MBD to selected parameters of calcium and phosphate metabolism, densitometry, activity of parathyroid glands, presence of diabetes mellitus, and duration of dialysis treatment.

RESULTS

Comparison of the histomorphometric characteristics demonstrated statistically significant correlations between the volume of bone trabeculae and s-procollagen 1 (.754) as well as s-calcitonin (.856). Similarly, there was a positive correlation between the size of tetracycline lines and volume of bone trabeculae (.705) and a strong negative correlation with the thickness of trabeculae (-.442). When assessing the serum levels of s-osteoprotegerin and serum RANKL, there was a correlation with osteoid thickness and bone trabeculae thickness. In case of s-osteoprotegerin, a statistical power was demonstrated in relation to osteoid thickness (.880); in case of s-RANKL, a statistical power was demonstrated in relation to the thickness of trabeculae (.830). When assessing the influence of dialysis duration, relationships to the volume of trabecular bone (.665) and volume of bone trabeculae (.949) were demonstrated. Finally, a relationship between s-1,25-hydroxyvitamin D and s-osteoprotegerin was observed (.739); also the relationships demonstrated were significantly lower volume of bone trabeculae in men (p = 0.067) and lower values of s-osteocalcin and s-procollagen 1 in diabetic patients (p = 0.014).

CONCLUSION

The results provide new noninvasive possibilities of CKD-MBD detection that are based on selected serum parameters of bone metabolism. Presented are possibilities of noninvasive assessment of different types of CKD-MBD using serum osteomarkers in relation to comprehensive CKD-MBD histomorphometry.