BACKGROUND: Metastatic pulmonary calcification, a complication of uraemia and disordered calcium metabolism, may be diffuse or localised. The factors that determine calcium precipitation are complex, but tissue alkalosis is thought to be important. As obstruction of the pulmonary artery theoretically causes local alkalosis a retrospective necropsy study was carried out to examine the relation between metastatic pulmonary calcification and vascular obstruction. METHODS: Five patients with focal and two with diffuse metastatic calcification in the lungs were identified over eight years. Lungs were studied macroscopically and by light microscopy, haematoxylin and eosin and histochemical stains being used for calcium. RESULTS: Underlying risk factors for calcification in these patients included renal failure in six and disseminated malignancy in five. In the five patients with localised calcification obstruction of the pulmonary artery by thrombus or tumour was found proximal or adjacent to areas of calcium deposition. In two patients metastatic calcification was confined to a lung with unilateral pulmonary artery thromboembolic occlusion. Calcification was not specifically associated with infarction, pneumonia, or diffuse alveolar damage. Lesions of the pulmonary artery were not seen in the two patients with diffuse bilateral metastatic calcification. CONCLUSION: In this small series there was a spatial association between pulmonary artery obstruction and localised metastatic calcification. It is proposed that pulmonary artery obstruction alters the microchemical environment of the lung, favouring tissue alkalosis and thereby enhancing parenchymal calcification in patients predisposed to this condition.
Three cases of myocardial fibre calcification found at post-mortem examination are described. In one case there was antemortem hypercalcaemia and hyperphosphataemia and the case was clearly an example of metastatic calcification. In the other two cases there was ischaemic myocardial necrosis and calcification was seen in fibres which were not overtly necrotic, but which were both in proximity to (the majority) and remote from the necrotic zones. Since renal failure with hyperphosphataemia was present in both cases, these were considered to be examples of augmented (by the hyperphosphataemia) dystrophic calcification. The histological, histochemical and ultrastructural features were identical in the three cases. Hydroxyapatite formation was observed initially in mitochondria, followed by spillage of crystals into the cytosol and ultimately into the interstitium. It is suggested that the fundamental lesion is a dysfunction of the fibre membrane; the similarity of this reaction with the calcification seen in skeletal muscle fibres in various myopathies is noted and a unifying hypothesis of the mechanism of skeletal and cardiac muscle fibre calcification is thereby suggested.
Metastatic calcification, a known complication of prolonged end-stage renal disease, is herein described for the first time in a 10-month-old boy with acute renal failure, manifesting as a painful and swollen arm. Imaging revealed diffuse calcification and technetium-99 methylene diphosphonate (99Tc-MDP) uptake around the humerus and axilla. Calcium and vitamin D restriction, followed by intravenous administration of sodium thiosulfate caused a full symptomatic, radio- and scintigraphic improvement.
Hemolytic uremic syndrome; Calcific uremic arteriolopathy; Sodium thiosulfate; Radionuclide imaging; Peritoneal dialysis; Alfacalcidol
Metastatic calcification is rare; it is found during autopsy in patients who underwent hemodialysis. Diffuse calcium precipitation of small and medium-sized cutaneous vessels, known as calciphylaxis, can result in progressive tissue necrosis secondary to vascular calcification. This condition most commonly involves the skin; however, a rare occurrence of visceral calciphylaxis has been reported. Here we report on an autopsy case. Despite a thorough evaluation, and even performing an autopsy, the underlying cause of acute-onset hypercalcemia, resulting in the production of pulmonary calciphylaxis and metastatic renal calcification associated with acute respiratory and renal failure, could not be determined. Metastatic calcification often lacks specific symptoms, and the degree of calcification is a marker of the severity and chronicity of the disease. This unusual autopsy case emphasizes the importance of rapidly progressing visceral calciphylaxis, as well as its early detection.
Calcification; Hypercalcemia; Calciphylaxis
Seven patients with chronic renal failure underwent intermittent hemodialysis for five to 37 months (111 patient-months on a twice-weekly basis) employing arteriovenous Teflon-Silastic cannulas and the modified two-layer Kiil hemodialyzer. A single-pass 37° C. dialysate system has been used. One patient died of an indirectly related cause. All other patients have been successfully rehabilitated and now carry on normal activity of moderate sedentary type. Complications included recurring infection and clotting of arteriovenous cannulas. Hypertension and anemia were common complications requiring careful control. Peripheral neuropathy was noted in five of the seven patients but was of clinical significance in only one patient. Metastatic calcification, osteoporosis and urolithiasis also occurred in this patient. Peptic ulcers with hemorrhage developed in two patients. The degree of rehabilitation and psychological adjustment achieved by this group of patients strongly indicates the need for expansion of dialysis facilities and further research into the medical and economic aspects of dialysis.
This case report suggests that calcifications in the sclera and choroid may be a feature of pseudohypoparathyroidism and shows a calcium distribution more extensive and severe than that characteristically seen in other metabolic conditions associated with calcium deposits in the eye. Ocular ectopic calcification is a part of the more generalised ectopic soft tissue calcification seen with pseudohypoparathyroidism. Evaluation of the contribution of the terminal renal failure and uraemia to the ectopic ocular calcification would require sequential evaluation of eyes with pseudohypoparathyroidism, but without the added complication of uraemia.
A total of 79 infants born at less than 32 weeks' gestation were studied with serial renal ultrasound scans to assess the incidence of nephrocalcinosis. Twenty one infants developed renal calcification giving an overall incidence of 26.6% in the study group. Affected infants were significantly smaller (mean (SD) birth weight 940 (323) g) and significantly less mature (mean (SD) gestation 26.9 (1.9) weeks). In 17 patients the calcification was represented by hyperechogenic renal pyramids alone, and in four patients renal calculi were demonstrated. Factors associated with renal calcification included hypophosphataemia, hypercalcaemia, hypercreatininaemia, and prolonged oxygen requirement during the first month of life. Multivariate analysis showed that the strongest clinical indicator of calcification was duration of oxygen treatment. Infants who still required oxygen treatment at 28 days had a 62% chance of developing renal calcification.
In a group of 32 patients with terminal renal failure the initial hypocalcaemia was corrected after two months' adequate maintenance haemodialysis. In seven patients hypercalcaemia occurred with a peak incidence after about six months' treatment. In six of these patients hypercalcaemia was transient and the plasma calcium became normal with haemodialysis alone. In one patient the hypercalcaemia was persistent and the plasma calcium reverted to normal only after subtotal parathyroidectomy. This patient had no radiological bone disease, a normal alkaline phosphatase, and no metastatic calcification of the soft tissues.
It is concluded that in some patients with terminal renal failure treated with maintenance haemodialysis autonomy of the parathyroids becomes evident in the absence of bone disease or a raised plasma alkaline phosphatase, and that subsequently with continued dialysis there is a spontaneous involution towards normal parathyroid function.
A patient with chronic renal failure, a dialysis encephalopathy syndrome and renal osteodystrophy associated with aluminium intoxication developed an avascular necrosis of the left femoral head. Histological examination of the excised head confirmed the zone of avascular necrosis and demonstrated an exuberant formation of cartilage around this zone. Calcification was sparse and the cartilage exhibited histological features similar to those seen in classical rickets. Histochemical and electron probe x-ray microanalysis demonstrated aluminium in the matrix around hypertrophic chondrocytes, at the tide mark of articular cartilage and at the mineralised tissue/osteoid interface of trabecular bone. Aluminium, therefore, preferentially localises at sites of calcification and possibly exerts an inhibitory effect on this reaction. This is taken to account for the relative failure of endochrondral ossification and the development of a rachitic appearance. A comparison with five other examples of avascular necrosis of the femoral head (occurring after renal transplantation, as an idiopathic phenomenon and as a complication of steroid therapy) showed that, in addition to the more commonly described appositional bone formation, cartilage formation and endochondral ossification were present in three of these comparison cases, although less prominent and of considerably less degree than in the main case.
Metastatic pulmonary calcification characterized by diffuse calcium deposition in the lungs is known to occur in patients with chronic renal failure. We present a case of a 47-year-old man with chronic renal failure presented with dyspnea, high-resolution computed tomography of the chest revealed multiple, centrilobular, calcified nodules and patchy areas of ground-glass opacity throughout both lungs, consistent with metastatic pulmonary calcification. Calcification was also seen in the bronchi and trachea.
Metastatic pulmonary calcification; HRCT; chronic renal failure
Two cases are reviewed, both of which developed tumoral calcinosis whilst receiving 1, alpha-hydroxy-cholecalciferol therapy. Tumoral calcinosis is an extreme form of peri-articular calcification, and its occurrence in patients with chronic renal failure is unusual. These peri-articular masses developed around the shoulders in both patients, and the action of 1, alpha-hydroxycholecalciferol as a possible factor promoting this form of metastatic calcification is discussed.
Metastatic myocardial calcification is a frequent cause of heart failure in hemodialysis patients. However, early detection is difficult, often resulting in a poor prognosis. A 47-year-old man with hemodialysis-dependent end-stage renal disease presented with progressive dyspnea. Levels of serum phosphate, calcium, and intact parathyroid hormone were poorly controlled. He developed pain in his right thumb 1 year before presentation, and the pain gradually increased and extended to the entire right hand. Hand radiography 1 month earlier had revealed significant progressive calcification. Echocardiography showed severe, diffuse hypokinesis and pericardial effusion as well as possible anterior myocardial calcification with high echogenicity. Chest computed tomography revealed a severely dilated heart with anterior massive myocardial calcification and a large amount of pericardial effusion, which was not detected on computed tomography performed 20 months earlier. The patient was diagnosed with heart failure associated with metastatic myocardial calcification and died suddenly 2 weeks later. This experience suggests that progressive metastatic calcification of the skin and subcutaneous tissue is useful for predicting myocardial calcification.
Cardiovascular disease; Hemodialysis/continuous renal replacement therapy; Mineral bone metabolism; Metastatic calcification; Heart failure; Hyperparathyroidism; Myocardium; Hand; Computed tomography
Generalized arterial calcification of infancy (GACI) is a life-threatening disorder in young infants. Cardiovascular symptoms are usually apparent within the first month of life. The symptoms are caused by calcification of large and medium-sized arteries, including the aorta, coronary arteries, and renal arteries. Most of the patients die by 6 months of age because of heart failure. Recently, homozygous or compound heterozygous mutations for the ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) gene were reported as causative for the disorder. ENPP1 regulates extracellular inorganic pyrophosphate (PPi), a major inhibitor of extracellular matrix calcification. A newborn was diagnosed with GACI. The infant died at the age of 7 weeks of cardiac failure and the parents were referred to Molecular Biology and Cytogenetic lab for further workup. Cytogenetics analysis was performed on the parents, which showed normal karyotypes and mutational analysis for the ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) gene was also performed. The mutational analysis showed that both father and mother of the deceased infant were heterozygous carriers of the mutation c.749C>T (p.P250L) in exon 7 of ENPP1 and it was likely, that the deceased child carried the same mutation homozygous on both alleles and died of GACI resulting from this ENPP1 mutation. The couple was counseled and monitored for the second pregnancy. Amniocentesis was performed at 15 weeks of gestation for mutational analysis of the same gene in the second pregnancy. The analysis was negative for the parental mutations. One month after the birth of a healthy infant, peripheral blood was collected from the baby and sent for reconfirmation. The results again were negative for the mutation and the baby was on 6 months follow up and no major symptoms were seen. The parents of the child benefited enormously by learning about the disease much in advance and also its risk of recurrence. The main aim of this study is to emphasize on two aspects: (i) the importance of modern molecular techniques in diagnosis such a syndrome and (2) the difficulties faced by the physician to provide appropriate diagnosis and the adequate genetic counseling to the family without molecular facilities.
Cytogenetics; ecto-nucleotide pyrophosphatase/phosphodiesterase 1 encoding gene; prenatal diagnostic testing; pyrophosphate
In patients with chronic renal failure on regular dialysis treatment, limboconjunctival degenerations and calcifications are commonly observed. In this study three groups of patients were followed over a period of 6 years. The first group consisted of 47 patients with renal failure, the second group of 17 patients with renal failure and hyperparathyroidism not controlled by drugs, and the third group seven patients with primary hyperparathyroidism without renal failure. The aim of this study was to determine the progression of the limboconjunctival changes over time. The hypothesis that an increase in serum calcium and phosphorus concentrations, as a result of tertiary hyperparathyroidism, could possibly add a corneal component to the limbal calcification was also tested. All patients with renal failure (in as much as the degenerative limbal features were not obscured by deposits of lime salts), had a type II white limbus girdle of Vogt. This limbal degeneration was observed in only 45% of controls. In all 47 patients with renal failure conjunctival calcification was observed; 26 of them also had limbal calcification. After 6 years 41 patients had developed limbal calcification. This progression was statistically significant. In 15 out of 17 patients with tertiary hyperparathyroidism a band-shaped keratopathy developed in addition to the limboconjunctival calcification.
Ectopic calcification is a frequent complication of many degenerative diseases. Here we identify the serum protein α2–Heremans-Schmid glycoprotein (Ahsg, also known as fetuin-A) as an important inhibitor of ectopic calcification acting on the systemic level. Ahsg-deficient mice are phenotypically normal, but develop severe calcification of various organs on a mineral and vitamin D–rich diet and on a normal diet when the deficiency is combined with a DBA/2 genetic background. This phenotype is not associated with apparent changes in calcium and phosphate homeostasis, but with a decreased inhibitory activity of the Ahsg-deficient extracellular fluid on mineral formation. The same underlying principle may contribute to many calcifying disorders including calciphylaxis, a syndrome of severe systemic calcification in patients with chronic renal failure. Taken together, our data demonstrate a critical role of Ahsg as an inhibitor of unwanted mineralization and provide a novel therapeutic concept to prevent ectopic calcification accompanying various diseases.
Of 57 patients with chronic renal failure and calcification of the anterior membranes of the eye eight developed inflammatory reactions, clinically indistinguishable from pingueculitis. In three patients an acute inflammatory reaction of the episcleral tissue and the conjunctiva over it developed which we considered to represent the red eye of renal failure. In these patients massive shedding of calcium phosphate salts was clinically evident. Histopathologically in all these patients calcific deposits were observed. Although sporadically polymorphonuclear leucocytes were present in the inflamed tissues we could not demonstrate crystal phagocytosis. We believe that in the red eyes in renal failure and, more specifically, in the red eyes of renal failure a crystal induced inflammatory mechanism is not operative.
Although it is known that bisphosphonates prevent medial vascular calcification in vivo, their mechanism of action remains unknown and, in particular, whether they act directly on the blood vessels or indirectly through inhibition of bone resorption. To determine this, we studied the effects of two bisphosphonates on calcification of rat aortas in vitro and on in vivo aortic calcification and bone metabolism in rats with renal failure. We produced vascular calcification in rats with adenine-induced renal failure fed a high-phosphate diet. Daily treatment with either etidronate or pamidronate prevented aortic calcification, with the latter being 100-fold more potent. Both aortic calcification and bone formation were reduced in parallel; however, bone resorption was not significantly affected. In all uremic rats, aortic calcium content correlated with bone formation but not with bone resorption. Bisphosphonates also inhibited calcification of rat aortas in culture and arrested further calcification of precalcified vessels but did not reverse their calcification. Expression of osteogenic factors or calcification inhibitors was not altered by etidronate in vitro. Hence, these studies show that bisphosphonates can directly inhibit uremic vascular calcification independent of bone resorption. The correlation between inhibition of aortic calcification and bone mineralization is consistent with a common mechanism such as the prevention of hydroxyapatite formation and suggests that bisphosphonates may not be able to prevent vascular calcification without inhibiting bone formation in uremic rats.
bone formation; bone histomorphometry; bone resorption; pyrophosphate; rat aorta; uremic osteodystrophy
Aims: To determine in a case-control study possible associations between the development of acute renal failure in preterm newborns and therapeutic interventions, particularly drug treatments.
Methods: The study population was 172 preterm infants of <38 weeks gestation; 71 had acute renal failure and 101 were controls closely matched for gestational age and birth weight. Maternal and neonatal information was collected for both groups through questionnaires and interviews. Routine data on renal variables were also collected. Univariate and multivariate logistic regression analyses were performed.
Results: Very low birthweight infants were at high risk of acute renal failure (79% of cases were <1500 g). However, the acute renal failure was transient. Mothers of infants with acute renal failure received more drugs during pregnancy and delivery (mainly antibiotics and non-steroidal anti-inflammatory drugs). Of the possible therapeutic interventions, intubation, catheterisation, and phototherapy were mainly applied to case subjects. A low Apgar score and patent ductus arteriosus were diagnosed in a greater percentage of neonates with acute renal failure. Moreover, in the first few days of life and before diagnosis of acute renal failure, case subjects received more drugs (antibiotics, non-steroidal anti-inflammatory drugs, and diuretics) and for a longer time. In the multivariate logistic analysis, medullary hyperechogenicity (odds ratio (OR) 4.491; 95% confidence interval (CI) 1.879 to 10.731) and ceftazidime administration (OR 5.082; 95% CI 1.493 to 17.297) were associated with a greater risk of acute renal failure.
Conclusions: The results suggest the need for careful monitoring of very low birthweight infants and attention to drug treatments, as it is difficult to differentiate between normality and renal failure in the first few days of life.
Background and Purpose:
Extracranial superficial temporal artery (STA) calcification is an unusual finding seen in patients with chronic kidney disease and has unknown ramifications with respect to intracranial ischemic disease. We sought to determine the association between the risk factors for vascular calcification and this rare phenomenon, in patients with chronic renal failure, and to assess the coexistence of cerebral ischemia.
Materials and Methods:
Medical records and laboratory data on risk factors for vascular calcification were retrospectively retrieved for 453 patients with a discharge diagnosis of end-stage renal disease (ESRD). CT head examinations were reviewed to identify and associate STA calcification with 1) risk factors for the vascular calcification, 2) intracranial artery calcification, and 3) cerebral ischemia (white matter and/or cortical ischemic changes).
STA calcification was present in 9.9% (45/453) of the studied cohort. The prevalence of cerebral ischemia was 24.4% (11/45) in patients with STA calcification and 9.3% (38/408) in patients without it. Diabetes mellitus (OR: 2.56, 95% CI: 1.059-6.208; P=0.037) was independently associated with the risk of STA calcification. The risk of cerebral ischemia, however, was not related to STA calcification (P=0.221).
The presence of diabetes mellitus is important in describing the risk of STA calcification in patients with ESRD, whereas age, gender, hypertension, serum calcium, serum phosphate, or serum hemoglobin levels are not. The risk of cerebral ischemia is not related to STA calcification but has the strongest association with diabetes mellitus.
Cerebrovascular disease; end-stage renal disease; superficial temporal artery calcification
A 61 year old man presented with mitral regurgitation and glomerulonephritis caused by suspected infective endocarditis. His glomerulonephritis remitted on immunosuppression but mitral valve replacement with a Carpentier-Edwards porcine xenograft later proved necessary. The patient became dialysis dependent and cadaveric renal allografting was complicated by delayed graft function and refractory pulmonary oedema. Cardiac catheterisation showed severe calcification and stenosis of the xenograft with a transvalvar gradient of 23 mm Hg and despite emergency valve replacement the patient died. The valve had been in place less than five years. The rapid calcification and stenosis of a bioprosthetic heart valve calls into question the use of such prostheses in patients with chronic renal failure.
In patients with chronic renal failure estimations of the extent of calcification fronts delineated by in vivo tetracycline labelling correlated well with estimates obtained after staining the fronts with haematoxylin dye (Raina method). Similarly there was a good correlation between the Raina method and the demonstration of calcification fronts with ultraviolet (UV) light fluorescence after immersion of the bone tissue in fixative containing a freshly prepared solution of 1% tetracycline. These studies indicate that this latter is a valid and useful technique for demonstrating calcification fronts in a situation where tetracycline cannot be administered systemically.
Two cases of renal cell carcinoma, both of which underwent extensive spontaneous regression, are reported. The first occurred in a 56 year old man, forming a well circumscribed renal cortical nodule which contained only very occasional foci of viable renal cell carcinoma with areas of hyalinisation and calcification, and with metaplastic ossification. The second lesion was removed from an 82 year old man, comprising a cystic cavity containing necrotic debris with only occasional viable foci of classical renal cell carcinoma. Spontaneous regression of renal cell carcinoma is a rare but recognised entity. These two cases emphasise the important differential diagnoses: metastatic secondary carcinomas, xanthogranulomatous pyelonephritis, and infective granulomatous conditions of the kidney. The importance of adequate tissue sampling of all renal nodules cannot be overemphasised in the processing for examination of lesions within the kidney.
A uraemic patient undergoing chronic haemodialysis developed diffuse metastatic pulmonary calcification and died from acute respiratory insufficiency after renal transplantation. Thirteen similar cases previously published are reviewed, with emphasis on the clinical and anatomical features of such calcinosis. The pathogenesis of this calcification in patients on maintenance haemodialysis and some rules for its prevention are discussed.
A 55 yr-old man presented with progressive muscle weakness and oliguria for 5days. Laboratory findings suggested rhabdomyolysis complicated with acute renal failure. A diagnosis of polymyositis was based upon the proximal muscle weakness on both upper and lower limbs, elevated muscle enzyme levels, muscle biopsy findings and the needle electromyography findings. The muscle biopsy showed extensive muscle necrosis and calcification. Investigations for underlying malignancy demonstrated hepatocellular carcinoma. The patient was managed with hemodialysis and high dose prednisolone. His renal function was fully recovered and his muscle power did improve slightly, but he died of a rupture of the hepatic tumor. In our view, this is an interesting case in that the hepatocellular carcinoma was associated with polymyositis and fulminant rhabdomyolysis-induced acute renal failure requiring hemodialysis.
Carcinoma, Hepatocellular; Polymyositis; Rhabdomyolysis; Kidney Failure, Acute
Background. Cardiovascular disease is a leading cause of death among renal transplant recipients. Aortic calcification is associated with increased mortality in dialysis subjects. The significance of aortic calcification among renal transplant recipients is unknown. Our objective was to prospectively examine the association of aortic calcification with cardiovascular events and all-cause mortality among asymptomatic incident renal transplant recipients.
Methods. One hundred and twelve renal transplant recipients underwent electron beam computed tomography. Aortic calcification was scored by the Agatston method. The mean follow-up time was 5.1 years. Cardiovascular events (heart failure, coronary artery disease, peripheral arterial disease and stroke) and all-cause mortality were recorded.
Results. The cohort consisted of 62% Caucasians, 38% African Americans and 62% male gender. The mean age was 49.0 ± 12.5 years. Thirty-four percent had aortic calcification. During follow-up, 12 cardiovascular events and 10 deaths were recorded. Subjects with aortic calcification had more cardiovascular events compared to those without aortic calcification (23.7 versus 4.1%, P = 0.001). Recipients with aortic calcification had higher mortality compared to those without aortic calcification but it did not reach statistical significance (15.8 versus 5.4%, P = 0.07). The univariate hazard ratio of aortic calcification score in a proportional hazard Cox model to assess event-free survival was 1.15 (1.04–1.27, P = 0.01). Diabetes and aortic calcification score were independently associated with survival. In addition to the predictors above, dialysis vintage was an independent predictor for combined future cardiovascular event and mortality.
Conclusions. In conclusion, aortic calcification is prevalent among renal transplant recipients and is predictive of future cardiovascular events. Aortic calcification is easily identified by non-invasive testing, and should be considered when assessing cardiovascular risk in asymptomatic renal transplant recipients.
cardiovascular events; renal transplantation; vascular calcification