Uremic tumoral calcinosis in hemodialysis patients: clinicopathological findings and identification of calcific deposits.

OBJECTIVE: Extraskeletal calcifications generally develop in uremic patients. Periarticular massive calcifications, referred to as uremic tumoral calcinosis (UTC), represent solitary or multifocal calcium phosphate deposits. Our objectives were to clinically analyze a series of 8 patients with UTC undergoing hemodialysis, and to characterize calcium deposits in UTC. METHODS: The clinical, radiological, and pathological features of 8 consecutive patients (4 men and 4 women, mean age 49 yrs) with UTC were analyzed, and treatment and outcome were evaluated. Calcific specimens from the 8 patients were analyzed by x-ray diffraction, Raman spectroscopy, and infrared spectroscopy. RESULTS: Unifocal UTC was observed in 5 patients, whereas multifocal lesions occurred in 3 patients. The most common sites of UTC were the shoulders, elbows, and hands. Elevated serum calcium and phosphorus and intact parathyroid hormone were detected in 63% (n = 5), 100% (n = 8), and 63% (n = 5) of the patients, respectively. An increased calcium-phosphorus (Ca P) product was observed in 6 patients. Medical intervention to decrease the Ca P product achieved complete remission in 3 of 5 patients with solitary UTC, whereas this treatment was ineffective for multiple UTC. The 8 calcium deposits were identified as carbonate apatite. CONCLUSION: The most important pathogenic factors in UTC are an increased Ca P product and hyperphosphoremia, which is not necessarily related to hyperparathyroidism. Medical intervention is effective for solitary UTC, but combined treatment (surgery and medical therapy) is required for multiple UTC. Calcium deposits in UTC are composed of carbonate apatite.

[Gadolinium for DSA in two patients with azotemia: Images of suitable quality and risk of acute renal failure]. / Angiografia con Gadolinio in due pazienti azotemici: la qualita' diagnostica ed il rischio d'insufficienza renale acuta.

BACKGROUND: Gadolinium is an alternative angiographic contrast agent in patients with impaired renal function and high risk for iodinated contrast adverse reaction. We report two cases of acute renal failure caused by gadolinium (0.6 and 0.9 mmol/kg of body weight) after the execution of digital subtraction angiography (DSA) to produce diagnostic-quality images in two elderly diabetic patients with pre-existing renal insufficiency. Both patients needed dialysis treatments for as long as a few weeks until their renal function improved. In our opinion, and according to the guidelines of European Society of Urogenital Radiology, gadolinium has not been assessed as less nephrotoxic than iodinated contrast agents. In fact, 1.8 to 4.8 g of iodine, equally attenuated with a relatively high dose (0.2 to 0.4 mmol) of a gadolinium chelate, is a low iodine dose and could hardly have any important nephrotoxic effects. CONCLUSIONS: The maximum dose of gadolinium-based contrast agents should never exceed 0.2 to 0.4 mmol/kg in azotemic patients who are undergoing DSA, even though these doses of gadolinium may not provide images of suitable quality for diagnosis and intervention.

Erosive azotemic osteoarthropathy of the hands in chronic ambulatory peritoneal dialysis and hemodialysis.

OBJECTIVE: We studied the prevalence and significance of erosive azotemic osteoarthropathy (EAO) and its relationship with other osteoarticular abnormalities of dialysis-associated arthropathy (DAA). METHODS: 112 patients undergoing maintenance dialysis were studied: 63 hemodialysis (HD) and 49 continuous ambulatory peritoneal dialysis (CAPD). X-ray of the hands, shoulders, pelvis and cervical spine were examined for destructive spondyloarthropathy (SDA), bone cysts (BC), EAO and subperiosteal resorption. Beta 2-microglobulin (beta 2-m) and PTH were also measured. RESULTS: Fifteen patients (13%) had EAO, usually in several joints of the hands, DIPs being the most frequently affected. Both patients on HD and those on CAPD had EAO, although the prevalence was higher in the HD group, 12 (19%) vs. 3 (6%). Patients with EAO were older (p < 0.05) and had more carpal tunnel syndrome (CTS) (p < 0.05) and BC (p < 0.01). Only 3 out of 15 patients with EAO had severe secondary hyperparathyroidism (sHPTH) (PTH > 500), while 9/15 had neither radiologic nor laboratory evidence of sHPTH. No differences were found regarding the duration of dialysis, or beta 2-m or PTH level. CONCLUSION: EAO is not related to sHPTH and should be included within the spectrum of the clinical manifestations of DAA. Due to its location and radiologic picture, it is possible that etiologic factors leading to primary osteoarthritis may play a role in the development and evolution of EAO.

Hepatic computed tomography for monitoring the iron status of haemodialysis patients with haemosiderosis treated with recombinant human erythropoietin.

1. A randomized, partial-crossover study was conducted in uraemic patients with dialysis-associated anaemia and transfusional iron overload to evaluate the effects of desferrioxamine chelation therapy and of recombinant human erythropoietin treatment on hepatic iron storage determined by computed tomography, as well as by serum ferritin concentration and transferrin saturation. 2. Twenty-one haemodialysis patients with moderate iron overload, confirmed by values of serum ferritin concentration, transferrin saturation and hepatic computed tomography density exceeding 1000 micrograms/l, 45% and 68 Hounsfield units respectively, were randomly allocated to three groups and were followed for 12 months. 3. During the first 6 months group 1 (n = 7) received desferrioxamine chelation therapy (30 mg/kg intravenously three times a week) and group 2 (n = 7) underwent recombinant human erythropoietin treatment (36 units/kg intravenously three times a week). Thereafter, in the second 6 months of observation patients in group 1 were switched to receive recombinant human erythropoietin. Because of a poor response in the desferrioxamine-treated group in the initial 6 months, patients in group 2 continued on the maintenance dose of recombinant human erythropoietin (18 units/kg three times a week) until the end of the trial. Patients in group 3 (n = 7) were maintained on placebo throughout the study. 4. In comparison with placebo, recombinant human erythropoietin treatment, but not desferrioxamine chelation therapy, reduced serum ferritin concentration, transferrin saturation and hepatic computed tomography density, and was associated with a rise in haemoglobin and packed cell volume. Hepatic computed tomography density, serum ferritin concentration and transferrin saturation decreased in 13 out of 14 patients (93%) during treatment with recombinant human erythropoietin.(ABSTRACT TRUNCATED AT 250 WORDS)

Predictive value of 99mTc pyrophosphate bone scintigraphy for vitamin D trials in uraemia.

The usefulness of 99mTc-Pyrophosphate (99mTc-PPi) bone scintigraphy was evaluated in the follow up of 21 haemodialysed patients without clinical or radiological evidence of osteodystrophy. 99mTc-PPi bone scintigraphy was semi-quantitatively analysed using Fogelman's score. Patients were randomised to receive vitamin D analogues (1 alpha hydroxyvitamin D3 or dihydrotachysterol, n = 12) or to serve as controls (n = 9), both groups being given oral calcium supplements. Bone scintigraphy deteriorated in patients only on calcium therapy but not in patients treated by vitamin D-analogues. Vitamin D therapy reduced secondary hyperparathyroidism in all cases but induced rapid intoxication with normal doses in 4 of the 12 treated patients. Since intoxicated patients had significantly lower Fogelman's score than the patients who tolerated the treatment well, 99mTc-PPi bone scintigraphy is proposed as a screening test before vitamin D-analogues trials.