Nephrolithiasis and nephrocalcinosis after renal transplantation: a case report and review of the literature

Cinacalcet chloride is efficient and safe in renal transplant recipients with posttransplant hyperparathyroidism

BACKGROUND

Persistent hyperparathyroidism (HPT) is observed in approximately 50% of kidney transplant recipients one year after transplantation. It may result in hypercalcemia, hypophosphatemia, bone demineralization, vascular calcification, lithiasis, and participate in chronic allograft nephropathy. We evaluated the use of the calcimimetic cinacalcet chloride to correct chronic hypercalcemia in posttransplant HPT, in a prospective single-center study.

METHODS

Nine patients with persistent hypercalcemia (>2.6 mmol/L) and stable graft function were treated with cinacalcet (30 mg/day, thereafter adapted to obtain normal serum Ca levels) for six months. Their immunosuppressive schedule included mycophenolate mofetil (MMF), steroids, and cyclosporine A (4), tacrolimus (4), or sirolimus (2).

RESULTS

Serum Ca levels significantly decreased from 2.75+/-0.15 to 2.59+/-0.10, 2.42+/-0.29 and 2.44+/-0.25 mmol/L by one, two, and six months, respectively (P<0.02, Wilcoxon test for paired data, for all the data points). Parathyroid hormone (PTH) serum levels decreased from 171+/-102 to 134+/-63 pg/ml by two months (P<0.05) and stabilized thereafter (148+/-99 pg/ml at six months; NS). No changes in glomerular filtration rate (49.8+/-18.6 and 51.3+/-19 ml/min at initiation and six months, respectively) and no variation in serum concentration of the immunosuppressive drugs were observed. Three patients withdrew the treatment because gastrointestinal intolerance.

CONCLUSION

Cinacalcet allows the correction of hypercalcemia with no interference in immunosuppressive treatment or renal function. However, whether the increased intolerance observed was due to the association of cinacalcet chloride with other drugs required in renal transplantation (e.g., MMF) needs to be assessed.

Renal transplantation in cats with calcium oxalate urolithiasis: 19 cases (1997–2004)

OBJECTIVE

To determine outcome of renal transplantation in cats with renal failure associated with calcium oxalate urolithiasis.

DESIGN

Retrospective case series.

ANIMALS

19 cats.

PROCEDURE

Medical records were reviewed for evaluation of signalment, preoperative clinical signs, physical examination results, dietary history, clinicopathologic data, abdominal imaging, postoperative diet, complications, and long-term outcome.

RESULTS

The domestic shorthair was the most common breed represented. There were 13 spayed females and 7 castrated males. Mean age was 6.8 years. Clinical signs included weight loss, lethargy, vomiting, anorexia, polyuria, and polydipsia. Before surgery, cats received commercially available canned or dry food (n = 10), a prescription renal failure diet (5), a commercial diet to manage struvite crystalluria (1), or an unknown diet (3). Seventeen cats were anemic. All cats were azotemic. Hypercalcemia was detected in 7 cats. Abdominal imaging revealed nephrolithiasis, ureterolithiasis, or both in all cats. Median duration of survival of all cats was 605 days. Eight cats were alive 282 to 2,005 days (median, 1,305 days) after surgery. Eleven cats died 2 to 1,197 days (median, 300 days) after surgery. Five cats formed calculi in their allograft (120 to 665 days). Two of the 5 cats that formed calculi were hypercalcemic. Four of the 5 cats died following complications associated with formation of calculi.

CONCLUSIONS AND CLINICAL RELEVANCE

Renal transplantation appears to be a viable option for cats in renal failure secondary to calcium oxalate urolithiasis. In addition to reported complications in renal transplant recipients, formation of calculi within the allograft may also occur.

Early calcification of renal allografts detected by protocol biopsies: causes and clinical implications

Interstitial calcification has been described in renal allografts, however, the etiology and significance of this finding for the graft are unclear. The aim of this study was to examine calcification in serial protocol biopsies, to test the hypothesis that calcification is related to parameters of calcium homeostasis in these patients and to analyze a possible relation between calcification and graft function at 1 year. We studied 213 patients with 586 protocol biopsies obtained 6 weeks, 3 and 6 months after transplantation. Calcifications increased over time, from 6.1% at 6 weeks to 17.8% at 6 months. Out of the 213 patients, 56 had calcification in one or more biopsies. Patients age and gender, underlying renal disease, dialysis mode and duration, previous transplantations, donor type, age and gender, HLA matches and ischemia time had no influence on calcification. Calcification was not related to rejection episodes, acute tubular lesions, calcineurin inhibitor toxicity or tubulointerstitial fibrosis and tubular atrophy. Patients with calcification had significantly higher serum parathormone and calcium levels. In patients with calcification, high PTH levels correlated with an inferior outcome of graft function at 1 year after transplantation (p<0.05). Therefore, treatment of hyperparathyroidism should be considered earlier and more often in these patients.

Hospitalized nephrolithiasis after renal transplantation in the United States

The national incidence of and risk factors for hospitalized nephrolithiasis (NEP) in renal transplant (RT) recipients has not been reported. We conducted a historical cohort study of 42 096 RT recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998. The 1-year incidence of NEP (ICD-9 codes 592.x) after RT in 1997 was compared to the rate of NEP in the general population using the National Hospital Discharge Survey. Associations with time to hospitalizations for a primary diagnosis of nephrolithiasis were assessed by Cox Regression. NEP was uncommon after RT (104 cases per 100 000 person years in 1997). However, females, but not males, had a statistically significant increased risk of NEP compared to the general population (rate ratio for females, 2.84, 95% confidence interval, 2.35-3.58). Kidney stones were more common than ureteral stones, and percutaneous procedures were more common than ureteroscopy or extracorporeal shock wave lithotripsy (ESWL). The only risk factor identified for NEP was renal failure due to stone disease (only one case). NEP was uncommon after RT, but was still more common than in the general population. We identified differences in the presentation and management of NEP after RT in comparison to the general population.

Intratubular calcification in a post-renal transplanted patient with secondary hyperparathyroidism

In this article, we present a case in which marked intratubular calcification occurred in the transplanted kidney. The patient received living renal transplantation without control of severe secondary hyperparathyroidism, and the tacrolimus hydrate was used as an immunosuppressive agent, the adverse effects of which can induce intratubular calcification. Biopsy of the renal allograft revealed many intratubular calcifications in the cortex region of the specimen, although the histological grade was borderline for the Banff classification. The pathogenic causes of intratubular calcification were difficult to distinguish from the adverse effects of tacrolimus and the uncontrolled hyperparathyroidism.

Urinary stones following renal transplantation

BACKGROUND

The formation of urinary tract stones following renal transplantation is a rare complication. The clinical features of stones after transplantation differ from those of non-transplant patients. Renal colic or pain is usually absent and rarely resembles acute rejection.

METHODS

We retrospectively studied 849 consecutive kidney transplant patients in The Rogosin Institute/The Weill-Cornell Medical Center, New York who were transplanted between 1980 and 1997 and had functioning grafts for more than 3 months, to determine the incidence of stone formation, composition, risk factors and patient outcome.

RESULTS

At our center, urinary stones were diagnosed in 15 patients (1.8%) of 849 functioning renal grafts for 3 or more months. Of the 15 patients, 10 were males and 5 were females in their third and fourth decade. Eight patients received their transplant from living donors and 7 from cadaveric donors. The stones were first diagnosed between 3 and 109 months after transplantation (mean 17.8 months) and 5 patients had recurrent episodes. The stones were located in the bladder in 11 cases (73.3%), transplanted kidney in 3 cases and in multiple sites in one case. The size of stones varied from 3.4 mm to 40 mm (mean 12 mm). The composition of stones was a mixed form of calcium oxalate and calcium phosphate in 5 cases and 4 patients had infected stones consisting of struvite or mixed form of struvite and calcium phosphate. Factors predisposing to stone formation included tertiary hyperparathyroidism (n = 8), hypercalciuria (n = 5), recurrent urinary tract infection (n = 5), hypocitraturia (n = 4), and obstructive uropathy (n = 2). Many cases had more than one risk factor. Clinically, painless hematuria was observed in 6 patients and dysuria without bacteriuria in 5 patients. None had renal colic or severe pain at any time. There were no changes in graft function at diagnosis and after removal of stones. Five patients passed stones spontaneously and 8 patients underwent cystoscopy for stone removal.

CONCLUSION

Urinary stone formation following kidney transplantation is a rare complication (1.8%). Hyperparathyroidism, hypercalciuria, recurrent urinary tract infection and hypocitraturia are the most common risk factors, but often there are multiple factors which predispose to stone formation. To detect stones and determine their location and size, ultrasonography appears to be the most useful diagnostic tool. Prompt diagnosis, the removal of stones and stone-preventive measures can prevent adverse effects on renal graft outcome.

[Incidence and treatment of urinary lithiasis in renal transplantation]

INTRODUCTION

Urinary calculi is an uncommon complication in kidney transplantation; several stone risk factors are found in transplanted patients, but in most cases there is not a relationship between these risk factors and stone formation. The treatment of these patients is complex due to their both immunosuppressive status and border-line renal function.

MATERIAL AND METHOD

From 1980 to February 2000, 1198 kidney transplant have been performed in our institution. We describe our series consisting in 22 urinary calculi (15 in the graft, 3 in the urether and 4 in the bladder) in 18 patients, including 7 stones detected in cadaveric donor patients.

RESULTS

We performed external shock wave lithotripsy in 7 patients, bench surgery in 4, endoscopic mechanic lithotripsy in 5, open surgery in 1 and observation in 6. Calcium oxalate (mono and dihidrate) was found in 9 of 13 calculi. Metabolic changes were found in 15 of the 18 patients, the most common was hiperuricemia. There were not complications of every treatment applied and 9% of them needed a savage treatment. We found recurrence in 4 cases (22.2%). Now 12 of the patients are stone-free (66.7%) and three have non-significative stones (83.3% without symptoms).

CONCLUSIONS

Detection of renal calculi in cadaveric renal donors is not a reason to refuse the graft for further transplantation. In both renal calculi up to 2 cm and uretheric calculi surgical treatment is assessed as first option. In caliceal stones smaller than 5 mm observations is the best treatment.

Hypercalcemia following renal transplantation in a cat

An 11-year-old 3.0-kg (6.6-lb) neutered male Persian was referred for renal transplantation. Serum total calcium concentration was slightly high prior to surgery, but the week after surgery, total and ionized calcium concentrations were extremely high, and a small mass was palpable on the right side of the trachea at the level of the thyroid and parathyroid glands. Exploratory surgery of the ventral aspect of the neck was performed, and a right external parathyroid mass was removed. One hour after surgery, the serum ionized calcium concentration was within reference limits, and the serum calcium concentration remained normal for the next 14 months without any specific treatment. The gross and histologic appearance of the mass, combined with the rapid decrease in serum calcium concentration following its removal, confirmed that the mass was a functional parathyroid adenoma. Although a common postoperative complication in people, hypercalcemia following renal transplantation appears to be a rare complication in cats. Surgery should be considered if the condition is a result of a parathyroid adenoma.

Operative treatment of tertiary hyperparathyroidism: a single-center experience

OBJECTIVE

To review the experience with the operative treatment of tertiary hyperparathyroidism (TH) from a single renal transplant center.

SUMMARY BACKGROUND DATA

Most patients with chronic renal failure show evidence of secondary hyperparathyroidism by the time maintenance hemodialysis begins. Persistent secondary hyperparathyroidism (i.e., TH) requiring surgical intervention is uncommon in the authors' experience.

METHODS

Charts of patients who underwent parathyroidectomy for TH were reviewed retrospectively. Information obtained included demographics, laboratory data, symptoms, operative procedure (including morbidity and mortality rates), and pathology. Comparisons of demographic data and allograft survival were made between the transplant population as a whole and a matched cohort group of patients.

RESULTS

Thirty-eight patients from 4344 renal transplant procedures during a 29-year period required parathyroidectomy for TH. All patients had hypercalcemia; 20 were asymptomatic and 18 had varying symptoms. Mean time from renal transplantation to parathyroidectomy was 997 +/- 184 days, with a mean preoperative calcium level of 12.2 +/- 0.14 mg/dl. Total parathyroidectomy with parathyroid autograft was performed in 26 of 34 primary procedures. There were no deaths. The operative morbidity rate was 6% (wound separation and vocal cord hemiparesis, one each). Pathology was reported in all patients and recently reviewed in 28 patients. Twenty-four had diffuse hyperplasia and nine had nodular hyperplasia; one had an adenoma. Parathyroid glands diagnosed as nodular hyperplasia were significantly larger by total mass than those with diffuse hyperplasia. Comparison of allograft survival between the study group and a matched cohort group of patients revealed no difference in long-term graft survival.

CONCLUSIONS

Operative intervention is recommended in patients with an asymptomatic increase in serum calcium to >12.0 mg/dl persisting for >1 year after the transplant, acute hypercalcemia (calcium >12.5 mg/dl) in the immediate posttransplant period, and symptomatic hypercalcemia.

A case study with delayed renal graft function as a consequence of severe secondary hyperparathyroidism

A 36-year-old Arab man had been treated with hemodialysis for 6 years. During that time he received no treatment with phosphate binders or 1,25-dihydroxy-vitamin D3. He thus developed a severe form of secondary hyperparathyroidism and presented with bone disease, pseudoclubbing of the fingers, and soft-tissue calcification. He was transplanted with a kidney from a living donor, but there was no immediate onset in renal function. A biopsy showed crystal deposition that was thought to be due to his secondary hyperparathyroidism. Four weeks after the renal transplantation with still no evidence of a functioning graft, a parathyroidectomy was performed. A few days later, graft function recovered, and the amount of the crystals in the kidney decreased. There is strong evidence that the severe secondary hyperparathyroidism prevented the onset of renal function. It is concluded that crystal deposition with graft dysfunction should be an absolute indication for parathyroidectomy.

Extracorporeal shock wave lithotripsy in a renal transplant patient

We report a case of nephrolithiasis in a transplanted kidney that was treated successfully with extracorporeal shock wave lithotripsy. The patient experienced transient partial obstruction after lithotripsy and, thus, intense monitoring of the transplant patient is necessary.

Calculus formation in renal transplant patients

Of 149 renal transplants performed between May 1965 and December 1980 a stapled ureteroureterostomy was done in 112 (75 per cent) using a commercially available stapling device. Calculus developed in 7 patients (6.3 per cent) in whom this technique was used, with the interval between transplantation and calculus formation being 13 months to 6 years. We conclude that the stapled ureteroureterostomy should be reserved for special instances, such as a short donor ureter or when the correction of urological complications demands a rapid ureteroureterostomy.

Stones in renal transplants

In a 50-year-old man (case 1) and a 17-year-old girl (case 2) stones developed in a functioning renal transplant. The respective intervals from transplantation to appearance of stone were seven years and six months. The serum calcium was elevated to approximately 3.00 mmol/l in case 1 and 2.65 mmol/l in case 2. The concentration of parathyroid hormone in serum was increased in case 1. Subtotal parathyroidectomy was performed in both patients, with removal of 2550 mg (case 1) and 150-160 mg (case 2) parathyroid tissue. In case 2 slight hypercalcaemia reappeared two months later. When stones in a transplanted kidney are associated with only slight hypercalcaemia and there is no deterioration of the renal function, conservative measures to reduce the serum calcium should be tried before subtotal parathyroidectomy is undertaken.

Urolithiasis after kidney transplantation--clinical and mineralogical aspects

Urolithiasis is a rare complication following kidney transplantation. Experience with this complication in 6 of 426 transplantations performed from 1968 to 1979 is reviewed. The clinical symptoms are different from the disease in non-transplant patients. Three major predisposing causes for the development of calculi after kidney transplantation were found in our patients--urodynamic disorders following complications of the ureterovesical anastomosis, persistent bacteriuria and renal tubular acidosis and, less importantly, the presence of hypercalcemia and hypercalciuria as a result of secondary hyperparathyroidism. Crystal-optical and x-ray-diffraction studies contributed to the interpretation of the constituents and texture of the calculi and of the aetiological factors concerned.

Calculi in renal transplants

Three patients who underwent live donor renal transplantation subsequently developed calculi in their allografts. Hypercalcaemia and secondary hyperparathyroidism were present in 2 cases and these were treated by subtotal parathyroidectomy. Urinary stagnation and infection were contributory factors in the third case and reimplantation of the ureter was necessary. In all patients no further calculi have developed following treatment and allograft function remains satisfactory.

Kidney stones and renal transplantation

Only 10 cases of renal calculi in transplanted kidneys are reported in the literature. Etiology is not uniform in all the cases. Some of these cases were managed conservatively. We herein report a case in which the etiology of the stone may be urinary tract infection. This patient was managed conservatively.

Pyelolithotomy of a renal transplant

A large calculus developed in a renal transplant patient and was removed by pyelolithotomy. Hyperparathyroidism was not present. Important factors to consider before performing a nephrolithotomy in a transplanted kidney are whether the transplant was a right or left kidney and the timing of the operation in relation to renal function and infection. The etiology for renal stone formation in renal transplant recipients includes hyercalciuria, renal tubular acidosis, antacid administration and infection.

Idiopathic ureterolithiasis in a renal transplant patient

Only 9 cases of ureteral stone formation in renal transplant recipients have been reported previously. The majority of these occurred in association with hyperparathyroidism. We herein describe a case in which a ureteral calculus caused partial obstruction within 3 months in a euparathyroid recipient of a living related renal transplant.