Parathyroidectomy for nephrolithiasis in primary hyperparathyroidism: Beneficial but not a panacea.

BACKGROUND: Nephrolithiasis is a classic indication for parathyroidectomy in primary hyperparathyroidism patients; however, the effects of parathyroidectomy on nephrolithiasis recurrence are not well studied. The aim was to determine effect of parathyroidectomy on time to first nephrolithiasis recurrence and recurrence rate per patient-years. METHODS: A retrospective cohort study of patients diagnosed with primary hyperparathyroidism and at least one episode of nephrolithiasis was performed. The patients were divided into observation, presurgery, and postsurgery groups. Endpoints were time to first recurrence of nephrolithiasis and average recurrence rate per patient-years. RESULTS: The cohort was comprised of 1,252 patients. In addition, 334 (27%) patients underwent parathyroidectomy and 918 (73%) were observed. The surgical and nonsurgical groups differed significantly in age, sex, Charlson, calcium, and primary hyperparathyroidism level. Overall recurrence rate was 31.3%. The 5-, 10-, and 15-year recurrence-free survival rates were 74.4%, 56.3%, 49.5%, respectively (presurgery), 82.4%, 70.9%, 62.8%, respectively (postsurgery; P < .0001), and 86.3%, 77.7%, and 70.6%, respectively (observation). The presurgery group had an increased risk of first recurrence compared with the observation group (hazard ratio 1.89; 95% confidence interval, 1.44-2.47). The average recurrence rates among all surgical patients who recurred were 1 event per 4.3 patient-years presurgery versus 1 event per 6.7 patient-years postsurgery (P = .0001). CONCLUSION: Recurrent nephrolithiasis is a significant problem in patients with primary hyperparathyroidism. Parathyroidectomy prolongs the time to first recurrence and decreases the number of re-recurrences over time but does not eliminate recurrences. Observation may also be a reasonable approach in selected patients.

XANTHINE NEPHROLITHIASIS IN JUVENILE CAPTIVE GIANT OTTERS (PTERONURA BRASILIENSIS).

Nephrolithiasis has been reported in several aquatic mammals including bottlenose dolphins (Tursiops truncatus), small clawed otters (Amblonyx cinereus), European river otters (Lutra lutra), North American river otters (Lontra canadensis), northern elephant seals (Mirounga angustirostris), Florida manatees (Trichechus manatus latirostris), and California sea lions (Zalophus californianus). Compositions of calculi in previous cases were predominantly calcium oxalate or ammonium acid urate. Xanthine urolithiasis is rare in veterinary medicine. Primary cases (without exposure to xanthine dehydrogenase inhibitors) occur as a consequence of hereditary xanthinuria, although the causal mutation has only been discovered in a subset of cases. Five captive juvenile giant otters (Pteronura brasiliensis) from two facilities were diagnosed with nephrolithiasis: three siblings from one set of parents and two siblings from another pair. Serum analyte assays revealed renal compromise in affected individuals. Computed tomography (CT) confirmed the presence of nephrolithiasis in one individual. Postmortem evaluation identified extensive bilateral nephrolithiasis on gross necropsy in four of five cases. Calculus analyses identified 100% xanthine composition. Histologic examination revealed marked nephrolithiasis with associated tubular necrosis and gastric mineralization. Nutrient composition of the diet including mineral and purine content was assessed. No association between diet and nephroliths was found in this study. This is the first report of xanthine nephrolithiasis in aquatic mammals. The potential role of diet and genetics in xanthine nephrolithiasis in the small inbred population of giant otters under human care needs further investigation to assess the implications of this disease process for the long-term captive management of this species.

Predictors of Nephrolithiasis, Osteoporosis, and Mortality in Primary Hyperparathyroidism.

CONTEXT: Primary hyperparathyroidism (PHPT) has a prevalence of 0.86% and is associated with increased risk of nephrolithiasis and osteoporosis. PHPT may also be associated with increased risk of cardiovascular disease and mortality. OBJECTIVE: To identify risk factors for nephrolithiasis, osteoporosis, and mortality in PHPT. DESIGN: Retrospective cohort study. SETTING: University teaching hospital. PATIENTS: Presented with PHPT between 2006 and 2014 (n = 611). MAIN OUTCOME MEASURE: Assessment of nephrolithiasis, osteoporosis, and mortality. RESULTS: Of patients with PHPT, 13.9% had nephrolithiasis. Most had previously documented stone disease, and only 4.7% of asymptomatic patients who were screened for renal stones had calculi identified, not very dissimilar to the rate in the non-PHPT population. Younger age (P < 0.001) and male sex (P = 0.003) were the only independent predictors of nephrolithiasis. Of patients with dual-energy X-ray absorptiometry data, 48.4% had osteoporosis (223/461). Older age (P < 0.001), lower body mass index (P = 0.002), and lower creatinine (P = 0.006) were independently associated with a diagnosis of osteoporosis. Higher PTH was independently associated with lower z score at the hip (P = 0.009); otherwise, calcium and PTH were not associated with lower z scores. Mortality in PHPT was associated with older age (P < 0.008), social deprivation (P = 0.028), and adjusted calcium (P = 0.009) but not independently with PTH at diagnosis. CONCLUSIONS: Screening for nephrolithiasis has a low yield, particularly in lower risk patients. Osteoporosis is only minimally associated with biochemical indices of PHPT. Mortality is associated with higher calcium (and possibly vitamin D deficiency) but not PTH.

Early Intervention during Acute Stone Admissions: Revealing "The Weekend Effect" in Urological Practice.

PURPOSE: Obstructing nephrolithiasis is a common condition that can require urgent intervention. In this study we analyze patient factors that contribute to delayed intervention during acute stone admission. MATERIALS AND METHODS: We retrospectively reviewed the HCUP SID (Healthcare Cost and Utilization Project State Inpatient Database) for Florida and California from 2007 to 2011. Patients who were admitted urgently with nephrolithiasis and an indication for decompression (urinary tract infection, acute renal insufficiency and/or sepsis) were included in the study. Intervention was timely or delayed, defined as a procedure that occurred within or after 48 hours, respectively. Adjusted multivariate models were fit to assess factors that predicted a delayed procedure as well as mortality. RESULTS: Overall 10,301 patients were admitted urgently for nephrolithiasis with indications for decompression. Early intervention occurred in 6,689 patients (65%) and was associated with a decrease in mortality (11, 0.16%), compared to delayed intervention (17 of 3,612, 0.47%, p=0.002). On multivariate analysis timely intervention significantly decreased the odds of inpatient mortality (OR 0.43, p=0.044). Weekend day admission significantly influenced time to intervention, decreasing patient odds of timely intervention by 26% (p <0.001). Other factors decreasing patient odds of timely intervention included nonCaucasian race and nonprivate insurance. Presenting medical diagnoses of urinary tract infection, sepsis and acute renal failure did not appear to influence time to intervention. CONCLUSIONS: Delayed operative intervention for acute nephrolithiasis admissions with indications for decompression results in increased patient mortality. Nonmedical factors such as the "weekend effect," race and insurance provider exerted the greatest influence on the timing of intervention.

[Complications of percutaneous nephrolithotripsy in staghorn nephrolithiasis].

The aim of the study was to analyze the complications of percutaneous nephrolithotripsy (PCNL) in staghorn nephrolithiasis. The analysis revealed that in case of "full" staghorn stone risk of complications of percutaneous nephrolithotripsy raises twice in comparison with cases of "incomplete" staghorn stones. The choice of least invasive method at treatment of patients with staghorn nephrolithiasis is one of challenges in urological practice. Superiority began to belonged so-called, least invasive interventions - percutaneous nephrolithotripsy, extracorporal shock-wave lithotripsy and also combined ("sandwich" - therapy) methods. In connection with development of modern methods of visualization, complication of percutaneous treatment methods of staghorn nephrolithiasis decrease, and efficiency and possibilities of their use raise. The analysis revealed that in aspect of development of complications after percutaneous nephrolithotripsy presence of "full" staghorn stone plays defining role, raises risk of development of complications twice in comparison with patients with presence "incomplete" staghorn stones.

A case-control study of the effects of nephrolithiasis in cats with chronic kidney disease.

OBJECTIVE: To determine whether nephrolithiasis was associated with an increase in mortality rate or in the rate of disease progression in cats with naturally occurring stage 2 (mild) or 3 (moderate) chronic kidney disease. DESIGN: Retrospective case-control study. ANIMALS: 14 cats with stage 2 (mild) or 3 (moderate) chronic kidney disease (7 with nephroliths and 7 without). PROCEDURES: All cats were evaluated every 3 months for up to 24 months. Possible associations between nephrolithiasis and clinicopathologic abnormalities, incidence of uremic crises, death secondary to renal causes, and death secondary to any cause were evaluated. RESULTS: There were no clinically important differences in biochemical, hematologic, or urinalysis variables between cats with and without nephroliths at baseline or after 12 and 24 months of monitoring. No associations were detected between nephrolithiasis and rate of disease progression, incidence of uremic crises, or death. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in cats with mild or moderate chronic kidney disease, nephrolithiasis was not associated with an increase in mortality rate or in the rate of disease progression. Findings support recommendations that cats with severe kidney disease and nephrolithiasis be managed without surgery.