Causes of frequency and nocturia after renal transplantation.

OBJECTIVE: To explore the role of bladder capacity, bladder pain, dysfunctional voiding, urgency, urinary tract infections (UTIs), and urinary output as potential causes of frequency and nocturia after renal transplantation. PATIENTS AND METHODS: Data were gathered from 52 adult renal transplant patients (35 men and 17 women, mean age 49 years), using a written questionnaire, medical records, frequency/volume charts, and urinary cultures. The mean time between transplantation and data collection was 5 months. Structural equation modelling (SEM) was used for the simultaneous assessment of direct and indirect relationships between explanatory variables and voiding frequency. RESULTS: Frequency and nocturia were found in 54% and 60% of the study population, respectively. Frequency was directly associated with a small bladder capacity, bladder pain, urgency, and a high daytime urine volume, and indirectly by UTIs (via urgency and bladder pain). Nocturia was associated with high nocturnal urine volume, small bladder capacity and dysfunctional voiding. A quarter of the patients had small bladders and another quarter had large bladders, the latter being associated with nocturnal polyuria. CONCLUSIONS: The presence of frequency, especially when accompanied by bladder pain, might aid the physician to identify patients with small bladders. The presence of nocturia can be the result of a high nocturnal urine volume, which increases the risk of bladder enlargement. Because both abnormal bladder conditions can contribute to graft dysfunction, we recommend a urological follow-up after renal transplantation, using frequency/volume charts.

Dysfunction of lower urinary tract in renal transplant children with nephrologic disease.

OBJECTIVES: To investigate the relationship between dysfunction of the lower urinary tract after renal transplantation and renal transplant function in children with an underlying nephrologic disease. METHODS: The research group consisted of 21 renal transplant children (12 girls and 9 boys, mean age 13.5 years, range 6 to 18) with an underlying nephrologic disease. To indicate renal transplant function, the calculated creatinine clearance rate (Ccr) according to Schwartz was used. The Ccr was measured at two points, 2 months after transplantation and at the moment of study. The average graft age was 34 months (range 5 to 85). The data on dysfunction of the lower urinary tract were gathered using a written questionnaire, frequency volume chart, free uroflowmetry, transabdominal ultrasonography, and medical records. To determine the relationship between the symptoms of dysfunction of the lower urinary tract and Ccr at the moment of study, we computed bivariate correlations and performed multivariate regression analyses in which the associations were studied while controlling for the Ccr 2 months after transplantation and graft age. RESULTS: A sensation of incomplete emptying (P = 0.03), postvoid residual urine volume (P = 0.06), and urinary tract infection (P = 0.004) correlated negatively with the Ccr at the moment of study. These effects remained present (P = 0.07, P = 0.03, and P = 0.003, respectively) while controlling for graft age and the Ccr at 2 months after transplantation in the regression analysis. CONCLUSIONS: The results of our study have shown that a postvoid residual urine volume and urinary tract infections after renal transplantation may result in renal transplant deterioration in children with an underlying nephrologic disease.