Correlation of sonographic patterns and renal function tests in patients with suspected urine obstruction at Moi Teaching and Referral Hospital –eldoret, kenya

Abstract

Background: Obstructive uropathy is known to result in urinary tract infections, renal injury and eventually end stage renal failure. The prevalence of this disease has not been established locally due to limited studies in this area. Ultrasound is the imaging modality of choice in the initial investigation of urine obstruction. This study sought to establish local baseline ultrasound imaging profile and determine the utility in detection of early kidney changes. Objective: The purpose of this study was to evaluate gray-scale and Doppler ultrasonographic patterns of patients referred with clinical suspicion of urine obstruction in correlation to creatinine and urea levels. Methods: A cross sectional study was carried out at the Radiology and Imaging Department, Moi Teaching and Referral Hospital in Eldoret between October 2014 and October 2015. Participants with clinical suspicion of urine obstruction were enrolled into the study by consecutive sampling. Clinical, sonographic data, creatinine and urea levels were collected using a structured questionnaire. Data analysis was done using SPSS version 21.0. Data was summarized into mean, median and percentage. ANOVA, chi square, linear regression models and Krukal-Wallis test were used to assess correlation. Level of statistical significance was 5%. Results: A total of 84 participants were evaluated. The median duration of symptoms was 12.0 (IQR: 2.0-30.0) months. The mean age was 61.5 ± 24.7 years with an age range of 0.25 – 105.7years. There was a male predominance n = 73 (86.9%). Prostate enlargement was seen in n = 47 (70.1%) male >17years. Urine retention was diagnosed in n = 33 (56.9%) participants without Foleys catheter. Normal ultrasonographic patterns were seen in n = 4 (4.8%). The children n = 9 (10.7%) were the minority with variable findings according to age. The average length of an adult kidney was 9.7 ± 1.7cm & 10 ± 1.8 cm for the right and left kidneys respectively. Grade 0 hydronephrosis was common n = 54 (64.3%) and 52 (62.7%) for the right and left kidney respectively. Loss of corticomedullary differentiation and echogenic renal cortex were seen in 79 (94%), 80 (95.2%) and 44 (52%), 45 (54 %) for the right and left kidney respectively. The mean RI was (0.689 ± 0.086), (0.687 ± 0.097) and (0.671 ± 0.080), (0.654 ± 0.0880) for right and left renal and interlobar arteries respectively. There was no correlation in distribution of mRI across the grades of hydronephrosis p=0.047, 0.099 and 0.032, 0.156 for the right and left renal and interlobar arteries respectively. There was a weak positive correlation between RI with levels of both creatinine and urea (p=0.003-0.026) except for the RI of the left renal artery in relation to urea (p=0.058).There was no statistical significant relation between creatinine and urea with renal cortical echotexture (p= 0.127, 0.146, 0.051) except for urea and right kidney echotexture (p=0037). Conclusion: Participants presented with longstanding symptoms of chronic urine obstruction. Patterns of chronic renal injury were mostly seen. There was no correlation in distribution of mRI across the grades of hydronephrosis. There was a weak positive correlation between RI with levels of both creatinine and urea except for the RI of the left renal artery in relation to urea. There was no association between renal cortical echotexture and renal function test except for urea and right kidney echogenicity. Recommendation: A combination of clinical presentation, renal function tests and ultrasound should be utilized for the initial assessment of renal injur