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