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Table of Contents
Year : 2022  |  Volume : 27  |  Issue : 2  |  Page : 185-189

Etiology of symptomatic upper urinary tract obstruction in southeast Nigeria

1 Department of Surgery, College of Medicine, University of Nigeria Ituku-Ozalla, Enugu, Nigeria
2 Department of Radiology, University of Nigeria Teaching Hospital Ituku-Ozalla, Enugu, Nigeria; Hansa Diagnostic Clinic, Enugu, Nigeria

Date of Submission05-Apr-2021
Date of Decision02-May-2021
Date of Acceptance06-Jun-2021
Date of Web Publication3-Mar-2022

Correspondence Address:
Ikenna I Nnabugwu
Department of Surgery, College of Medicine, University of Nigeria Ituku-Ozalla, PMB 01129 Enugu.
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijmh.IJMH_12_21

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Background: The causes of upper urinary tract (UUT) obstruction vary from one geographical location to another, and across gender and age. Similarly, the site of obstruction along the ureter varies with the nature of the obstructing lesion. Data in this regard from southeast Nigeria are deficient. Objective: To determine the causes of symptomatic UUT obstruction in southeast Nigeria. Materials and Methods: The medical records of individuals with confirmed UUT obstruction presenting from January 2011 to November 2017 were reviewed for information on the cause and location of obstruction. In addition, the pattern of the obstructions caused by UUT stones was compared across the gender and age of individuals. All statistical analyses were done using SPSS® version 21. Results: The medical reports of 267 individuals are included for analysis. Overall, urinary stone is the most prevalent cause of UUT obstruction, with a male-to-female ratio of 1.25. From 50 years of age onward, obstructing UUT stones are commoner in females (χ2 = 5.03; P = 0.03). In addition, obstructing UUT stones are more common on the right (55.1%) and in the upper ureter (48.9%) in univariate analyses. Congenital pelvi-ureteric junction (PUJ) obstruction is observed to be the most prevalent congenital cause of UUT obstruction. Uterine fibroids in females and advanced prostate cancer in males are also notable causes of ureteric obstruction. Conclusion: Beyond urinary stone and congenitally defective PUJ, uterine fibroids and prostate cancer are other notable causes of ureteric obstruction in southeast Nigeria.

Keywords: Etiology, obstruction, symptomatic, upper urinary tract, urinary stones

How to cite this article:
Anyimba SK, Nnabugwu II, Onuh AC. Etiology of symptomatic upper urinary tract obstruction in southeast Nigeria. Int J Med Health Dev 2022;27:185-9

How to cite this URL:
Anyimba SK, Nnabugwu II, Onuh AC. Etiology of symptomatic upper urinary tract obstruction in southeast Nigeria. Int J Med Health Dev [serial online] 2022 [cited 2022 Dec 7];27:185-9. Available from: https://www.ijmhdev.com/text.asp?2022/27/2/185/339021

  Background Top

The UUT can be obstructed at different points and in varying degrees by a number of pathologic conditions. When significantly obstructed, the flow of urine is impeded, and over time, some recognized structural and functional changes occur in the kidney and in the segment of the urinary tract proximal to the site of obstruction.[1] Theoretically, any point along the urinary tract is at risk of being obstructed, but practically some points are at a greater risk of obstruction in comparison to others. The UUT obstruction has been documented at the PUJ,[2] at various points along the ureter, and at the ureterovesical junction.[3] Significant persistent obstruction at the lower urinary tract invariably succeeds in transmitting raised intraluminal pressure into the upper urinary tract reminiscent of upper urinary tract obstruction, but by definition, not considered UUT.[4]

Commonly, a significant obstruction of the upper urinary tract is either partial or incomplete. However, “complete” or near-complete obstruction does occur.[5] Irrespective of the degree of obstruction, the consequences thereof are similar if the obstruction significantly compromises the caliber of the lumen long enough.[1] Dilatation of the segment of the urinary tract proximal to the site of obstruction suggests significant obstruction.[6] Beyond proximal dilatation, impaired excretory and other functions of ipsilateral kidney lend support to the existence of significant and persistent obstruction to urine flow.[7],[8]

The causes of UUT obstruction are known to include intraluminal, intramural, and extrinsic factors. Though these causes are generally similar across societies, their distribution may vary from society to society, across age and gender.[9] In Pakistan, Ali and colleagues[10] report that 52% of cases of UUT obstruction are due to urinary stones, whereas in Cameroun, Halle and colleagues[11] report that 35% of cases of obstructive uropathy are due to urinary stones. Regarding the congenital causes of UUT obstruction, PUJ obstruction and ureteroceles are reported with differing incidences from different societies.[12],[13] In addition, a number of extrinsic factors such as uterine leiomyoma and other benign as well as malignant pelvic tumors,[14],[15] ureteric endometriosis,[16] and retroperitoneal fibrosis[17] have also been reported in the literature as significantly obstructing the UUT.

Data regarding the pattern and the etiologic factors of UUT obstruction in our setting are limited. The aim of this study, therefore, is to generate data in this regard that will be of benefit in supporting health research, in guiding health education, and in ensuring evidence-based patient evaluation and management.

  Materials and Methods Top

The medical records of patients who underwent intravenous urography (IVU) or computerized tomography scan urography (CT-urography) as part of making a diagnosis of symptomatic UUT obstruction and identifying the cause thereof from January 2011 to November 2017 were retrieved for this study. From the medical records, the age and gender of these patients were extracted. In addition, the site and the cause of obstruction were noted. The mid-ureter was defined as the segment of the ureter from the level of the superior margin to the level of the inferior margin of the sacrum. The ureter distal to this segment was defined as the lower ureter whereas that proximal to this segment, including the PUJ, was defined as the upper ureter.

Descriptive statistics were determined for the variables of interest. Regarding patients presenting with obstructing UUT stones, the relationship between age and gender was evaluated with univariate analysis. All analyses were done using Statistical Package for Social Sciences (IBM SPSS) version 21 (IBM Co., Armonk, NY, USA). The institution’s Health Research Ethics Committee gave approval for this study.

  Results Top

A total of 301 medical reports with evidence of obstructed UUT are identified. Thirty-four cases are consequent on infravesical obstruction, and they are excluded from further analysis. Among the rest (267 medical reports), there are 129 males (48.3%) from the ages of three months to 80 years (mean 42.69 ± 15.59 years), and 138 females (51.7%) from the ages of three months to 74 years (mean 43.86 ± 14.14 years). There is no significant difference in comparing these means (F = 0.415; P = 0.52).

Obstruction is evidently unilateral and at various locations in 92 (66.7%) females and 111 (86%) males: 42 (30.4%) females have left-sided obstruction; 51 (39.5%) males have left-sided obstruction (χ2 = 13.74; df = 2; P = 0.001). Various causes of unilateral UUT obstruction are identified, as shown in [Table 1].
Table 1: Frequency distribution of the observed causes of unilateral and bilateral UUT obstruction in females and males

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The UUT stone is the most prevalent cause of unilateral obstruction of the UUT. On the other hand, congenital PUJ obstruction is the most prevalent congenital cause of unilateral UUT obstruction. Tumors within the pelvis comprising uterine leiomyoma, cervical malignancy, and other pelvic tumors, as a group, constitute the most prevalent cause of bilateral UUT obstruction in females.

There is bilateral ureteric obstruction in 64 (24.0%) of the 267 medical reports: 46 (17.2%) females and 18 (6.7%) males. In 11 (23.9%) of the 46 females and in six (33.3%) of the 18 males, the bilateral obstruction is at the upper ureter; whereas in 32 (69.6%) females and 12 males, the bilateral obstruction is at the lower ureter. The observed causes of bilateral UUT obstruction are also shown in [Table 1].

Of the 267 cases of UUT obstruction, 155 cases are due to UUT stone: 69 cases in females and 86 cases in males. [Figure 1] shows the distribution of obstructing UUT stones in females and males according to age.
Figure 1: Frequency distribution of obstructing stones in females and males according to age of patient

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Of the 69 females, 20 (29.0%) have left-sided stones, 37 (53.6%) have right-sided stones, and 12 (17.4%) have bilateral stones; whereas of the 86 males, 38 (44.2%) have left-sided stones, 39 (45.3%) have right-sided stones, and 9 (10.5%) have bilateral stones (χ2 = 4.25; df = 2; P = 0.12).

In all, there are 176 calculous ureteric obstructions in 155 people during the study period. [Table 2] shows that the upper ureter may be more frequently obstructed than the other segments of the ureter.
Table 2: Location of obstructing UUT stone in the individual ureters across the genders

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[Table 2] shows that upper ureteric stones are more frequently encountered, but there is no statistical evidence in support of this finding (χ2 = 1.78; df = 2; P = 0.41).

  Discussion Top

The UUT can be obstructed at different points by a number of lesions. Some of these obstructing lesions are intraluminal, whereas others are either intrinsically associated with the wall of the urinary tract, or extraluminally compressing or invading the same. These causes of UUT obstruction are known to vary with age, gender, and society.

In similarity to findings elsewhere,[1],[10],[18] this study shows that the most prevalent cause of both unilateral and bilateral UUT obstruction in the study area is the urinary stone [Table 1]. Presentation with an obstructing stone appears to be more prevalent in males with a ratio of 1.25 (χ2 = 7.606; df = 1; P = 0.006), similar to the ratio of 1.32 reported by Bouslama and colleagues[19] from Algeria, but less than 1.83 reported by Moon and colleagues[3] from Korea. The observed gender variation in the prevalence of upper urinary stones may not be unconnected with differences in physical activities of daily living.[20] However, the observation from univariate analysis of male predominance before the age of 50 years, and female predominance beyond the age of 50 years (χ2 = 5.03; P = 0.02; [Figure 1]), suggests that other factors beyond physical activities of daily living may contribute. This is in keeping with observations from other studies that suggest that estrogens may offer some protection against lithogenesis at some point from nucleation to clinical activity.[21],[22]

In some studies, obstructing ureteric stones have been observed to be more prevalent on the right with no particular explanation.[3],[23] There is no evidence in support of the observation from this study that UUT stones are more prevalent on the right (55.1%) than on the left (χ2 = 4.25; df = 2; P = 0.12). Though bilateral ureteric obstruction by urinary stones does occur, unilateral ureteric obstruction is encountered more often.

It is also worthy to note that obstruction at the upper ureteric segment appears more prevalent (50.6%) than obstruction at the mid-segment (14.8%), or the lower segment of the ureter (34.7%). This finding that more stones are impacted at the upper segment of the ureter compared with other segments [Table 2] may be because the stones encountered in this study are relatively large at the onset of descent, resulting in impaction at the first encountered point of narrowing.[3],[24],[25] On the other hand, stone impaction occurred least at the mid-ureter, probably because of the absence of any point of inherent narrowing in this segment. There is no evidence of any difference between males and females in the distribution of the location of urinary stones from this review (χ2 = 1.78; df = 2; P = 0.41).

Beyond urinary stones, the second most common non-congenital cause of ureteric obstruction in females is uterine fibroids and in males it is advanced prostate cancer [Table 1]. These findings may not come as a surprise considering that women and men of African descent tend to present with larger uterine fibroids and more aggressive prostate cancer, respectively, with an attendant risk of unilateral or bilateral ureteric obstruction by extrinsic compression and by invasion.[14],[26],[27]

The most prevalent congenital cause of UUT obstruction from this study [Table 1] is congenital PUJ obstruction, which is seen in 10.5% of all subjects. In our setting, there is no observable difference in the distribution of congenital PUJ obstruction across gender, probably due to the limited study participants. The median age of people presenting with congenital PUJ obstruction of 32.0 years (IQR = 25.3–50.0) from this review is in keeping with observations by Fontenot Jr, et al.[28] in the United States and in other settings where presentation with symptoms is the order. In addition, at a hospital prevalence rate of 89.3%, unilateral congenital PUJ obstruction is more prevalent in this setting as is observed in other settings.[2],[29]

Limitations: This is a review of experience in a tertiary care center, and findings thereof may not be generalized.

In conclusion, the urinary stone constitutes the most common cause, whereas congenital PUJ obstruction is the most common congenital cause of UUT obstruction in our setting. With respect to the obstructing urinary stone, there is no predilection for left or right UUT. However, the upper ureteric segment is obstructed more often than the lower ureteric segment, a finding that does not vary with gender. Obstructing urinary stones are more prevalent in males overall, but beyond the age of 50 years, there is some evidence of a female preponderance. Symptomatic presentation with congenital PUJ obstruction is likely to be in young adulthood. Beyond these, compression by large uterine leiomyoma in females and invasion by advanced prostate cancer in males are notable causes of ureteric obstruction.


We recommend a multi-center based study to be able to define succinctly the causes of UUT obstruction in our region.


The authors are grateful to Peter Uzoma, Zara Ozumba, and Ifunanya Achimalu for their contributions in data collection.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

Authors’ contributions

SKA contributed in the conception and design of the research, in the acquisition of data, and in the drafting of the article. IIN contributed in the conception and design of the research, in the collection, analysis, and interpretation of data, and in the drafting of the article. ACO contributed in the design of the research, in the generation of data, and in the critical revision of the draft manuscript for important intellectual content. All authors have read and have approved of the final version of the article before it being submitted for publication.

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  [Figure 1]

  [Table 1], [Table 2]


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