Open Journal of Urology, 2013, 3, 219-221
http://dx.doi.org/10.4236/oju.2013.35041 Published Online September 2013 (http://www.scirp.org/journal/oju)
Hydronephrosis and Ureteral Obstruction in Crohn’s
Disease*
Robert Jansen, Stanley Zaslau#
Division of Urology, West Virginia University, Morgantown, USA
Received August 2, 2013; revised September 1, 2013; accepted September 8, 2013
Copyright © 2013 Robert Jansen, Stanley Zaslau. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Hydronephrosis and ureteral obstruction are rare sequelae of Crohn’s disease. Chronic obstruction can ultimately lead to
dysfunction of the affected kidney, and atypical presenting symptoms create pitfalls in diagnosis. Few reviews in the
literature focus on this process and are limited to isolated case reports and case reviews. We performed a PubMed
search using such terms as “Hydronephrosis” AND “Crohn’s disease” AND/OR “ureteral obstruction”. References
from selected papers were reviewed for relevance and used for information-gathering as well. Ureteral obstruction most
commonly occurs on the right side, due to ileal involvement. Clinical diagnosis is difficult, as symptoms are no tably no t
genitourinary in origin; rather they are more musculoskeletal in nature. Treatment centers on disease control and tem-
porary drainage of the affected kidney. Though rare, hydronephrosis and ureteral obstruction may develop as a result of
inflammatory bowel disease. Due to atyp ical presenting symptoms, a high clinical susp icion is needed to affirm the di-
agnosis and ensure proper treatment.
Keywords: Hydronephrosis; Ureteral Obstruction; Crohn’s Disease
1. Background/Etiology
First described by Hyams et al. in 1943, ureteral obstruc-
tion is a rare but clinically si gn ificant sequella o f Cro hn ’s
disease [1]. As the pathophysiology of Crohn’s disease
involves inflammation, fistulas, local abscess formation,
and fibrosis, obstructive hydronephrosis can occur if any
of these processes involve areas of the bowel adjacent to
the ureters. Hydronephrosis occurs most commonly on
the right side via involvement of the terminal ileum; as
other areas of the bowel may be affected including the
sigmoid colon, in rare cases obstruction may be seen on
the left side. Obstruction usually occurs at the level of the
linea terminalis. The incidence of ureteral obstruction is
difficult to ascertain, as much of the literature focuses on
isolated case reports and case reviews; the reported inci-
dence is 0.3% - 25% [2-5]. At presentation, patients are
usually in the 3rd decade of life [6-8] and though Ben-
Ami and Block report 5.6 years and 3.9 years respec-
tively with Crohn’s disease prior to diagnosis, others
have reported patients presenting as long as 22.6 years
after initial Crohn’s diagnosis [3,6-8].
2. Pathophysiology
Ureteric compression occurs due to development of a
phlegmon with subsequent inflammation and retroperi-
toneal fibrosis. Presence of abscess or fistula in the ante-
rior retroperitoneal compartment has been implicated in
ureteral obstruction and at times, a dense cicatrix encas-
ing the ureter may arise at well [8,9]. Obstruction is usu-
ally noted at the level of the linea terminalis or SI joint
[2,6,7,10-12]. Most commonly, hydronephrosis will oc-
cur on the right side due to enteritis of th e terminal ileum
and the location of the right ureter posterior to th e termi-
nal ileum. Left-sided hydronephrosis occurs with sig-
moid colon o r je jun al involv ement and as such, the ureter
may be obstructed more proximally with jejunal disease.
One case report describes left ureteral obstruction arising
due to a right lower quadrant mass; the mass was associ-
ated with a fistulous tract extending through the root of
the mesentery to the left retroperitoneal sp ace [13].
3. Diagnosis
Surprisingly, urinary symptoms are quite rare in cases of
Crohn’s-related ureteral obstruction. Present reported
on l y 1 of 10 patients experiencing irritative void i n g s y mp-
toms, while other authors report a complete absence of
*No conflicts of interest or financial disclosures to report.
#Corresponding author.
C
opyright © 2013 SciRes. OJU

R. JANSEN, S. ZASLAU 220
urinary complaints in their respective series [8.13 ]. Com-
mon physical findings reported by many include flank
pain, hip pain, or anterior thigh pain resulting in diffi-
culty walking [7-8,12-13]. Abdominal, vaginal, or rectal
examination may reveal the presence of a mass in the
right or left lower abdo minal quadrants [8].
Computed tomography allows for full visualization of
any conglomerate mass in relationship to the level of ure-
teral obstruction, though bowel wall thickening and in-
flammation may be the only signs of direct involvement.
Intravenous pyelography will show hydronephrosis with
tapering of the affected ureter, usually at the level of the
pelvic brim. Medial deviation of the ureter is sometimes
seen as well [13].
One would suspect that ureteral involvement with
Crohn’s disease would lead to urinary tract infections;
however this is certainly not commonplace. In a series of
27 patients by Block et al., only 15 had grossly abnormal
urinary sediment on routine examination; 12 patients had
normal urinalyses and 21 patients had sterile urine cul-
tures [8]. Should a urinary tract infection arise, E. coli is
the most common pathogen, with Pseudomonas aerugi-
nosa, Streptococcus faecalis, Aerobacter aerogenes, En-
terococci, and Klebsiella implicated as well [8].
4. Treatment
A primary goal in the treatment of Crohn’s-related ure-
teral obstruction is drainage of the affected kidney to
prevent the deterioration of renal function. The table be-
low demonstrates available minimally invasive treatment
options for ureteral obstruction related to Crohn’s Dis-
ease. The indwelling ureteral stent can be placed cysto-
scopically to allow for the maintenance of ureteral pa-
tency and drainage of the kidney. While traditional stents
require changes every 3 - 4 months, long-term stents can
also be considered. Typical stents placed for patients
with Crohn’s disease are 6 French in diameter. However,
in our experience, placement of more flexible 4.7 French
stents may be associated with reduced flank and pelvic
pain. For patients who do not tolerate ureteral stents due
to pain or there is significant ureteral stricture that pro-
hibits stent placement, percutaneous nephrostomy tube
drainage may be considered. Drainage via an 8 French to
12 French nephrostomy tube provides excellent renal
drainage. Typically placed by interventional radiology
and changed every 3 to 4 month s, this drainage modality
is associated with less pelvic pain. However, patients
sometimes find the percutaneous flank drainage bags to
be cumbersome. Some situation s mitigate placement of a
percutaneous nephrostomy tube with a universal stent of
the ureter. This form of renal drainage allows both renal
drainage and the maintenance of ureteral patency. Used
rarely in our practice, these stents can be considered for
patients with hydronephrosis and significant intraperito-
neal inflammation that is causing retroperitoneal com-
pression with subsequent inflammation.
Table 1: Minimally invasive treatment options for ure-
teral obstruction:
 Indwelling ureteral stent
 Percutaneous nephrostomy
 Percutaneous nephrostomy with universal stent of the
ureter
Along with renal drainage, mild cases of Crohn’s dis-
ease with subsequent obstruction have successfully been
treated medically, while more moderate to severe cases
will require surgical intervention. “Pulse therapy” with
corticosteroids, in conjunction with mesalamine and re-
nal drainage, proved successful in 4 patients on whom
Ben-Ami et al. reported in two different studies [3,14].
Angelberger et al. reported success with one patient in
his series who had a milder form of Crohn’s disease than
the others in his cohort [6]. While there is a paucity of
data on the newer immunostimulatory and immunomo-
dulatory agen ts used for the management of Crohn’s d is-
ease with ureteral obstruction, we postulate that similar
improvements in the degree of hydronephrosis and renal
obstruction will be observed. We postulate that the im-
provements in obstruction may be quicker with the in-
travenous forms of the newer immunostimulatory and
immunomodulatory agents.
A surgical approach involves resection or bypass of
the affected bowel with or without ureterolysis. Bowel
resection with primary reanastamosis is commonly per-
formed and the preferred method of treatment, however
in severe cases in which it is deemed too difficult to ex-
tricate the bowel without injuring the ureter, temporary
bypass may be performed with later resection of the af-
fected segment [6-9]. Ureterolysis can be reserved for the
presence of a dense cicatrix encasing the ureter, however
success rates vary and the ultimate need for ureterolysis
is debatable [8,15]. Ureterolysis as a sole modality for
the treatment of ureteral obstruction is unlikely to be suc-
cessful when performed as a monotherapy. It will most
likely be successful when combined with primary medi-
cal therapy for Crohn’s disease or if medical disease re-
mission can be induced prior to ureterolysis. Good me-
thods to follow the relative presence of inflammatory
disease include immune markers such as C-reactive pro-
tein and the erythrocyte sedimentation rate. Ureterolysis
or any other surgical intervention is likely to be most
Table 1. Minimally invasive treatment options for ureteral
obstruction.
Indwelling ureteral stent
Percutaneous nephrostomy
Percutaneous nephrostomy with universal stent of the ureter

R. JANSEN, S. ZASLAU 221
successful when inflammatory markers are at their lowest
levels and preferably in the normal range.
Following bowel resection, decompression of the ure-
ter may be seen via intravenous pyelogr aphy as early as 7
or 8 days postoperatively [7,8]. Success rates approach
100% [3,8], though occasionally prolonged dilation of
the ureter and kidney occurs [7].
5. Conclusion
While hydronephrosis and ureteral obstruction are rare
sequelae of Crohn’s disease, chronic obstruction can ul-
timately lead to dysfunction of the affected kidney, and
atypical presenting symptoms create pitfalls in diagnosis.
Consideration of these problems by the treating medical
team as well as early identificati on of obstructi on may pre-
serve renal function. Minimally invasive treatments of
ureteral obstruction include uret eral stents while more sig-
nificant cases of obstruction may require ureterolysis. The
best treatment modalities for ureteral obstruction will in-
volve m axim i zati on of m edi cal t hera py fo r t he u nde rly ing
bowel disease and selection of the appropriate urinary
drainage method for obstruction that will cause the patient
the least amount of morbidity.
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