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Q: Kidney condition ( Answered 4 out of 5 stars,   0 Comments )
Subject: Kidney condition
Category: Health > Conditions and Diseases
Asked by: research_help-ga
List Price: $40.00
Posted: 24 May 2005 11:45 PDT
Expires: 23 Jun 2005 11:45 PDT
Question ID: 525101
This is a repost of a previous question. I accidentally mentioned
"G**gle Answers" in the original question so it has been locked all day.  Please
answer THIS question as I will expire the previous question when it is

1. What does it mean if someone's kidney is a "double collector"? (How
does this differ from a normal kidney?)
2. What percent of the population is "double collector"?
3. What kinds of problems can having a "double collector" kidney cause?
4. Is there anything specific that someone with this condition can do
to minimize problems?

[Note: "double collector" might not be the scientific term for this condition]

I realize that G**gle Answers is not a substitute for professional
medical advice.  This information is being used to prepare someone for
a meeting with a urology specialist.

If you can answer most, but not all, of this question, please ask for
clarification if it will be an acceptable answer.

Request for Question Clarification by pinkfreud-ga on 24 May 2005 11:50 PDT
I'd like to verify that I'm heading in the right direction. Is this
the condition to which you refer?

"Duplex kidney (double kidney) consists of a single renal mass with
more than one collecting system."

Clarification of Question by research_help-ga on 24 May 2005 12:09 PDT
Pinkfreud - I'd like to give you a definitive clarification, but I am
not sure. I can give you the facts, but I'll leave it to your further
research to determine if this is it. Patient has recurring kidney
stones and had a CT scan.  ER doctor informed the patient that he has
a "double collector" kidney which means that collection takes place in
more than one tube which is a likely factor in the multiple occurences
of kidney stones.

If it helps, it does sound like your research is leading you in the right direction.

Request for Question Clarification by pinkfreud-ga on 24 May 2005 15:43 PDT
I'm unlocking this, since I have been unable to verify the exact
meaning of the term "double collector." I hope another Researcher will
be able to pin this down. If you are able to learn any additional
details, please post them for us.
Subject: Re: Kidney condition
Answered By: welte-ga on 24 May 2005 17:52 PDT
Rated:4 out of 5 stars
Hi, and thanks for your question.  As you state, this answer is now
substitute for formal medical advice.  That in mind, I'll address each
point in turn.  References can be found at the end.


1. What does it mean if someone's kidney is a "double collector"? (How
does this differ from a normal kidney?)

"Double collector" is a somewhat colloquial term, uncommonly used
term, referring to a condition where one has two ureters from one or
each kidney to the bladder.  Other terms used include "duplicated
collection system," "duplicated ureter," "bifid ureter."

It's commonly associated with ureteroceles (a dilation of the ureter
closest to the bladder).  The Explore Diseases website discusses this
issue briefly:

A more in depth journal article published in the Brazil Journal of
Pediatrics discusses this disorder, as well as its surgical treatment.

de Jesus LE, Judice MM, Mello EG.  J Pediatr (Rio J). 2003
Mar-Apr;79(2):173-80.  [Ureteral duplications and ureteroceles -
surgical treatment] [Article in Portuguese]

While original article is in Portuguese, the full text English version
can be found here:
The PDF (English) version is here:

The following journal article contains an MRI image of a left-sided
duplicated ureter (see Figure 6 on Page 3):

2. What percent of the population is "double collector"?

The following reference answers this question:
Schlussel RN, Retik AB. Anomalies of the ureter. In: Walsh PC, Retik
AB, Vaughan ED, Wein AJ, eds. Campbell?s Urology, 7th ed.
Philadelphia: WB Saunders Company; 1998: 1814?1858.

This source is cited in the journal article below, giving 
"Like ureteral injuries, ureteral duplication is uncommon, occurring
in 0.68% to 0.8% of the population."

Pearlstein DP. Brandt M. Introcaso JH. Shah M. Martin T. Sulkowski RJ.
 Penetrating trauma causing partial disruption of a duplicated ureter:
case report.  Journal of Trauma-Injury Infection & Critical Care.
50(4):755-8, 2001 Apr.

The above article also discusses how ureteral duplication occurs:

"Ureteral duplication is genetically determined and is most often
unilateral. Anatomically, this condition usually presents as double
ureters with their bladder orifices inverted in relation to the
collecting systems they drain. This phenomenon has been termed the
Weigert-Meyer law. It is manifested by the orifice of the lower pole
occupying the usual, lateral position, whereas the orifice of the
upper pole ureter can be found anywhere along an ectopic pathway
extending caudal and medial, all the way to the prostate."


3. What kinds of problems can having a "double collector" kidney cause?

The primary potential problems caused by duplicated ureters are
Intractable urinary infections.  Another problem can be
vesico-ureteral reflux, where variable amounts of urine flow backwards
from the bladder back to the ureter.  Partial ureteral duplication can
result in ureteroureteric reflux, where urine flows into the partially
duplicated ureter, but hits a blind end and must flow backwards
(retrograde), causing delayed urine drainage.  Reference [21] below
discusses this condition:

"Partial ureteric duplication may cause delayed drainage of urine from
the upper tracts because of ureteroureteric "see-saw" reflux. This can
be eliminated by the procedure of ureteropyelostomy, in which the
partially duplicated ureter is converted into a bifid renal pelvis.
This operation leaves a short anastomotic suture line and has a low
complication rate. We report seven patients who have undergone
ureteropyelostomy for symptomatic ureteroureteric reflux. All remain
symptom-free after follow-up for a minimum of 1 year."

As mentioned, one of the duplicated ureters can be "blind," meaning it
doesn't travel all the way to the bladder.  Rarely, stones can lodge
in this blind ureter.  Reference [14] discusses such a case:

Another description of obstructed duplicated collecting systems can be
found here, from the Yonsei Medical Journal:


Ureteroceles (dilations of a ureter) have been associated with
duplicated ureters, which can result in urinary tract infections. 
Reference [24] discusses the treatment of two girls who had this
combination of conditions.  References [21,30] also discuss treatment
of this condition.

From Reference [24]:
"Herein we report two cases of complete ureteric duplication
associated with ureterocele. A 4-month-old girl with non-visualizing
left kidney was hospitalized with complaints of cloudy urine and
fever. An antegrade left pyelogram revealed a completely duplicated
collecting system; a duplex tortuous ureter, and round radiolucent
filling defect in the bladder. Under the diagnosis of completely
duplicated ureter associated with the upper pole ureterocele,
ureterocystoneostomy was performed. A circumferential incision was
made around the base of the ureterocele and the Politano-Leadbetter
technique was employed. Her postoperative course was uneventful.
However, an excretory urogram showed a mild hydronephrotic upper pole.
A 1-year and 4-month-old girl with the history of repeated urinary
tract infections and fever attacks was admitted. The excretory urogram
showed a left hydronephrotic lower pole with a "drooping flower" and
no opacification of the upper pole. A radiolucent filling defect was
seen in the bladder. A left antegrade pyelogram demonstrated the
massively dilated upper pole with a hydroureter terminating in the
ureterocele. Left heminephrectomy with partial ureterectomy was
performed and left hydronephrosis and hydroureter with an atrophic
kidney were seen. The postoperative course was uneventful."

Cancer in the duplicated ureter is rare, but has been described. 
References [13, 23, 25] discuss such cases.


The duplicated ureter can also insert in the wrong place.  Such
ectopic ureters have been described inserting in to the vagina, the
vas deferens,  See References [5, 27] for example.


4. Is there anything specific that someone with this condition can do
to minimize problems?

The primary problems that might be amenable to lifestyle-type changes
would be the formation of stones and urinary tract infections. 
According to Reference [31], as cited in Reference [32], "[k]idney
stones affect up to 5% of the population, with a lifetime risk of
passing a kidney stone of about 8-10%."

Reference [32] goes on to say
" improved standards of living and is strongly associated with race or
ethnicity and region of residence.  A seasonal variation is also seen,
with high urinary calcium oxalate saturation in men during summer and
in women during early winter.  Stones form twice as often in men as
women. The peak age in men is 30 years; women have a bimodal age
distribution, with peaks at 35 and 55 years. Once a kidney stone
forms, the probability that a second stone will form within five to
seven years is approximately 50%Calcium oxalate (alone or in
combination) is the most common type of urinary stone Low urine volume
is the most common abnormality and the single most important factor to
correct so as to avoid recurrences Risk of a recurrent stone is about

From the Summary Points of Reference [32], to minimize the formation
of renal calcium oxalate stones, one should strive for a diet low in
salt (<50 mmol/day) and low in animal proteins (<52 grams/day).  The
article also states that diets low in calcium are not encouraged,
since they can result in increased urinary oxalate excretion (making
stones worse) and a negative calcium balance (bad for the bones).

A family history of kidney stones increases one's risk by a factor of
3.  Other risk factors include insulin resistant states (e.g. Type II
Diabetes), hypertension, primary hyperparathyroidism, gout, chronic
metabolic acidosis, and surgical menopause.

Reference [32] is, unfortunately, not available for free online, but
might be worth obtaining from your local library (or purchasing
online) if you are interested in a more in depth discussion of kidney
stones.  The article includes multiple summary boxes that put together
the multiple risk factors for various types of stones.  You might also
request a reprint from Dr. Parmar at this address:

In patients who are particularly symptomatic, surgery may be an option
to correct the anatomic duplication of the ureter.


1. Chen KS. Chuang CK. Wu CH. Liaw CC. Lee N. Upper urinary tract
tumor in a duplicated collecting system: report of three cases and
review of the literature. [Review] [11 refs] [Journal Article. Review.
Review of Reported Cases] Chang Gung Medical Journal. 26(5):377-82,
2003 May.
UI: 12934856
 ?  ? 

2. Volkan B. Ceylan E. Kiratli PO. Radionuclide imaging of rare
congenital renal fusion anomalies. [Case Reports. Journal Article]
Clinical Nuclear Medicine. 28(3):204-7, 2003 Mar.
UI: 12592127
 ?  ? 

3. Sauvage P. Becmeur F. Moog R. Kauffmann I. Is one-stage ureterocele
repair possible in children?. [Journal Article] European Urology.
42(6):607-13; discussion 613, 2002 Dec.
UI: 12477658
 ?  ? 

4. Yu TJ. Extravesical diverticuloplasty for repair of a paraureteral
diverticulum and the associated refluxing ureter. [Journal Article]
Journal of Urology. 168(3):1135-7, 2002 Sep.
UI: 12187254
 ?  ?  ? 

5. Damry N. Hall M. Avni F. Ectopic vaginal insertion of a duplicated
ureter: demonstration by magnetic resonance imaging (MRI). [Case
Reports. Journal Article] Jbr-Btr: Organe de la Societe Royale Belge
de Radiologie. 84(6):270, 2001.
UI: 11817480

6. Pearlstein DP. Brandt M. Introcaso JH. Shah M. Martin T. Sulkowski
RJ. Penetrating trauma causing partial disruption of a duplicated
ureter: case report. [Journal Article] Journal of Trauma-Injury
Infection & Critical Care. 50(4):755-8, 2001 Apr.
UI: 11303181
 ?  ? 

7. Gallucci M. Vincenzoni A. Schettini M. Fortunato P. Cassanelli A.
Zaccara A. Extracorporeal shock wave lithotripsy in ureteral and
kidney malformations. [Journal Article] Urologia Internationalis.
66(2):61-5, 2001.
UI: 11223745
 ?  ? 

8. el Ghoneimi A. Lottmann H. Odet E. Bonnin F. Aigrain Y.
[Ureteropyelostomy for obstructed duplicated ureter an easy and
reliable operation in infants]. [French] [Journal Article] Annales d
Urologie. 32(4):241-6, 1998.
UI: 9791553
 ?  ? 

9. Mondet F. Ravery V. Roux C. Hoffmann C. Delmas V. Boccon-Gibod L.
[Inverted Y partial ureteral duplication. Apropos of an unusual case].
[Review] [16 refs] [French] [Case Reports. Journal Article. Review.
Review, Tutorial] Progres en Urologie. 8(2):262-5, 1998 Apr.
UI: 9615939
 ?  ? 

10. Kosinski H. Remarks on the arterial vascularization of double
kidney. [Journal Article] Folia Morphologica (Warszawa). 56(2):111-6,
UI: 9529760
 ?  ? 

11. Reunanen M. Endoscopic collagen injection: its limits in
correcting vesico-ureteral reflux in duplicated ureters. [Journal
Article] European Urology. 31(2):243-5, 1997.
UI: 9076474
 ?  ? 

12. Slaughenhoupt BL. Mitcheson HD. Lee DL. Ureteral duplication with
lower pole ectopia to the vas: a case report of an exception to the
Weigert-Meyer law. [Review] [3 refs] [Case Reports. Journal Article.
Review. Review of Reported Cases] Urology. 49(2):269-71, 1997 Feb.
UI: 9037295
 ?  ? 

13. Yasui T. Asaka H. Andoh Y. [Primary adenocarcinoma of renal pelvis
and ureter associated with incomplete ureteral duplication: a case
report]. [Japanese] [Case Reports. Journal Article] Hinyokika Kiyo -
Acta Urologica Japonica. 42(4):307-10, 1996 Apr.
UI: 8693966
 ?  ? 

14. Ozmen E. Ozkardes H. Ozkan S. Ozen HA. Calculi in a blind-ending
limb of a duplicated ureter. [Case Reports. Journal Article]
Scandinavian Journal of Urology & Nephrology. 27(4):541-2, 1993.
UI: 8159929
 ?  ? 

15. Husmann DA. Allen TD. Resolution of vesicoureteral reflux in
completely duplicated systems: fact or fiction?. [Journal Article]
Journal of Urology. 145(5):1022-3, 1991 May.
UI: 2016784
 ?  ? 

16. Cofer BR. Kaufman PN. Nussbaum MS. Cirulli C. Penetrating injury
of a duplicated ureter: case report. [Case Reports. Journal Article]
Journal of Trauma-Injury Infection & Critical Care. 31(1):140-2, 1991
UI: 1986121
 ?  ? 

17. Mosli HA. Rawas MM. Farsi HM. Rimawi MH. Blind ending branch of
duplicate ureter associated with urolithiasis of contra-lateral
kidney: case report and review of literature. [Case Reports. Journal
Article] East African Medical Journal. 67(10):737-9, 1990 Oct.
UI: 2282898
 ?  ? 

18. Gassner JR. Cullen GM. Walsh JP. Osseous metaplasia of
transitional cell carcinoma within a duplicated ureter. [Case Reports.
Letter] AJR. American Journal of Roentgenology. 153(5):1101-2, 1989
UI: 2801434

19. Hannerz L. Wikstad I. Celsi G. Aperia A. Influence of
vesicoureteral reflux and urinary tract infection on renal growth in
children with upper urinary tract duplication. [Journal Article] Acta
Radiologica. 30(4):391-4, 1989 Jul-Aug.
UI: 2775602
 ?  ? 

20. Musi L. Campobasso P. Cappellari F. Mercurella A. Belloli G.
[Ectopic ureter]. [Italian] [Journal Article] Pediatria Medica e
Chirurgica. 11(2):129-35, 1989 Mar-Apr.
UI: 2762191
 ?  ? 

21. Sole GM. Randall J. Arkell DG. Ureteropyelostomy: a simple and
effective treatment for symptomatic ureteroureteric reflux. [Journal
Article] British Journal of Urology. 60(4):325-8, 1987 Oct.
UI: 3690203
 ?  ? 

22. Aragona F. Glazel GP. Zacchello G. Andreetta B. Familial
occurrence of blind-ending bifid and duplicated ureters. [Case
Reports. Journal Article] International Urology & Nephrology.
19(2):137-9, 1987.
UI: 3667127
 ?  ? 

23. Sreenevasan G. Por PK. Mukherjee AK. Sabapathy AK. Carcinoma in
one limb of an incompletely duplicated ureter. [Case Reports. Journal
Article] British Journal of Urology. 60(1):79-80, 1987 Jul.
UI: 3620852

24. Uchibayashi T. Hisazumi H. Kunimi K. Yamaguchi K. Kawaguchi S.
Ohkawa M. [Complete ureteric duplication associated with ureterocele:
two cases report]. [Japanese] [Case Reports. Journal Article]
Hinyokika Kiyo - Acta Urologica Japonica. 33(1):79-84, 1987 Jan.
UI: 3577969
 ?  ? 

25. Banya Y. Abe T. Sasaki H. Aoki H. Fujioka T. Akasaka T. Kubo T.
Ohori T. [A case of primary ureteral carcinoma in the duplicated renal
pelvis and ureter diagnosed by transurethral uretero-renoscopy].
[Japanese] [Case Reports. Journal Article] Hinyokika Kiyo - Acta
Urologica Japonica. 32(3):454-61, 1986 Mar.
UI: 3728247
 ?  ? 

26. Rubenstein DJ. Brenner RJ. Misleading features of blind-ending
bifid ureter on computerized tomography examination. [Case Reports.
Journal Article] Journal of Urology. 134(2):342-3, 1985 Aug.
UI: 4020988
 ?  ? 

27. Glasser J. Lefleur R. Subramanyam B. Al-Askari S. Ectopic
duplicated ureter opening into ipsilateral vas deferens. [Case
Reports. Journal Article] Urology. 23(3):309-12, 1984 Mar.
UI: 6702048
 ?  ? 

28. Balogh F. Kelemen Z. Legradi J. [Ureteroureterostomy following
Coffey operation (author's transl)]. [German] [Case Reports. Journal
Article] Urologe (Ausg. A). 19(3):138-9, 1980 May.
UI: 7404895
 ?  ? 

29. Gotovac J. Rosin A. [Surgical treatment of the vesico-ureteral
reflux in completely duplicated ureter]. [Croatian] [Journal Article]
Lijecnicki Vjesnik. 97(9):523-7, 1975 Oct.
UI: 1223583
 ?  ? 

30. Gutierrez J. Chang CY. Nesbit RM. Ipsilateral uretero-ureterostomy
for vesicoureteral reflux in duplicated ureter. [Journal Article]
Journal of Urology. 101(1):36-9, 1969 Jan.
UI: 4882623
 ?  ? 

31. Asplin JR, Favus MJ, Coe FL. Nephrolithiasis. In: Brenner BM, ed.
Brenner and Rector's the kidney. 5th ed. Philadelphia: Saunders, 1996:
 ?  ? 

32. Parmar MS.  Kidney stones.  BMJ. 2004 Jun 12;328(7453):1420-4.


I hope this information was helpful.  Please feel free to request clarification.

research_help-ga rated this answer:4 out of 5 stars

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