The Influence of Bladder Fullness on Upper Urinary Tract Dimensions and Renal Excretory Function

Vol. 117, May Printed in U .S .A.

THE JOURNAL OF UROLOGY

Copyright © 1977 by The Williams & Wilkins Co.

THE INFLUENCE OF BLADDER FULLNESS ON UPPER URINARY TRACT DIMENSIONS AND RENAL EXCRETORY FUNCTION W. B. GILL* AND G. A. CURTIS From the Department of Surgery/Urology, University of Chicago, Chicago, Illinois

ABSTRACT

Nearly full bladders (375 ml.) produced significantly greater dimensions of the renal calices, pelves and ureters on excretory urograms compared to nearly empty bladders. These dimensions were frequently to the point of being considered pathological dilatations. On planimetry the urographic areas of the pelviocaliceal systems decreased by 43 per cent on the right side and 38 per cent on the left side when the nearly full bladder was compared to the nearly empty bladder in 10 patients. Renal excretory function also was affected by nearly full bladders. Urea clearances after 1 hour were 24 per cent lower and creatinine clearances were 9 per cent lower when starting with a nearly full bladder as compared to starting with an empty bladder. The implications of these findings are of potential significance with respect to 1) interpretation of excretory urograms and 2) chronic urine holding in patients with recurrent urinary tract infections, impaired renal function and/or urolithiasis. The influence of bladder fullness on upper urinary tract dimensions and renal function in normal humans usually has been neglected or considered to be insignificant. 1 • 2 The degree of filling and/or distension of the upper urinary tract on excretory urography (IVP) has been ascribed typically to either the state of hydration (diuresis increases the dimensions) or pathologic obstruction, 3 --5 and not related to normal physiological variations in the degree to which the bladder is filled. Chance observation of a young woman who urinated part way through an IVP (diagnostic study for recurrent cystitis) revealed a marked diminution in the size of the renal calices, pelvis and ureter on the next film, 5 minutes after emptying the bladder. We then embarked on a systematic study of 10 patients with respect to the effects of bladder fullness on the pyelographic dimensions of the upper urinary tract and renal excretory function. We concluded that bladder fullness beyond 375 ml. rather consistently increased the dimensions and filling of the upper urinary tract on IVP and decreased renal excretory function as measured by urea and creatinine clearances. MATERIALS AND METHODS

Ten individuals who required an IVP as part of an evaluation for recurrent urinary tract infections or microscopic hematuria cooperated in this study. Table 1 indicates the patients' age, sex and race. Renal excretory function was evaluated by 1-hour clearances of urea and creatinine6 with initially empty bladders and bladders filled with 375 ml. liquid. The 125 ml. water was given orally to non-dehydrated patients every 30 minutes throughout the study. The empty bladder hourly period preceded the urethral catheter instillation of375 ml. sterile water (4 patients) or sterile saline (6 patients) for the start of the nearly full bladder hourly period. Only 1 patient with a bladder filled with 375 ml. liquid became significantly uncomfortable before the hour period ended and urinated at 45 minutes. The clearance periods preceded the IVPs. Nearly full bladders refer to bladders containing 375 ml. or more liquid.

TABLE 1.

Comparison of renal clearances with initially empty and nearly full (375 ml.) bladders Creatinine Clearances

Urea Clearances

Empty Nearly Age-Race-SexE t Blad Nearly Decrease Blad Full Decrease (yrs ) mp Y • Full Blad- by Full · by Full · der. der Bladder der Bladder Bladder (ml.Imm.) (ml./min.) (%) (~./ (~./ (%) mm.) mm.) 18-W-F 35-W-F 26-B-M 68-B-M 65-W-M 28-B-M 30-W-M 42-W-F 52-B-F 38-W-F Mean

* Urine volume

75 53 75 45 46 90 76 57 48 84 65

(3.2)* (4.0) (4.0) (3.3) (5.8) (5.1) (4.2) (2.9) (1.9)

(2.8) (3.7)

39 (2.9)* 44 (3.0) 52 (4.5) 27 (3.1) 37 (4.6) 71 (5.0) 69 (2.9) 42 (2.7) 45 (2.9) 63 (3.1) 49 (3.5)

48 17 31 40 20 21 9

26 6

25 24

110 132 129 80 88 180 130 107 72 118 115

100 116 121 68 79 143 121 108 76 106 104

9 12 6 15 10 21 7 -1 -5 11 9

(milliliters per minute).

Anatomical changes in the upper urinary tract with bladder fullness were evaluated by IVP in non-dehydrated patients. Immediately after the patient urinated a moderate degree of bladder fullness was produced by instilling 375 ml. sterile water or saline via a 16F catheter per urethram. The catheter was withdrawn promptly and 60 ml. hypaque was administered intravenously 10 minutes later. After 5, 10 and 15-minute post-injection x-ray films were made the patients were asked to empty their bladders and additional x-rays were made at 20, 25 and 30 minutes post-injection. Planimetry was used to quantitate the urographic areas of the renal pelviocaliceal systems and the 2-dimensional changes therein between the empty and full bladder. t Only 1 of these patients had high volume (500 ml.) unilateral vesicoureteral reflux on voiding cystourethrograms done prior to these studies. RESULTS

Figures 1 to 3 are examples of the differences in the uro-

graphic appearances of the upper urinary tracts with nearly Accepted for publication July 30, 1976. Read at annual meeting of American Urological Association, Las full and empty bladders. Table 2 compiles the urographic Vegas, Nevada, May 16-20, 1976. dimensions of the renal pelviocaliceal systems with nearly full Supported in part by the E. F. Andrews Foundation and National and empty bladders. After voiding, the urographic areas deInstitutes of Health Grant IROl-AM-17719. * Requests for reprints: Section of Urology, Box 403, University of t Planimeter, Gelman Instruments, Ann Arbor, Michigan. Chicago, Chicago, Illinois 60637. 573

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FIG. 1. IVP of 35-year-old white woman demonstrates decreased dimensions and filling of upper urinary tract. A, nearly full bladder. B, nearly empty bladder.

bladder and a 143 ml. nearly full bladder clearances. This bracketing of higher clearances with an initially empty bladder on either side of an initially nearly full bladder further substantiates the validity of the clearance depressing effects of a nearly full bladder. We also have used a nearly full bladder to facilitate ureteral visualization during retrograde pyelography. Figure 4 demonstrates the complete visualization of the ureters obtained by leaving 400 ml. water in the bladder prior to removing the ureteral catheters with injection of contrast medium. DISCUSSION

FIG. 2. IVP of 52-year-old black woman. A, nearly full bladder. B, nearly empty bladder. Note especially striking changes ofleft upper tract.

creased by an average of 38 per cent on the left side and 43 per cent on the right side. The decreased dimensions were apparent within 5 minutes after urination to empty the bladders. Table 1 compares the renal clearances with initially empty bladders and bladders filled with 375 ml. liquid in the 10 patients studied. The urea clearances were decreased in all 10 patients in the initially full bladder as compared to the initially empty bladder clearances. The average decrease in urea clearance was 24 per cent. The urine excretion rates are given in parentheses (milliliters of urine per minute) for each clearance period immediately after the urea clearance. Simultaneously performed creatinine clearances showed a decrease with a nearly full bladder in 8 of these 10 patients. The creatinine clearances were decreased an average of 11.4 per cent in these 8 patients and 9 per cent for the total 10 patients. Patient 6 had a third hourly clearance period (after empty and nearly full clearances) starting with an empty bladder that had a return of the urea clearance up to 86 ml. (90 ml. initial empty bladder, 71 ml. full bladder) and a return of the creatinine clearance to 17 4 ml. after an initial 180 ml. empty

The results indicate that nearly full bladders of normal individuals produce an increase in dimensions (dilation) of the renal pelviocaliceal systems on IVP and a decrease in renal excretory clearance of urea and to a lesser extent creatinine. Because the urographic dimensions were observed to change within 5 minutes after the bladders were emptied these changes seem to be readily reversible. Since only 1 patient was uncomfortable after 45 minutes, to the point of having to urinate rather than waiting the full hour clearance period, one can assume that the bladder volumes obtained in these studies are volumes that probably are obtained not infrequently in everyday life. For some high pressure jobs and social situations these volumes are probably rather commonly obtained for considerable periods. The mechanisms by which these changes in dimensions and clearances are produced have not been evaluated by us other than noting that the ureteral dimensions also are increased down to the ureterovesicaljunctions. Based upon the extensive work ofTanagho, 7 Zimskind, 8 and Rosen9 and their associates, one might expect that the nearly full bladders produced increasing compression of the intramural ureters and/or changes in trigonal stretching, which effected a partial stopflow situation with respect to urine from the ureters that was quickly transmitted to the renal pelviocaliceal system and presumably the intranephronic urine as well. The greater decreases in urea clearances than the creatinine clearances would be expected from an incomplete stop-flow situation with greater back diffusion of urea. Since only 1 individual had high volume unilateral reflux it would seem that vesicoureteral reflux did not have a significant role in the effects observed with a nearly full bladder.

BLADDER FULLNESS EFFECT ON URINARY TRACT DIMENSIONS AND RENAL FUNCTION

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Fm. 3. IVP of 65-year-old black man. A, nearly full bladder. B, nearly empty bladder. Note prominent filling of ureters on nearly full bladder film. TABLE

2. Planimetry comparison of renal peluiocaliceal areas on !VP with nearly full and empty bladders Right Pelviocaliceal Area

Left Pelviocaliceal Area

Decrease Decrease Nearly Nearly Emty byEmp;r- Full Blad- Emty ~yEmfat Full Blad- Bla Bla der mgBa der ing Bla der der (cm.2) (cm. 2) der der (cm.2) (cm. 2) (%) (%)

Mean

9.34 9.17 10.56 14.44 8.33 7.78 8.61 8.33 3.61 11.94 9.21

5.00 5.28 5.50 8.33 4.17 4.44 4.17 5.83 2.22 6.90 5.18

46.5 42.4 47.9 42.3 49.9 42.9 51.5 30.0 38.5 42.2 43.41

10.49 6.94 11.11 13.33 9.72 6.39 7.50 8.06 4.72 11.39 8.97

5.88 3.75 5.61 8.89 4.44 5.56 5.83 4.44 3.33 6.39 5.41

44.0 45.9 49.5 33.3 54.3 12.9 22.3 44.9 29.4 43.8 38.03

Lapides and associates have reported on the deleterious effects of infrequent voiding, leading to chronic overdistension of the bladder and urinary tract infections in women. 10 Presumably our high pressure urban society has led many of us to hold urine longer and distend the bladder greater than was the original physiological design. Our ancestors in rural settings rarely let their bladder fill beyond the initial symptoms of micturition desire. One can speculate that increased bladder fullness with the consequent transmission to increased ureteral, renal pelviocaliceal and, perhaps, intranephronic dimensions may lead not only to decreased renal excretory function but perhaps also may affect renal endocrine functions with altered renin and erythropoietin metabolism as well in extreme circumstances. One also can envision that chronic urine holding with a nearly full bladder would lead to an increased urinary transit time for 1) renal carcinogens (increased contact time and/or mucosal penetration) and 2) kidney stone solutes, which would result in increased time for crystal growth, decreased flow rate, which may favor crystal adhesion and perhaps increased supersaturation from greater reabsorption of water, urea and other solubilizing factors. In conclusion one should emphasize that 1) the interpretation of IVPs should take into account the state of bladder fullness when interpreting possible pathological dilations of the upper urinary tract collecting systems, 2) a nearly full bladder may facilitate visualization of the upper urinary tract (especially the ureters) and 3) the prolonged holding of bladder urine could be deleterious to individuals with impaired renal function, interstitial nephritis and/or nephrolithiasis. REFERENCES

Fm. 4. Retrograde urogram obtained by leaving 400 ml. water in bladder before removing ureteral catheters with contrast injection. Note complete filling of ureters down to ureterovesical junctions. Xray made 2 minutes after ureteral catheter withdrawals.

1. Werwath, K.: Zur kritischen Wertung von Urogrammen und zur Frage der Bewiihrung der Ausscheidungsurographie als diagnostische wie funktionelle Untersuchungsmethode. Deut. Ztschr. f. Chir., 248: 563, 1936-1937. 2. Campbell, M.: Clinical Pediatric Urology. Philadelphia: W. B. Saunders Co., p. 58, 1951. 3. Emmett, J. L.: Clinical Urography, 2nd ed. Philadelphia: W. B. Saunders Co., p. 31, 1964. 4. Friedenberg, R. M.: Radiographic examination of the ureter. In: The Ureter. Edited by H. Bergman. New York: Harper & Row, Publishers, Inc., chapt. 9, p. 188, 1967. 5. Boyarsky, S.: Urodynamic studies. In: Diagnostic Urology. Edited by J. Glenn. New York: Harper & Row, Publishers, Inc., chapt. 6, p. 126, 1964. 6. Brulles, A., Gras, J., Magrina, N., Torres, N. and Caralps, A.: Relation between urea clearance and glomerular filtration

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7. 8. 9.

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rate according to urine flow/minute. Clin. Chim. Acta, 24: 261, 1969. Tanagho, E. A., Meyers, F. H. and Smith, D. R.: The trigone: anatomical and physiological considerations. 1. In relation to the ureterovesical junction. J. Urol., 100: 623, 1968. Zimskind, P. D., Davis, D. M. and Decaestecker, J.E.: Effects of bladder filling on ureteral dynamics. J. Urol., 102: 693, 1969. Rosen, D. I., Constantinou, C. E., Sands, J.P. and Govan, D. E.: Dynamics of the upper urinary tract: effects of changes in bladder pressure on ureteral peristalsis. J. Urol., 106: 209, 1971. Lapides, J., Costello, R. T., Jr., Zierdt, D. K. and Stone, T. E.: Primary cause and treatment of recurrent urinary infection in women: preliminary report. J. Urol., 100: 552, 1968.

COMMENT We all have seen IVPs similar to those depicted without realizing the importance of bladder fullness on dilation of the upper tracts. These authors have quantitated this relationship well. Can we really be sure that the reasons for such dilation are hydrodynamic rather than being mediated by nerve reflexes? G.D. REPLY BY AUTHORS Although one cannot be absolutely certain of the mechanism(s) mediating the effects of bladder fullness on the upper urinary tract, we believe that the evidence strongly favors the hydrodynamic mechanical obstruction hypothesis.