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A Matrix Calculus Causing Bilateral Ureteral Obstruction and Acute Renal Failure
@)22-5347/95/1543-1125$03.00/0 WEJOURNAL OF U n o ~ Y Copyright 0 1995 by h E n l C m UnomicAL ASSOCIATION, INC.
Val. 154, 1125-1 126. September 1996 Printed in U S A
A MATRIX CALCULUS CAUSING BILATERAL URETERAL OBSTRUCTION AND ACUTE RENAL FAILURE LEE ANNE MATTHEWS
AND
J. PATRICK SPIRNAK
From Case Western Reserve University School of Medicine and MetroHealth Medical Center, Cleveland, Ohio
KEYWORDS: calculi, kidney, ureter
Matrix calculi are radiolucent concretions composed primarily of a noncrystalline mucoprotein matrix. They are typically associated with urinary infection and management requires surgical extraction. To our knowledge we report the first case of bilateral ureteral obstruction and acute renal failure caused by matrix calculi. CASE REPORT
A 77-year-old man presented to the emergency room with anuria and urosepsis. Serum chemistry studies revealed blood urea nitrogen 177 mg./dl. (normal 8 to 24), serum creatinine 14.3 mg./dl. (normal 0.7to 1.5)and serum calcium 9.8 mg./dl. (normal 8.4to 10.4).The patient underwent dialysis and received intravenous antibiotics. Renal ultrasound showed right hydronephrosis and left hydroureter. Bilateral percutaneous nephrostomy tubes were placed and nephrostograms confirmed bilateral ureteral obstruction with multiple filling defects in the leR ureter (fig. 1).Abdominal x-ray was normal (fig. 2). Computerized tomography (CT) revealed calcified material in both ureters and the bladder (fig. 3). Urinalysis showed pyuria, bacteriuria and a pH of 7.5. Urine culture yielded Proteus mirabilis. The patient had no history of urolithiasis. Creatinine became stable at 2.5 mgJdl. Cystoscopy was performed and a tan gelatinous material was retrieved from the bladder. The material could not be completelyirrigated or extracted from the bladder. A matrix calculus was suspected, and cystolithotomy and left ureterolithotomy were performed. The right ureter was successfully milked of the proteinaceous material. The specimen weighed 40 gm. and Accepted for publication February 17, 1995.
FIG.2. Abdominal x-ray shows no evidence of radiopaque
CalCUlU.
FIG.3. Abdoahal CT demonstrates high attenuation material in bladder and ureters.
chemical analysis revealed a matrix calculus that was 65% matrix and 3596 crystalline component by weight (fig. 4). FIG. 1. Lee nephrostogram reveals multiple radiolucent filling infrared spectnurcopic analysis determined the c r y s e e defects in ureter. component to be a complex phosphate compound of calcium 1125
MATRIX CALCULUS
1126
hydrogen phosphate and magnesium hydrogen phosphate. Followup nephrostograms showed the patient to be stone-
free. DISCUSSION
Urinary calculi contain a crystalline salt component and a noncrystalline mucoprotein matrix. The matrix component of calcigerous calculi is 2.5% of the dry weight, whereas in matrix calculi it averages around 65% (range 42 to 84).1 The matrix is composed of approximately 64% protein, 9% free sugars, 5% glucosamines, 10%water and 12% inorganic ash.' The role of matrix in stone formation remains unclear. Some believe that matrix serves as an architectural template with the deposition of crystals being a secondary phenomenon. Others believe matrix to be a coprecipitate in a basically mineralogical process. Furthermore, why matrix calculi fail to undergo complete calcification is not known. Diminished
renal excretion of calcium has been proposed but urine studies from these patients are often normal.2 Matrix stones are typically tan in color and have a gelatinous or putty-like consistency. They often feel gritty because of the crystalline component. Although matrix calculi are usually radiolucent, finely stippled calcifications may sometimes be identified on plain film.On CT these nonopaque calculi can be identified and usually distinguished from other causes of radiolucent filling defects in the collecting system. The crystalline component, frequently a calcium salt, results in a relatively high attenuation on CT. These stones can also be identified on ultrasound but there may or may not be acoustic shadowing depending on the amount of mineralization.3 These studies cannot Werentiate matrix from uric acid calculi. There has been 1report of matrix calculi with no mineral content and soft tissue attenuation on CT.3 Matrix calculi are best treated by percutaneous or surgical extraction, sterilization of the urine and maintenance of a dilute urine. Extracorporeal lithotripsy is unsuccessful due to the gelatinous nature of this stone and its lack of a crystalline structure. Urinary obstruction frequently occurs since these stones are able to conform to the shape of the ureter. To our knowledge our report represents the first case of bilateral ureteral obstruction. Matrix calculi invariably occur in the presence of urinary infection, usually Proteus species or Escherichia coli.2 Matrix stones have been noted to occur frequently in chronic stone formers.2 REFERENCES
1. Boyce, W.H.and King, J. S., Jr.: Crystal-matrixinterrelations in calculi. J. Urol., 81: 351, 1959. 2. Stoller, M. L., Gupta, M., Bolton, D. and Irby, P. B.: Clinical correlates of the gross, radiographic and histologic features of urinary matrix calculi. J. Endourol., 8:335, 1994. 3. Sheppard, P.W. and white, F. E.: Demonstration of a matrix calculus using computed tomography. Brit. J. Ftad., 60:1028, 1987.
Val. 154, 1125-1 126. September 1996 Printed in U S A
A MATRIX CALCULUS CAUSING BILATERAL URETERAL OBSTRUCTION AND ACUTE RENAL FAILURE LEE ANNE MATTHEWS
AND
J. PATRICK SPIRNAK
From Case Western Reserve University School of Medicine and MetroHealth Medical Center, Cleveland, Ohio
KEYWORDS: calculi, kidney, ureter
Matrix calculi are radiolucent concretions composed primarily of a noncrystalline mucoprotein matrix. They are typically associated with urinary infection and management requires surgical extraction. To our knowledge we report the first case of bilateral ureteral obstruction and acute renal failure caused by matrix calculi. CASE REPORT
A 77-year-old man presented to the emergency room with anuria and urosepsis. Serum chemistry studies revealed blood urea nitrogen 177 mg./dl. (normal 8 to 24), serum creatinine 14.3 mg./dl. (normal 0.7to 1.5)and serum calcium 9.8 mg./dl. (normal 8.4to 10.4).The patient underwent dialysis and received intravenous antibiotics. Renal ultrasound showed right hydronephrosis and left hydroureter. Bilateral percutaneous nephrostomy tubes were placed and nephrostograms confirmed bilateral ureteral obstruction with multiple filling defects in the leR ureter (fig. 1).Abdominal x-ray was normal (fig. 2). Computerized tomography (CT) revealed calcified material in both ureters and the bladder (fig. 3). Urinalysis showed pyuria, bacteriuria and a pH of 7.5. Urine culture yielded Proteus mirabilis. The patient had no history of urolithiasis. Creatinine became stable at 2.5 mgJdl. Cystoscopy was performed and a tan gelatinous material was retrieved from the bladder. The material could not be completelyirrigated or extracted from the bladder. A matrix calculus was suspected, and cystolithotomy and left ureterolithotomy were performed. The right ureter was successfully milked of the proteinaceous material. The specimen weighed 40 gm. and Accepted for publication February 17, 1995.
FIG.2. Abdominal x-ray shows no evidence of radiopaque
CalCUlU.
FIG.3. Abdoahal CT demonstrates high attenuation material in bladder and ureters.
chemical analysis revealed a matrix calculus that was 65% matrix and 3596 crystalline component by weight (fig. 4). FIG. 1. Lee nephrostogram reveals multiple radiolucent filling infrared spectnurcopic analysis determined the c r y s e e defects in ureter. component to be a complex phosphate compound of calcium 1125
MATRIX CALCULUS
1126
hydrogen phosphate and magnesium hydrogen phosphate. Followup nephrostograms showed the patient to be stone-
free. DISCUSSION
Urinary calculi contain a crystalline salt component and a noncrystalline mucoprotein matrix. The matrix component of calcigerous calculi is 2.5% of the dry weight, whereas in matrix calculi it averages around 65% (range 42 to 84).1 The matrix is composed of approximately 64% protein, 9% free sugars, 5% glucosamines, 10%water and 12% inorganic ash.' The role of matrix in stone formation remains unclear. Some believe that matrix serves as an architectural template with the deposition of crystals being a secondary phenomenon. Others believe matrix to be a coprecipitate in a basically mineralogical process. Furthermore, why matrix calculi fail to undergo complete calcification is not known. Diminished
renal excretion of calcium has been proposed but urine studies from these patients are often normal.2 Matrix stones are typically tan in color and have a gelatinous or putty-like consistency. They often feel gritty because of the crystalline component. Although matrix calculi are usually radiolucent, finely stippled calcifications may sometimes be identified on plain film.On CT these nonopaque calculi can be identified and usually distinguished from other causes of radiolucent filling defects in the collecting system. The crystalline component, frequently a calcium salt, results in a relatively high attenuation on CT. These stones can also be identified on ultrasound but there may or may not be acoustic shadowing depending on the amount of mineralization.3 These studies cannot Werentiate matrix from uric acid calculi. There has been 1report of matrix calculi with no mineral content and soft tissue attenuation on CT.3 Matrix calculi are best treated by percutaneous or surgical extraction, sterilization of the urine and maintenance of a dilute urine. Extracorporeal lithotripsy is unsuccessful due to the gelatinous nature of this stone and its lack of a crystalline structure. Urinary obstruction frequently occurs since these stones are able to conform to the shape of the ureter. To our knowledge our report represents the first case of bilateral ureteral obstruction. Matrix calculi invariably occur in the presence of urinary infection, usually Proteus species or Escherichia coli.2 Matrix stones have been noted to occur frequently in chronic stone formers.2 REFERENCES
1. Boyce, W.H.and King, J. S., Jr.: Crystal-matrixinterrelations in calculi. J. Urol., 81: 351, 1959. 2. Stoller, M. L., Gupta, M., Bolton, D. and Irby, P. B.: Clinical correlates of the gross, radiographic and histologic features of urinary matrix calculi. J. Endourol., 8:335, 1994. 3. Sheppard, P.W. and white, F. E.: Demonstration of a matrix calculus using computed tomography. Brit. J. Ftad., 60:1028, 1987.