Eli K. Michaels

Bacteriuria Following Extracorporeal Shock Wave Lithotripsy of Infection Stones

Extracorporeal shock wave lithotripsy effectively pulverizes infected (struvite) renal calculi. However, after treatment minute residual fragments that may harbor bacteria and cause persistent bacteriuria remain in the renal collecting system for months. We investigated prospectively the incidence of persistent Proteus mirabilis bacteriuria after extracorporeal shock wave lithotripsy among 15 consecutive women with Proteus mirabilis urinary tract infections and struvite calculi. All patients received parenteral gentamicin for 3 to 8 days (mean 4.7 days) immediately before and after extracorporeal shock wave lithotripsy. Oral antimicrobials then were administered for 14 to 34 days (mean 25 days). Ten patients have maintained a sterile urine or experienced urinary reinfection by other organisms during 8 to 19 months (mean 13 months) of subsequent bacteriological surveillance. Of these 10 patients 9 had residual fragments. Five patients had Proteus mirabilis bacteriuria after 1 to 7 months of surveillance, including 3 with residual fragments. The mean stone size, methods and duration of renal drainage procedures, and duration of antimicrobial therapy were similar for the 2 patient groups. Proteus mirabilis was isolated from the cultures of only 3 of 11 retrievable stone fragments. In contrast to intact infected renal calculi, residual stone fragments after extracorporeal shock wave lithotripsy often are susceptible to sterilization with antimicrobials.

Extracorporeal Shock Wave Lithotripsy for Struvite Renal Calculi: Prospective Study with Extended Followup

To clarify the significance of retained stone particles after extracorporeal shock wave lithotripsy (ESWL) for struvite renal calculi we followed 22 otherwise healthy women for 16 to 52 months (mean 39 months). Each patient had persistent Proteus mirabilis bacteriuria before ESWL and received a standardized regimen of antimicrobial therapy in the perioperative period only. Of the 22 patients 19 (86%) were cured of the persistent bacteriuria. Of these 19 patients 16 had retained stone particles at the beginning of surveillance and 10 had retained particles at last followup. None of the particles produced symptoms or enlarged. However, 1 of the patients who was rendered stone-free had a P. mirabilis reinfection at 20 months and a new stone developed. Of the 22 patients 3 (14%) had continued persistent P. mirabilis bacteriuria after ESWL. Two patients were subsequently cured of the infection with antibiotics alone (1), and with antibiotics and extraction of a new ureteral stone (1). The remaining patient had expansion of retained stone particles after 51 months of surveillance. We conclude that a stone-free kidney is an unrealistic objective of ESWL monotherapy for struvite renal calculi. However, the treatment usually will eradicate the accompanying persistent bacteriuria and sterile stone particles will not enlarge during the first 2 to 4 years after treatment.

Use of a neural network to predict stone growth after shock wave lithotripsy

OBJECTIVES To determine whether a neural network is superior to standard computational methods in predicting stone regrowth after shock wave lithotripsy (SWL) and to determine whether the presence of residual fragments, as an independent variable, increases risk. METHODS We reviewed the records of 98 patients with renal or ureteral calculi treated by primary SWL at a single institution and followed up for at least 1 year; residual stone fragment growth or new stone occurrence was determined from abdominal radiographs. A neural network was programmed and trained to predict an increased stone volume over time utilizing input variables, including previous stone events, metabolic abnormality, directed medical therapy, infection, caliectasis, and residual fragments after SWL. Patient data were partitioned into a training set of 65 examples and a test set of 33. The neural network did not encounter the test set until training was complete. RESULTS The average follow-up period was 3.5 years (range 1 to 10). Of 98 patients, 47 had residual stone fragments 3 months after SWL; of these 47, 8 had increased stone volume at last follow-up visit. Of 51 patients stone free after SWL, 4 had stone recurrence. Coexisting risk factors were incorporated into a neural computational model to determine which of the risk factors was individually predictive of stone growth. The classification accuracy of the neural model in the test set was 91%, with a sensitivity of 91%, a specificity of 92%, and a receiver operating characteristic curve area of 0.964, results significantly better than those yielded by linear and quadratic discriminant function analysis. CONCLUSIONS A computational tool was developed to predict accurately the risk of future stone activity in patients treated by SWL. Use of the neural network demonstrates that none of the risk factors for stone growth, including the presence of residual fragments, is individually predictive of continuing stone formation.

ESWL monotherapy for large-volume renal calculi: Efficacy and morbidity

We assessed the efficacy and morbidity of extracorporeal shock-wave lithotripsy (ESWL) monotherapy in the treatment of 25 consecutive patients with large-volume renal calculi (surface area greater than or equal to 5.0 cm2). Eighteen of the calculi were infection (struvite) stones and 7 were sterile stones. In 21 cases internal ureteral stents were positioned before ESWL, but no patient underwent pretreatment percutaneous nephrostomy (PCN) or percutaneous nephrostolithotomy (PNL). An average of 2.1 procedures including ESWL, PCN, or ureteral interventions were required to achieve a stone-free renal collecting system and ureter, or residual stone particles less than 4 mm in diameter confined to the renal collecting system. Sixty percent of the patients required no ancillary procedures after ESWL. There were no differences in the mean duration of hospitalization, need for post-treatment ancillary procedures, time to clearance of ureteral fragments, and incidence of residual stone particles among patients with infection and sterile stones. Of 23 patients observed greater than three months (mean 10.9 mos) after ESWL, 43 percent had residual stone particles in the renal collecting system. Expansion of these particles or stone recurrence in the absence of residual particles has not been observed. We conclude that large volume renal calculi may be managed effectively and safely with ESWL monotherapy.

Inadvertent Fracture of Gallstones During Extracorporeal Shock Wave Lithotripsy

Abstract We report a case of inadvertent fragmentation of gallstones during extracorporeal shock wave lithotripsy for treatment of a renal stone.

Nephrocalcin in Patients with Renal Cell Carcinoma

Nephrocalcin, an acidic glycoprotein that inhibits calcium oxalate crystal growth, has been previously localized in proximal tubules of kidneys by an immunohistochemical staining method and purified from tissue culture media of 2 renal carcinoma cell lines. A polyclonal antibody specific to nephrocalcin was raised in rabbits and the level of nephrocalcin was quantitatively determined in urine of 19 renal cell carcinoma patients (0.241 +/- 0.341 microgram nephrocalcin per mg. creatinine) and compared to healthy controls (0.022 +/- 0.012 micrograms nephrocalcin per mg. creatinine). Nephrocalcin levels after tumor nephrectomy decreased dramatically in 5 patients and to a lesser degree in 7. A specific nephrocalcin fraction that was eluted from an anion exchange column with low ionic strength was detected in urine of the renal cell carcinoma patients, and this fraction decreased or disappeared after tumor nephrectomy in 6 of 9 patients studied. Amino acid composition, phosphate content and dissociation constants toward calcium oxalate monohydrate crystals were investigated in the nephrocalcin from tumor patients and compared to that from healthy controls. Our studies demonstrate that nephrocalcin in patients with renal cell carcinoma is atypical and usually in much higher quantity. Further studies are needed to determine the clinical significance of these observations.

Immunohistochemical localization of nephrocalcin, a kidney-specific glycoprotein, to renal cell carcinoma

OBJECTIVES Nephrocalcin (NC), an acidic glycoprotein produced by renal proximal tubule cells and functioning as an inhibitor of calcium oxalate monohydrate crystalization, has been previously shown to have increased urinary excretion in patients with renal cell carcinoma (RCC). The current study uses immunohistochemical techniques to localize NC to cells of primary RCC. METHODS We studied 29 kidneys removed because of RCC. Slides were deparaffinized and stained after incubating with anti-NC antibody by using the avidin-biotin-peroxidase complex techniques. Uptake of stain by tumor cells and adjacent normal renal cells was compared. RESULTS Twenty-seven kidneys (93%) showed positive staining for RCC tumor cells; 2 kidneys staining positive for normal proximal tubule cells failed to stain adjacent RCC tumor cells (7%). CONCLUSIONS The data suggest that enhanced production of urinary NC in patients with RCC derives from cells of the primary tumor.

Diagnostic Artificial Erection Without Corpus Cavernosum Injection

The vacuum erection device can be used to produce an artificial erection for documentation of penile curvature. This technique is illustrated in the preoperative evaluation of a patient with Peyronies disease.

Extracorporeal shock-wave lithotripsy in hypertensive patients Importance of pretreatment cardiac evaluation

Abstract We report a case of acute hypertension and congestive heart failure during extracorporeal shock-wave lithotripsy in a woman with pre-existing hypertension.

The Risk of Persistent Bacteriuria after Extracorporeal Shock Wave Lithotripsy of Infection Stones: A Prospective Study

Extracorporeal shock wave lithotripsy (ESWL) effectively pulverizes infected (struvite) renal calculi. However, after ESWL minute residual fragments which may harbor bacteria and cause persistent bacteriuria can remain in the renal collecting system for months. We investigated prospectively the incidence of persistent Proteus mirabilis bacteriuria after ESWL among 20 consecutive women with P. mirabilis urinary tract infections and struvite calculi. All patients received parenteral gentamicin for three to 13 (mean 4.9) days immediately before and after ESWL. Oral antimicrobials were then administered for 14 to 70 (mean 31) days. Fifteen patients maintained a sterile urine or experienced urinary reinfection by other organisms during five to 22 (mean 14) months of subsequent bacteriologic surveillance. Nine of these 15 patients had residual fragments at last follow-up. Five patients developed P. mirabilis bacteriuria after one to seven months of surveillance. Three of these five patients had residual fragments. The mean stone size, methods of and duration of renal drainage procedures, and duration of antimicrobial therapy were similar for the two patient groups. P. mirabilis was isolated from the cultures of only three of 16 retrievable stone fragments. In contrast to intact infected renal calculi, residual stone fragments after ESWL are often susceptible to sterilization with antimicrobials.