Urologic Issues for the Nephrologist 신장내과 위 지 완

Contents Management of Stone Disease Management of Urinary Tract Obstruction Investigation of Hematuria

Management of Stone Disease

Changing use of techniques for stone removal The management of urinary tract stones has been irrevocably changed by the introduction of extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), and ureteroscopy

Advances in Imaging for Urinary Tract Stones TOC Non-contrast CT or Ultrasonography Sensitivity CT 88% > USG 54-57%

Treatment of Urinary Tract Stones Spontaneous stone passage can be expected in up to 80% of patients with a stone size smaller than 4mm Stones >7mm : spontaneous stone passage is very low The location is also important Distal ureteral stone: ~70% pass spontaneously Midureteral stone: 45% Proximal ureteral stone: 25%

Treatment of Urinary Tract Stones Intervention indication Persistent pain (>72 hours) despite adequate analgesia Persistent obstruction with risk of impaired renal function Bilateral obstruction Associated urinary tract sepsis Medical expulsive therapy <10mm Alpha blocker (Tamsulosin, terazosin, doxzosin) Nifedipine 30mg once daily Relaxes the distal ureter -> stone passage

Acute Surgical Intervention Well enough for general anesthesia Ureteroscopic stone destruction Alternatively, a double-J stent can be inserted, which will relieve obstruction until definitive treatment is performed Uncontrolled urinary tract infection Percutaneous nephrostomy (PCN) - preferred option It can be performed with local anesthesia and is less likely than endoscopic surgery to cause septicemia Contrast material is injected through a percutaneous nephrostomy tube placed in the lower pole calyx (arrow).The contrast material outlines a single large calculus (arrowheads) producing complete obstruction at the pelviureteral junction.

Management of Symptomatic Nephrolithiasis

Treatment options Radioopaque(Ca), ≤2cm Preference Procedure 1 ESWL 2 PNL Radioopaque(Ca), >2cm Preference Procedure 1 PNL 2 ESWL Radiolucent(Uric acid) Preference Procedure 1 Oral chemolysis 2 ESWL+ oral chemolysis Staghorn stone Preference Procedure 1 PNL 2 ESWL

Extracorporeal Shock Wave Lithotripsy First-line treatment for more than 75% of stone patients Acoustic shock wave energy is delivered to a stone under fluoroscopic or ultrasound guidance Treatment sessions - 30 minutes, 1500~2500 shock waves Stones up to 20mm in size, stone-free rates 60-98% Cystine and calcium oxalate monohydrate stones - resistant

Extracorporeal Shock Wave Lithotripsy Contraindication Aortic or renal artery aneurysm Uncontrolled urinary tract infection Coagulation disorders Pregnant women Complication Hemorrhage Hematoma Infection Injury to adjacent organs

Percutaneous Nephrolithotomy

Percutaneous Nephrolithotomy Procedure Retrograde ureteral catheter placed Renal collecting system accessed(dorsal calyx of the lower pole) under fluoroscopic guidance Dilatation of the tract with a nephrostomy balloon dilatator Calculi extracted with grasping forceps using nephroscope, fragmented using an ultrasonic, pneumatic lithotripsy probe Complication Hemorrhage Sepsis Fluid overload (similar to transurethral resection syndrome) Injury to spleen, pleura, or colon

Ureteroscopy Ureteroscopy continues to be the treatment of choice for the majority of middle and distal ureteral stones Semirigid or flexible (allow access to the renal pelvis and calyces) Stone fragmentation by laser, ultrasound, pneumatic devices Laser use - allowing intrarenal stone fragmentation, low tissue penetration, minimal stone displacement Complications of ureteroscopy (particularly graspers and baskets) Ureteral avulsion, perforation, extravasation, mucosal damage, hematuria, infection, stricture Advances in laser technology now enable stones to be reduced to dust-like particles, reducing the need for graspers and baskets and hence reducing complications.

Stones in Transplanted Kidneys The management of stone disease in a transplanted kidney is challenging because of the solitary kidney, the anatomic location within the pelvis, and the difficulty with retrograde access to the ureter and kidney Early active intervention is indicated Prophylactic stenting, ureteroscopy, and PCNL are preferred to ESWL because stone targeting may not be possible

Management of Urinary Tract Obstruction

Causes and Presentation Malignant disease can be a result of direct tumor invasion or external compression by metastatic lymph node involvement or, rarely, true metastasis to the ureter 70% - genitourinary (cervical, bladder, prostate) in origin Remainder – breast, gastrointestinal carcinomas and lymphoma Presentation Vary significantly Remain unrecognized until the patient develops anuria and uremia 

Acute Management of Urinary Tract Obstruction Relief of obstruction is crucial to reverse renal impairment and to preserve remaining renal function Bladder outflow obstruction: urethral or suprapubic catheter Upper tract obstruction: double-J ureteral stent In whom the procedure fails: PCN Tumor infiltration can distort trigonal anatomy, making identification of ureteral orifices for double-J stent insertion impossible Stents fail to relieve obstruction in 40-50% of cases of external ureteral compression

Acute Management of Urinary Tract Obstruction Patient with sepsis, not be fit for general anesthesia PCN → antegrade ureteral stenting Bilateral ureteral obstruction Not always necessary to insert bilateral PCN tubes Significant palliation and return to nearly normal renal function can be accomplished by drainage of a single kidney, preferably the unit with the better preserved parenchyma as determined by CT scan or ultrasound Complications of ureteral stent or PCN Migration, obstruction(stent>PCN), infection(PCN>stent), fragmentation, erosion through the urinary tract, lower urinary tract symptoms As many as 70% of patients with stents report lower urinary tract symptoms (LUITS), mainly urgency, frequency, and nocturia as well as pain along the urinary tract. Extra-anatomic stents are an alternative for patients in whom conventional stent insertion has failed or for whom permanent nephrostomy drainage is unacceptable. An extra-anatomic stent is placed by an initial percutaneous puncture and insertion of the upper end of a long (50-cm) double-J stent into the kidney. A subcutaneous tunnel is then created to bring the stent to the level of the iliac crest. Another tunnel is fashioned to bring the lower end of the stent out suprapubically, followed, finally, by suprapubic puncture of a full bladder and insertion of the lower end (Fig. 61-6).11 Extra-anatomic stents are usually changed at 6-month intervals, and preliminary experience confirms their value in maintaining ureteral patency and avoiding PCN

Investigation of Hematuria

Casuses of hematuria

Outcome of Evaluation in a Hematuria A prospective analysis of 1,930 patients with hematuria to evaluate current diagnostic practice.J Urol. 163:524-527 2000

Evaluation of Macroscopic Hematuria All adults with a single episode of macrohematuria require full urologic evaluation, including renal imaging and cystoscopy The only exception < 40 years Hx of characteristic of glomerular hematuria (dark brown hematuria lasting 24 to 48 hours coincides with intercurrent mucosal infection, usually of the upper respiratory tract) Should be referred first for nephrologist Typically seen in IgAN

Evaluation of Microhematuria Patients with urinary tract infection should be treated appropriately, and urinalysis should be repeated 6 weeks after treatment. The use of adjuncts to AMH workup such as urine cytology and other urine biomarkers is no longer advocated.