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NEPHROLITHIASIS Suo Wang Department of Urology, the First Affiliated Hospital, College of Medicine, Zhejiang University Slide 2 Chapter 1 Etiology, Epidemiology, and Pathogenesis 1 About 3% to 12% of the population will develop symptomatic nephrolithiasis during their lifetime; 2 Male: female is 3 6:1; 3 different prevalence of stone disease in different race, area, climate, age, weight and body mass index; ; 4 Upper: lower urinary tract stones is 5:1. Slide 3 PHYSICOCHEMISTRY It begins with urine that becomes supersaturated with respect to stone-forming salts, such that dissolved ions or molecules precipitate out of solution and form crystals or nuclei. Once formed, crystals may flow out with the urine or become retained in the kidney at anchoring sites that promote growth and aggregation, ultimately leading to stone formation. Slide 4 MINERAL METABOLISM Urine must be supersaturated for stones to form. Supersaturation alone is not sufficient for crystallization to occur in urine, owing to the presence of urinary inhibitors; PTH enhances proximal tubular reabsorption of calcium and reduces renal phosphate excretion; Upper urinary tract stones: oxalate Lower urinary tract stones: phosphate Slide 5 Urine pH Oxalate, phosphate, uric acid inhibitors of crystal nucleation, growth, or aggregation (Nephrocalcin, uropontin, and Tamm-Horsfall protein) Inflammation, bacteria Acidic urine ( Uric acid, Cystine ) Alkaline urine ( phosphate, carbonate ) Slide 6 Infection Stones: Infection stones, namely struvite, are composed primarily of magnesium ammonium phosphate hexahydrate but may in addition contain calcium phosphate in the form of carbonate apatite. Struvite stones occur only in association with urinary infection by urea-splitting bacteria. Uric acid stone The most important determinant of uric acid stone formation is low urinary pH. Slide 7 Plain film of a patient with bilateral staghorn calculi composed entirely of struvite. This patient had a history of recurrent urinary tract infections dating back 15 years. Slide 8 A, Plain film tomographic appearance of a lower pole partial staghorn uric acid calculus. B, The addition of intravenous contrast material demonstrates the stone as a filling defect during the excretory portion of the intravenous pyelogram. (Uric acid calculi ) Slide 9 Cystine calculi are radiopaque on plain film but are less dense than other calcium-based calculi. Notice the stone within the lower pole of this duplicated system (A). Similar to uric acid stones, the cystine calculus is more clearly distinguished during the excretory phase of the intravenous pyelogram (B). Slide 10 Slide 11 Risk factors: 1. Epidemiology : race, area, climate, age, genetics. 2. Anatomy: Obsrtuction, BPH. 3. infection: Struvite stones. 4. Dietary factors ; 5. others:malignance, bowel diseases. Slide 12 Slide 13 Slide 14 Pathophysiology Stone formation occurred in kidney and urinary bladder. Kidney ureter; bladder urethra Slide 15 Outcomes of urinary tract calculi : Direct injuries; Obstruction, hydronephrosis, urinary retention; Infection, UTI; Malignance. squamous cell carcinoma of the renal pelvis. Slide 16 Renal and ureteral calculi. Three distinct narrowings of ureter 1. the ureteropelvic junction; 2. crossing of the iliac vessels; 3. the ureterovesical junction. Chapter 2 Upper Urinary Tract Calculi Slide 17 The ureter demonstrating sites of normal functional or anatomic narrowing at the ureteropelvic junction (UPJ), the iliac vessels, and the ureterovesical junction (UVJ). Slide 18 Clinical presentation: Hematuria, gross or microscopic hematuria, latter is more common; dull flank pain; renal colic, severe flank pain in the costovertebral angel area of the back and extending anteriorly and inferiorly on the abdomen, sometimes cause pain in scrotum and testes; Symptoms of bladder irritability may be noted when ureteral stone approaches the bladder; Nausea, vomit; Symptoms of urinary tract infection: fever, lower urinary tract syndrome. Slide 19 Physical examination: Tenderness in the flank area on the side of involved kidney; A palpable mass in the upper quadrant area in some patients with chronic hydronephrosis; Nausea, vomit; Symptoms of urinary tract infection: fever, lower urinary tract syndrome. Slide 20 Diagnosis Patient history and physical examination; Hematuria and pain, especially renal coli after movement; Urinalysis: hematuria, pyuria, urinary PH changes, crystals; Differentiated diagnosis: acute appendititis, ectopic pregnancy, bile duct stone, pyelitis. Slide 21 1 KUB: 90% stones could be found in KUB. calcium oxalate, calcium phosphate, magnesium ammonium phosphate, cystine stones are usually radiopaque. U ric acid and xanthine stones are negative in KUB. 2 IVU intravenous pyelogram may be obtained to confirm the presence of radiolucent stones and also to identify any anatomic abnormalities that may predispose the patient to stone formation. IVU is also useful in detecting the site and extent of obstruction. In patients with significant azotemia (creatinine>3mg/dl), caution should be exercised in use of IVU. 3 Sonography non-invasive, the first-line imaging modality when renal colic is suspected in pregnancy. 4 Metabolic evaluation. Diagnosis Slide 22 Slide 23 Slide 24 Slide 25 Slide 26 steinstrasse Slide 27 Slide 28 Slide 29 Slide 30 4 RGP: retrograde pyelography 6 CT, to quickly image the entire collecting system in a rapid sequence, is also useful to detect non-opaque calculi as well as opaque calculi. 7 ECT 8 cystoscopy, ureteroscopy Diagnosis Slide 31 Slide 32 management Many factors should be considered in choosing the appropriate management: the size, location of the calculi, obstruction, infection, renal function. Slide 33 Conservative management Size