3/2/2014
Management of Urinary Tract Stones
Debbie Sullivan, PhD, PA-C March 6, 2014
Objectives
• Identify risk factors for developing urinary tract stones (UTS) • Recognize signs and symptoms associated with UTS • Compare and contrast diagnostic studies useful in evaluating the patient with UTS • Discuss indications and rationale for metabolic work- up of patients with stone disease • Describe medical and surgical management of stone disease
Overview of Stone Disease
} UTS affects up to 12% of population during their lifetime } Prevalence has increased annually over the past 5 years } Third most common affliction of the urinary tract, exceeded only by infections and pathologic conditions of the prostate } Recurrence rates approach 50% at 10 years } Mortality is rare, although there is a 28% chance of renal deterioration with certain stone types
1 3/2/2014
Most Common Types of Stones
} Calcium oxalate } Uric acid } Struvite } Cystine
2 3/2/2014
Risk Factors: Dietary/Lifestyle
} Diet high in animal protein, increase in fatty acids; decrease in fiber } Dehydration/ low urine volume } High sodium intake } High temperatures } Sedentary lifestyle; immobilization } Family history of urinary stones
Risk Factors: Metabolic Conditions
} Hypercalciuria } Hyperoxaluria } Hyperuricosuria } Hypocitraturia } Urine pH } Acidic } Alkaline
Risk Factors: Disease States
} Metabolic acidosis } Chronic diarrhea } Inflammatory bowel disease } Hyperparathyroidism } Metabolic/obesity syndrome } Sarcoidosis } Medullary sponge kidney } Adult polycystic kidney disease } Pregnancy
3 3/2/2014
Risk Factors: Medications
} Vitamin C } Vitamin D } Triameterene } Protease inhibitors: indinavir and nelfinavir } Furosemide } Acetazolamide } Urisosuric agents: salicylates, probenecid } Long term use of antacids containing silica
Signs and Symptoms of UTS
} Renal colic: acute onset of severe colicky flank pain radiating to the groin or scrotum } As stone descends, pain may localize to the abdomen } As stone approaches the UVJ, pain may be more lower abdominal, with dysuria, urgency, frequency } Infection may occur in presence of stone } Cystitis } Pyelonephritis or pyonephrosis
Signs and Symptoms of UTS
} Gross or microscopic hematuria is present in ~90% of patients; however, absence of hematuria does not rule out stone } Nausea and vomiting } Fever } Leukocytosis } Sepsis: fever, tachycardia, hypotension } Indicates medical emergency!
4 3/2/2014
Differential Diagnoses
} Renal, ureteral or bladder stone } Hydronephrosis } Bacterial cystitis or pyelonephritis } Acute abdomen: appendicitis; bowel, biliary, pancreatic sources; AAA } GYN: ectopic pregnancy, ovarian cyst or torsion } Male: testicular torsion } Radicular pain (sciatica, L1 herpes zoster) } Referred pain (orchitis)
Laboratory Studies
} Urinalysis: nitrites, leukocyte esterase } Urine culture/sensitivity: even if UA negative } Women: pregnancy test } Hematologic tests: } CBC } BMP
Diagnostic Imaging
} CT of abdomen and pelvis } Non-contrast } Detects most stones and screens for other conditions } Renal ultrasound } Includes kidneys and bladder } May show hydronephrosis } Plain KUB
5 3/2/2014
Metabolic Work-up
} Controversy over whether or not to get metabolic work up with first stone } High risk patients should probably have metabolic work up: } Pediatric stone formers } Recurrent/chronic UTI } Solitary kidney } Family hx of stones } Staghorn or multiple stones } Gout, GI diseases associated with stones; bone disease
Metabolic Work-up
} Stone analysis if recovered stone } UA and urine culture } 24 hour urine study: pH, volume, sodium, potassium, calcium, magnesium, phosphate, uric acid, oxalate, citrate, protein, creatinine and qualitative cystine } Serum studies: sodium, potassium, bicarbonate, chloride, calcium, phostate, uric acid, alkaline phosphatase, creatinine, parathyroid hormone
Indications for Acute Intervention
} Complete or high grade unilateral obstruction } Any degree of bilateral obstruction } Any degree of obstruction in patient with a solitary kidney } Urinary infection or sepsis } Any degree of obstruction with a rising creatinine } Inability to tolerate liquids or oral medication } Pain not controlled by oral analgesics
6 3/2/2014
Medical Management
} Trial of passage: reasonable where renal function is adequate, sufficient pain control, adequate oral intake, absence of infection and stone size < 10 mm } Stone more likely to pass when located in distal ureter } 70-80% of stones ≤ 5 mm will pass, mean time = 22 days
Medical Management
} Oral hydration } Oral pain medications } Medical expulsion therapy (MET) NOT FDA APPROVED } Patients undergoing trial of passage should be followed with periodic imaging to monitor stone position and assess for hydronephrosis
Medical Expulsion Therapy (MET)
} Alpha-blockers } Ureter contains alpha-1 receptors that mediate contraction of the ureteral smooth muscle, so alpha blockers relax the ureter smooth muscle } Increases stone passage rate } Decreases time to pass stone by 2-4 days } Decreases pain during stone passage
7 3/2/2014
Medical Expulsion Therapy (MET)
} Tamsulosin (Flomax) has been most widely studied } Terazosin (Hytrin) and doxazosin (Cardura) equally effective } Calcium channel blockers have also been studied } Nifidepine (Adalat, Procardia and others)
Surgical Interventions
} Surgical interventions should be delayed until infection has resolved following appropriate antimicrobial therapy } Interventions to relieve obstruction may be needed before definitive stone treatment } Ureteral stent } Percutaneous nephrostomy tube (PCN)
Ureteral Stent
•Temporary measure to bypass the obstruction to allow kidney to drain •Relieve pain from hydronephrosis •May cause lower urinary tract symptoms •After definitive stone treatment, stent has to be removed •Stent may be placed in conjunction with ESWL or ureteroscopic laser lithotripsy •Complications: stent migration, UTI, breakage, encrustation, obstruction
8 3/2/2014
Percutaneous Nephrostomy (PCN)
} Conscious sedation; usually done by Interventional Radiologist } External drainage bag will require minimal care } Potential source for infection } Need to exchange on a regular basis if in longer than 4 weeks
Surgical Interventions
} Extracorporal Shock Wave Lithotripsy (ESWL) } Ureteroscopic stone extraction } Percutaneous nephrolithotomy } Open stone extraction
ESWL } Non-invasive; general anesthesia; outpatient procedure } Absolute contraindications: } Pregnancy } Coagulopathy } UTI } Renal artery or abdominal aorta aneurysm } Intrarenal vascular calcifications near shock wave focus
9 3/2/2014
Potential Complications
} Renal or retroperitoneal hematoma } Ecchymosis or petechiae } UTI: 5% } Sepsis: < 3% } Steinstrasse (“stone street”) 4-8% } Ureteral stricture – < 2%
Ureteroscopic Stone Extraction
} Requires general anesthesia } Extraction of lower ureteral calculus } Baskets and graspers may be used } Stone-free rates approach 95% } Variety of lithotrites, such as Holmium laser, placed through the ureteroscope to fragment stones } Stenting following ureteroscopy is optional
Potential Complications
} Ureteral avulsion: ≤ 0.5% } Ureteral perforation: < 5% } Submucosal tunneling: < 5% } Stricture: 1% } UTI: < 4% } Bleeding and pain
10 3/2/2014
Percutaneous Nephrolithotomy (PCNL)
} PCNL removes stone through percutaneous access that traverses through the back and into the kidney } Treatment of choice for renal or proximal ureteral stones or staghorn calculi } Indicated if failure of other treatments, renal stones > 2 cm, stone in calyceal diverticulum or UPJ obstruction with stone
Contraindications to PCNL
} UTI/sepsis } Coagulopathy } Safe renal access not possible
Potential Complications
} Bleeding: risk of transfusion 3% } Sepsis } Renal pelvis perforation } Pneumothorax/hydrothorax } Intraperitoneal injury
11 3/2/2014
Bladder Stones
} Cystoscopic extraction } Bladder irrigation reserved for patients who cannot tolerate or who refuse surgical removal } Men with bladder stones and enlarged prostate at increased risk for Bladder Outlet Obstruction; may need prostate treatment in conjunction with cystoscopy or cystolithopaxy
Stone Prevention } Hydrate, hydrate, hydrate! } Limit sodium in diet } Alkalinizing agents: potassium citrate, 60 mEq 3 or 4 times daily for those with hypocitraturia } Uric acid lowering agents if hyperuricosuric (allipurinol) } Absorption inhibitor: cellulose phosphate for patients with absorptive hypercalciuria } Diuretics: thiazides can correct renal calcium leak
Summary Points
} Infection must be adequately treated before stone removal procedure is undertaken } Obstruction is an indication for immediate intervention } Bilateral obstruction is a urologic emergency } Without prevention, 50% of patients will have recurrent stone disease within 5 years
12 3/2/2014
Questions?
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