Canadian Undergraduate Urology Curriculum (CanUUC): Urinary Calculus Disease Last revised by Dr Sero Andonian on May 2017 Urinary Calculus Disease: Objectives List the signs/symptoms and differential diagnoses of an acute stone episode 2. Describe the imaging studies available to diagnose renal or ureteral calculi. 3. List the classes of medications effective for treating the pain of renal colic. 4. Outline the basic treatment options for renal and ureteral calculi 1. Urinary Calculus Disease: Objectives (contd) Describe the clinical scenarios requiring
urgent decompression of a ureteral stone. 6. List the basic principles of stone formation and prevention. 5. Urinary Calculus Disease: Why care? Lifetime prevalence ( 1 in 11) Males 10.6% Females 7.1% Recurrence rates are 7-10% per year First presentation usually in young adults
Age 20-40 Estimated $2 billion dollars spent on the diagnosis and management of urolithiasis in the US in 2001 Scales et al., Euro Urol, 2012 Urinary Calculus Disease: Signs and Symptoms: Colic nature of the pain
Rapid onset Unable to achieve comfortable position (writhing) Radiates from flank to groin Testis/labia Associated nausea/emesis May develop ileus Hematuria Gross, microscopic (present in 90%; absence doesnt r/o) Irritative LUTS May indicate stone near the UVJ/distal ureter BEWARE OF FEVER Urinary Calculus Disease: Where do stones get stuck? 1) 2) 3) UVJ
UPJ: Ureteropelvic Junction where the renal pelvis meets the ureter Pelvic brim: at the level of the common iliac vessels UVJ: Uretero-vesical junction where the ureter meets the bladder Urinary Calculus Disease: Differential Diagnosis Vascular: AAA Bowel:
Inflammatory bowel disease, appendicitis, diverticulitis Gynecologic: PID, ruptured ovarian cyst, ectopic pregnancy Neurologic/Musculoskeletal: Radicular pain, herpes zoster, muscle spasm/strain Genito-urinary: Cystitis, pyelonephritis, torsion, UPJ obstruction Urinary Calculus Disease: Investigations
AFTER CAREFUL History and Physical Labs: Urinalysis (microscopy is gold standard to look for crystals) Consider Pregnancy Test (HCG) in females CBC&diff (Look for WBC, creatinine (R/o renal failure) Imaging:
KUB (Kidney-Ureter-Pelvis) Plain Radiograph of abd/ pelvis Non-contrast Low-Dose CT abdopelvis (NCCT) IVP - more or less historical or in remote settings Ultrasound Fulgham et al., J Urol, 2013 - first line in pregnancy Urinary Calculus Disease: Urinalysis (Microscopic) 90% will have at least microhematuria May have some pyuria May May Not
not indicate UTI have crystals specific for stone disease Urinary Calculus Disease: Diagnosis - Imaging KUB: First-line for initial and FU imaging 80-90% of stones are radio-opaque Phleboliths (calcified pelvic vessels could be mistaken for ureteral stones) IVP: Cant use in patients with Iodine allergy or
Renal Failure Demonstrates stone location & degree of obstruction Time consuming & contrast risk CT (Non-contrast) LOW-DOSE protocol Quick, sensitive, GOLD STANDARD for renal colic Fulgham et al., J Urol, 2013 Diagnosis: KUB Advantages: 80-90% of stones are radio-opaque
Minimal radiation Disadvantages: No detection of concurrent pathology Bowel gas Easy to miss midureteral stones over Diagnosis: Non-Contrast Renal Colic Low-Dose CT Abd/Pelvis Advantages: All stone types are visible except indinavir Sensitivity - 97%; Specificity - 96% Rapid Readily available
Does not require contrast Other pathologies identified Information about stone and collecting system obtained Fulgham et al., J Urol, 2013 Diagnosis: Non-Contrast Renal Colic Low-Dose CT Abd/Pelvis Disadvantages: Increased radiation dose compared with KUB should always use Low-Dose protocols especially in thin (BMI <30) patients Cost No
physiologic information such as obstruction Has supplanted the KUB KUB useful for following radio-opaque stones Fulgham et al., J Urol, 2013 and determining suitability for Shockwave Diagnosis: Intravenous Pyelogram (IVP) Scout film Intravenous contrast Serial Xrays Nephrogram phase (1min) Pyelogram phase (5 min)
Delayed views (ureter) Post void Time consuming (up to 2 hrs) Contrast reaction risk Diagnosis: Non-contrast CT (NCCT) What are you looking for? Stone size (height and width) Stone density (Stones >500HU are opaque on KUB) Location Renal (Pelvis; upper, mid, or lower calyx) Ureteral (UPJ, proximal, mid, distal, or UVJ) Presence of hydronephrosis or hydroureter Evidence of stranding Gas in the collecting system Emphysematous (necrotizing) infection Rare but important finding necessitating
Diagnosis: Non-contrast CT Hydronephrosis (Note the L renal pelvis is dilated when compared with R renal pelvis) Non-contrast CT: Ureteral Calculus Dilated ureter above stone (hydroureter) Ureteral Calculus: Non-contrast CT Stone visualization & location (i.e. L proximal ureter)
All stones, except indinavir, are opaque on CT Tissue ring sign Calculus Disease: Initial Management of Renal Colic Pain control Narcotics Oral/IM/IV NSAIDS (renal function) (Avoid if planning SWL) Oral/rectal/IV Acetaminophen Anti-emetics
IV hydration prn IF FEVER - CONSULT UROLOGY DISCUSS ANTIBIOTICS Alpha-blockers as medical expulsive therapy (MET) Tamsulosin (Explain that these are off-label and associated with dizziness and retrograde Calculus Disease: Initial Management Based on Size <5mm Discharge home with instructions to drink >2L of water/day Tamsulosin for ureteral stones 90% will pass spontaneously Should follow-up with urology within 1-2 weeks
Fear is silent obstruction (painless) with UPJ or proximal ureteral stones leading to irreversible renal loss >5mm (renal or ureteral) or signs of obstruction Consult urology +/- tamsulosin Ordon et al., Can Urol Assoc J, 2015 Urinary Calculus Disease: CONSULT UROLOGY URGENTLY IF: Obstructing
stone + FEVER/Infection Bilateral Ureteral Stones Renal failure Solitary Kidney Impending renal failure These require urgent decompression with ureteral (double J) stents or Urinary Calculi: Treatment 1.
Extracorporeal shock wave lithotripsy (SWL) 2. Ureteroscopic laser lithotripsy (URS) 3. Ureteral stones <1cm or renal stones <2cm Ureteral stones or SWL failures Percutaneous nephrolithotomy (PCNL) Large >2cm renal stones Ordon et al., Can Urol Assoc J, 2015
Renal Calculi: Clinical Points Spontaneous stone passage depends on: 1) Location: Proximal vs. distal (distal stones more likely to pass) 2) Size: ~90% of stones <5mm will pass 3) Time since onset: Most stones pass by ~40 days Ordon et al., Can Urol Assoc J, 2015 Stone Size: Probability of Spontaneous Stone Passage Probability of passage: <4mm- ~90% 4-7mm- ~50% >7mm- <10%
Ueno et al. Urol, 1977; Ordon et al., Can Urol Assoc J, 2015 Urinary Calculus Disease Treatment: Extracorporeal Shockwave Lithotripsy (SWL) Least invasive Conscious sedation Fragments stones that the patient then passes High patient satisfaction May require more time to become stone free Renal calculi <2cm SWL:
Absolute Contra-indications Pregnancy Bleeding Disorder/anticoagulation (NSAIDS pre-op) Febrile UTI Obstruction Distal to the stone being treated SWL: Relative Contra-indications Radiolucent stones due to difficulty in localizing. To localize these stones: Could use ultrasound Could use retrograde pyelography or IVP
Pacemaker (Need to use gated shockwaves; Pacemakers in the path of shockwaves could be damaged) Calcified renal artery/AAA Severe orthopedic deformities Post SWL follow-up: Tamsulosin improves stone-free rates KUB in 2-4 weeks post-treatment May continue to pass fragments for several weeks Ultrasound to rule out silent obstruction Fulgham et al., J Urol, 2013; Ordon et al., Can Urol Assoc J, 2015
SWL success depends on: Stone Size (Better if <1cm) Stone Location (Better if renal pelvic) Stone Density/ Composition (Better if HU<1000) Hounsfield unit density on NCCT Patient <10cm) Worse Habitus (Better if skin-to-stone distance
if associated renal anomalies: UPJ Obstruction Horseshoe kidney Ordon et al., Can Urol Assoc J, 2015 Complications of SWL Hematuria Hematochezia Ureteral obstruction - 5-30% Depends on size of initial stone steinstrasse (stone fragments obstructing ureter) Intervention as per other ureteral stones Sepsis - 1% Perinephric Hematoma - <1% Hypertension/DM- no convincing evidence that SWL leads to long term HTN or DM When do we not use SWL?
Stone >2cm in largest diameter or multiple stones Stone Burden composition Particularly cystine or brushite stones Patient needs to be stone-free such as pilots Or stone-free faster Patient
habitus (skin-to-stone distance >10cm) Failed SWL 2nd treatment reasonable Diminishing returns of 3 or more treatments Ordon et al., Can Urol Assoc J, 2015 Ureteroscopic (URS) Holmium Laser Lithotripsy for Ureteral Stones Advantages: Near 100% stone free rate Low retreatment rates Treatment available in most centres
SWL tends to be in regional centres only Disadvantages: General anesthesia is usually required Ureteral stent (DJ) may be left Stent symptoms are bothersome to patients Lower patient satisfaction Typically
for ureteralOrdon calculi et al., Can Urol Assoc J, 2015 Ureteroscopic Equipment: Scopes Semi-rigid Flexible Stone Fragmentation Holmium:YAG laser Stone
are either: Retrieval Baskets Graspers One of the best innovations in urology over the last 2 decades Urinary Calculus Disease: Percutaneous Nephrolithotripsy Typically for large (>2cm) renal calculi Advantages:
Ability to remove large or multiple stone burden with high success rate (>95%) Disadvantages: General anesthesia More invasive than URS Risk of bleeding <5% require transfusion Injury to surrounding organs Risk of hydropneumothorax Percutaneous Nephrolithotripsy: Complications
Sepsis or SIRS Bleeding requiring transfusion or selective angioembolization. Perforation of the renal pelvis Stricture UPJ or infundibulum Residual stone fragments Hemothorax/pleural effusion (<10%) Adjacent organ injury (colon perforation) STONE PREVENTION Stone Prevention: Basic Work-Up for ALL PATIENTS Urinalysis
and culture Urea splitting organisms (Proteus, Pseudomonas, Klebsiella, mycoplasma, Serratia, Staph Aureus) Acidic urine - uric acid/cystine/CaOxalate stones Alkaline urine - struvite stones Serum electrolytes (Na, K, Cl, HCO3), urea, creatinine, and uric acid If elevated normalized serum calcium then obtain PTH to rule out Primary Hyperparathyroidism Send stone for analysis Dion et al., Can Urol Assoc J, 2016 Stone Prevention: Detailed Metabolic Work-Up Indications
Children (<18 years of age) Bilateral, recurrent or multiple stones Non-calcium stones (e.g., uric acid, cystine) Pure calcium phosphate stones Complications from stones (AKI, sepsis, or admission) Any stone requiring percutaneous nephrolithotomy Solitary kidneys (anatomical or functional) Patients with renal insufficiency Systemic disease (gout, osteoporosis, bowel disorders,
hyperparathyroidism, renal Dion tubular acidosis,etc.) et al., Can Urol Assoc J, 2016 Stone Prevention: Detailed Metabolic Work-Up: In addition to the Basic metabolic work-up, it includes: Two 24-hour urine collections: Volume, creatinine, calcium, sodium, potassium, oxalate, citrate, uric acid, magnesium Cystine if suspect cystine stone or if the stone analysis is cystine Dion et al., Can Urol Assoc J, 2016
Stone Prevention: General Advice Increase Hydration to 2-3L per day to achieve daily urine output of 2.5L Diet: Maintain normal calcium intake (1000-1200mg with meals) Used to advice low calcium diets Proven to be false
Minimize foods high in oxalate (Spinach, peanut, rhubarb) Minimize salt (<2300mg/d) and animal protein Increase fiber, vegetables and citrus-rich fruits Consider urinary alkalinization: Mainly for uric acid and cystine stones Dion et al., Can Urol Assoc J, 2016 Potassium citrate - preferred Stone Prevention: Calcium Stones (80%) Most stones are calcium oxalate Some are calcium phosphate or mixed Etiology
Hypercalciuria Increased intestinal absorption Bone resorption (PTH) Renal leak 25% also have hyperuricosuria Hyperoxaluria Usually increased intestinal absorption - SB resection/IBD Ingestion of oxalate-rich foods
Dion et al., Can Urol Assoc J, 2016 Hypocitraturia Stone Prevention: Prevention of Calcium Stones: Hydration - 2-3L of urine per day Normal dietary calcium intake (10001200mg/d) Dietary limitations: Salt - potentiates hypercalciuria Oxalates Tea/chocolate/Spinach/Rhubarb Animal protein
Consider Thiazide for hypercalciuria Consider potassium citrate for acidic urine (pH<6.0) and hypocitraturia Dion et al., Can Urol Assoc J, 2016 Stone Prevention: Struvite Stones (5-10%): Triple phosphate Calcium Magnesium, ammonium phosphate Alkaline urine pH due to urea splitting organisms
Proteus, Pseudomonas, Klebsiella, Mycoplasma, Serratia, Staph Aureus NOT E COLI Must clear all stone material and infection SWL often not useful May form staghorn stones quickly Dion et al., Can Urol Assoc J, 2016 Stone Prevention: Uric Acid Stones (10%): Radiolucent
- not visible on KUB Occur in patients with low urine volume and acidic urine (pH<6.0) Purine-rich diets High cell turnover - cancer treatment Prevention: Hydration Alkalinize urine Dion et al., Can Urol Assoc J, 2016 Stone Prevention: Cystine Stones:
Usually first detected in children Often positive family history AR defect in absorption of dibasic amino acids COLA Only cystine is insoluble Rapid formation of staghorn stones Must remove all stone material aggressively SWL has limited application Prevention: Hydration (Need to produce >3L of urine per day) Low salt and animal protein Alkalinize, penicillamine, thiola, captopril (not effective) Dion et al., Can Urol Assoc J, 2016 Take Home Points: Urinary Calculi
KUB is a useful initial investigation Low-Dose non-contrast CT is the diagnostic gold standard Fever with an obstructing ureteral stone requires emergent intervention (decompression stent/nephrostomy) Obstructing stones in a solitary References: Dion M, Ankawi G, Chew B, et al. CUA guideline on the evaluation and
medical management of the kidney stone patient 2016 update. Can Urol Assoc J 2016;10(11-12):E347-58. Fulgham PF, Assimos DG, Pearle MS, Preminger GM. Clinical effectiveness protocols for imaging in the management of ureteral calculous disease: AUA technology assessment. J Urol. 2013;189(4):1203-13. Ordon M, Andonian S, Blew B, et al. CUA Guideline: Management of ureteral calculi. Can Urol Assoc J. 2015 ;9(11-12):E837-51. Scales CD Jr, Smith AC, Hanley JM, Saigal CS; Urologic Diseases in America Project. Prevalence of kidney stones in the United States. Eur Urol. 2012 ;62(1):160-5. Ueno A, Kawamura T, Ogawa A, Takayasu H. Relation of spontaneous passage of ureteral calculi to size. Urology. 1977;10(6):544-6.
