URINARY STONEUrolithiasis

Ernie G. Bautista IIJanuary 2014

FEU-NRMFSchool of Medicine

URINARY STONEUrolithiasis

1. CASE2. REVIEW OF ANATOMY3. CLASSIFICATION OF STONE4. DIAGNOSIS5. TREATMENT6. PREVENTION

CASE

• 52 y/o, male

• Presented to the ER with severe right flank pain radiating to the RLQ

• BP =154/96, PR = 79 bpm, RR = 24 cpm and T = 36.7° C

• The pain was insidious in onset and had an intensity of 10/10 on verbal analog scale which decreased to 8/10 after administration of Toradol and Morphine medications provided in the ER.

• The pain was constant, lasting 3 hours in duration, and he had 2 episodes of emesis since its onset.

• He did not report experiencing any chest pain, dyspnea, fever or bowel and bladder dysfunction.

• His medical history included a similar pain in the left flank 2 years earlier which was diagnosed as kidney stones.

Physical Examination

• E/N• He did not display any signs of edema or

nausea, abdominal discomfort or indigestion.

• Abdomen was soft with diffuse tenderness which increased over the RLQ.

• Urinalysis: moderate increase in specific gravity (1.030), significant hematuria (3+) and a trace of protein.

Diagnostic Imaging

• Abdominal radiograph - right ureteric calculus

• Discharged from the ER with the hope that he would then pass the stone naturally.

• Unfortunately, the following day, the patient returned reporting that the medications did not significantly affect his pain and his referral to the urology department was expedited.

• CT scan: – 7mm calcific density in the right

proximal ureter with associated moderate hydronephrosis and perinephric stranding

–Multiple 1–2mm non-obstructing calculi were additionally noted in the left renal parenchyma.

• Diagnosis: right ureteric calculus • Managed with pain

reliever(Ketoroloc, Morphine and Naproxen) and antiemetic medications.

• The consulting urologist concluded that because his symptoms were refractory to analgesics, and because the calculus was unlikely to pass on its own, emergency laser lithotripsy was indicated.

• Because his urine appeared murky and was presumed to be infected and the lithotripsy was abandoned.

• As an alternative, a ureteric stent was placed to help drain the dilated and infected collecting system.

• Antibiotics and Tamsulosin were additionally prescribed.

• The patient was scheduled for stent and calculus removal two months later and instructed to attempt natural passage of the stone during this period.

URETER

• Smooth muscle fibers propel urine from the kidneys to the urinary bladder

• 25–30 cm (10–12 in) long • ~3–4 mm in diameter• Histology: transitional epithelium

and an additional smooth muscle layer in the more distal 1/3 to assist with peristalsis.

UPJ

UVJ

What are the 3 common sites of obstruction?

UROLITHIASIS

• Urinary calculus disease

• Obstruction (partial or complete) of the urinary tract by >1 calculi

• Affects 10% of the population over the course of lifetime

UROLITHIASIS

CLASSIFICATION OF STONE

• Urinary stones can be classified according to the following aspects: 1. stone size2. stone location3. stone composition (mineralogy)4. x-ray characteristics of stone5. aetiology of stone formation6. risk group for recurrent stone formation

Stone composition (mineralogy)

X-ray characteristics of stone

Radiopaque Poor Radiopaque

Radiolucent

•Calcium oxalate dihydrate•Calcium oxalate monohydrate•Calcium phosphates

•Magnesium ammonium phosphate (struvite)•Apatite•Cystine

•Uric acid•Ammonium urate•Xanthine•2,8-dihydroxyadenine•‘Drug-stones’

Aetiology of stone formation

Non-infection stones• Calcium oxalates• Calcium phosphates• Uric acid

Infection stones• Magnesium-

ammonium-phosphate• Apatite• Ammonium urate

Genetic causes• Cystine*• Xanthine• 2,8-

dihydroxyadenine

‘Drug stones’

High risk stone formersI. General factors• Early onset of urolithiasis in life (especially

children and teenagers)• Familial stone formation• Brushite containing stones (calcium

hydrogen phosphate; CaHPO4 . 2H2O)• Uric acid and urate containing stones• Infection stones• Solitary kidney

High risk stone formers

II. Diseases associated with stone formation

• Hyperparathyroidism• Nephrocalcinosis• Gastrointestinal diseases or disorders (i.e.

jejuno-ileal bypass, intestinal resection, Crohn’s disease, malabsorptive conditions

• Sarcoidosis

III. Drugs associated with stone formation

High risk stone formers

IV. Genetically determined stone formation

• Cystinuria (type A, B, AB)• Primary hyperoxaluria (PH)• Renal tubular acidosis (RTA) type I• 2,8-dihydroxyadenine• Xanthinuria• *Lesh-Nyhan-Syndrome (inc. uric acid)• Cystic fibrosis

High risk stone formers

V. Anatomical and urodynamic abnormalities associated with stone formation

• Medullary sponge kidney (tubular ectasia)• Ureteropelvic junction (UPJ) obstruction• Calyceal diverticulum, calyceal cyst• Ureteral stricture• Vesico-uretero-renal reflux• Horseshoe kidney• Ureterocele• Urinary diversion (via enteric hyperoxaluria)• Neurogenic bladder dysfunction

DIAGNOSIS

DIAGNOSIS

I. Medical history and PE• Loin pain, vomiting, and sometimes

fever• Asymptomatic vs SymptomaticII. IMAGING STUDIES• Ultrasonography used as d 1’

procedure

• Non-contrast enhanced CT > intravenous urography (IVU) standard method for diagnosing acute flank pain

Recommendation

NCCT should be used to confirm a stone diagnosis in patients presenting with acute

flank pain because it is superior to IVU

• Uric acid & xanthine stones – Radiolucent on plain films and can be

detected by NCCT

DIAGNOSIS

III. Basic AnalysisBLOOD• Serum blood sample– Creatinine, Uric acid, Ionized calcium, sodium,

Potassium

• Blood cell count• CRP• Coagulation test (PTT and INR) - If

intervention is likely or planned

DIAGNOSIS

III. Basic AnalysisURINE• Urinary sediment/dipstick test out of spot

urine sample– red cells– white cells– nitrite– urine pH level by approximation

• Urine culture or microscopy

Analysis of Stone Composition• Stone analysis should be performed in all

first-time stone formers.• Repeat stone analysis is needed in case

of:– recurrence under pharmacological

prevention;– early recurrence after interventional therapy

with complete stone clearance;– late recurrence after a prolonged stone-free

period

• Preferred analytical procedures are– X-ray diffraction– Infrared spectroscopy

1. For renal/ureteral colic2. Sepsis in the obstructed

kidney3. Stone relief

TREATMENT

For Renal/Ureteral Colic

• 1st choice: treatment should be started with an NSAID–Diclophenac sodium* – Indomethacin– Ibuprofen

• 2nd choice: – Hydromorphine– Pentazocine– Tramadol

Management of sepsis in the obstructed kidney

• Decompression– placement of an indwelling ureteral catheter

under GA for a period of time– percutaneous placement of a nephrostomy

catheter

• Collect urine following decompression for antibiogram.

• Start antibiotic tx after

Definitive treatment of the stone should be delayed until sepsis is resolved.

Stone relief

I. Observation of Kidney StonesII. Medical expulsive therapy (MET)III. Chemolytic dissolution of stonesIV. ESWL (extracorporeal shock wave lit

hotripsy)V. Endourology techniques

I. Percutaneous nephrolitholapaxy (PNL)II. Ureterorenoscopy (including retrograde

access to renal collecting system)

VI.Open and laparoscopic surgery

Stone relief

I. Observation of Kidney Stones • Ureteral stone < 10 mm and if active

stone removal is not indicated, observation with periodic evaluation is an option for initial treatment.

• May be given medical therapy to facilitate stone passage during the observation period*.–Medical expulsive therapy (MET)

Likelihood of passage of ureteral stones

II. Medical expulsive therapy (MET)

• Alpha-blockers (tamsulosin*, doxazosin, terazosin, alfuzosin and naftopidil)

• Calcium-channel blockers (nifedipine)• Alpha-blockers + Corticosteroids

Duration of MET tx: 1 month

III. Chemolytic dissolution of stones

• Knowledge of stone composition is therefore mandatory prior to chemolysis.

3.1. Percutaneous irrigation chemolysis

3.2. Oral chemolysis

3.1. Percutaneous irrigation chemolysis

At least 2 nephrostomy catheters should be used to allow irrigation of the renal collecting system, while preventing chemolytic fluid draining into the bladder and reducing the risk of increased intrarenal pressure

Methods of percutaneous irrigation chemolysis

3.2. Oral Chemolysis• Efficient ONLY for uric acid calculi.• Tx is based on alkalinisation of the

urine1. alkaline citrate or 2. Na bicarbonate

• pH should be adjusted to b/w 7.0 & 7.2.

Recommendations:• Dipstick monitoring of urine pH .• Compliance.

IV. ESWL (extracorporeal shock wave lithotripsy)

•Shock wave rate: optimal shock wave frequency is 1.0 Hz•Prospective randomised trials have shown that lowering wave frequency from 120 to 60-90 shock waves/minute improves the stone-free rate, especially in stones >100 mm2

Extracorporeal shockwave lithotripsy

• Can remove > 90% of stones in adults

• Success rate for ESWL depends on the efficacy of the lithotripter and upon the following factors:– size, location of stone mass (ureteral, pelvic

or calyceal), and composition (hardness) of the stones

– patient’s habitus– performance of ESWL

Contraindications of ESWL

• Pregnancy• Bleeding diatheses• Uncontrolled urinary tract infections• Severe skeletal malformations and

severe obesity• Arterial aneurysm in the vicinity of the

stone treated• Anatomical obstruction distal of the

stone

ESWL-related complications

V. Endourology techniques

A. Percutaneous nephrolitholapaxy (PNL)– a minimally invasive surgical procedure

for the removal of renal (kidney) stones

1. Rigid nephroscopes2. Flexible nephroscopes3. Intracorporeal lithotripsy

Rigid nephroscopes

Flexible nephroscopes

Intracorporeal lithotripsy

• Intracorporal lithotripsy is usually necessary prior to extraction of larger fragments.

• Intracorporeal stone disintegration can be performed in several different ways:– Laser Lithotripsy– Electrohydraulic Lithotripsy– Ballistic Lithotripsy– Ultrasonic Lithotripsy

Intracorporeal lithotripsyLaser

LithotripsyElectrohydraulic

Lithotripsy (EHL)

Ballistic Lithotripsy

Ultrasonic Lithotripsy

>uses a holmium:YAG laser to vaporize kidney stones

>can fragment all types of kidney stones

>a ureteroscope is first placed. Then, fibers of different sizes can be placed through the endoscope to reach the stone.

>Uses two electrodes to produce a spark that creates a shockwave to break apart the stone

>D/A: potential for damaging adjacent tissue

>Uses a small endoscopic jackhammer to generate energy that uniquely targets inflexible stones

>D/A: requires a rigid lithotriper and a straight ureteroscope.

>First intracorporeal technique

>A rigid probe inserted to the site emits high-frequency sound waves

Laser Lithotripsy Electrohydraulic Lithotripsy (EHL)

Pre-operative imaging

• Pre-procedural imaging for PNL, which includes a contrast media study, is mandatory to assess stone comprehensiveness, view the anatomy of the collecting system, and ensure safe access to the kidney stone.

• Ultrasonography or CT of the kidney and the surrounding structures can provide information about interpositioned organs within the planned percutaneous path.

Positioning of the patient: prone or supine?

• Traditionally, the patient is positioned prone for PNL.

• The supine position is as safe as the prone position.

• Compared with the prone position, the advantages of the supine position for PNL are:– shorter operating time;– possibility of simultaneous retrograde

transurethral manipulation;– more convenient position for the operator;– easier anaesthesia.

B. Ureterorenoscopy URS(including retrograde access to

renal collecting system)• Instruments– Rigid scopes– Flexible scopes– Digital scopes

• Stones that cannot be extracted directly must first be disintegrated.

• If it is difficult to access stones in need of disintegration within the lower renal pole, it may help to displace the calculi into a more accessible calyx.

Complications of URS*

VI. Open and laparoscopic surgery for removal of renal

stones

6.1. Open surgery6.2. Laparoscopic surgery

Open surgery

• Become a 2nd or 3rd treatment option after ESWL and endourological surgery (i.e. URS and PNL)

• Incidence of open stone surgery– developed countries - 1.5%– developing countries - from 26% to 3.5

%

Indications for open surgery

1. Concomitant open surgery2. Non-functioning lower pole (partial nephrectomy),

non-functioning kidney (nephrectomy)3. Patient choice following failed minimally invasive

procedures; the patient may prefer a single procedure and avoid the risk of needing more than one PNL procedure

4. Stone in an ectopic kidney where percutaneous access and ESWL may be difficult or impossible

5. For the paediatric population, the same considerations apply as for adults

Indications for open surgery

6. Complex stone burden7. Treatment failure of ESWL and/or PNL, or failed

ureteroscopic procedure8. Intrarenal anatomical abnormalities: infundibular

stenosis, stone in the calyceal diverticulum (particularly in an anterior calyx), obstruction of the ureteropelvic junction, stricture

9. Morbid obesity10.Skeletal deformity, contractures and fixed

deformities of hips and legs11.Co-morbid medical disease

Laparoscopic surgery• Laparoscopy is associated with lower

post-operative morbidity, shorter hospital stay and time to convalescence, and better cosmetic results with comparably good functional results

• It can also be an alternative to PNL in the absence of availability (developing countries) or PNL failure and as an adjunct to PNL, especially when access proves difficult (ectopic kidneys).

Laparoscopic ureterolithotomy

• Although highly effective, it is not a first-line therapy in most cases because of its – invasiveness, – longer recovery time, – and the greater risk of associated

complications compared to ESWL and URS

Laparoscopic ureterolithotomy

• Indications for laparoscopic kidney-stone surgery include:– Complex stone burden– Failed previous ESWL and/or

endourological procedures– Anatomical abnormalities–Morbid obesity– Nephrectomy in case of non-functioning

kidney

Laparoscopic ureterolithotomy

• Indications for laparoscopic ureteral stone surgery include:– Large, impacted stones–Multiple ureteral stones– In cases of concurrent conditions

requiring surgery–When other non-invasive or low-invasive

procedures have failed

Recommendations

• Laparoscopic or open surgical stone removal may be considered in rare cases where ESWL, URS, and percutaneous URS fail or are unlikely to be successful.

• When expertise is available, laparoscopic surgery should be the preferred option before proceeding to open surgery. An exception will be complex renal stone burden and/or stone location.

Recommendation

• Treatment choices should be based on the size and location of the stone and available equipment for stone removal.

PREVENTION

THANK YOU!

MANAGEMENT OF URINARY STONES and RELATED PROBLEMS DURING PREGNANCY

Diagnostic option

• Ultrasonography is the method of choice in the practical and safe evaluation of a pregnant women.

• In symptomatic patients with suspicion of ureteral stones during pregnancy, limited IVU, MRU, or isotope renography is a useful diagnostic method.

Management

• If intervention becomes necessary, – placement of a internal stent, – percutaneous nephrostomy, or – ureteroscopy

Recommendation

• Following the establishment of the correct diagnosis, conservative management should be the firstline treatment for all non-complicated cases of urolithiasis in pregnancy (except those who have clinical indications for intervention)