Urolithiasis Xử trí

Medical Expulsive Therapy

Medical expulsive therapy is recommended if active stone removal is not indicated. This increases the stone expulsion rate of the Steinstrasse and reduces the requirement for endoscopic intervention. If complications of urolithiasis (eg infection, refractory pain, deterioration of renal function) develop, medical expulsive therapy should be discontinued and active stone removal should be performed.

Alpha Blockers

Example drugs: Doxazosin, Tamsulosin

Alpha blockers inhibit ureteral spasm and uncontrolled contraction, which can reduce pain and accelerate and increase the likelihood of passage of stone, preventing hospital admission or surgical intervention. This is a treatment option for patients with uncomplicated distal ureteral stones measuring ≤10 mm. This may be offered for adult patients with ≤10 mm stones in the mid- or proximal ureter. Alpha blockers may be given to patients who underwent SWL to facilitate passage of stone fragments or as adjunctive treatment for patients undergoing SWL for ureteral stones <10 mm. This can be used in the treatment of patients with distal ureteral stones >5 mm. Combining alpha blockers with other agents (eg phosphodiesterase-5 [PDE5] inhibitors, corticosteroids, and phytotherapeutic compounds) may provide greater efficacy than monotherapy alone.

Chemolitholysis and Drugs Used for Stone Prevention

Acetohydroxamic Acid

Acetohydroxamic acid is a urease inhibitor. This is a treatment option for patients with residual or recurrent struvite stones after failure of surgical interventions.

Alkaline Citrate (Sodium and Potassium)

Alkaline citrate is a urinary alkalinizer used to prevent uric acid or cystine calculi formation. Potassium citrate is recommended as first-line therapy for patients with uric acid stones. This is recommended in patients with hypercalciuria and indicated for patients with enteric hyperoxaluria or hypocitraturia. This is also used as an adjuvant with uricosuric agents in gout therapy. Potassium citrate may be a treatment option for patients with recurrent stones that are predominantly calcium oxalate and for children with hypercalciuria or hypocitraturia. This is effective in correcting the acidosis of certain renal tubular disorders. This is contraindicated in patients with severe renal impairment with oliguria or azotemia, untreated Addison’s disease, and severe myocardial damage.

Allopurinol

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Allopurinol inhibits xanthine oxidase and reduces the production of uric acid without disrupting the biosynthesis of vital purines. This is a first-line treatment of hyperuricosuria. This is used in the prevention of gout and renal calculi due to uric acid or calcium oxalate, prophylaxis, and treatment of uric acid nephropathy. Allopurinol decreases the risk of recurrent calcium oxalate stones in the presence of hyperuricosuria (urinary uric acid excretion >800 mg/day). This may be used as an adjunct in patients with uric acid stones, and alkalinization of urine with Potassium citrate is not adequate or successful. This is contraindicated in patients with idiopathic hemochromatosis and asymptomatic hyperuricemia.

Febuxostat

Febuxostat is a treatment option to prevent stone recurrence in patients with calcium oxalate or uric acid stones and a second-line treatment option for hyperuricosuria.

Sodium Bicarbonate

Sodium bicarbonate raises blood and urinary pH by dissociation to provide bicarbonate ions, which neutralizes the hydrogen ion concentration. This is used to alkalinize the urine, and the dose is titrated to achieve the desired urinary pH. This is used to dissolve uric acid stones and is indicated for patients with hypocitraturia. This is contraindicated in patients with alkalosis, hypernatremia, severe pulmonary edema, hypocalcemia, and unknown abdominal pain.

Thiazide Diuretics

Thiazide diuretics may be used for recurrent stone formers with calcium oxalate or calcium phosphate stones or high-risk first-time stone formers, such as patients with hypertension, solitary kidney, or large stone burden, or those refractory to other risk-mitigating procedures. This is recommended for patients with hypercalciuria >8 mmol/day.

Chlorthalidone

Chlorthalidone is a long-acting antihypertensive or diuretic that enhances the excretion of sodium, chloride ions, and water by interfering with the transport of sodium ions across the renal tubular epithelium. This is used as treatment for hypercalciuria and calcium stone recurrence. Chlorthalidone is contraindicated in patients with known anuria and hypersensitivity to other sulfonamide-derived drugs.

Hydrochlorothiazide 

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Hydrochlorothiazide inhibits the sodium reabsorption in the distal tubules, and as a result, the excretion of sodium, water, potassium, and hydrogen ions increases. This is used as a treatment for hypercalciuria and calcium stone recurrence. Hydrochlorothiazide is contraindicated in patients with known anuria and hypersensitivity to other sulfonamide-derived drugs.

Tiopronin

Tiopronin is also known as alpha-mercaptopropionylglycine. This is an active reducing agent that undergoes a thiol-disulfide exchange with cystine and forms a tiopronin-cystine disulfide. This is recommended for patients with cystine stones not responsive to dietary modifications and urinary alkalinization or with large recurrent stone burdens. Tiopronin decreases the amount of soluble cystine in the urine and reduces the formation of cystine calculi. This is contraindicated in patients with a prior history of developing agranulocytosis, aplastic anemia, or thrombocytopenia.

Other Therapies

Phytate

Phytate is also known as myo-inositol-1,2,3,4,5,6-hexakis dihydrogen phosphate (InsP6). This may lower the risk of stone formation. Phytate has been shown to inhibit crystallization of calcium oxalate and calcium phosphate in urine. This is present in legumes, whole grains, nuts, and seeds.

Theobromine

Theobromine may be useful in preventing uric acid stone formation by inhibiting the nucleation and growth of uric acid crystal. This is present in high amounts in cocoa and chocolate.

Supportive Therapy

Analgesics

For pain during acute episodes of renal colic, nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended for treatment. Nonsteroidal anti-inflammatory drugs (NSAIDs) and Paracetamol are effective for managing acute stone colic and provide superior analgesic efficacy compared with opioids. NSAIDs are recommended as the firstline analgesic for renal colic, with selection guided by cardiovascular risk factors and potential adverse effects. Opioids (eg Hydromorphone, Pentazocine, Tramadol, Ketamine) may be used as secondline options in the acute setting. 

Conservative Treatment/Observation

Since most stones are small, about 5 mm in size, the patient is advised to pass stones through normal urination, which usually happens within 2-3 days. A collection kit is provided with the filter, and the patient is instructed to collect the passed stone for testing and analysis. This is an option for patients with uncomplicated ureteral stones ≤10 mm and an option for adults and children with asymptomatic renal stones <5 mm. This may be offered for adult and pediatric patients with asymptomatic, nonobstructing kidney stones. Migratory bladder stones in adults can often be left untreated, particularly when they are small and asymptomatic.

Lifestyle Modification

Diet Therapy

All stone formers are advised to have a fluid intake that will achieve a urine volume of at least 2.5 liters daily. Good hydration is important for stone prevention. Advise patients to avoid carbonated drinks. Limit sodium intake to 4-5 g and consume 1,000-1,200 mg dietary calcium per day. Limit the intake of oxalate-rich foods and maintain normal calcium consumption.

Increase the intake of fruits and vegetables. Hypocitraturia is common among patients with stone disease and promoted by renal tubular acidosis (RTA), chronic diarrhea, and carbonic anhydrase inhibitors. Limiting the intake of animal protein (0.8-1.0 g/kg/day) may help reduce stone recurrence. Patients with a history of uric acid stones should be counseled to increase the intake of alkali and decrease the intake of acids; increase the urine pH; and reduce the urinary acidity.

Weight Management

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Obese or overweight patients should achieve a normal body mass index (BMI) through dietary modification and increased physical activity to prevent recurrent kidney stones.

Goals of Surgery

The goals of surgery are relief from pain, clearance of infection, and reversal of kidney function impairment associated with ureteral or kidney stones.

Bladder Stone Interventions

Minimally invasive techniques for bladder stone removal are now widely used to reduce complications and shorten hospital stay and recovery time, with treatment options including open, laparoscopic, roboticassisted laparoscopic, endoscopic (transurethral or percutaneous) surgery, and shock wave lithotripsy. Transurethral cystolithotripsy should be offered as the preferred treatment for adults with bladder stones whenever feasible. Percutaneous cystolithotripsy should be offered to adults when transurethral cystolithotripsy is not feasible or advisable. Open cystolithotomy may be suggested as an option for very large bladder stones in adults and children. Open, laparoscopic, and extracorporeal shockwave lithotripsy (SWL) are alternative options when endoscopic treatment is not advisable in adults and children.

Indications for Active Removal of Ureteral Stones

Indications for active removal of ureteral stones include stones with a low likelihood of spontaneous passage; uncomplicated distal ureteral stones ≤10 mm that have not passed after 4-6 weeks of observation, with or without medical expulsive therapy; persistent obstruction; renal insufficiency; ureteral stones >10 mm; and persistent pain despite adequate analgesic therapy.

Indications for Active Removal of Renal Stones

Indications for active removal of renal stones include choice of treatment or patient preference; comorbidity (eg hypertension, diabetes, obesity, dyslipidemia, and gout); infection (eg pyelonephritis); obstruction caused by stones; patients who are high-risk stone formers; stone growth; stones >15 mm; stones <15 mm if observation is not an option; and symptomatic stones (eg presence of pain and hematuria).

Special Problems Encountered in Stone Removal

Special problems encountered in stone removal include the presence of caliceal diverticulum stones, the patient having horseshoe kidneys, and patients with ureteropelvic junction (UPJ) obstruction.

Extracorporeal Shockwave Lithotripsy (SWL)

Extracorporeal shockwave lithotripsy is a non-invasive and non-aesthetic procedure. This is a first choice of treatment for stone size <1.5 cm. This is recommended for patients with ureteral stones <10 mm. This may be offered when surgical treatment is indicated for adult patients with distal ureteral stones ≤10 mm and proximal ureteral stones <2 cm. This is a treatment option for symptomatic patients with a total non-lower pole renal stone burden ≤20 mm or ≤10 mm lower pole renal stones. This is a treatment option for renal stones >20 mm in cases where percutaneous nephrolithotomy (PNL) is not an option. Success depends on the efficacy of the lithotripter and some factors such as the size, composition, and location of the stones; the patient's habitus; and the performance of SWL. Contraindications include arterial aneurysms, anatomical obstruction distal to the stones, bleeding disorders, infection, severe skeletal malformations, severe obesity, pregnancy, and uncontrolled urinary tract infections (UTIs). Complications associated with SWL include Steinstrasse, regrowth of residual stones, renal colic, macroscopic hematuria, bacteriuria, sepsis, pain, and hematoma. Steinstrasse is the accumulation of stone fragments or stone gravel in the ureters. The major factor for its formation is the size of the stone. If asymptomatic, then conservative treatment is the initial option. For Steinstrasse associated with UTI and fever, percutaneous nephrostomy is indicated. When large stone fragments are present, SWL or ureteroscopy is indicated.

Percutaneous Nephrolithotomy (PNL) 

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Percutaneous nephrolithotomy is the standard procedure for large renal calculi. This is recommended first-line therapy for symptomatic patients with a total renal stone burden >20 mm or patients with staghorn calculi. This is a recommended procedure to remove large renal stones in patients with urinary diversion and for ureteral stones that cannot be reached via a retrograde approach or are unsuitable for shock wave lithotripsy. Stones >20 mm in the renal pelvis and/or upper/middle calyces should be managed primarily with PNL, as SWL often requires multiple treatment sessions and carries a higher risk of ureteral obstruction (eg colic or Steintrasse), frequently necessitating additional procedures.  Miniaturized PNL is recommended for treatment of medium-sized (<3.0-3.5 cm) renal stones. This may be an option for patients with diverticular stones or pediatric patients with medium-sized renal stones. This may be offered over URS for adult patients with 1–2 cm kidney stones because of its higher stonefree rate.

PNL may be offered for adult and pediatric patients with ureteral stones >2 cm or stones not successfully treated with prior retrograde URS or SWL, or those not amenable to these procedures. This is a treatment option for patients with <10 mm lower pole renal stones. Different rigid and flexible endoscopes are used in this procedure, and it depends on the preference of the surgeon. Contraindications include patients on anticoagulant therapy, untreated UTI, tumor in the presumptive access tract area, potential malignant kidney tumor, and pregnancy. Complications associated with PNL include fever, bleeding, embolization, organ injury, sepsis, urinary leakage, and problems due to residual stones.

Uteroscopic Lithotripsy (URS)—Rigid and Flexible 

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Uteroscopic lithotripsy is a minimally invasive procedure that is used for both ureteric and renal stones as an alternative treatment to SWL. This can be performed under a local, intravenous, or general anesthetic. URS may be used in patients who had failed previous treatment attempts, stones too large for SWL, strictures, tumors, stones in children, those with bleeding disorders, and the obese. This is a recommended first-line treatment option for patients with mid- or distal ureteral stones who are not suitable for or failed medical expulsive therapy. This is recommended for patients with ureteral stones measuring 10-20 mm and recommended for patients with suspected cystine or uric acid ureteral stones who failed medical expulsive therapy. URS is recommended as first-line treatment for severely obese patients with ureteral or renal stones. This may be offered when surgical treatment is indicated for adult patients with distal ureteral stones ≤10 mm and proximal ureteral stones <2 cm. This is a treatment option for symptomatic patients with a total non-lower pole renal stone burden ≤20 mm or ≤10 mm lower pole renal stones and a treatment option for renal stones >20 mm in cases where PNL is not an option. Stone-free rate status with larger stones is achieved earlier with URS. Complications associated with URS include sepsis, ureteral stricture, ureteral injury, and UTI.

Endoscopic Combined Intrarenal Surgery (ECIRS)

A combined approach for removal of kidney or ureter stones is indicated in the following conditions: Difficulty of angle to approach from the calyx of the percutaneous puncture to other calyces to avoid multiple tracts; diverticular stones with a difficult angle to the infundibulum or presence of narrow infundibulum; impacted UPJ stones with complete obstruction and ureteral strictures that require an antegrade incisional procedure; ipsilateral medium to large renal stones and contralateral small renal stones; large and complex stones; and large renal and concomitant ureteral stones or strictures.

Open, Laparoscopic, or Robotic-Assisted Stone Surgery

An open, laparoscopic, or robotic-assisted stone surgery is an alternative for select patients with stones requiring complete removal within a single surgical session, such as infection stones, or with urinary tract anatomical abnormalities requiring simultaneous reconstruction. This is a treatment option for patients who have undergone failed SWL, PNL, or URS, or in cases where said procedures are unlikely to be successful.

Management of Stone-induced Obstruction

Stone-induced obstruction is present with all signs of UTI and/or anuria and is considered a urological emergency. This requires urgent decompression of obstructed collecting systems by placement of an indwelling ureteral stent or percutaneous placement of a nephrostomy tube.