Recommendations
Key Recommendations
Refer the patient for immediate urological assessment if they have a stone in the kidney or ureter together with signs and symptoms of infection, or an obstruction alone.[47][66]
In the absence of urgent considerations, the main goal of initial treatment for an acute stone event is symptomatic relief with hydration and analgesia as needed.[67][68]
[ 
]
For pain management, give a non-steroidal anti-inflammatory drug (NSAID) by any route first-line.[47][69][Evidence C] Alternatively, give intravenous paracetamol. Consider an opioid only if NSAIDs and intravenous paracetamol are contraindicated or not giving the patient enough pain relief.[16]
Consider watchful waiting if the patient has an asymptomatic renal stone <5 mm or an asymptomatic renal stone 5-10 mm and agrees to this approach following an informed discussion of risks and benefits.[16]
Prompt treatment of ureteric stones is important because of the risk of obstruction and kidney damage.[16]
Consider medical expulsive therapy (MET) using an alpha-blocker for distal ureteric stones <10 mm.[16]
For stones ≥10 mm, smaller stones that remain despite conservative therapies, and ureteric stones that are causing ongoing and intolerable pain, additional surgical treatment is necessary. Recommended surgical approaches are based on site of stone (renal or ureteral) and stone size, and include:
Shock wave lithotripsy
Ureteroscopy
Percutaneous nephrolithotomy.
If the patient is an adult with a ureteric stone with ongoing and intolerable pain or the ureteric stone is unlikely to pass, ensure they have surgical treatment within 48 hours of diagnosis or readmission.[16]
If the patient is pregnant, refer to a specialist (e.g., an obstetrician and/or urologist).[47]
Advise adult patients to drink 2.5 to 3 litres of water per day and children and young people (depending on their age) 1 to 2 litres.[16][43][44] In patients that are known stone formers, a target output of 2 to 2.5 litres per day is recommended; intake volume may need to be up to 4 litres per day to achieve this.[71][72][73] Encourage the patient to establish a healthy lifestyle, including physical activity habits, to achieve and maintain a healthy weight.[74] Also encourage the patient to adopt a low sodium intake and a normal calcium intake.[16][46]
Refer the patient for immediate urological consultation if:
They have a stone in the kidney or ureter, and signs and symptoms of obstruction. This will need to be treated with urgent decompression.
They have a urinary tract infection in the setting of an obstructing stone. This is an emergency that requires antibiotics and renal decompression to decrease the chance of life-threatening septic shock.[47][66]
Start empirical broad-spectrum antibiotic therapy pending sensitivity results based on urinalysis cultures.[47] Empirical regimens differ across locations; seek local guidance with the aid of a local antibiogram.
Drainage can be accomplished in two ways. A urologist can place a ureteric stent past the obstruction and achieve drainage. Alternatively, a percutaneous nephrostomy tube can be placed by interventional radiology.[47]
Delay definitive stone removal until:[47]
Drainage has been performed for several days
If present, the infection is cleared following a complete course of antimicrobial therapy.
Then proceed to manage the stone according to site and size (see sections below).
If the patient is symptomatic with confirmed bacteriuria, but there is no obstruction or signs of sepsis, start empirical antibiotics pending sensitivity results based on urinalysis cultures. Then treat the stone based on site (renal or ureteral) and size (see sections below).
If the patient has confirmed bacteriuria but is asymptomatic, it may be more appropriate to treat the stone based on site (renal or ureteral) and size before treating the infection (see sections below); seek specialist advice.
The empirical regimen depends on various factors, including the type of infection, patient factors, and local antibiotic resistance patterns; consult local guidelines for more information on choice of antibiotics.
In the absence of urgent considerations, the main goal of initial treatment for an acute stone event is symptomatic relief with hydration and analgesia as needed.[67][68]
[ ]
For pain management, give:
An NSAID by any route first-line[47][69][Evidence C]
Intravenous paracetamol if NSAIDs are contraindicated or are not giving the patient sufficient pain relief.[16]
Consider opioids only if NSAIDs and intravenous paracetamol are contraindicated or not giving the patient enough pain relief.[16] If giving opioids, co-prescribe an antiemetic for opioid-induced nausea.
If the patient is an adult with a ureteric stone with ongoing and intolerable pain or the ureteric stone is unlikely to pass, ensure they have surgical treatment within 48 hours of diagnosis or readmission.[16] See Surgical intervention section below.
Do not use antispasmodics in patients with suspected renal colic.[16][47]
Consider watchful waiting for the patient with:[16]
Asymptomatic renal stone <5 mm
Asymptomatic renal stone 5-10 mm and the patient (or their family or carers, as appropriate) agrees to this approach after an informed discussion of the possible risks and benefits.
Prompt treatment of ureteric stones is important because of the risk of obstruction and kidney damage.
Consider medical expulsive therapy (MET) using an alpha-blocker for distal ureteric stones <10 mm in adults and children.[16]
MET using an alpha-blocker such as tamsulosin or alfuzosin may be of benefit in promoting larger (but still <10 mm) distal ureteral stone passage; however, efficacy rates have been questioned.[76][77][78][79][80][81][82][83] In practice in the UK, tamsulosin is most commonly used.
These agents can cause ureteric relaxation of smooth muscle and antispasmodic activity of the ureter leading to stone passage.[84]
Discontinue treatment if complications develop (infection, refractory pain, or deteriorating renal function).[47]
Patients should be made aware that prescribing alpha-blockers for this indication is considered an off-label use of these drugs. Additionally, tamsulosin has been associated with intraoperative floppy iris syndrome, therefore it should not be prescribed if a patient has planned cataract surgery.
If there is spontaneous passage of stones, most pass within 4 to 6 weeks. The chance of spontaneous passage decreases with increasing stone size. Limited data estimate that 75% of stones <5 mm pass spontaneously, with an average time to stone expulsion of 17 days.[47]
Such patients in general are followed up with periodic imaging, with either a KUB and renal ultrasound or a non-contrast computed tomography (NCCT) abdomen and pelvis to monitor stone position and degree of hydronephrosis.
Surgical intervention is indicated in the presence of persistent obstruction, failure of stone progression, sepsis, or persistent or increasing colic.
If the patient is an adult with a ureteric stone with ongoing and intolerable pain or the ureteric stone is unlikely to pass, ensure they have surgical treatment within 48 hours of diagnosis or readmission.[16] See Surgical intervention section below.
Further management is based on stone size, location, and composition, in addition to anatomical and clinical features. For larger stones (≥10 mm), smaller stones that remain despite conservative therapies, and ureteric stones that are causing ongoing and intolerable pain, additional surgical intervention may be necessary.
If the patient is an adult with a ureteric stone with ongoing and intolerable pain or the ureteric stone is unlikely to pass, ensure they have surgical treatment within 48 hours of diagnosis or readmission.[16]
More info: Surgical treatment
Historically, open surgery was the only way to remove stones. However, with the development and success of endourology, a term used to describe less invasive surgical techniques that involve closed manipulation of the urinary tract with scopes, open surgery is now very rarely performed. Options include shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), ureteroscopy, and laparoscopic stone removal. Each of the surgical options has its own specific indications and considerations, but in general they are all relatively comparable in terms of safety and efficacy.[85]
Shock wave lithotripsy (SWL) is the least invasive method of definitive stone treatment and is suitable for most patients with uncomplicated stone disease. In SWL, shock waves are generated by a source external to the patient's body and are then propagated into the body and focused on a stone. The shock waves break stones by both compressive and tensile forces. The stone fragments then pass out in the urine. Limitations to SWL include stone size and location. However, SWL is often done without any need for general anaesthesia so can usually be performed as an outpatient procedure. Adjunctive treatment with tamsulosin or a diuretic appears to be effective in assisting stone clearance in patients with renal and ureteric calculi.[86][87] While SWL has been shown to have limited success with lower pole stones, there is evidence to suggest that ancillary manoeuvres such as percussion, diuresis, and inversion increase stone-free rates.[88][89] Contraindications to SWL treatment include pregnancy, aortic and/or renal artery aneurysms, uncontrolled hypertension, disorders of blood coagulation, and uncontrolled urinary tract infections.[90]
Ureteroscopy involves placing a small semi-rigid or flexible scope per urethra and into the ureter and/or kidney. Once the stone is visualised, it can be fragmented using a laser and the fragments grasped with a stone retrieval device and removed. The procedure is more invasive than SWL, but is generally thought to have a higher stone-free rate.[91] [
]
The procedure can often be carried out as a day case. It can be safely performed in coagulopathic patients using a holmium laser. Single-use flexible ureteropyeloscopy (FURS) demonstrates comparable efficacy with reusable FURS in treating renal calculi.[92] Ureteroscopic stone-free rates are better and fewer auxiliary procedures are needed with FURS than SWL for distal ureteric stones regardless of size and for proximal ureteric stones >10 mm.[91][93][94] While PCNL is the first-line therapy for large stones, FURS has been reported to achieve a mean stone-free rate as high as 93.7% (77.0% to 96.7%) for stones >20 mm in size (mean 25 mm) with acceptable overall complication rates (10.1%).[95][96] However, ureteroscopic removal has a higher complication rate and longer hospital stay, and a greater number of total procedures on average are needed than with PCNL.[97][98][99] A ureteric stent, an internal tube extending from the kidney to the bladder, may be left temporarily in place after ureteroscopy to promote collecting system drainage while any oedema from the stone or the procedure resolves. Stents are recommended in cases of functionally or anatomically solitary kidneys, ureteric stricture, noted ureteral injury, or cases with a planned second stage procedure. Do not routinely use post-treatment stenting after uncomplicated ureteroscopy for ureteric stones <20 mm. Pre-stenting of the ureter may enhance the stone-free rate achieved with ureteroscopy, which may also reduce complications such as ureteric injury.[100][101][102]Percutaneous nephrolithotomy (PCNL) is a minimally invasive form of treatment that is usually reserved for renal stones (particularly in the lower pole) and those that are large (>20 mm), have failed therapy with SWL and ureteroscopy, or are associated with complex renal anatomy.[103] Percutaneous access into the kidney is gained from the flank. Current evidence indicates that both fluoroscopy and ultrasound guidance may be successfully used for obtaining percutaneous renal access.[104] Combining ultrasound and fluoroscopy seems to improve the outcome, both with regard to success in achieving access and reducing complications.[105] Once access is gained, a sheath is placed into the kidney and a nephroscope is used to help remove the stone. At this point, stone or urine culture should be taken directly from the renal pelvis, if possible.[47] For larger stones, ultrasonic and/or ballistic lithotripsy is usually used to break and remove the stone. PCNL usually requires a hospital stay and has more potential complications than either SWL or ureteroscopy. In stones of 20-30 mm, SWL is associated with poor stone-free rates (34%) compared with those achieved with PCNL (90%).[106]
Mini-PCNL (which uses a smaller scope and sheath than standard PCNL) results in higher stone-free rates for stones 10-20 mm than ureteroscopy, but incurs greater blood loss and longer length of hospital stay as the procedure is more invasive.[107][108] Mini-PCNL may be an option for stones <20 mm, as some evidence suggests equivalent stone-free rate with fewer bleeding complications than standard PCNL (due to smaller tract size).[109][110][111] However, for an equivalent stone-free rate, mini-PCNL usually requires longer operating time than the standard procedure, due to the smaller size of operating equipment, because the scopes/sheaths are smaller.[111]
Laparoscopic stone removal is another minimally invasive method to remove ureteric or renal stones. However, it is still more invasive, requires a longer hospital stay, and has a much higher learning curve than ureteroscopy or SWL. With the advances in SWL and endourological surgery (i.e., ureteroscopy and PCNL) during the past 20 years, the indications for open stone surgery have markedly diminished. Laparoscopic or open surgical stone removal may still be indicated in rare cases where SWL, ureteroscopy, and percutaneous ureteroscopy fail or are unlikely to be successful; anatomical deformities preclude a minimally invasive approach; the patient requires concomitant open surgery, pyeloplasty, or a partial nephrectomy; or in patients with a large stone burden requiring a single clearance procedure.[47][103]
Renal stone <10 mm that fails to pass despite initial conservative management
If the patient is an adult:[16]
Offer shock wave lithotripsy (SWL)
Do not give pre-treatment stenting to adults having SWL
Consider ureteroscopy if SWL is contraindicated, fails, or is not indicated because of anatomical reasons
Consider percutaneous nephrolithotomy (PCNL) if SWL and ureteroscopy are not suitable options or have failed.
If the patient is aged under 16 years:[16]
Consider ureteroscopy or SWL
Consider PCNL if SWL and ureteroscopy are not suitable options or have failed.
Renal stone 10-20 mm
If the patient is an adult:[16]
Consider ureteroscopy or SWL
Do not give pre-treatment stenting to adults having SWL
Consider PCNL if SWL and ureteroscopy are not suitable options or have failed.
If the patient is aged under 16 years, consider ureteroscopy, SWL, or PCNL.[16]
Renal stone >20 mm (including staghorn stones)
If the patient is an adult:[16]
Offer PCNL
Consider ureteroscopy if PCNL is not a suitable option.
If the patient is a child aged under 16 years, consider ureteroscopy, SWL, or PCNL.[16]
Consider pre-treatment stenting for children and young people having SWL for renal staghorn stones.[16]
Ureteric stone <10 mm that fails to pass despite initial conservative management
If the patient is an adult:[16]
Offer SWL
Do not give pre-treatment stenting to adults having SWL
Consider ureteroscopy if stone clearance is not possible within 4 weeks with SWL, SWL is contraindicated or fails, or the stone is not targetable with SWL
Do not routinely give post-treatment stenting to adults who have had ureteroscopy for ureteric stones <20 mm.
If the patient is aged under 16 years:[16]
Consider ureteroscopy or SWL.
Ureteric stone 10-20 mm
If the patient is an adult:[16]
Offer ureteroscopy
Do not routinely give post-treatment stenting to adults who have had ureteroscopy for ureteric stones <20 mm
Consider SWL if local facilities allow stone clearance within 4 weeks
Do not give pre-treatment stenting to adults having SWL
Consider PCNL for impacted proximal stones when ureteroscopy has failed.
If the patient is aged under 16 years, consider ureteroscopy or SWL.[16]
Ureteric stone >20 mm
Ureteric stones of this size are rarely seen in practice. Therefore, these stones are treated on a case-by-case basis depending on regionally available treatments and expertise.[16]
A symptomatic stone occurs in 1 out of every 200 to 1500 pregnancies with 80% to 90% of these occurring in the second or third trimester.[112] It has been reported that 48% to 80% of stones pass spontaneously during pregnancy.[113] Patients with stone disease during pregnancy are at risk of adverse maternal and neonatal outcomes, such as preterm birth, C-section delivery, pre-eclampsia, and gestational diabetes.[114]
If the patient is pregnant, refer to a specialist (e.g., an obstetrician and/or urologist).[47] The specialist will consider either a ureteric stent or percutaneous nephrostomy tube if the patient is pregnant and:
Their renal colic is not controlled with oral analgesia
or
They have an obstructing stone and signs of infection (fever or urinalysis/urine culture showing a possible urine infection).
These tubes should be changed every 6 to 8 weeks due to concern for rapid encrustation as a result of the metabolic changes seen with pregnancy.
If the patient has no evidence of infection, the specialist will arrange ureteroscopy. Ureteroscopy has been demonstrated to be safe in pregnancy.[115]
SWL and PCNL are contraindicated in pregnancy.
For all patients, dietary modification with adequate hydration is an essential aspect of ongoing management.[45]
For patients at risk for or with a history of recurrent stones, tailor secondary preventative measures towards underlying metabolic factors that promote stone formation.
Diet and lifestyle
Advise the patient (and their family or carers, as appropriate) to:
Drink 2.5 to 3 litres (adults) or 1 to 2 litres (children) of water each day[16]
Add fresh lemon juice to drinking water[16]
Lemon juice is high in citrate leading to higher urinary citrate, which may stop calcium from binding to other stone constituents, therefore preventing stone formation and recurrence.[16]
Not restrict calcium intake and maintain a normal calcium intake of 700-1200 mg/day for adults, and 350-1000 mg/day for children and young people (depending on age)[16]
The patient should only restrict their calcium intake if there are very strong reasons to do so.
This is to help prevent stone recurrence.[16] Dietary calcium restriction can lead to less binding of calcium to oxalate in the gastrointestinal tract, promoting hyperoxaluria and potentiating the risk for stone formation; furthermore, it could have detrimental effects on bone health.
Consume no more than 6 g of salt per day (adults) or 2-6 g of salt per day (children and young people, depending on age)[16]
A high consumption of sodium causes hypercalciuria by reduced proximal tubular re-absorption of calcium. Urinary citrate is reduced. The risk of forming sodium urate crystals is increased and the effect of thiazide in reducing urinary calcium is counteracted by a high sodium intake.
Eat plenty of fruits, vegetables, and fibre.[47]
Fruit and vegetable intake should be encouraged because of the beneficial effects of fibre.
The alkaline content of a vegetarian diet also gives rise to a desirable increase in urinary pH.
People with nephrolithiasis are often advised to avoid a high protein diet. The European Association of Urology recommends limiting animal protein to 0.8 to 1 g/kg/day.[47] However, the National Institute for Health and Care Excellence (NICE) in the UK does not give a recommendation regarding protein intake based on its assessment that the evidence on the effectiveness of low protein intake in reducing stone recurrence is inconclusive.[16]
Encourage the patient to establish a healthy lifestyle, including physical activity habits, to achieve and maintain a healthy weight.[74]
Additional dietary advice may be given for specific patient groups (based on the types of stones they form) in a specialist metabolic clinic setting.
Ongoing medical therapy
Oral alkalinisation therapy with medications such as potassium citrate and sodium bicarbonate may be beneficial in dissolving uric acid stones and preventing uric acid supersaturation. It may be used for treating uric acid stones that do not require urgent surgical treatment, as well as asymptomatic stones.[47] The ideal goal for alkalinisation therapy for most uric acid stones is to maintain the urine pH between 7.0 and 7.2.[47] In practice, a pH of 6.5 to 7.0 is often targeted if there is any concern about calcium-based stones. Potassium citrate is the first-line therapy. In patients with congestive heart failure or renal failure, extra care should be taken when prescribing alkalinisation therapy. Alkalinisation therapy also plays an important role in preventing calcium and cystine stones.
Where specific metabolic abnormalities exist, individualised preventative therapies may be required in addition to dietary modification.[47][71][116] These patients will need to be managed in a specialist metabolic clinic setting where they can be offered tailored advice and interventions. These abnormalities and recommended interventions include:
Uric acid stones: urinary alkalinisation with potassium citrate or sodium bicarbonate[47]
Hypercalciuria and recurrent stones that are more than 50% calcium oxalate: thiazide diuretic or potassium citrate (after the patient has restricted their sodium intake to no more than 6 g per day)[16]
Hypocitraturia and recurrent stones that are more than 50% calcium oxalate: urinary alkalinisation (e.g., potassium citrate); sodium bicarbonate or sodium citrate can be considered if the patient is at risk for hyperkalaemia[16][116]
Hyperoxaluria: oxalate chelator (e.g., calcium, magnesium, or colestyramine), potassium citrate, pyridoxine; a rare condition
Cystinuria: high fluid intake alongside urinary alkalinisation with potassium citrate, thiol binding agent (e.g., tiopronin which is tolerated better than d-penicillamine); a genetic abnormality requiring life-long management.[3]
Most of these strategies are applied to children with nephrolithiasis, although there are a limited number of well-designed trials in this age group.[117][118]
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