What are the symptoms and treatment options for kidney stones?

Kidney Stone Symptoms and Treatment

Clinical Presentation

Kidney stones typically present with severe loin pain (renal colic), accompanied by dysuria, urinary frequency, hematuria, fever, flank pain, and groin pain. 1

The acute presentation includes:

• Severe flank/loin pain that may radiate to the groin 1, 2
• Hematuria (blood in urine) 1, 2
• Urinary symptoms including dysuria, frequency, and oliguria 1, 2
• Fever if infection is present 1

Immediate Diagnostic Workup

Ultrasound should be the primary diagnostic tool and should not delay emergency care, though it has only 45% sensitivity for ureteral stones and 88% specificity for renal stones. 3

Non-contrast CT is the gold standard after ultrasound for acute flank pain, providing 93.1% sensitivity and 96.6% specificity, with assessment of stone location, burden, density, and anatomy. 3 Low-dose CT protocols maintain diagnostic accuracy while reducing radiation exposure. 3

Essential laboratory evaluation includes:

• Urinalysis (dipstick) 3
• Blood tests: creatinine, uric acid, ionized calcium, sodium, potassium, blood cell count, C-reactive protein 3
• Urine culture before any intervention 3
• Stone analysis for all first-time stone formers 3

Acute Pain Management

NSAIDs (diclofenac, ibuprofen, metamizole) are first-line treatment for renal colic, as they reduce the need for additional analgesia compared to opioids. 3 However, use the lowest effective dose due to cardiovascular and gastrointestinal risks, and exercise caution in patients with reduced kidney function. 3

Opioids are second-line analgesics, with hydromorphine, pentazocine, or tramadol preferred over pethidine due to lower vomiting rates. 3

Emergency Situations Requiring Urgent Intervention

If sepsis and/or anuria occur with an obstructed kidney, urgent decompression via percutaneous nephrostomy or ureteral stenting is mandatory. 3 Definitive stone treatment must be delayed until sepsis resolves. 3

The emergency protocol includes:

• Immediate antibiotics before and after decompression 3
• Urine collection for antibiogram testing 3
• Re-evaluation of antibiotic regimen based on culture results 3
• Intensive care may be necessary 3

Conservative Management and Medical Expulsive Therapy

For stones ≤5mm, spontaneous passage occurs in 75% of cases, typically within 17 days, with passage rates of 89% for distal stones <5mm. 3

Medical expulsive therapy (alpha-blockers) is first-line for ureteral stones >5mm in the distal ureter when active removal is not immediately required. 3 MET should be stopped if complications arise (infection, refractory pain, or declining renal function). 3

Active Stone Removal Indications

Stones should be removed if there is:

• Stone growth 3
• High risk of stone formation 3
• Persistent symptoms despite conservative management 3
• Stones unlikely to pass spontaneously (>5mm in upper ureter, >10mm anywhere) 3

Treatment Selection by Stone Size and Location

For Ureteral Stones

Ureteroscopy is the preferred first-line treatment for most ureteral stones requiring intervention. 3 The European Association of Urology provides specific algorithms based on stone location and size. 3

For Renal Stones (1.6cm example)

For a 1.6cm renal pelvic stone, flexible ureteroscopy (fURS) or percutaneous nephrolithotomy (PCNL) are first-line options, with PCNL providing higher stone-free rates. 4

• PCNL (mini-PCNL 12-22F or standard >22F) provides similar stone-free rates, with mini-PCNL reducing blood loss, transfusion rates, and hospital stay. 3
• Extracorporeal shock wave lithotripsy (ESWL) is less effective for stones >15mm and should be considered second-line. 4

PCNL Complications

Reported complications include fever (10.8%), transfusion (7%), thoracic complications (1.5%), sepsis (0.5%), organ injury (0.4%), and mortality (0.05%). 3

Stone-Specific Medical Management

Uric Acid Stones

Oral alkalinization with potassium citrate or sodium bicarbonate (target pH 7.0-7.2) is first-line therapy, achieving 80.5% dissolution success rates. 5, 3 Allopurinol should not be routinely offered as first-line therapy since most patients have low urinary pH rather than hyperuricosuria. 3

Calcium Oxalate Stones

Thiazide diuretics and/or potassium citrate should be offered to patients with recurrent calcium stones, particularly those with hypercalciuria or hypocitraturia. 3 Allopurinol is indicated for patients with hyperuricosuria (>800mg/day) and normal urinary calcium. 3

Cystine Stones

Potassium citrate to achieve urine pH of 7.0 is first-line, with cystine-binding thiol drugs (tiopronin preferred over d-penicillamine) for refractory cases. 3

Prevention Strategies

Increase fluid intake to achieve at least 2L of urine output daily to prevent recurrence. 4, 6

Additional dietary modifications include:

• Adequate calcium intake (1000-1200mg/day) 6
• Limit sodium to 2-3g/day (or 3-5g NaCl/day) 6
• Limit animal protein to 0.8-1.0g/kg body weight/day 6
• Avoid vitamin C and D supplements 6
• Limit oxalate-rich foods for calcium oxalate stone formers 6

Follow-up 24-hour urine collection within 6 months of treatment initiation is recommended to assess response to dietary and medical therapy. 3