What are the symptoms of kidney stones?

Symptoms of Kidney Stones

Kidney stones typically present with severe, sudden-onset flank pain (renal colic) that radiates to the lower abdomen and groin, often accompanied by blood in the urine (hematuria), and the pain occurs in waves rather than being constant. 1

Primary Clinical Presentation

The hallmark symptom is renal colic—severe, colicky pain caused by ureteral hyperperistalsis as the stone moves through the urinary tract. 1 This pain:

• Occurs in waves with periods of severe pain alternating with less intense discomfort 1, 2
• Does NOT worsen with external pressure on the flank (if it does, consider pyelonephritis or perinephric abscess instead) 2
• Is caused by internal obstruction and distension of the collecting system rather than external compression 2

Hematuria (blood in urine) is extremely common, resulting from irritation and trauma to the ureter as the stone passes. 1

Location-Specific Symptoms

The pain pattern varies dramatically based on where the stone is located:

• Kidney stones (non-obstructing): May cause dull, aching flank pain or be completely asymptomatic if not causing obstruction 1
• Upper ureteral stones: Severe flank pain radiating to the upper abdomen 1
• Mid-ureteral stones: Pain radiating anteriorly toward the groin 1
• Distal ureteral stones: Pain radiating to the groin, testicle in men, or labia in women 1

Associated Urinary Symptoms

• Frequent urination 3
• Dysuria (painful urination) 3, 4
• Oliguria (reduced urine output) 3

RED FLAG Symptoms Requiring Emergency Evaluation

These indicate potentially life-threatening complications:

• Fever with flank pain: Suggests infected obstructed stone—a urological emergency 1
• Anuria (complete cessation of urine output): Indicates bilateral obstruction or obstruction of a solitary kidney 1
• Signs of sepsis: High fever, hypotension, tachycardia, altered mental status 1
• Cloudy or foul-smelling urine with fever and chills: Indicates urinary tract infection complicating the stone 1

Stone Size and Symptom Severity

• Stones <5 mm: Typically cause milder symptoms with 75% spontaneous passage rate 1
• Stones ≥5 mm: Cause more severe symptoms with 62% passage rate 1
• Stones smaller than 5 mm normally pass spontaneously, while larger stones may require intervention 3

Important Clinical Pitfall

Asymptomatic stones are common—stones remaining in the kidney without causing obstruction may be discovered incidentally on imaging and cause no symptoms whatsoever. 1 This is particularly true for lower pole kidney stones that are not obstructing. 2