Synopsis

Kidney stones are hard, crystalline mineral deposits that form in the kidneys when urine becomes too concentrated, allowing minerals like calcium, oxalate, and uric acid to crystallize and bind. They can vary in size from tiny grains to large stones that obstruct urine flow, and may pass unnoticed or cause intense pain and urinary symptoms.

There are several types of kidney stones:

• Calcium oxalate stones (most common)

• Calcium phosphate stones

• Uric acid stones

• Struvite stones (from infection)

• Cystine stones (rare, genetic)

Common symptoms include:

• Severe, sharp pain in the back or side (renal colic)

• Pain radiating to the lower abdomen or groin

• Blood in urine (hematuria)

• Nausea and vomiting

• Frequent or painful urination

• Cloudy or foul-smelling urine

Risk factors include:

• Dehydration

• High-oxalate or high-sodium diet

• Obesity

• Digestive disorders (e.g., Crohn’s, gastric bypass)

• Family or personal history of stones

When to see a doctor:
Seek immediate care if you experience severe pain, fever, chills, nausea, or difficulty urinating. Imaging and urinalysis are used for diagnosis. Small stones may pass on their own; larger stones may require medications, lithotripsy, or surgical removal.

Variant names

Renal calculi
Nephrolithiasis
Urolithiasis
Urinary stones