Kidney Stones Symptoms: Pain, Blood in Urine & More

What Are Kidney Stones?

Kidney stones (medically known as nephrolithiasis) are hard deposits of minerals and salts that form inside the kidneys. They develop when the urine contains too much of certain substances – such as calcium, oxalate, or uric acid – which then crystallize. Kidney stones vary in size from a grain of sand to several centimetres in diameter. Small stones often pass unnoticed, while larger ones can cause significant discomfort and complications.

Common Symptoms of Kidney Stones

Symptoms depend largely on the size and position of the stone. Many people only notice a kidney stone when it moves into the ureter and causes a blockage.

Pain

The most characteristic symptom is a renal colic – an intense, wave-like pain that typically:

• begins in the side or flank area of the back
• can radiate to the lower abdomen, groin, or genitals
• comes and goes in waves
• is considered one of the most severe pains a person can experience

Urinary Symptoms

• Blood in the urine (hematuria): The urine may appear pink, red, or brown.
• Painful urination: A burning or stinging sensation when passing urine.
• Frequent urge to urinate: A persistent need to urinate, even when little urine is produced.
• Cloudy or foul-smelling urine: May indicate an accompanying urinary tract infection.

Other Symptoms

• Nausea and vomiting: Common accompanying symptoms during severe pain episodes.
• Fever and chills: These signs may indicate a serious infection (pyelonephritis) and require immediate medical attention.
• Restlessness and discomfort: Patients often struggle to find a comfortable position.

When to Seek Immediate Medical Attention

Certain symptoms require urgent medical care:

• Fever above 38.5 °C combined with flank pain
• Chills or rigors
• Little or no urine output
• Severe, unrelenting pain
• Known single kidney or impaired kidney function

These signs may indicate an obstructed kidney with infection – a potentially life-threatening condition that requires prompt evaluation and treatment.

Diagnosis of Kidney Stones

Doctors use several tests to diagnose kidney stones:

• Ultrasound: A quick, radiation-free first-line imaging test to detect stones and urinary obstruction.
• CT scan: The gold standard in emergency diagnostics – provides detailed information about the size, location, and type of stone.
• Urinalysis: Checks for blood, bacteria, or crystals in the urine.
• Blood tests: Assess kidney function and detect signs of infection or inflammation.

Causes and Risk Factors

Kidney stones form due to a combination of factors:

• Insufficient fluid intake (the most common cause)
• Diet high in salt, protein, or oxalate-rich foods (e.g., spinach, rhubarb)
• Family history of kidney stones
• Metabolic disorders (e.g., hyperparathyroidism, gout)
• Chronic bowel diseases (e.g., Crohn's disease)
• Certain medications

Treatment Options

Treatment depends on the size, type, and location of the stone:

• Small stones (under 5 mm): Often pass on their own with adequate fluid intake and pain management.
• Extracorporeal shock wave lithotripsy (ESWL): Sound waves break up the stone from outside the body.
• Ureteroscopy (URS): Minimally invasive removal of the stone using a thin scope passed through the urethra.
• Percutaneous nephrolithotomy (PCNL): Surgical removal of very large stones through a small incision in the back.

Prevention

The most important measure for preventing kidney stones is adequate hydration – drinking at least 2 to 2.5 litres of fluid per day. Additional strategies include dietary adjustments and, for recurrent stone formers, targeted medical therapy.

References

1. Türk C. et al. – EAU Guidelines on Urolithiasis. European Association of Urology (2023). Available at: www.uroweb.org
2. Moe O.W. – Kidney stones: pathophysiology and medical management. The Lancet, 367(9507):333–344 (2006).
3. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) – Kidney Stones. U.S. Department of Health and Human Services (2023). Available at: www.niddk.nih.gov