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Understanding kidney stones
Audience: patients-public, students-learners ยท Review state: published
What they are
Kidney stones are hard deposits of minerals and salts that form inside the kidneys when urine becomes concentrated, letting crystals stick together and grow. They range from grains of sand to stones several centimeters across.
Small stones often pass out of the body unnoticed; larger ones can get stuck in the urinary tract and cause severe pain.
Symptoms
The classic symptom is sudden, severe pain in the side and back, below the ribs, which may move to the lower abdomen and groin as the stone travels. Pain often comes in waves.
Other signs include pink, red, or cloudy urine, pain or burning when urinating, nausea and vomiting, and a frequent urge to urinate. Fever and chills with these symptoms suggest infection and need urgent care.
Causes and risk factors
Not drinking enough fluid is the biggest driver, especially in hot climates or with heavy sweating. Diet plays a part: high salt, high animal protein, and high sugar intakes raise risk, as does obesity. A personal or family history of stones makes recurrence more likely.
Most stones are calcium oxalate stones; other types include uric acid, struvite, and cystine stones, and knowing the type guides prevention.
Treatment and prevention
Small stones usually pass on their own with plenty of fluids and pain relief; doctors may prescribe medicine to relax the ureter and help the stone along. Larger or stuck stones can be broken up with shock waves or removed with small instruments.
Prevention centers on drinking enough water to keep urine pale, moderating salt and animal protein, and keeping normal dietary calcium, which actually protects against the most common stone type. Anyone who has passed a stone benefits from having it analyzed, because prevention advice depends on the stone's makeup.
Limitations
General educational overview, not medical advice and not a diagnosis. Severe flank pain, fever, or inability to pass urine needs urgent medical care.