What should you know about large kidney stones?

A kidney stone is a hard deposit that can move from the kidney into the tube carrying urine to the bladder. A larger stone may be less able to pass through the urinary tract and can obstruct flow. This may cause severe cramping pain in the side or back, pain that travels towards the groin, nausea, blood in the urine, or painful urination. Some stones cause no symptoms until they move.

Dehydration can make urine more concentrated and may contribute to stone formation, but a stone's size and position determine the immediate concern. A [Kidney Stones](/conditions/kidney-stones/) assessment can help explain the condition and related symptoms such as [Flank Pain](/symptoms/flank-pain/) or [Abdominal Pain](/symptoms/abdominal-pain/).

Arrange prompt medical assessment rather than waiting for a large stone to pass. A clinician may ask about pain, urine changes, fever, vomiting and previous stones. An [Abdominal Ultrasound](/treatments/diagnostics-and-screening/abdominal-ultrasound/) may help assess the kidneys and urine drainage; other tests may be chosen according to the findings.

Drink normally unless a clinician has advised a fluid restriction, and do not force large amounts of fluid during severe pain or vomiting. Use only pain relief that is suitable for you and follow the label or medical advice. Keep any passed stone if you can do so safely, as it may help guide future care.

Seek emergency care for severe pain with fever or chills, repeated vomiting, confusion, fainting, or very little or no urine. A blocked urinary system with infection can become serious. Get prompt advice for [Difficulty Passing Urine](/symptoms/difficulty-passing-urine/), [Painful Urination](/symptoms/painful-urination/), or pain that is not controlled.

Ask where the stone is, whether urine flow is blocked, how kidney function will be checked, and what treatment options fit its size and position. Ask which symptoms mean you should return urgently and how to reduce the chance of another stone.