Why do kidney stones cause flank pain?

The ureters are narrow tubes that carry urine from the kidneys to the bladder. When a stone moves into one, urine may build up above it and stretch the tissues. The ureter can also contract around the stone, producing waves of pain that may come and go rather than stay at one steady level. Flank Pain is a very common presentation of Kidney Stones, although flank pain also has many causes unrelated to stones.

Pain may begin between the ribs and hip on one side and travel toward the lower abdomen, groin, or genital area as a stone moves lower. Restlessness, nausea, sweating, blood in the urine, or urinary urgency can accompany the pain. The pattern and associated symptoms help a clinician decide what to investigate.

Arrange a medical assessment for new or severe flank pain, especially if you also have urinary symptoms. The assessment may include questions about the pain, an examination, a urine test, blood tests, and imaging when appropriate. These checks can look for obstruction, infection, and causes other than a stone.

Take medicines only as directed or after checking that they are safe with your medical history and current prescriptions. Avoid driving or operating machinery if pain, dizziness, or prescribed pain medicine affects your concentration. Keep a note of when the pain starts, where it travels, and any changes in urine.

Get urgent medical help for flank pain with fever or chills, inability to pass urine, repeated vomiting, fainting, confusion, or pain that is severe and not controlled by the plan you have been given. A urinary blockage with infection can become serious. Visible blood in urine or pain during pregnancy also warrants prompt clinical advice.

You can ask what is causing the pain, whether urine flow is obstructed, whether an infection has been checked for, and which symptoms should change your follow-up plan. If a stone is identified, ask about its location, pain control, and how you will know whether further treatment is needed.