What should you know about unilateral flank pain?

Flank pain is felt between the ribs and hip, often toward the back. A pulled muscle may hurt more with movement or touch. Urinary causes can include a kidney stone, a urinary tract infection or a kidney infection. Burning urination, needing to pass urine often, cloudy urine or blood in the urine make a urinary cause more relevant. Colicky pain that comes in waves may occur with a stone, while infection may bring fever, chills or feeling unwell. Pain can also come from the spine, skin nerves or digestive organs, so the symptom alone cannot identify one diagnosis.

Record when the pain began, which side is affected, whether it is constant or wave-like, and what changes it. Drink normally unless a clinician has told you to restrict fluids, and avoid strenuous lifting until the cause is clearer. Do not use leftover antibiotics. A clinician can examine your abdomen and back, review urine symptoms and decide whether urine testing or other assessment is needed. Seek advice promptly if the pain persists, returns or is accompanied by urinary changes.

Get urgent medical help for severe or rapidly worsening pain, fever with flank pain, repeated vomiting, faintness, confusion, inability to pass urine, or visible blood in the urine. Urgent assessment is also sensible during pregnancy or when you have one functioning kidney, known kidney disease or significant immune suppression. These features can signal infection, obstruction or another problem needing timely treatment.

Could this pain be coming from my kidney, urinary tract, muscles or spine? Do my symptoms suggest urine testing? Which changes should prompt urgent review? What pain relief is suitable with my medicines and health conditions?