What should you know about intense flank pain?

The flank is the area between the ribs and hip on either side of the back. Pain there may be sharp, cramping, aching or tender to touch. Kidney Stones can cause severe waves of pain that move toward the groin, sometimes with nausea or blood in the urine. Kidney Infection may cause flank pain with fever, chills, feeling unwell or urinary symptoms. Urinary Tract Infection can cause burning, urgency or frequent urination, although back or side pain suggests the infection may need prompt review. Muscles, nerves and digestive organs can also be involved.

Rest from lifting and note whether movement changes the pain. Drink normally unless a clinician has told you to restrict fluids; forcing large amounts may worsen discomfort in some situations. Record urine colour, frequency, burning, nausea, fever, bowel symptoms and whether pain travels. Take only pain relief that is safe for your health and medicines, following professional or label directions. Do not rely on home treatment when pain is intense or unfamiliar.

Seek same-day medical advice for severe or persistent flank pain, fever, vomiting, painful urination, blood in urine, reduced urine or pregnancy. Go to urgent care for confusion, fainting, severe weakness, inability to keep fluids down, or pain with a very unwell appearance. A blocked infected kidney can become serious, so fever combined with flank pain should not be watched at home.

Ask whether the pain pattern fits a stone, infection or muscle cause; whether urine testing or imaging is needed; which pain medicines are appropriate; and which changes should bring you back urgently.