Flank and Side Pain — Kidney Stones and Other Causes
Also described as kidney pain, side pain, loin pain, pain in the back side.
Severe one-sided pain that comes in waves from the back around to the groin, often with nausea and blood in the urine, is characteristic of a kidney stone. Flank pain with fever and chills suggests kidney infection and needs same-day treatment.
🚨 Get emergency care if you have
- •Flank pain with fever and chills — possible kidney infection
- •Pain with vomiting that prevents keeping fluids down
- •Inability to pass urine
- •Flank pain in a single-kidney patient or in pregnancy
- •Pain with visible blood and clots
What causes flank pain?
Kidney or ureteric stone
Colicky pain radiating to the groin, with nausea and microscopic or visible blood.
Kidney infection (pyelonephritis)
Flank pain with fever, chills and burning urination. Needs prompt antibiotics.
Musculoskeletal strain
Pain reproduced by movement or pressing the area, without urinary symptoms.
Kidney cyst or mass
Usually painless, sometimes causing a dull ache or visible blood.
Referred spinal pain
From the thoracolumbar spine, following a nerve's course around the flank.
How it is investigated
- ✓Urine routine examination
- ✓Ultrasound kidneys, ureters and bladder
- ✓Non-contrast CT KUB — the definitive test for stones
- ✓Kidney function and inflammatory markers
Not every patient needs every test. The consultation decides which of these apply to you.
Frequently asked questions
Will a kidney stone pass on its own?▼
Most stones under 5 mm pass with fluids, pain relief and sometimes medication to relax the ureter. Larger stones, or stones causing obstruction, infection or uncontrolled pain, need intervention — ESWL, laser or ureteroscopy — which Iswarya Hospital performs as day-care procedures.
How do I know it is a kidney stone and not back pain?▼
Stone pain is usually severe, comes in waves, radiates from the back around to the groin, and makes it hard to sit still, often with nausea and blood in the urine. Muscular back pain is reproduced by movement or pressure and does not affect urination. A CT KUB settles it.
This page is general health information, not a diagnosis or a substitute for a consultation. Symptoms overlap between harmless and serious conditions, and only an examination can tell them apart. If you are worried, see a doctor.
Plan your first visit
Not sure which specialist to see? Tell our care team the reason for your visit and we will help you choose.
- Bring previous prescriptions, relevant test reports or scan images, a medication list and photo ID.
- If you plan to use insurance, bring your policy details. OPD, tests and admission benefits depend on your individual plan and approval.
- Your first consultation determines which tests or treatments are needed; not everyone needs every test listed on this page.
Appointments are requests until confirmed. In a medical emergency, call 044 2025 2025 or go to the nearest emergency department.