When to seek care for flank pain

Overview

Flank pain is discomfort or pain on one side of your body, between your ribs and hip. It often comes from your kidney, urinary tract, or muscles in that area.

Yes, flank pain is a common reason people visit their doctor or emergency department. Many adults experience it at some point.

Flank pain can affect people of all ages. Kidney stones are more common in men, while urinary tract infections are more common in women. Muscle strain can happen to anyone.

Symptoms

Common symptoms

• Pain on one side of your back or side, between the ribs and hip
• Pain that spreads to your lower belly or groin
• Pain when you urinate
• Needing to urinate often or urgently
• Nausea or vomiting
• Fever or chills

Symptoms in children

• Fussiness or crying more than usual
• Pain that makes them curl up or hold their side
• Vomiting or refusing to eat
• Urine that looks pink, red, or cloudy

Symptoms in older adults

• Feeling confused or more tired than usual
• Less specific pain – they may just say their side hurts
• Loss of appetite or not wanting to drink
• Fever or chills, but sometimes no fever at all

Causes

Main causes

• Kidney stones – hard deposits that form in your kidney and can cause sharp pain
• Urinary tract infection that has spread to the kidney (called pyelonephritis)
• Muscle strain – from lifting, twisting, or overuse
• Kidney infection – usually from a bladder infection that travels up
• Shingles – a painful rash that can appear on one side of your body

Risk factors

• Not drinking enough water
• Having a personal or family history of kidney stones
• Having a urinary tract infection that isn't treated
• Certain medical conditions like diabetes, gout, or high blood pressure
• Prolonged bed rest or heavy lifting

When to see a doctor

See a doctor urgently if:

• Flank pain with fever, chills, nausea, or vomiting
• Blood in your urine
• Pain that is severe or comes in waves
• Trouble urinating or inability to urinate

Book a routine appointment if:

• Mild flank pain that comes and goes
• Pain that started after an injury or lifting something heavy
• A dull ache that lasts more than a few days

Diagnosis

Your doctor will ask about your pain, when it started, and any other symptoms. They will also check your back and belly for tenderness.

Tests that may be done

• Urine test – to check for infection or blood
• Blood test – to look for signs of infection or kidney problems
• Ultrasound – a painless scan that can see stones or swelling in your kidney
• CT scan – a more detailed X-ray that can find small stones or other issues

What to expect at your appointment

The doctor may press gently on your back or side to see where it hurts. You might be asked to give a urine sample. If the cause is not clear, you may have a scan. The visit usually takes 30 to 60 minutes. Results from urine and blood tests may be ready in a few hours.

Treatment

Treatment for flank pain depends on what is causing it. Many causes get better with self-care and medication. Infections require antibiotics. Kidney stones often pass on their own with pain relief and plenty of fluids.

Self-care at home

• Drink at least 8 glasses of water a day (unless your doctor says otherwise)
• Rest and avoid heavy lifting or strenuous activity
• Apply a warm heating pad to the painful area for 15–20 minutes
• Use over-the-counter pain relievers as directed – ask your pharmacist for advice

Medical treatments

If you have a kidney infection, your doctor will prescribe antibiotics. For kidney stones, you may be given medication to help relax the ureter (the tube from kidney to bladder) so the stone can pass more easily. Pain relievers are also given. In some cases, stones may need to be broken up with sound waves (lithotripsy) or removed with a small procedure.

When is surgery considered?

Surgery is rarely needed for the most common causes of flank pain. It may be considered if a kidney stone is too large to pass, if there is a blockage, if an abscess (pus pocket) forms, or if a tumor is found.

Living with this condition

Follow your treatment plan. If you have an infection, finish all your antibiotics even if you feel better. If you have kidney stones, keep drinking water to help pass them. Watch for any return of pain or fever.

Lifestyle tips

• Stay well hydrated – drink water throughout the day
• Maintain a healthy weight
• Avoid holding in urine – go when you feel the need
• If you have muscle strain, ease back into activity slowly

Diet and exercise

A balanced diet with plenty of fruits and vegetables is good for overall kidney health. If you have had kidney stones, your doctor may suggest eating less salt or avoiding foods high in oxalates (like spinach or nuts). Gentle stretching and walking can help muscle strain, but avoid heavy lifting until you're healed.

Mental health and emotional wellbeing

Chronic or recurring flank pain can be stressful and worrying. It is normal to feel anxious or frustrated. Talk to your doctor about these feelings – they can suggest ways to cope, like relaxation techniques or speaking to a counselor.

Prevention

Some causes of flank pain can be reduced by staying hydrated, treating urinary tract infections early, and avoiding heavy lifting when possible. Kidney stones can sometimes be prevented with diet changes, but not all cases can be avoided.

Vaccines

Vaccines do not directly prevent flank pain, but staying up to date on vaccines like the flu shot can help prevent illnesses that might lead to infections.

Screening programmes

There is no routine screening for flank pain in healthy people. If you have had kidney stones or repeated infections, your doctor may suggest regular urine tests or imaging to watch for new stones.

Complications

If left untreated

• Kidney infection can spread into the bloodstream (sepsis) – a life-threatening emergency
• Large kidney stones can block the flow of urine and damage the kidney
• Chronic pain that affects daily life
• Recurring infections that may require longer treatment

Long-term outlook

The outlook for most people with flank pain is good. With the right diagnosis and treatment, most causes improve or resolve completely. Even serious infections usually heal with antibiotics. If you have a condition like recurring kidney stones, you can manage it with your doctor's help and enjoy a full, active life.

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