urine on one side

Overview

This refers to a sharp or dull pain that you feel on one side of your back, side, or lower belly while you are passing urine. It can be a sign of a problem in your kidney or the tube that carries urine from your kidney to your bladder (called the ureter).

Yes, kidney stones and urinary tract infections are common conditions that can cause this type of pain. Many people experience it at some point.

It can affect people of any age and gender, though kidney stones are more common in men, and urinary tract infections are more common in women.

Symptoms

Common symptoms

• Sharp, cramping pain on one side of your back or lower abdomen during urination
• Pain that comes in waves and may move to your groin or thigh
• Nausea or vomiting
• Blood in your urine (pink, red, or brown)
• Frequent or urgent need to urinate

Symptoms in children

• Fussiness or crying while urinating
• Holding their abdomen or back
• Fever without a clear cause

Symptoms in older adults

• Flank pain that may be less intense than in younger people
• Confusion or changes in mental state
• Loss of appetite or fatigue

Causes

Main causes

• Kidney stones blocking the flow of urine
• Urinary tract infection that has spread to the kidney (pyelonephritis)
• Injury or trauma to the kidney area
• Enlarged prostate (in men) pressing on the ureter

Risk factors

• Not drinking enough water
• Diet high in salt or animal protein
• Personal or family history of kidney stones
• Recurrent urinary tract infections
• Being male over 50 (for prostate problems)

When to see a doctor

See a doctor urgently if:

• If you have severe pain and cannot get comfortable
• If you have fever or chills alongside the pain
• If you see blood in your urine

Book a routine appointment if:

• If you have mild pain that lasts more than a day
• If you have felt this pain before and it is familiar
• If you have a known condition like kidney stones or recurrent UTIs and the pain does not improve

Diagnosis

A doctor will ask about your symptoms and examine your back and belly. They will likely order tests to find the cause.

Tests that may be done

• Urine test (urinalysis) to check for infection or blood
• Blood tests to check kidney function
• Imaging tests like ultrasound or CT scan to look for stones or blockage

What to expect at your appointment

The tests are usually quick and painless. You may be asked to give a urine sample. For imaging, you lie on a table while a machine takes pictures. The results help your doctor decide the best treatment.

Treatment

Treatment depends on the cause. For infections, antibiotics are prescribed. For stones, pain relief and plenty of fluids often help small stones pass. Larger stones may need procedures to break them up or remove them.

Self-care at home

• Drink plenty of water (unless advised otherwise by your doctor)
• Apply a heating pad to the painful area for comfort
• Avoid drinks that can irritate the bladder, like caffeine and alcohol

Medical treatments

Your doctor may prescribe medicines to relieve pain or help pass stones. For infections, a course of antibiotics is given. Do not take any medication without your doctor's advice, as some can hide symptoms.

When is surgery considered?

If a stone is too large to pass on its own or is causing a blockage, a procedure called lithotripsy (using shock waves to break the stone) or ureteroscopy (using a thin scope to remove it) may be recommended. Surgery is done under sedation or anaesthetic.

Living with this condition

Most causes of one-sided pain when urinating can be fully treated. After treatment, you can return to normal activities. If you have a chronic condition like recurrent stones, you may need long-term changes to prevent future episodes.

Lifestyle tips

• Stay well-hydrated – aim for 6-8 glasses of water a day
• Reduce salt in your diet
• Limit foods high in oxalates (like spinach, nuts) if you form calcium oxalate stones

Diet and exercise

A balanced diet with plenty of fruits and vegetables supports kidney health. Moderate exercise is fine, but avoid heavy lifting if you have a large stone or recent procedure.

Mental health and emotional wellbeing

Dealing with recurrent pain can be stressful. It is normal to feel anxious. Talk to your doctor about any worries. Joining a support group may help.

Prevention

Not all cases can be prevented, but drinking enough water and eating a balanced diet reduces the risk of kidney stones and infections. If you are prone to stones, your doctor may give specific dietary advice.

Vaccines

There is no vaccine that directly prevents this symptom. However, staying up to date with routine vaccines helps prevent infections that might affect the kidneys.

Screening programmes

Screening is not routine. If you have a family history of kidney stones or recurrent infections, talk to your doctor about monitoring.

Complications

If left untreated

• Kidney damage from prolonged blockage
• Sepsis (a severe infection spread through the blood)
• Chronic kidney disease if the problem is long-term

Long-term outlook

With proper treatment, most people recover fully. Even large stones can be successfully removed. The key is to see a doctor early to avoid complications.

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