Flank pain in children

Overview

Flank pain is pain on the side of the body, between the ribs and the hip. In children, it can be a sign of a problem in the kidney, urinary tract, or nearby muscles and bones. It is not a condition itself but a symptom that needs attention.

Flank pain is less common in children than in adults, but it is not rare. It can happen at any age.

Flank pain affects both boys and girls. It can happen to children of all ages, from babies to teenagers.

Symptoms

Common symptoms

• Pain on one side of the body, between the ribs and hip
• Pain that comes and goes or stays steady
• Pain that may spread to the lower belly or groin
• Pain when urinating or a constant need to pee

Symptoms in children

• Fussiness or crying more than usual
• Holding the side or belly
• Not wanting to eat
• Wetting the bed after being dry at night
• Fever or chills
• Nausea or vomiting

Symptoms in older adults

• This section is for children. In older adults, flank pain may have different causes and symptoms, which are not covered here.

Causes

Main causes

• Urinary tract infection (UTI) – an infection in the bladder or kidney
• Kidney stones – hard deposits that form in the kidney
• Constipation – hard stool pressing on the urinary system
• Muscle strain – from sports or playing hard
• Hydronephrosis – swelling of the kidney due to urine backup
• Injury to the side or back

Risk factors

• Being a girl (for UTIs)
• Not drinking enough fluids
• Family history of kidney stones
• Urinary tract abnormalities at birth
• Recent infection or fever

When to see a doctor

See a doctor urgently if:

• Flank pain with any emergency symptom listed above
• Flank pain with fever in a child under 2 years old
• Flank pain after a fall or injury

Book a routine appointment if:

• Mild flank pain that lasts more than a day
• Pain that comes and goes for several days
• Pain that affects normal activities or sleep
• Any flank pain in a child who has had kidney problems before

Diagnosis

A doctor will ask about your child's symptoms and medical history, and do a physical exam. They may press gently on the belly and back to find where it hurts.

Tests that may be done

• Urine test – to check for infection, blood, or signs of stones
• Blood test – to check kidney function and infection
• Ultrasound – a painless scan that looks at the kidneys and bladder
• X-ray or CT scan – sometimes used to see stones or blockages
• Voiding cystourethrogram (VCUG) – a special X-ray to see how the bladder works

What to expect at your appointment

Most tests are quick and painless. Your child may need to give a urine sample or have blood drawn. The doctor will explain the results and what they mean for treatment.

Treatment

Treatment depends on the cause of the flank pain. Most causes are managed with medicines or simple measures at home. Always follow your child's doctor's advice.

Self-care at home

• Give your child plenty of water to drink
• Rest and avoid rough play
• Use a warm compress on the sore side (if child is old enough and comfortable)
• Offer a soft, fibre-rich diet if constipation is suspected

Medical treatments

For infections, doctors may prescribe antibiotics. For kidney stones, treatment may include drinking extra fluids or medicine to help pass the stone. For hydronephrosis or other structural problems, doctors may monitor with scans or use a tube called a stent to help urine flow. Pain relief may be offered with over-the-counter medicines, but always ask the doctor or pharmacist first.

When is surgery considered?

Surgery is rarely needed for flank pain in children. It may be considered for large kidney stones that do not pass, or for certain urinary blockages that do not improve with other treatments.

Living with this condition

After treatment, most children can go back to normal activities. If flank pain keeps coming back, the doctor may recommend regular check-ups to monitor the kidneys and urinary tract.

Lifestyle tips

• Encourage regular drinking of water throughout the day
• Help your child learn to empty their bladder fully when peeing
• Avoid holding urine for long periods
• Treat constipation early with a healthy diet

Diet and exercise

A balanced diet with plenty of fruits, vegetables, and whole grains can help prevent constipation and some types of kidney stones. Physical activity is important, but avoid heavy contact sports if the child has a known kidney problem.

Mental health and emotional wellbeing

Flank pain can be scary for a child and stressful for parents. Feeling worried about the cause or the need for tests is normal. Talk to your child calmly and reassure them. Seek support from your doctor or a child psychologist if needed.

Prevention

Not all causes can be prevented, but many can be reduced with healthy habits. Drinking enough water, treating UTIs early, and avoiding constipation can help lower the risk.

Vaccines

There are no vaccines directly for flank pain. However, staying up to date on routine vaccinations helps prevent infections that could lead to kidney problems.

Screening programmes

No routine screening for flank pain in children. If your child has had kidney issues before, doctors may do regular urine tests or ultrasounds to check.

Complications

If left untreated

• Kidney infection can spread to the blood (sepsis)
• Kidney stones may grow larger and block urine flow
• Chronic kidney damage if hydronephrosis is left untreated
• Recurring pain and infections

Long-term outlook

With prompt medical care, most children with flank pain recover fully. Even serious causes like a large kidney stone or a kidney infection can be treated successfully. Your child's doctor will help you manage the condition and keep your child healthy.

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