kidney in children

Overview

Kidneys are two bean-shaped organs that filter your child's blood, remove waste and extra water, and make urine. Kidney problems in children can range from mild infections that clear up quickly to long-term conditions that need ongoing care. In this article, we explain the basics of kidney health in children, common signs to look out for, and how to help your child stay healthy.

Kidney and urinary tract conditions in children are fairly common. Urinary tract infections (UTIs) affect many children at some point, and around 1 in 100 children may have a kidney or urinary tract abnormality. However, severe chronic kidney disease in childhood is rare.

Kidney problems can affect children of all ages, from newborns to teenagers. Some conditions appear from birth, while others develop after infections, injury, or due to a family history of kidney disease.

Symptoms

Common symptoms

• Pain or burning when passing urine
• Need to urinate more often than usual, or wetting the bed after being dry
• Blood in the urine, or urine that is cloudy, dark, or smells unusual
• Swelling in the face, hands, feet, or tummy
• High blood pressure
• Fever, especially without another clear cause
• Tiredness and low energy
• Poor appetite or nausea

Symptoms in children

• Not growing or gaining weight as expected (failure to thrive)
• Tummy pain or pain in the side of the back
• Irritability or changes in behaviour
• Unexplained fever, especially in babies
• Swelling around the eyes, more noticeable in the morning

Symptoms in older adults

• Older adults with kidney problems may sometimes have fewer or different symptoms, such as confusion, muscle cramps, or unusual sleepiness. However, this article focuses on children, so if you are caring for an adult, please also speak with their healthcare provider.

Causes

Main causes

• Birth differences in the structure of the kidneys, bladder, or urinary tract
• Urinary tract infections that spread to the kidneys
• Inflammation of the kidney's filter unit (glomerulonephritis), which can happen after some infections
• Nephrotic syndrome, a condition where the kidneys leak too much protein into the urine
• Inherited conditions that run in families, such as polycystic kidney disease (cysts on the kidneys)
• Rarely, injury, reactions to medication, or other diseases that affect the kidneys

Risk factors

• Family history of kidney disease or urinary tract problems
• Being born prematurely
• A history of frequent urinary tract infections
• Having only one kidney, or a kidney that is smaller than usual
• Conditions such as diabetes or high blood pressure in older children

When to see a doctor

See a doctor urgently if:

• If your child has blood in the urine
• If your child has new swelling, high fever, or severe pain
• If a child under 1 year stops feeding well or seems unusually sleepy
• If your child passes much less urine than usual

Book a routine appointment if:

• If your child has repeated urinary tract infections
• If your child has been bed-wetting after being dry for several months
• If you notice an unusual smell or colour to urine
• If your child seems more tired or is eating less than usual

Diagnosis

To diagnose kidney problems in children, a doctor usually starts with a detailed history and a physical examination. They will ask about your child's symptoms, growth, and any family history. Tests help show how well the kidneys are working and what might be causing the problem.

Tests that may be done

• Urine test (urinalysis) to look for blood, protein, or signs of infection
• Blood test to check kidney function and waste products
• Ultrasound of the kidneys and bladder – a painless scan that shows their shape and size
• A special X-ray (voiding cystourethrogram, VCUG) to show if urine flows backwards into the kidneys
• Rarely, a kidney biopsy – a small sample of kidney tissue taken with a needle under anaesthetic

What to expect at your appointment

Most tests are non-invasive and painless. Your child may be asked to give a urine sample in a cup, and sometimes a small ultrasound wand is passed over the tummy. If a biopsy is needed, it will be done under sedation or anaesthesia so the child feels no pain. A kidney specialist (nephrologist) will explain the results and what they mean.

Treatment

Treatment for kidney problems in children depends on the specific condition, how severe it is, and your child's age. Many conditions are managed with medications and lifestyle changes. Some structural blockages may need a procedure to correct them. The aim is always to protect kidney function and help your child grow and develop normally.

Self-care at home

• Encourage your child to drink plenty of water unless a doctor says otherwise
• Help your child maintain good hygiene in the genital area to reduce urinary infection risk
• Make sure your child gets enough rest and physical activity for their age
• Keep a record of symptoms, urine output, and medications to share with the doctor

Medical treatments

Medical treatment might include antibiotics to clear an infection, medicines to control blood pressure, or treatments that calm the immune system for certain kidney conditions. Some children need extra vitamins or a special diet. Your child's healthcare team will decide on the safest plan and explain the benefits and side effects. Never give your child any medication without asking a qualified professional.

When is surgery considered?

Surgery may be needed in some cases, such as a blockage in the urinary tract, urine flowing backward into the kidneys (reflux), or a kidney that needs to be removed because it is not working and is causing repeated infections. The surgeon will explain the procedure and what happens afterwards.

Living with this condition

If your child has a long-term kidney condition, a regular routine helps. This includes taking medicines at the same time each day, attending check-ups, and watching for any new symptoms. It may be helpful to have a folder of test results and a list of questions for doctors.

Lifestyle tips

• Keep up a healthy daily routine, including meals, play, and sleep
• Encourage physical activity that suits your child's energy levels
• Avoid giving your child any over-the-counter remedies or herbal products without asking the doctor
• Talk to the school about any support your child may need

Diet and exercise

Most children with kidney problems only need simple healthy eating and regular activity. If kidneys are not working well, the doctor may recommend limiting salt, potassium, or phosphorus. Follow the dietitian's advice specifically for your child. Keep exercise fun and do not overdo it – a child can usually join in most activities unless the medical team says otherwise.

Mental health and emotional wellbeing

Living with a long-term illness can be stressful for a child and the whole family. Your child might feel different from friends or worry about tests and hospital visits. It is normal to feel upset or anxious. Talk openly, listen gently, and ask for help from a psychologist or counselor if needed.

Prevention

Many kidney problems in children cannot be prevented because they develop before birth or come from inherited genes. However, some urinary tract infections can be prevented with good hygiene, staying hydrated, and avoiding constipation. Regular check-ups help detect problems early.

Vaccines

Routine childhood vaccinations protect against some infections that can indirectly affect the kidneys, such as chickenpox and pneumonia. Your child should follow the normal immunisation schedule. If your child has kidney disease, talk to the doctor about any extra vaccinations.

Screening programmes

Screening is not offered to all children, but if there is a family history of kidney disease, the doctor may check blood pressure and urine at routine visits. Premature babies or those with known kidney differences may need regular kidney scans.

Complications

If left untreated

• Damage to kidney tissue, leading to chronic kidney disease
• High blood pressure, which can strain the heart and blood vessels
• Poor growth and development
• Kidney stones or repeated infections
• In severe cases, kidney failure, which needs dialysis or a transplant

Long-term outlook

With early diagnosis and modern treatment, most kidney problems in children improve or even resolve completely. Many children with kidney conditions go on to lead full, active lives. Some chronic conditions need lifelong care, but a good quality of life is very possible. Always work closely with your child's healthcare team and never be afraid to ask questions.

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