Horseshoe Kidney (Renal Fusion) in Children

What is horseshoe kidney in children?

Horseshoe kidney is when the two kidneys join (fuse) together at the bottom. They form a U shape like a horseshoe. It is also known as renal fusion. The condition occurs when a baby is growing in the womb, as the baby’s kidneys move into place. Horseshoe kidney can occur alone or with other disorders.

What causes horseshoe kidney in a child?

Researchers aren’t sure exactly why horseshoe kidney occurs. It may be caused by a problem with chromosomes. Horseshoe kidney can occur along with some genetic disorders, such as Turner syndrome and Edward syndrome.

Which children are at risk for horseshoe kidney?

The condition happens more often in boys than girls.

What are the symptoms of horseshoe kidney in a child?

In most cases, a child has no symptoms. Some children may have nausea or pain in the belly. A child may also have kidney stones. This is a condition in which minerals and proteins form stones in the kidney. They may then block the urinary tract.

Some children may have urinary tract infections (UTIs). UTIs can cause symptoms such as:

• Fever
• Foul-smelling urine
• Sudden need to urinate
• Need to urinate often
• Loss of control of urine (incontinence)
• Pain while urinating
• Trouble urinating

The symptoms of horseshoe kidney can be like other health conditions. Take your child to their healthcare provider for a diagnosis.

How is horseshoe kidney diagnosed in a child?

The healthcare provider will ask about your child’s symptoms and health history. They may also ask about your family’s health history. They will give your child a physical exam. Your child may also have tests, such as:

• Renal ultrasound (sonography).  This is a painless test that uses sound waves and a computer to create images of body tissues. During the test, a healthcare provider moves a device called a transducer over the belly in the kidney area. This sends a picture of the kidney to a video screen. The healthcare provider can see the size and shape of the kidney. They can also see a growth, kidney stone, cyst, or other problems.
• Voiding cystourethrogram (VCUG).  A VCUG is a type of X-ray that looks at the urinary tract. A thin, flexible tube (catheter) is placed in the urethra. This tube drains urine from the bladder to the outside of the body. The bladder is filled with a liquid dye. X-ray images are taken as the bladder fills and empties. The images will show if there is any reverse flow of urine into the ureters and kidneys.
• Intravenous pyelogram (IVP).  This is an imaging test that uses an X-ray to view the urinary tract. Contrast dye is given so that the tract can be seen on film. An IVP also shows the rate and path of urine flow through the urinary tract.
• Blood tests. These look at how well the kidneys are working.
• Urine test. This test checks for blood and protein in the urine and signs of infection.

How is horseshoe kidney treated in a child?

The condition can’t be changed or cured. But a child with no symptoms may not need any treatment. If your child has symptoms or related problems, those will be treated. For example, if your child has developed a urinary tract infection, a kidney stone, or reflux, these problems would need to be treated. Your child may be referred to an expert such as:

• Urologist. This is a healthcare provider who treats problems of the urinary tract and the male genital tract.
• Nephrologist. This is a healthcare provider who treats problems of the kidneys.

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is. Your child may also see other healthcare providers to make sure they do not have one of the conditions linked to horseshoe kidney.

Talk with your child’s healthcare providers about the risks, benefits, and possible side effects of all treatments.

What are possible complications of horseshoe kidney in a child?

About 1 out of 3 children with horseshoe kidney will have a problem with the heart and blood vessels, nervous system, or genitourinary system. These problems may include:

• Hydronephrosis. This is swelling of the kidneys caused by a buildup of urine. It can happen because of a urinary tract blockage.
• Wilms tumor. This is a tumor of the kidneys that can occur in early childhood.
• Kidney cancer. This is when cells grow uncontrolled into lumps in the kidney.
• Ventricular septal defect. This is a hole in part of the heart that causes blood to not flow normally.
• Scoliosis. This is an abnormal curvature of the spine.
• Undescended testes. This is when the testicles stay in the abdomen and don't descend into the scrotum.

Horseshoe kidney can also occur along with other problems with the heart and blood vessels, digestive system, or bones.

How can I help my child live with horseshoe kidney?

A child with horseshoe kidney is more at risk for kidney injury. This is because the fused kidneys often sit lower down and closer to the front of the body. A child with horseshoe kidney may not be able to play contact sports. Your child’s healthcare provider may also advise that your child wear a medical alert bracelet.

When should I call my child’s healthcare provider?

Call the healthcare provider if your child has:

• Symptoms that don’t get better, or get worse
• New symptoms such as less urination or blood in the urine

Key points about horseshoe kidney in children

• Horseshoe kidney is when the two kidneys join (fuse) together at the bottom. They form a U shape like a horseshoe. It is also known as renal fusion.
• The condition occurs when a baby is growing in the womb, as the baby’s kidneys move into place. Horseshoe kidney can occur alone or with other disorders.
• Researchers aren’t sure exactly why horseshoe kidney occurs. It may be caused by a problem with chromosomes. Horseshoe kidney can occur along with some genetic disorders, such as Turner syndrome and Edward syndrome.
• About 1 out of 3 children with horseshoe kidney will have a problem with the heart and blood vessels, nervous system, or genitourinary system. 
• The condition can’t be changed or cured. But a child with no symptoms may not need any treatment. If your child has symptoms or related problems, those will be treated.
• A child with horseshoe kidney is more at risk of kidney injury. A child with horseshoe kidney may not be able to play contact sports.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

• Know the reason for the visit and what you want to happen.
• Before your visit, write down questions you want answered.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your healthcare provider gives you for your child.
• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
• Ask if your child’s condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if your child does not take the medicine or have the test or procedure.
• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your child’s healthcare provider after office hours. This is important if your child becomes ill and you have questions or need advice.