Horseshoe Kidney

Horseshoe kidney is a condition in which the kidneys are fused together at the lower end or base. By fusing, they form a "U" shape, which gives it the name "horseshoe."

  • Horseshoe kidney occurs during fetal development, as the kidneys move into their normal position in the flank area (area around the side, just above the waist).
  • Horseshoe kidney occurs in about one in 500 children.
  • Horseshoe kidney can occur alone or in combination with other disorders. The most common disorders seen with horseshoe kidney include:
    • Turner syndrome: a genetic disorder seen in girls that causes them to be shorter than others and to not mature sexually as they grow into adulthood. Sixty percent of girls with Turner syndrome have horseshoe kidneys.
    • Trisomy 18: a serious chromosome abnormality involving defects in nearly all organ systems, including horseshoe kidney in 20 percent of children affected

What complications are associated with horseshoe kidney?

One-third of people with horseshoe kidneys have at least one other complication involving the cardiovascular system, the central nervous system, or the genitourinary system (which is the reproductive organs and urinary system) such as the following:

  • kidney stones: crystals and proteins that form stones in the kidney that may lead to a urinary tract obstruction
  • hydronephrosis: enlargement of the kidneys that is usually the result of a urinary tract obstruction
  • Wilms tumor: an embryonic (newly formed) tumor of the kidneys that usually occurs during early childhood
  • renal cancer or polycystic kidney disease
  • hydrocephaly and/or spina bifida
  • various cardiovascular and gastrointestinal conditions, or skeletal problems

What are the symptoms of horseshoe kidney?

While each child may experience symptoms differently, the most common symptoms of horseshoe kidney include:

  • urinary tract infection: usually uncommon in children under 5 years and unlikely in boys at any age
  • kidney stones: if the stones remain in the kidney, your child may have no symptoms. If the stones pass through her urinary tract, she could experience the following symptoms:
    • flank (around the side, just above the waist) pain
    • restlessness
    • sweating
    • nausea and/or vomiting
    • blood in urine
    • changes in urinary frequency
    • chills
    • fever
    • cloudy urine
  • hydronephrosis: occurs when there is a urinary tract obstruction and the kidney(s) become enlarged and potentially damaged. Symptoms of hydronephrosis may include the following:
    • abdominal mass
    • poor weight gain
    • decreased urination
    • urinary tract infection

About one-third of children with horseshoe kidney have no symptoms.

How is horseshoe kidney diagnosed?

If your child is not experiencing symptoms, she may not need diagnosis or treatment. If she is experiencing symptoms, her physician may order one or more of the following diagnostic tests:

  • renal ultrasound: This is an imaging technique that uses a computer and high-frequency sound waves to create images of blood vessels, tissues, and organs. Physicians are able to view internal organs as they function, and assess blood flow through various vessels.
  • voiding cystourethrogram (VCUG): This is a specific x-ray that examines the your child's urinary tract. A catheter (hollow tube) is placed in her urethra (tube that drains urine from the bladder to the outside of the body) and her bladder is filled with a liquid dye. X-ray images are taken as her bladder fills and empties. The images show if there is any reverse flow of urine into the ureters and kidneys.
  • intravenous pyelogram (IVP): This is an imaging technique that uses an x-ray to see the structures of the urinary tract. An intravenous contrast of dye is given so that the structures can be seen on film. This technique reveals the rate and path of your child's urine flow through the urinary tract.
  • blood and urine tests: These determine how well your child's kidneys may be functioning.

How we address horseshoe kidney

There is no known cure for a horseshoe kidney, but if your child has complications, her symptoms will be treated. Treatment approaches may include:

  • antibiotics (to treat an underlying infection)
  • surgical intervention (for symptomatic kidney stones)

If your child has no symptoms, she may not need to be treated.

If your child has hydronephrosis, your doctor may want to discuss several other non-surgical or surgical treatment options.