Renal Fusion (Horseshoe Kidney)

Most people are born with two kidneys, which are located in the back of the abdominal cavity on either side of the body covered by the ribs. But factors can occasionally interfere with the development of the kidneys as is the case for people with renal fusion abnormalities. The following information will help you talk to your urologist when your condition, or that of your child, belongs to this family of diseases.

					Increase Text Size

What happens under normal conditions?

The kidney is the organ whose principal function is to filter toxins from the blood and maintain an appropriate chemical environment so that the body's other organ systems can function properly. Other functions that the kidneys serve include maintaining appropriate blood pressure and ensuring that enough red blood cells are produced by the bone marrow. As a child develops in its mother's uterus, the kidneys are formed lower in the abdomen and gradually ascend to their final position as they develop.

Horseshoe kidney occurs in about one in 500 children. It occurs during fetal development as the kidneys move into their normal position. With horseshoe kidney, however, as the kidneys of the fetus rise from the pelvic area, they fuse together at the lower end or base. By fusing, they form a "U" shape, which gives it the name "horseshoe." It is believed that this condition exists more frequently in males.

Horseshoe kidneys are much more frequently symptomatic than other varieties of fused and ectopic kidneys. Up to 70 percent of children and adults with this abnormality will have symptoms, which can include abdominal pain, nausea, kidney stones and urinary tract infections. Although still rare, cancerous tumors are somewhat more likely to occur in horseshoe kidneys than in normal kidneys. Blood in the urine, a mass in the abdomen and flank pain can be symptoms of a kidney tumor.

In a child without symptoms, treatment may not be necessary. If your child has complications, they may require supportive treatment, which means their symptoms will be treated, but there is no cure for the condition. As with ectopic kidneys, obstruction and vesicoureteral reflux are very common in these patients and may require surgical correction.

It is important to note that if the patient's only complaint from the horseshoe kidney is pain, surgery frequently will not relieve the pain.

Reviewed January, 2010

					Increase Text Size

Back to top

Glossary Terms

abdomen:
	Also referred to as the belly. It is the part of the body that contains all of the internal structures between the chest and the pelvis.
abnormality:
	A variation from a normal structure or function of the body.
bone marrow:
	A soft, reddish substance inside some bones that is involved in the production of blood cells.
cancer:
	An abnormal growth that can invade nearby structures and spread to other parts of the body and may be a threat to life.
ectopic:
	Used to describe an organ or body part occurring in a position or form that is not usual.
ectopic kidney:
	Kidney that developed in an abnormal position.
fetal:
	Relating to or characteristic of a fetus (unborn offspring after eight weeks of development).
fetus:
	An unborn offspring from the end of the eighth week of conception until birth.
flank:
	The area on the side of the body between the rib and hip.
horseshoe kidney:
	A rare condition where the kidneys fuse together at the lower end and form a "U" shape.
infection:
	A condition resulting from the presence of bacteria or other microorganisms.
ions:
	Electrically charged atoms.
kidney:
	One of two bean-shaped organs that filter wastes from the blood and discharge these waste products in urine. The kidneys are located on either side at the level of the 12th ribs toward the back. The kidneys send urine to the bladder through tubes called ureters.
kidney stone:
	A stone that develops from crystals that form in urine and build up on the inner surfaces of the kidney, in the renal pelvis or in the ureters. (Also see nephrolithiasis.)
kidneys:
	One of two bean-shaped organs that filter wastes from the blood and discharge these waste products in urine. The kidneys are located on either side at the level of the 12th ribs toward the back. The kidneys send urine to the bladder through tubes called ureters.
pelvic:
	Relating to, involving or located in or near the pelvis.
reflux:
	Backward flow of urine. Also referred to as vesicoureteral reflux (VUR). An abnormal condition in which urine backs up from the bladder into the ureters and occasionally into the kidneys, raising the risk of infection.
renal:
	Pertaining to the kidneys.
stone:
	Small hard mass of mineral material formed in an organ.
tumor:
	An abnormal mass of tissue or growth of cells.
ureter:
	One of two tubes that carry urine from the kidneys to the bladder.
ureteral:
	Pertaining to the ureter. Also referred to as ureteric.
urinary tract:
	The system that takes wastes from the blood and carries them out of the body in the form of urine. Passageway from the kidneys to the ureters, bladder and urethra.
urinary tract infection:
	Also referred to as UTI. An illness caused by harmful bacteria, viruses or yeast growing in the urinary tract.
urine:
	Liquid waste product filtered from the blood by the kidneys, stored in the bladder and expelled from the body through the urethra by the act of urinating (voiding). About 96 percent of which is water and the rest waste products.
urologist:
	A doctor who specializes in diseases of the male and female urinary systems and the male reproductive system. Click here to learn more about urologists. (Download the free Acrobat reader.)
uterus:
	A hallow, muscular organ in the pelvis cavity of females in which the embryo is nourished and develops before birth.
vas:
	Also referred to as vas deferens. The cordlike structure that carries sperm from the testicle to the urethra.

Back to top