Horseshoe kidney


The horseshoe kidney is a developmental disorder of the kidneys in unborn children in the womb. However, the kidneys are still functional and the baby is healthy. In some cases, however, the horseshoe kidney is also the cause of urinary tract symptoms or an indication of a genetic disease. Read more about the horseshoe kidney here!

ICD codes for this disease: ICD codes are internationally valid medical diagnosis codes. They are found e.g. in medical reports or on incapacity certificates. Q63ArtikelübersichtHufeisenniere

  • description
  • symptoms
  • Causes and risk factors
  • Examinations and diagnosis
  • treatment
  • Disease course and prognosis

Horseshoe kidney: description

The two kidney plants develop during the first weeks of an embryo and are usually separated from each other in the back of the abdomen. In a horseshoe kidney, however, the two kidney plants are fused together at the lower pole and this connection is not formed until birth. Viewed in cross-section, the kidneys form a U-shaped arch reminiscent of a horseshoe - hence the name horseshoe kidney.

The connection between the two kidneys (called isthmus) can consist of functional kidney tissue or of strand-like connective tissue. Both kidneys work independently, so that the horseshoe kidney usually works normally. However, if the connection leads to an unfavorable change of position of the organs or to a kinking of the ureter, the urine from the kidney can no longer flow freely and accumulates. This can result in kidney damage, infections and kidney stones.

The horseshoe kidney is the most common kidney fusion anomaly. About one in 400 children is born with it. Boys are more affected than girls.

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Horseshoe kidney: symptoms

The adhesion of the two subpoles of the kidneys in the horseshoe kidney does not cause any symptoms. However, the altered position of the kidneys, which may be associated with a kinking of the ureter, promotes various kidney and urinary tract disorders. Constrictions in the urine drainage promote backflow, inflammation and the formation of kidney stones. These conditions may include severe colic and fever, which can endanger not only the kidney function but sometimes the patient's life as well.

If a horseshoe kidney is known in a patient, special attention must be paid to the following symptoms:

  • Decrease in urine volume
  • Change in growth rate in children
  • Blood or stones in the urine
  • Change in urine odor
  • spasmodic flank pain
  • Inguinal or deep back pain
  • sudden increase in body temperature (fever)

If any of these symptoms occur, a doctor's visit is strongly advised to clarify the cause.

Further malformations or genetic diseases

About one third of all people with a horseshoe kidney have additional malformations that also affect the genitourinary tract (urinary and genital tract) or other areas of the body (such as the digestive system).

Certain genetic disorders are more often associated with a horseshoe kidney, Ulrich-Turner syndrome and trisomy 18 (Edwards syndrome):

The Turner syndrome is a genetic disorder in girls / women: The affected have only one X-sex chromosome and not two as usual. The symptoms include a horseshoe kidney and other organ malformations, for example, short stature, lack of secondary sexual characteristics, deep hairline on the neck and wing-shaped skin folds on the side of the neck.

In trisomy 18, chromosome 18 exists in a triple (rather than a double) version. This results in complex malformations - in addition to a horseshoe kidney, for example, also malformations in the head area (such as small face, small mouth, large occiput), short stature and a characteristic finger position.

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Horseshoe kidney: causes and risk factors

The horseshoe kidney is a congenital developmental disorder: usually the two renal algae develop in the unborn child with no direct connection to each other in the pelvic region. From there, they then ascend into the area of ​​the lumbar spine, turning so that the renal pelvis points inward (medial).

In the case of a horseshoe kidney, on the other hand, the two kidney plants fuse together in the first two months of life at the lower pole (rarely at the upper pole). In addition, ascent and rotation are disturbed: The horseshoe kidney is slightly lower than "normal" kidneys. In addition, the renal pelvis often have to the ventral side - and thus also the outgoing urethra (Urether), which can run over the isthmus and thereby can be bent. This can disturb the urine drainage and promote the development of urinary tract infections and kidney stones.

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Horseshoe kidney: examinations and diagnosis

Since many people with a horseshoe kidney show no symptoms, the malformation is often discovered only by accident - such as in an ultrasound examination in case of suspected kidney disease. In the ultrasound, the shape and position of the kidney can be easily and quickly examined, and a horseshoe kidney is immediately recognizable on the images.

If more detailed information about the malformation is necessary, magnetic resonance imaging (MRI) or computed tomography (CT) can be used to produce a detailed cross-sectional image of all abdominal organs.

Urine and blood tests provide information about kidney function and possible inflammation of the kidney.

If the urinary outflow is disturbed or there is a urinary reflux from the bladder to the kidney, seizure urography (AUG) can be used to determine the severity and location of the disorder. For this purpose, the patient is injected with a contrast agent that excretes the body via the kidneys. Immediately after administration, X-rays are taken at regular intervals to follow the path of the contrast agent via the kidneys and the urinary tract and urinary bladder. These structures are particularly well represented by the contrast agent. This makes it possible to easily identify bottlenecks or backwater.