Horseshoe kidney
Encyclopedia
Horseshoe kidney, also known as renal fusion or super kidney, is a congenital disorder
affecting about 1 in 400 people. In this disorder, the patient's kidney
s fuse together to form a horseshoe
-shape during development in the womb. The fused part is the isthmus
of the horseshoe kidney.
Fusion abnormalities of the kidney can be categorized into two groups: horseshoe kidney and crossed fused ectopia. The horseshoe kidney is the most common renal fusion anomaly.
because the normal embryologic ascent of the kidneys is arrested by its presence in people with central fusion of the kidneys. Horseshoe kidney is often asymptomatic, though persons affected by this condition may experience nausea
, abdominal discomfort, kidney stones and urinary tract infection
s at greater frequency than those without renal fusion. There is currently no cure for renal fusion other than symptomatic treatment.
The prevalence of horseshoe kidneys in females with Turner Syndrome
is about 15%.
It can be associated with trisomy 18.
Congenital disorder
A congenital disorder, or congenital disease, is a condition existing at birth and often before birth, or that develops during the first month of life , regardless of causation...
affecting about 1 in 400 people. In this disorder, the patient's kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s fuse together to form a horseshoe
Horseshoe
A horseshoe, is a fabricated product, normally made of metal, although sometimes made partially or wholly of modern synthetic materials, designed to protect a horse's hoof from wear and tear. Shoes are attached on the palmar surface of the hooves, usually nailed through the insensitive hoof wall...
-shape during development in the womb. The fused part is the isthmus
Isthmus
An isthmus is a narrow strip of land connecting two larger land areas usually with waterforms on either side.Canals are often built through isthmuses where they may be particularly advantageous to create a shortcut for marine transportation...
of the horseshoe kidney.
Fusion abnormalities of the kidney can be categorized into two groups: horseshoe kidney and crossed fused ectopia. The horseshoe kidney is the most common renal fusion anomaly.
Presentation
In patients with this condition, the central portion of the kidney may be found just inferior to the inferior mesenteric arteryInferior mesenteric artery
In human anatomy, the inferior mesenteric artery, often abbreviated as IMA, supplies the large intestine from the left colic flexure to the upper part of the rectum, which includes the descending colon, the sigmoid colon, and part of the rectum...
because the normal embryologic ascent of the kidneys is arrested by its presence in people with central fusion of the kidneys. Horseshoe kidney is often asymptomatic, though persons affected by this condition may experience nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
, abdominal discomfort, kidney stones and urinary tract infection
Urinary tract infection
A urinary tract infection is a bacterial infection that affects any part of the urinary tract. Symptoms include frequent feeling and/or need to urinate, pain during urination, and cloudy urine. The main causal agent is Escherichia coli...
s at greater frequency than those without renal fusion. There is currently no cure for renal fusion other than symptomatic treatment.
Associated conditions
While most cases of horseshoe kidneys are asymptomatic and discovered upon autopsy, the condition may increase the risk for:- Kidney Obstruction - abnormal placement of ureter may lead to obstruction and dilation of the kidney.
- Kidney Infections - associated with vesicoureteral refluxVesicoureteral refluxVesicoureteral reflux is an abnormal movement of urine from the bladder into ureters or kidneys. Urine normally travels from the kidneys via the ureters to the bladder...
. - Kidney Stones - deviant orientation of kidneys combined with slow urine flow and kidney obstruction may lead to kidney stones.
- Kidney Cancer - increased risk of renal cancer, especially Wilms' tumorWilms' tumorWilms' tumor or nephroblastoma is cancer of the kidneys that typically occurs in children, rarely in adults.Its common name is an eponym, referring to Dr. Max Wilms, the German surgeon who first described this kind of tumor....
, transitional cell carcinomaTransitional cell carcinomaTransitional cell carcinoma is a type of cancer that typically occurs in the urinary system: the kidney, urinary bladder, and accessory organs. It is the most common type of bladder cancer and cancer of the ureter, urethra, and urachus...
, and an occasional case report of carcinoid tumor. Despite increased risk, the overall risk is still relatively low.
The prevalence of horseshoe kidneys in females with Turner Syndrome
Turner syndrome
Turner syndrome or Ullrich-Turner syndrome encompasses several conditions in human females, of which monosomy X is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent...
is about 15%.
It can be associated with trisomy 18.