Horseshoe kidney

　　Horseshoe kidney is formed by the fusion of the lower poles of the two kidneys (more than 90% of the lower poles) at the midline of the body. Generally, scholars believe that this abnormal kidney shape is the result of compression and fusion of the renal primordial cells on both sides of the two umbilical arteries during early embryogenesis. The fusion part is mostly at the lower pole, forming the isthmus. The isthmus is composed of renal parenchyma (more or less) and connective tissue. It is located in front of and above the bifurcation of the abdominal aorta and the inferior vena cava. The two kidneys cannot rotate normally due to the restriction of lower pole fusion, making the renal hilum angle opposite to normal. The renal artery can come from the iliac artery, from the bifurcation of the abdominal aorta, or from the inferior mesenteric artery. The ureter is shorter than the normal ureter and descends to the bladder in front of the isthmus.

　　Even without symptoms, horses with horseshoe kidneys often are discovered due to associated congenital anomalies. Boatman et al. statistically analyzed 96 patients with horseshoe kidneys, among whom about 1/3 had at least one anomaly in another system, and many newborns and older patients had multiple congenital anomalies. Autopsy results showed that anomalies in other systems often occurred in newborns or infants, the main anomalies including the skeletal system, cardiovascular system, central nervous system, and abnormal anorectal conditions. There were also about 20% of children with trisomy 18, 60% of female patients with Turner's syndrome (Turner's syndrome), bicornuate uterus, or vaginal septum; 40% of male patients with hypospadias or incomplete descent of the testes, more than half of the patients with vesicoureteral reflux; horseshoe kidneys can occur alone or concurrently with other urinary system malformations such as hypospadias, duplicated ureters, renal cysts, and other malformations such as bone, cardiovascular, rectal, and anal conditions. They can also be associated with hydronephrosis, frequent urinary tract stones, recurrent urinary tract infections, or tumors.

　　The most common clinical manifestations of horseshoe kidney are three types:

　　1. The first is pain and mass at the umbilical cord.

　　2. The second is gastrointestinal dysfunction symptoms, such as abdominal pain and constipation.

　　3. The third type is complications of the urinary system, such as infection, hydronephrosis, and calculus. Most cases are discovered during surgery or misdiagnosed as other abdominal diseases, such as appendicitis, pancreatitis, and duodenal bulb ulcer.

        The horseshoe kidney is a congenital disease. Among congenital diseases, the more common ones include chromosomal diseases, neural tube defects, horseshoe kidneys, and metabolic genetic diseases. Clinically, they are manifested as developmental malformations, functional disorders, and incomplete intellectual development. If prenatal diagnosis of congenital diseases can be made, it can prevent the birth of affected children, which is of great benefit to the family and society.

　　This disease can be diagnosed by renal pelvis contrast, and on the renal pelvis film, it can be seen that the angle formed by the longitudinal axis of the two kidneys and the spine (renal vertebral angle) is downward, rather than upward as in the normal ones. Sometimes in the venous road film, due to poor renal function on one side or poor technical conditions, the shadow that is visible is mistaken for incomplete renal rotation, and attention should be paid to this point when considering the diagnosis.

　　1. Urinary tract plain film and contrast:According to the close proximity of the renal shadows to the spine and the low position, the long axis being parallel or the upper pole tilting outward, and the lower pole tilting inward, horseshoe kidney can be suspected, and sometimes the outline of the isthmus connecting the lower pole of the kidney can be seen. Urinary road造影 can make an accurate diagnosis, the most obvious sign is that the lower renal pelvis points to the median line, and the long axis of the renal pelvis and renal pelvis is from the upper end outward to the lower end inward in the shape of an inverted '8', and the ureter approaches the median line.

　　2. Ultrasound:It can clearly show the connection of the lower poles of the two kidneys, crossing the inferior vena cava and the anterior abdominal aorta.

　　3. CT:It can directly show the fusion part of the lower poles of the two kidneys, that is, the isthmus crosses the front of the aorta, and due to poor renal rotation, the renal pelvis is located in front of the kidney, and the ureter crosses the front of the isthmus on both sides and descends downward. But the position of the horseshoe kidney is generally lower, and it needs to be scanned to a lower position to determine the diagnosis.

　　4. MR and Radionuclide:It can also show the fusion of the lower poles of the two kidneys in the coronal view.

　　What should be paid attention to in the diet and health care of horseshoe kidney patients? Briefly described as follows:

　　1. Eat more

　　Eat more high-nutrition, rich in rough fiber foods.

　　2. Avoid eating

　　Avoid spicy and刺激性 food; drink less strong tea; eat less spinach, tofu, and other foods that are prone to stones; avoid smoking and drinking.

　　The renal function of this disease is often not significantly abnormal, so no special treatment is needed when there are no complications. If there is infection, effusion, calculi, or severe compression symptoms, appropriate treatment measures should be taken according to the situation. For a long time, there has been controversy about whether surgery is needed for horseshoe kidneys and when to perform surgery. Currently, the more consistent view is that no special treatment is needed when the renal function is normal and there are no complications. When complications such as renal积水, urinary tract calculi, frequent urinary tract infections, or tumors occur, surgery should be performed to correct the malformation, including cutting the isthmus, renal pelvis ureteral resection and shaping, lithotripsy, and so on.