Solitary kidney

　　Etiology:

　　The embryonic development of URA is not significantly different from that of BRA, and the main problem lies in the ureteral bud. The renal tissue and ureteral bud on one side are disordered during the embryonic period and fail to develop, while the contralateral kidney often presents with compensatory hypertrophy. The undeveloped kidney has no renal parenchyma, renal pelvis, and renal pedicle remnants, and the ureter is fibrous cord tissue without lumen.

　　This disease often combines other urogenital abnormalities, such as wandering vessels, ectopic kidney, malrotation of the kidney, obstruction of the renal pelvis and ureteral junction, hypospadias, cryptorchidism, double uterus, double ureters, absence of the contralateral adrenal gland, seminal vesicle, testis, fallopian tube, ovary, anal atresia, and spinal deformities, etc.

　　In addition, patients often have abnormalities in other organ systems, such as cardiovascular system (30%), digestive system (25%), musculoskeletal system (14%), etc. Therefore, if a patient is found to have more than one system abnormality in addition to the absence of a single kidney, a comprehensive examination of all systems should be performed.

　　The compensatory hypertrophied solitary kidney can fully meet the normal physiological needs, without affecting life, and can be asymptomatic, often not discovered throughout life. Occasionally, due to the infection, trauma, calculus, hydrops, or tuberculosis of the contralateral kidney, it is discovered only after thorough urological examination.

　　Most URA patients do not have specific clinical manifestations, and most reports come from autopsies. Because both kidneys have relative independence, the normal kidney on the other side does not have a higher susceptibility. Argues et al. conducted a large amount of research on the long-term effects of URA patients, and the results showed that the incidence of proteinuria in middle-aged solitary kidney patients is 20%, hypertension is 47%, and renal function decline is 13%. If the absence of the vas deferens or epididymis tail, or the absence of the vagina, with separation or atrophy accompanied by unicorns or bicornuate uterus are found during physical examination, one should be vigilant.

　　If solitary kidney patients use antibiotics, they must choose drugs with low nephrotoxicity and use them after bacterial culture and drug sensitivity testing. If renal insufficiency is present, the dosage and administration time of the drug should be determined according to the creatinine clearance rate results to avoid poisoning. Blood transfusion should also be done in small quantities and multiple times with fresh blood to avoid increasing the renal burden. Strengthen physical exercise to improve physical fitness.

　　1. Cystoscopy examination:The bladder trigone area is asymmetric, one ureteral crest is atrophic and flat, and the ureteral orifice is absent. Some may have an orifice, but the catheter insertion is obstructed; the other ureteral orifice is usually in the normal position, but can also be ectopic in the midline, posterior urethra, or seminal vesicle.

　　2. Abdominal flat film + KUB intravenous urography (IVU):One kidney shadow is absent and does not show up, while the other kidney shadow is enlarged, and other malformations of solitary kidneys can also be found.

　　3. Ultrasound, CT, renal scan, and renal arteriography can all assist in diagnosis.

　　1. Routine urine tests can be conducted every 1 to 3 months, while kidney ultrasound and kidney function tests can be done once a year; seek medical attention at any time if there are symptoms or abnormalities.

　　2. Strict dietary management, less smoking and drinking, more water intake, avoid overeating, and control protein intake.

　　3. 'Congenital solitary kidney' is not a problem of weakness of the physique, and it is not necessary to 'exercise to enhance physical fitness'; mild health exercises can be done.

　　4. Not suitable for fitness, as excessive sweating is prone to kidney stones.

　　5. High-intensity muscle training increases creatinine production, increasing the burden on the kidneys.

　　6. Diet should be light and nutritious, try to consume high-quality protein, such as dairy products, soy products, nuts, and the protein in poultry is high-quality protein; consume an appropriate amount of high-quality protein every day; and also consume other minerals in appropriate amounts, avoid excessive levels of trace elements such as lead, copper, and phosphorus, and drink pure water as much as possible. Avoid spicy and刺激性, fried, grilled, and explosive foods with high fat and carbohydrate content.

　　1. Treatment

　　Generally, no treatment is required. If complications such as hydronephrosis caused by poor rotation or other complications occur, they should be treated according to specific circumstances. The general principle is to protect renal function as much as possible, and then decide on the treatment plan under this premise. The clinical significance of this condition lies in the diagnosis of other urological diseases, and before surgical treatment, the possibility of a solitary kidney should be considered. This is to avoid discovering that the contralateral kidney is absent after the affected kidney is removed or after the surgery has caused severe damage to the renal function of the affected side, resulting in a permanent regret.

　　2. Prognosis

　　There is no clear evidence to show that patients with a single kidney have a higher susceptibility to other diseases. However, some people believe that patients with a single kidney have a higher incidence of diseases such as pyelonephritis, kidney stones, ureteral stones, tuberculosis, glomerulonephritis, and so on. The current emphasis on preventing infection and its sequelae has greatly reduced the incidence and mortality rate of patients with a single kidney. 5% of patients die due to kidney injury, while such patients may survive if they have two kidneys. Therefore, it is recommended that patients with URA should be more cautious and careful in their activities. Rugui et al. reported that URA patients are prone to hypertension, hyperuricemia, and decreased renal function, but no proteinuria occurs. Arguero evaluated the incidence of hypertension and proteinuria in 157 middle-aged URA patients, which were 47% and 19% respectively, but the incidence of renal insufficiency was only 13%. Despite this, the lives of these patients have not been significantly affected.