The human kidneys are normally two, one on the left and one on the right, located in the “renal fossa” (behind the abdominal cavity, on both sides of the crest), which is the central organ of the body responsible for removing waste, maintaining fluid balance and secreting some hormones. In the average healthy adult, the kidney is 10-12 cm long, 5-6 cm wide and 3-4 cm thick, and a smaller kidney is also known clinically as renal atrophy, which means that one kidney is significantly smaller than the other, or both kidneys are smaller than “normal”. There are different causes of renal atrophy, but it is generally believed that various acute and chronic injuries can affect the kidneys and thus renal function; and the presence of persistent, prolonged stress-chronic injury is a major factor in renal atrophy. What are the causes and symptoms of renal atrophy? Renal atrophy can be caused by congenital factors and many diseases. The diseased kidney can decrease in function or even lose function, such as restricted blood circulation to the organ leading to a reduction in the size of different structures within the kidney, and when this lesion extends to the whole kidney, the reduction in kidney size usually occurs only in the middle and late stages of the disease process. Common causes include: 1. congenital kidney dysplasia; 2. long-term kidney infection: chronic pyelonephritis, renal tuberculosis, etc. can cause problems with the internal structures of the kidney; 3. kidney ischemia: kidney atrophy occurs when the blood supply to the kidney becomes impaired. The most common is renal tissue damage due to renal artery stenosis; 4, renal artery obstruction: the same effect as ischemia, the obstruction is sometimes a thrombus or clot; 5, reflux nephropathy: urine backflow after loss of ureteral anti-reflux mechanism, a combination of pressure and infection; 6, renal vascular compression: the result of tumor or cyst compression in specific areas. 7, systemic diseases causing renal unit and renal capillary or macrovascular lesions, such as end-stage diabetes, glomerulonephritis, hypertensive disease, etc. 8, traumatic or after surgery, the kidney parenchyma or blood supply is lost, such as more serious renal trauma, after partial nephrectomy (removal of tumor requires blocking blood vessels), etc. Some special conditions leading to renal atrophy may show very unique symptoms, but the common symptoms of renal atrophy are: frequent urination, hematuria, weakness, swelling, low back pain, hypertension, painful urination, itchy skin, anemia, etc. Treatment of renal atrophy First of all, the way to treat renal atrophy is closely related to the cause, and thus the methods are different. The cause of atrophy is often external factors causing poor blood supply to the kidney or direct internal structural damage, and understanding the cause is the most effective way to control the shrinkage of the kidney. For example, renal artery dilation and stenting can be done for vascular obstruction; for chronic kidney disease resulting in atrophy, if atrophy has already occurred, kidney function is difficult to reverse and the appropriate treatment is dialysis; in case of chronic urinary tract infection (chronic pyelonephritis), appropriate antibiotics and administration methods should be chosen to control it. The degree of unilateral or bilateral atrophy is related to the severity of the primary disease. However, the first thing to do is to assess the extent of the existing kidney function before proceeding further. If the unilateral kidney has completely lost function, there may be nothing better to do than remove it. However, once it is found that even little function remains, it should be protected as much as possible with a view to recovery. Testing of kidney function Kidney malfunction can lead to a range of physical problems. There are many indicators to evaluate its function, which fall under the scope of nephrology and urology, including urinalysis, glomerular function, renal blood flow, tubular function, blood creatinine and urea nitrogen, imaging and nephrography. In urinalysis, urine color, urine volume, specific gravity, PH value, microscopy, etc.; glomerular and renal blood flow can be detected by creatinine and urea clearance; renal blood flow has para-aminomaluric acid (PHA), filtration fraction, etc.; renal tubular function has concentration, dilution, acidification, etc. Blood creatinine and urea nitrogen are the simplest and most direct methods to evaluate renal function, but if the lesion is unilateral and the healthy side of the kidney is functioning well it cannot be well indicated by creatinine, etc. In urology will also be judged by imaging methods such as imaging and nephrography to separate the body. Dietary points of attention for renal atrophy For patients who have been diagnosed with renal atrophy or other renal dysfunction, it is important to understand the diet to avoid increasing the kidney load, here are some tips: 1. Low protein intake Reduce the burden on the kidneys. If supplementation is really needed, choose high-quality protein or essential amino acid added products, such as egg whites, fish and lean meat. 2, low salt diet Sodium is the electrolyte for the kidneys to carry out the balance, renal insufficiency processing ability is reduced, avoid made or canned food, and seasonings. 3, avoid saturated fatty acids lead to inflammatory reactions and aggravate various types of kidney disease, such as Western fast food 4, avoid high potassium foods renal insufficiency can cause high potassium, foods containing high potassium are bananas, dried fruit, beef, pork and soybean paste. 5.Avoid high purine food Offal, beef, pork, lamb, etc., and beer. Kidney atrophy is a complex and serious problem that often requires long-term treatment and frequent checkups. Taking care of the kidneys is self-explanatory and it is important to stay in close contact with your doctor.