The severity of kidney shrinkage depends on the patient’s kidney function. If the kidney function is normal, the severity of kidney shrinkage may be relatively small. If the patient’s kidney function has problems, even reaching uremia, kidney shrinkage is relatively serious. There are many reasons for kidney shrinkage, as follows: First, it may be congenital renal insufficiency, and these patients tend to have normal renal function. Secondly, it is often seen in patients with end-stage renal disease, such as renal failure or even uremia, which may result in shrinkage of kidney size, and the prognosis of these patients is relatively poor. Third, chronic pyelonephritis or renal tuberculosis can lead to kidney shrinkage. Fourthly, renal artery stenosis may cause kidney shrinkage due to insufficient blood supply to the kidneys. Therefore, the cause of renal shrinkage should be further clarified through relevant examinations.