GFR is glomerular filtration rate. Different hydronephrosis affects glomerular filtration rate differently, glomerular filtration rate may increase after acute hydronephrosis is relieved, and glomerular filtration rate may not necessarily increase after chronic hydronephrosis is relieved. 1. Acute hydronephrosis: for example, ureteral stones, kidney stones suddenly fall and block the ureter, causing sudden increase in renal pressure resulting in hydronephrosis, which leads to a decrease in glomerular filtration rate, when the stones or obstruction are removed, hydronephrosis is relieved, glomerular filtration rate generally can be increased, and with the healing of the condition, the level of glomerular filtration rate may even be restored to the normal level. 2. Chronic hydronephrosis: such as chronic ureteral stenosis, chronic ureteral tumor, etc. Early symptoms are not obvious, and in the late stage, it causes the damage of kidney function, and the decrease of glomerular filtration rate caused by this chronic hydronephrosis is basically irreversible and hard to recover. If you have symptoms of hydronephrosis or reduced glomerular filtration rate, please seek medical treatment in regular hospitals in time, and under the professional guidance of doctors, actively treat it.