Acute nephritis is commonly seen in children. Once acute nephritis occurs, the main clinical manifestations in patients typically include hematuria, which can be visible or microscopic. It is also accompanied by varying degrees of edema, elevated blood pressure, and even transient renal failure. As for how long patients with acute nephritis need to stay in bed, current studies suggest a minimum of 2-3 weeks of bed rest. If the patient’s hematuria disappears, urinary protein decreases, and edema subsides, they can gradually start moving out of bed. If the condition remains stable, activities can shift from indoors to outdoors. However, if visible hematuria reoccurs, or if edema reappears after activity, it is necessary to continue bed rest for another 4-6 weeks. Therefore, students suffering from acute nephritis often need to take a leave of absence from school and should be closely monitored for changes in their condition under a doctor's guidance.