Renal effusion may cause fever, renal effusion may be caused by inflammation, urinary stones and other reasons, the following are elaborated: 1, urinary stones, if the patient has ureteral stones lead to ureteral impassability, renal effusion, at this time there will also be frequent urination, urinary urgency, pain in urination, fever, nausea, vomiting and other symptoms, is due to urinary tract infection caused by urinary stone and fever. At this time to give extracorporeal shock wave lithotripsy, anti-inflammatory treatment, herbal medicine, if necessary, ureteroscopy lithotripsy and other treatments, after the discharge of the stone renal effusion will naturally be eliminated, the fever will be cured. 2, inflammation, such as perirenal inflammation can be caused by renal effusion, if not treated in a timely manner can be caused by perirenal abscesses, at this time need to be actively given to anti-inflammatory treatment, penicillin or cephalosporins can be applied to give the antibiotics to the treatment.