Hydronephrosis grade two, this "grade two" is likely a classification used in ultrasound or CT imaging. For hydronephrosis, the presence of condition itself indicates that the pathology has already affected kidney function. The most common causes include ureteral obstruction, or obstruction at the renal pelvis exit, typically due to stones or tumors, or narrowing caused by plastic tubes. Once hydronephrosis occurs, these conditions have already altered kidney function, necessitating further diagnosis to identify the cause, with surgery possibly being required. The most common objective assessment is a CT scan of the urinary system, with enhanced CT being the most accurate for understanding the severity of the hydronephrosis. Also, it helps identify the location of the ureteral obstruction, and thirdly, it can help ascertain the cause and provide treatment.