Hi, Thanks for writing in. An 8 mm stone in the left kidney is a concern for urinary obstruction. It is important to know the exact location of the stone at present and for this you might require repeat ultrasound scan. You should be under treatment of the urologist. They will decide if you require a procedure called lithotripsy to break the stone in to smaller parts and allow it to be passed out in urine. If there is hydroureteronephrosis then you must consult the doctor immediately because obstruction to passage of urine for more than ten days can cause obstructive uropathy and this can cause permanent damage to the affected kidney as it happened to your mother. Doing regular kidney function tests is important. Please continue drinking adequate amounts of water and visiting washrooms regularly. Do not hold urine.