Nutcracker syndrome, a vascular compression disorder (compression of the left renal vein between the superior mesenteric artery and aorta), may present with hematuria and left flank pain. Take the medication as prescribed and ask for a referral to a nephrologist. Recurrent infection may be associated with this condition. Regular follow-up is highly recommended to make sure that persistent hematuria do not lead to renal vein thrombosis or renal venous hypertension. Take care and do keep us posted.