14 yrs female c/o acute pain in both knee jts.& Fever. O/E knee jts tender and swollen, local crepts felt by palpation of jts, edema feet and puffiness of face, gross pallor present. Invs: Hb% 5.2; platelet count 20000; TLC 3000 , sickling negative; previous h/o blood transfusion.
CxR_normal.Plz help me to reach diagnosis.