A female patient presents with upper respiratory tract infection. Two days after, she develops hematuria. What is the probable diagnosis?

IgA nephropathy is associated with upper respiratory tract infections Gross hematuria usually appears simultaneously or within the first 48-72 hours after the infection begins; persists <3 days; loin pain- due to renal capsular swelling. Urine is usually brown rather than red, and clots are unusual.