Causes of sudden blood loss

Acute glomerulonephritis

is a disease caused by beta-hemolytic streptococcal infection, typical symptoms are urine blood, proteinuria, edema, etc.

3,

urethral stones

and metabolic abnormalities, urinary tract infection and other factors, stones in the urethra movement, can cut through the urethral mucosa, causing bleeding phenomenon, manifested as sudden urine blood.