What does blood in urine and refusal to eat mean in a dog?

Blood in urine has several causes; most are urinary - urethritis, cystitis, kidney issues, stones, tumors - or trauma from impact. Poisoning causing hemolysis (onions, leeks, rat poison) also does it, as do blood parasites from ticks (babesia, anaplasma, Lyme). Mild urethritis keeps spirits and appetite, so observe with antibiotics; with lethargy, fever, or anorexia, see a vet to avoid worsening.