A few years back we had the same decision to make when our cat needed treatment. We had no other available credit, but I worked out a payment plan directly with the vet. The cat completely recovered, but he's a lot more starved for attention. We joke that he knows he's down to eight lives. The debt has long since been paid off, and the cost seems irrelevant now.
A worthy perspective . . . depending on the individual specifics in this case.