I can't be sure -I'm not a vet, but I would think that maybe the cause of a cloudy x-ray could be fluid?
If it is fluid build-up in his abdomen, it can be caused by a number of things. I would wait on the results of the blood test, and see what they tell you.
It is possible that diuretics could help if fluid accumulation is present. But of course, there is always a cause. You need to find the cause, and address that first.
How is his heart? Sometimes heart weakness can cause fluid retention.
As Ginger said, it's entirely possible that it's fluid in the abdominal cavity that is causing the cloudiness in the x-ray. The term for this fluid is ascites (pronounced uh-SITE-ees) and it has many possible causes.
It is not something to be ignored because the things that can cause a leakage of fluid into the peritoneal cavity are all very serious. It is caused by the leakage of fluid from blood vessels, from the lymph system, from abdominal masses or even from the internal organs themselves.
Some of the causes are severe liver disease, right-sided heart failure, hypoalbuminemia (a decrease in the blood albumin level), an abdominal mass, bleeding disorders, lymphatic diseases or an obstruction of the caudal vena cava or hepatic vein compromising blood circulation
Treatment, of course, depends on the cause. Until a definitive diagnosis is given, try to keep him as calm as possible because the fluid retention can make breathing difficult. Please keep us updated on his condition.
Ghilly