Congestive heart failure can cause a sudden weight gain like that if it is a fluid build-up. There can be fluids in the chest cavity or in the abdominal cavity and several underlying causes. Liver failure of some sort, infection, cancer can all cause ascites (that is the build-up of fluids in the abd. cavity) and it can be drained off occasionaly and the vet tries to treat the underlying cause. Fluid pills will be used in either case, fluid restrictions as well as salt intake, will need to be monitored. Hepatotoxicity is a side effect of Metronidazole but in large doses....The recommended dose is 25mgm/kg of body weight twice a day..
It seems my replies are longer than most but I research thru my vet text books for reliable info and try to pass it on. Forgive me if I bore you with these posts. |