Urinary tract infections occur more frequently in females than male dogs. Dogs with bladder infections normally feel fine otherwise. They have normal appetites and activity levels. Pyelonephritis however causes a more severe illness. Appetite can be poor, fever, vomiting, and lethargy may occur.
Gross hematuria can also be an indicator of a problem with the body's blood clotting system.
The most frequent cause of this is rodenticide poisoning. Many rat and mouse poisons on the market interfere with the clotting mechanism, causing severe, potentially fatal hemorrhage in dogs ingesting toxic amounts. This hemorrhage can be external or internal, and may involve the urinary tract. Poisoned dogs are generally very weak and listless. Other clotting disorders such as hemophilia and von Willebrand's disease are also seen in dogs.