Abnormal or unpleasant odors may be caused by diseased or necrotic tissue in the respiratory or upper gastrointestinal tracts, including mouth and nasal cavity. Diseased teeth are a common cause in dogs and cats. In addition, certain metabolic diseases may produce distinctive breath odor, e.g. ketoacidosis, uremia.
Practically elderly is a person who needs special consideration due to advanced age. Which can happen in late 50s or in late 80s. If he or she can punch your lights out for calling them elderly, and you cannot run from them either, they possibly aren't.
In an elderly person, a UTI can produce severe symptoms, including hallucinations, falling, fever and night sweats or chills, and pain or a burning sensation in the infected area. When a UTI is left untreated in an elderly person, it can lead to more serious consequences, such as dehydration and further infection. If the infection spreads into the bloodstream, then it can cause fatal problems like acute or chronic kidney failure.