Changes in appetite
Drinking much more or much less than usual
Vomiting or diarrhea
Lethargy or unusual hiding
Sudden weight loss or gain
Coughing, sneezing, wheezing, or trouble breathing
Nasal or eye discharge
Bad breath or drooling
Difficulty urinating, frequent urination, or blood in urine
Straining to poop or poop changes
Limping or signs of pain
Excessive scratching, hair loss, or skin redness
Fever or feeling unusually warm
Swollen abdomen
Seizures, collapse, or disorientation
Changes in behavior or grooming
Pale, yellow, or blue gums
Not using the litter box normally