- Lack of response or complete loss of consciousness
- Seizures
- Collapse, or weakness so severe that the pet is unable to stand
- Bleeding that won’t stop
- Severe trauma or pain
- Bloated abdomen along with nonproductive vomiting
- Vomiting, diarrhea, and/or refusal to eat for a day or more
- Straining or complete inability to urinate, especially in male cats
- Shallow or rapid breathing accompanied by pale or bluish gums