TL;DR: Unproductive straining in cats is a high-priority medical emergency because it often mimics a life-threatening urinary blockage. You should contact a veterinarian immediately to differentiate between constipation and a critical inability to urinate.
What does it mean when my cat is straining in the litter box?
When a cat repeatedly visits the litter box and strains without producing stool, it is known as tenesmus. This behavior is often a sign of underlying discomfort or irritation in the colon or rectum. However, it is very easy to mistake straining to urinate for straining to defecate. Both conditions look remarkably similar to the untrained eye, but they carry very different risks.
Is my cat straining in the litter box considered a medical emergency?
- Unproductive straining is a high-urgency symptom that requires immediate veterinary assessment.
- While simple constipation is uncomfortable, a urinary blockage—where a cat is unable to pass urine—is a life-threatening emergency that can lead to kidney failure or a ruptured bladder within hours.
- Because it is difficult to distinguish between a cat trying to poop and a cat trying to pee, any unproductive straining should be treated as an emergency until a veterinarian can confirm the bladder is empty and soft.
How can a photo or video of my cat straining help a veterinarian?
- Safely capture a photo or a short video of your cat while they are straining to assist triage professionals.
- A veterinarian can identify subtle differences in body posture, tail positioning, and vocalization that help differentiate between a gastrointestinal issue and a urinary crisis.
- Providing visual evidence of discharge or the cat's specific stance allows the medical team to prioritize your pet appropriately upon arrival.
Clinical Context (Merck Veterinary Manual)
In cats straining to defecate, physical examination should be performed to determine the presence of perineal hernia, foreign material, pain, or masses; abdominal palpation and rectal examination can confirm the presence of large volumes of retained fecal matter. Plain abdominal radiographs may help establish inciting factors of fecal retention. Consider causes such as narrowed pelvic inlet from suboptimal healing of pelvic fractures, enlarged sublumbar lymph nodes or prostate gland, colonic stricture due to trauma or neoplasia, and megacolon. Other diseases affecting neuromuscular control of the colon and rectum include hypothyroidism, dysautonomia, and lesions of the spinal cord or pelvic nerves. Hypokalemia and hypercalcemia can also adversely affect muscular control. Certain drugs (e.g., opioids, diuretics, antihistamines, anticholinergic agents, sucralfate, aluminum hydroxide, potassium bromide, and calcium channel-blocking agents) can promote constipation. Clinical signs include tenesmus and passage of firm, dry feces, with feces appearing thin or "ribbon-like" if hindered by an enlarged prostate or sublumbar lymph nodes; affected animals may also exhibit lethargy, depression, anorexia, vomiting, and abdominal discomfort.
Chapter: Gastroenterology
Source: The Merck Veterinary Manual, 11th Edition (Page 381)