TL;DR: Brown, foul-smelling vaginal discharge in cats is a symptom of Pyometra, a life-threatening uterine infection that requires immediate emergency veterinary surgery. Seek medical care right away to prevent fatal complications such as sepsis or organ failure.
What causes brown, foul-smelling vaginal discharge in my cat?
In cats, especially those that have not been spayed, the appearance of brown, foul-smelling vaginal discharge is a clinical sign often associated with Pyometra. This is a severe, life-threatening infection of the uterus where the organ fills with bacteria and pus. The brown color typically indicates a mix of blood and infected material, while the strong odor is caused by the bacterial overgrowth within the reproductive tract.
Is brown vaginal discharge in cats a veterinary emergency?
- Seek emergency veterinary evaluation immediately, as Pyometra is considered a high-priority, critical medical crisis.
- Without immediate surgical intervention and aggressive antibiotic treatment, the infection can lead to uterine rupture, sepsis (blood poisoning), and organ failure.
- Watch for accompanying signs such as lethargy, vomiting, increased thirst, or a bloated abdomen, which require instant medical attention.
How can taking a photo of the discharge help with my cat's triage?
- Capture a clear photograph of the discharge on the cat's fur or a white paper towel to provide vital information for the triage process.
- A photo allows a veterinarian to quickly identify the nature of the discharge and distinguish it from normal heat cycles or minor localized infections.
- Visual evidence helps the medical team prepare for immediate emergency surgery or diagnostic imaging before you even arrive at the clinic.
Clinical Context (Merck Veterinary Manual)
In a cat presenting with brown, foul-smelling vaginal discharge, emergency triage should prioritize differentiating vaginitis from open-cervix pyometra, a critical differential diagnosis. Pyometra can manifest with a purulent or sanguineous vaginal discharge if the cervix is open, accompanied by lethargy, anorexia, polyuria, polydipsia, and vomiting, potentially progressing rapidly to shock and death. Physical examination may reveal dehydration and uterine enlargement. Diagnostic evaluation should include a digital examination of the vagina, vaginoscopy, cytology, and culture of the exudate, as well as abdominal radiographs or ultrasonography to evaluate the uterus. A complete blood count, biochemical profile, and urinalysis should be performed to evaluate renal function, acid-base status, and sepsis.
Chapter: Reproductive
Source: The Merck Veterinary Manual, 11th Edition (Page 1400)