TL;DR: Testicular swelling in cats is typically caused by infection, injury, or tumors and requires a veterinary exam within 24 to 48 hours. Seek immediate emergency care if your cat also exhibits fever, lethargy, or vomiting.
What causes my cat to have swollen or asymmetrical testicles?
When one or both testicles in a cat appear larger than usual or asymmetrical, it typically indicates inflammation, infection, or abnormal tissue growth. Common causes include:
- Orchitis (inflammation of the testes)
- Epididymitis (inflammation of the sperm duct)
- Testicular tumors
- Physical trauma or insect stings
- Localized abscesses caused by bite wounds
Is testicular swelling in my cat a veterinary emergency?
The urgency level for testicular swelling is generally considered Medium. While rarely an immediate life-threatening emergency, it is often painful and requires timely intervention:
- Schedule a veterinary visit within 24 to 48 hours.
- Seek immediate care if your cat shows signs of lethargy, vomiting, or a high fever.
- Untreated cases can lead to permanent damage or systemic infection.
How can a photo of my cat’s swelling help with veterinary triage?
Taking a clear, well-lit photo of the affected area can significantly assist a veterinary professional in performing a remote triage. A photo helps the vet determine:
- If the skin is discolored or has visible puncture wounds from a fight.
- If the swelling is localized to the skin versus the underlying organs.
- How quickly your cat needs to be seen and whether a specialized exam is required.
Clinical Context (Merck Veterinary Manual)
Acute inflammation of the testis or epididymis (orchitis or epididymitis) can be caused by trauma, infection (fungal, bacterial, or viral), or testicular torsion, and may present as pain and swelling of the testes, epididymides, and/or scrotum; however, these conditions are rare in cats unless due to trauma. Careful palpation of the scrotal contents should be performed to identify involved structures, though patient discomfort and edema can make this challenging. Ultrasonography, with sedation or analgesia as needed, is helpful to further evaluate affected structures and to confirm the presence of testicular torsion or focal lesions such as masses or abscesses. The scrotum should be evaluated for evidence of dermatitis or trauma.
Chapter: Urology, Infectious Disease, Surgery
Source: The Merck Veterinary Manual, 11th Edition (Page 1400)