Encephalitis in Cats: When Brain Inflammation Is the Cause

In this guide

Encephalitis simply means inflammation of the brain, and in cats it is less a single disease than a symptom of several very different underlying problems. Because the signs, seizures, disorientation, wobbliness, sudden behaviour change, can look similar regardless of cause, working out what is actually driving the inflammation is the central challenge for your vet, and it usually takes more than one visit.

What can cause it

• Feline infectious peritonitis (FIP), a coronavirus-related disease that is one of the more common causes of encephalitis in younger cats, particularly the 'dry' or neurological form
• Toxoplasmosis, a parasite that can affect the brain in cats with a weakened immune system
• Bacterial or fungal infections that have spread to the brain, sometimes from a severe ear or sinus infection
• Feline immunodeficiency virus (FIV), which can cause inflammation in the brain in its later stages
• Autoimmune or unexplained (idiopathic) inflammation, where no clear infectious cause is found despite thorough testing
• Rabies, rare in a vaccinated pet cat but still relevant in India given ongoing exposure risk from stray dogs and other animals, which is exactly why rabies vaccination is non-negotiable even for indoor cats

Signs to watch for

• Seizures, ranging from subtle twitching to full convulsions
• Sudden disorientation, circling, or pressing the head against furniture or walls
• Unusual aggression or a marked change in temperament
• Wobbly, uncoordinated movement
• Partial or complete blindness that comes on suddenly
• Lethargy that progresses over days rather than resolving

How it is diagnosed

There is no single test for encephalitis. Your vet will typically start with bloodwork and specific tests for FIP, FIV, and toxoplasmosis, and depending on findings and access to specialist facilities, may recommend a referral for MRI imaging and a cerebrospinal fluid tap, both of which usually mean a trip to a larger veterinary hospital or referral centre in a metro city, since this equipment is not widely available. A rabies risk assessment, based on vaccination history and any possible exposure, is also part of the initial workup given how relevant rabies remains in India.

Treatment

Treatment depends entirely on the cause. Anti-inflammatory or immunosuppressive medication, most often corticosteroids, is used for autoimmune or idiopathic cases. Antiparasitic medication treats toxoplasmosis, and antibiotics or antifungals address a bacterial or fungal cause. Seizures themselves are managed separately with anti-seizure medication regardless of the underlying cause, since stopping seizure activity quickly protects the brain from further damage. The outlook varies enormously depending on the cause, from a good recovery with prompt treatment to a guarded prognosis in cases such as neurological FIP, which is why identifying the specific cause matters so much rather than simply treating the symptoms.

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