Can necrotizing encephalitis spread to other pets?

Most cases of necrotizing encephalitis are immune-mediated or non-infectious in origin and are not directly contagious. If an infectious cause is suspected, your vet will conduct further testing to confirm.

Is MRI always required for diagnosis?

MRI is the most sensitive imaging tool for evaluating brain lesions and is commonly used for both diagnosis and monitoring. Whether it is required depends on your vet's clinical assessment and available resources.

What can I do at home during a seizure?

Keep your pet safe from injury, record a video of the episode, note the time and duration, then contact your vet or go to an emergency clinic as soon as possible.

What is the prognosis for necrotizing encephalitis?

Prognosis varies considerably depending on the underlying cause, extent of lesions, and response to treatment. Some pets stabilise or improve, but long-term monitoring and management are usually required.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Necrotizing Encephalitis in Dogs & Cats: Seizures, Vision Loss, MRI & Care Guide [2025]

Necrotizing encephalitis is a common immune-mediated brain disease in small-breed dogs, causing seizures and neurological signs that require long-term immunosuppressive treatment.

Take 1 minute to check the symptoms first

Last updated: 2026/01/06

Pethealthmap Editorial Team

Sources: ACVIM, AVMA, National Taiwan University Veterinary Teaching Hospital

When to See a Vet

Seek immediate emergency care

•Continuous seizure lasting more than several minutes with inability to regain consciousness
•Sudden complete blindness or frequent bumping into surroundings
•Prolonged lethargy with no response to sound

Schedule a clinic visit soon (within 24–72 hours)

•Intermittent seizure episodes with brief periods of consciousness in between
•Declining vision or repeatedly bumping into objects
•Unsteady gait or noticeably altered sense of direction

01What symptoms indicate something is wrong?

Necrotizing encephalitis typically presents with neurological signs first, including seizures, vision changes, and altered consciousness. The condition can progress suddenly or gradually.

Recurrent or intermittent seizures that may increase in frequency over time
Sudden or gradual vision loss, ranging from reduced sight to complete blindness
Altered consciousness, lethargy, or reduced responsiveness to stimuli
Unsteady gait, falling, or significant disorientation
Early referral to a neurologist or an imaging-equipped veterinary hospital is recommended

Seek emergency care immediately if you notice the following symptoms:

⚠️ Continuous seizure lasting several minutes with no return to consciousness
⚠️ Sudden complete blindness or repeated collisions with surroundings
⚠️ Prolonged lethargy with no response to sound or stimulation

02How to assess abnormal signs at home: key observations and emergency criteria

Documenting observations at home helps your vet assess disease progression and severity — video recordings and timing logs are especially valuable.

Note the time each episode begins, how often they occur, and how long each lasts in seconds or minutes
Use your phone to record video of any seizures, abnormal walking, or vision problems
Observe mental status: responsiveness, lethargy, and reaction to sounds
Track changes in appetite, water intake, and body weight
Note any changes in bowel or bladder habits and when they occur
Bring all records and videos to the specialist appointment for review

03How will the vet make a diagnosis? Common diagnostic tests

A thorough neurological examination and diagnostic workup are typically required; imaging and CSF analysis help clarify the cause and extent of disease.

Full physical and neurological examination to assess which brain regions are affected

Complete blood count and biochemistry panel to rule out metabolic or infectious causes

Urinalysis to help evaluate overall metabolic status

Brain MRI is the preferred imaging modality to identify lesions and their extent

Cerebrospinal fluid (CSF) collection or tissue biopsy may be performed when needed to clarify the diagnosis

04Treatment and care after diagnosis: medications, diet adjustments, and home care guide

Treatment focuses on controlling inflammation and managing symptoms. Long-term imaging and clinical monitoring are essential, and home care is as important as regular follow-up visits.

Anti-inflammatory and supportive treatments are tailored to the underlying cause and disease severity
Provide a calm, stable living environment with appropriate diet and environmental support
Continue logging seizure frequency, vision status, and behavioural changes for ongoing monitoring
Schedule follow-up visits and repeat imaging as directed by your vet
Return promptly to your vet or seek emergency care if the condition worsens or changes rapidly

05What to prepare before seeing the vet: key information to help speed up diagnosis

Record when symptoms first appeared, the timing of each episode, and how frequently they occur

Have video clips ready of any seizures, falls, or vision abnormalities

List current medications, supplements, and any prior test results

Bring any previous imaging or diagnostic reports to help expedite the assessment

If MRI may be needed, call ahead to confirm which clinics have MRI capability

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

Related Symptoms (You May Also Be Looking For)

Vision loss

Walking in circles

Convulsion

Balance problems