Encephalitis in Dogs: Symptoms, Causes & Veterinary Care

Recognizing Encephalitis in Dogs

Encephalitis (brain inflammation) presents with diverse neurologic signs depending on affected brain regions. Early recognition is vital.

Common Clinical Signs

• Mentation changes: Lethargy, depression, stupor, coma
• Seizures: Focal or generalized; often the first sign
• Behavior alterations: Aggression, anxiety, disorientation, circling, head pressing
• Cranial nerve deficits: Blindness, facial paralysis, nystagmus, strabismus, dysphagia
• Motor dysfunction: Ataxia, paresis/paralysis, tremors, abnormal gait
• Autonomic signs: Fever, vomiting, diarrhea, respiratory irregularities
• Pain: Hyperesthesia, neck rigidity (if meningoencephalitis)

Etiologic Categories

• Infectious: Viral (distemper, rabies), bacterial, fungal, protozoal (Neospora, Toxoplasma), rickettsial
• Immune-mediated: GME, NME, NLE (breed-associated: Pugs, Maltese, Yorkshire Terriers)
• Idiopathic: No identifiable cause after extensive workup
• Paraneoplastic: Associated with distant neoplasia

Diagnostic Approach

1. Neurologic exam to localize lesion
2. MRI (gold standard for parenchyma)
3. CSF analysis (cell count, protein, cytology, PCR, culture)
4. Infectious disease titers/PCR (distemper, tick-borne, fungal)
5. Blood work (CBC, chemistry, bile acids, infectious serology)

When to Seek Emergency Care

Immediate veterinary attention for:

• Seizures lasting >5 min or cluster seizures
• Sudden collapse or inability to rise
• Progressive neurologic deterioration
• Fever >104°F (40°C) with neurologic signs

Encephalitis is life-threatening. Rapid referral to a veterinary neurologist improves outcomes.