Case Study: MRI + CSF Reveal Inflammatory Brain Disease

Signalment & Presentation

Patient: “Bella,” 4-year-old female spayed Labrador Retriever
Chief Complaint: New-onset seizures

Bella’s owner reported two generalized seizures within 24 hours. Prior to this, she had been healthy with no known medical issues. After the second episode, she appeared disoriented and fatigued but returned to near normal between events.

Initial Workup

Bella was evaluated by her primary veterinarian.

Findings:

• Physical exam: Normal
• Neurologic exam: Subtle abnormalities (mild proprioceptive delay)
• Bloodwork:
  • CBC: Normal
  • Chemistry panel: Normal
  • Glucose: Normal
  • Liver values: Normal

Interpretation:
No evidence of metabolic or toxic cause for seizures.

At this point, the focus shifted to intracranial disease.

Advanced Imaging — MRI

Bella underwent a high-field MRI of the brain.

MRI Findings:

• Multifocal hyperintense lesions within the forebrain
• Poorly defined margins
• Mild surrounding edema

Interpretation:
Findings were highly suggestive of inflammatory brain disease, but not definitive for cause.

At this stage, MRI answered:
“Is there a structural abnormality?” → Yes

But not yet:
“What is causing it?”

Cerebrospinal Fluid (CSF) Analysis

Based on MRI findings, CSF was recommended.

Results:

• Elevated nucleated cell count
• Predominantly mononuclear inflammation
• Increased protein

Diagnosis:
Meningoencephalitis (inflammatory brain disease)

Why Both MRI and CSF Mattered

This case highlights the distinction:

• MRI
  • Identified that a structural brain abnormality was present
  • Localized the disease
  • Narrowed the differential list
• CSF
  • Confirmed inflammation
  • Helped differentiate from neoplasia
  • Guided treatment decisions

Neither test alone would have provided the full picture.

Treatment & Outcome

Bella was started on:

• Anti-seizure medication
• Immunosuppressive therapy

Follow-up:

• No additional seizures after stabilization
• Neurologic status improved over several weeks

Clinical Takeaway

In dogs with seizures and normal bloodwork, intracranial disease must be considered.

• MRI determines whether a structural brain problem exists
• CSF determines what type of disease is present
• Skipping imaging risks missing treatable inflammatory conditions
  Performing CSF without imaging risks incomplete or misleading diagnosis