Cerebrospinal fluid: steroid-responsive meningitis-arteritis
10-month-old Beagle with a temperature of 40.1 °C, stiffness and severe neck pain for a week; it walks with its head lowered. The neurological examination is otherwise normal. CSF is collected from the cisterna magna.
| Parameter | Result | Reference |
|---|---|---|
| Nucleated cells (CSF) | 620/µL | < 5 |
| Predominant cell type | Non-degenerate neutrophils (85%) | — |
| Protein (CSF) | 95 mg/dL | < 25–30 |
| Bacteria / culture | None seen / negative | — |
What is the most likely diagnosis?
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A. Bacterial meningitis
It is rare in dogs and usually shows degenerate neutrophils, bacteria and a sicker animal, often with a focus (otitis media, wound). Here neutrophils are non-degenerate and culture is negative.
B. Meningoencephalitis of unknown origin (granulomatous or necrotising)
It usually causes multifocal or forebrain neurological signs and mononuclear pleocytosis (lymphocytes and monocytes), mainly in small breeds. It does not fit isolated neck pain and neutrophils.
C. Cervical disc herniation
It causes neck pain, but not fever or such marked neutrophilic pleocytosis; CSF is usually normal or mildly abnormal. It is also very unlikely at 10 months.
D. Steroid-responsive meningitis-arteritis
Correct. A young dog of a predisposed breed (Beagle, Boxer, Bernese, Nova Scotia) with fever and neck pain, and CSF with non-degenerate neutrophilic pleocytosis, raised protein and negative culture. High IgA in CSF and serum supports the diagnosis; it is treated with immunosuppressive corticosteroids tapered gradually.
lightbulb Key takeaway
Analyse CSF within 30–60 minutes (cells degrade quickly) and assess cell count, cell type and protein. Neutrophils in a young dog with neck pain and fever suggest meningitis-arteritis; mononuclear pleocytosis suggests meningoencephalitis of unknown origin or infection. Serum C-reactive protein is useful for monitoring relapses.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.