Corticosteroids are the cornerstone of MUO treatment, used either as monotherapy or in combination with a second immunosuppressive agent. No gold standard protocol exists, and treatment choice is currently guided by clinician and owner preference. Journal of Vete…
Prednisolone monotherapy produces median survival times of 28 to 602 days, while combination therapy with corticosteroids plus a second immunosuppressive agent is associated with improved survival times ranging from 250 to 1,834 days. Journal of the… One-third of dogs deteriorate within the first 72 hours after treatment initiation regardless of protocol. Journal of Vete… Without treatment, MUO is considered fatal. Journal of the…
Dexamethasone is an acceptable alternative to prednisolone for initial induction, with 0.5 mg/kg/day IV and 2.0 mg/kg/day IV producing equivalent short-term neurological outcomes over a four-day hospitalization period; neither dose regimen has demonstrated superiority in short-term efficacy or gastrointestinal safety. Frontiers in Ve…
Second-line immunosuppressive agents used in combination with corticosteroids include cytosine arabinoside (CA), cyclosporine, lomustine, procarbazine, leflunomide, mycophenolate mofetil, and azathioprine. Journal of the…+2 No prospective head-to-head comparisons between these agents exist. Journal of the…
Cyclosporine added to prednisolone is associated with a lower relapse rate compared with prednisolone alone in dogs with spinal MUO (meningomyelitis). For dogs treated with corticosteroids alone that experience clinical relapse, addition of a second immunosuppressive agent is recommended. Journal of the…
CA administered as a continuous rate infusion (CRI) at the time of diagnosis improved 3-month survival times compared with subcutaneous CA injection; however, adding CA to a cyclosporine-and-prednisone protocol at diagnosis did not improve outcomes. Journal of Vete…
Whole-brain radiation therapy (5 × 4 Gy) combined with prednisolone is a second-line option, particularly for cases requiring rapid symptom relief or with a relapsing history. Neurological status improved in all 10 treated dogs, with 4/10 returning to neurologically normal shortly after completing radiation. Mean time to progression was 691 days and mean overall survival was 723 days. Radiation-induced side effects were not observed. Frontiers in Ve…
Negative prognostic indicators that should inform treatment urgency include the presence of seizures, multifocal or brainstem lesions, cystic T1W-hypointense MRI lesions suggestive of necrotizing encephalitis, and obtundation — the last of which is the highest risk factor for early euthanasia. Journal of Vete…
CSF pleocytosis supporting MUO diagnosis is defined as a total nucleated cell count >5 cells/μL with >50% mononuclear cells, combined with compatible MRI findings and negative infectious disease serology (Toxoplasma IgG >1:400 or IgM >1:64; Neospora IFA ≥1:800). Journal of Vete… CSF protein is often elevated and may range from 30 mg/dL to >1,500 mg/dL. Journal of the…
| Drug/Protocol | Dose or Protocol | Efficacy | Key Caveat |
|---|---|---|---|
| Prednisolone monotherapy | Immunosuppressive doses (specific mg/kg not provided in sources) | Median survival 28–602 days Journal of the… | High relapse rate; one-third deteriorate within 72 h Journal of Vete… |
| Dexamethasone (low dose) | 0.5 mg/kg/day IV | Equivalent short-term outcome to high dose Frontiers in Ve… | No long-term data Frontiers in Ve… |
| Dexamethasone (high dose) | 2.0 mg/kg/day IV | Equivalent short-term outcome to low dose Frontiers in Ve… | No GI safety advantage demonstrated Frontiers in Ve… |
| Prednisolone + cyclosporine | Corticosteroid + cyclosporine (specific mg/kg not provided in sources) | Fewer relapses vs. prednisolone alone Journal of the… | Preliminary data only Journal of the… |
| Prednisolone + CA CRI | CRI at time of diagnosis | Improved 3-month survival vs. SC CA Journal of Vete… | Adding CA to cyclosporine + prednisone did not improve outcomes Journal of Vete… |
| Whole-brain radiation (5 × 4 Gy) + prednisolone | 5 fractions × 4 Gy | Neurological improvement in 10/10; mean OS 723 days Frontiers in Ve… | Best suited for relapsing or rapidly progressive cases Frontiers in Ve… |
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