Stanley, an approximately 6-year-old, MN, DSH, named Stanley presents to a neurologist for a recheck exam. Stanley was originally evaluated on March 16th for acute non-ambulatory paraparesis and back pain. He appeared healthy until March 1st, when the owner noticed Stanley had an upper respiratory infection and a left thoracic limb injury. Stanley was taken to his primary veterinarian and treated at that time.
On March 15th, Stanley woke up with limited mobility in his pelvic limbs and was taken to another veterinary clinic. Radiographs were performed, he was placed on multiple medications, and referred for further evaluation. On the day of initial presentation to the neurologist, Stanley was dragging himself with his thoracic limbs, but was able to move his pelvic limbs. MRI and infectious disease testing were recommended. A trial of medications was elected, and Stanley improved at first, but when prednisolone was tapered, he stopped walking again. He also had GI upset associated with antibiotic therapy. Samples from two joints (specific joints not indicated) are submitted.
Scopio Practice Tip
Synovial fluid viscosity and sample volume limits ability to perform cell counts using in clinic automated hematology instrumentation, BUT direct preparations allow the clinical pathologist to provide an estimate of total cellularity, so cell counts are not typically necessary. Even better, fluid from more than one joint is included as a single site submission with Scopio and if the first tap is non-diagnostic, repeat sampling can be added to the case for no additional charge!
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- Very high cellularity for synovial fluid.
- Windrowing of cells (lining up), which occurs in viscous fluids (synovial, salivary).
- >95% of the nucleated cellularity in both joints is neutrophils with no blood contamination.
Interpretation: Marked suppurative arthritis.
Other interpretations that may be provided in this case: Marked neutrophilic inflammation, marked neutrophilic/suppurative polyarthritis.
Inflammatory polyarthritis: Inflammatory polyarthritis with this cellular composition (predominantly neutrophils) is well described in dogs with immune mediated polyarthritis (IMPA), but this finding is very uncommon in cats. In both species, polyarthritis can be of infectious, autoimmune, or idiopathic origin and can be further subclassified as erosive versus non-erosive, which aids in determining underlying etiology.
Clinical follow up: Infectious disease panel (serology) was performed and included FeLV, FIV, FCoV, Toxoplasma and Cryptococcus. All returned negative except FCoV 1:1600. FCoV may be repeated to determine trend and exposure versus infection. Clavamox and prednisolone (immunosuppressive dose) were started. Stanley is currently doing well, lameness is resolved, and the plan is to wean him off prednisolone over the next 2-3 months and stop Clavamox in 4 weeks with monitoring for return of clinical signs.