VCS80610_IMPA_2023.pptx

Immune-Mediated Polyarthritis VCS 80610 Fall 2023 Andrew Woolcock, DVM, DACVIM Purdue University College of Veterinary Medicine Nitro • 4 year old MN • German Shepherd • Presented due to 4 week history of shifting leg lameness www.dogcare.com Nitro Physical Exam Findings Fever (103.5*F) Polyart...

Immune-Mediated Polyarthritis VCS 80610 Fall 2023 Andrew Woolcock, DVM, DACVIM Purdue University College of Veterinary Medicine Nitro • 4 year old MN • German Shepherd • Presented due to 4 week history of shifting leg lameness www.dogcare.com Nitro Physical Exam Findings Fever (103.5*F) Polyarthropathy (swollen joints – L&R carpi, R stifle, L&R tarsi) Painful on joint manipulation Minimal ambulation Classification of Joint Disease • Inflammatory – Infectious • Septic • Rickettsial • Viral – Immunologic • Erosive • Non-Erosive • Degenerative Joint Disease* • Neoplasia Immune-Mediated Polyarthritis Erosive Non-Erosive Rheumatoid Arthritis Greyhound polyarthritis Immune-Mediated Polyarthritis Non-Erosive – 4 TYPES Type 1 Idiopathic Most Common Type 3 Secondary to gastrointes tinal disease Type 2 Secondary to a nonjoint infection Type 4 Secondary to non-joint neoplasia Rheumatoid Arthritis CAUSES Antibodies directed against host immunoglobulins (Type II HS) Immune-Mediated IMMUNENeoplasia MEDIATED Severe immune-complex deposition (Type III HS) Infection Severe synovitis with secondary bone destruction Toxin Vaccine Reaction Rare in dogs and cats DIC Idiopathic Immune-Mediated Polyarthritis Antibodies directed against synovial membrane Antigen-antibody complex deposition CLINICAL SIGNS Lameness Fever Abnormal gait Limited ambulation Depression Anorexia LABORATORY ABNORMALITIES Maybe none Inflammatory leukogram Inflammatory synovial fluid DOGS>cats Middle-aged, large breed dogs Immune-Mediated Polyarthritis • As you plan for joint taps, rule out secondary causes: Infectious Erosive Neoplastic Immune-Mediated Polyarthritis • As you plan for joint taps, rule out secondary causes: Infectious • Rickettsial  Borrelia burgdorferi, Ehrlichia spp., Anaplasma spp., Rickettsia rickettsii, Bartonella spp. • SNAP 4DX, serology/PCR Immune-Mediated Polyarthritis • As you plan for joint taps, rule out secondary causes: Infectious • Bacterial  Septic; usually monoarthritis vs. hematogenous • Culture synovial fluid Immune-Mediated Polyarthritis • As you plan for joint taps, rule out secondary causes: Infectious • Fungal  Osteomyelitis more common than true arthritis • Radiographs to evaluate for lytic lesions/osteomyelitis Immune-Mediated Polyarthritis • As you plan for joint taps, rule out secondary causes: Erosive • Tends to be more severe/painful • Radiographs to evaluate for an erosive process • Don’t need to radiograph every affected limb in a polyarthritis Immune-Mediated Polyarthritis • As you plan for joint taps, rule out secondary causes: Neoplastic • Neoplastic vs. paraneoplastic • Primary joint neoplasia rare (more likely primary bone tumor) • Paraneoplastic IMPA has been reported • Radiographs, synovial fluid collection, bone FNA Indications for Arthrocentesis • • • • • • • • Joint effusion Joint pain Lameness Abnormal gait Weakness Unexplained fever Multisystemic immune disease Neck pain Normal Abnormal Normal Synovial Fluid Analysis GROSS ANALYSIS CYTOLOGIC ANALYSIS Synovial Fluid Analysis GROSS ANALYSIS 1. Color 2. Turbidity 3. Viscosity 4. Protein Synovial Fluid Analysis CYTOLOGIC ANALYSIS 1. Cell Count 2. Cytology NORMAL < 1500 cells/μL GREY AREA 15003000 cells/μL INFLAMMATOR Y >3000 cells/μL DEGENERATIV E Normal to MILD increase Synovial Fluid Analysis CYTOLOGIC ANALYSIS 1. Cell Count 2. Cytology Synovial Fluid Analysis NON-septic, suppurative or lymphocytic synovial fluid is the hallmark of IMPA Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Immunosuppressive medication VERY “Pred-responsive” Steroids tend to quickly resolve the fever and improve joint comfort Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Immunosuppressive medication In large/giant breed dogs, high dose corticosteroids: • Reduce muscle mass • Increase ligament laxity Adjunctive agents are appealing Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Colopy et al, JVIM 2010 14 dogs with IMPA treated with leflunomide (w/o steroids) 8/14 – complete remission 5/14 – partial remission 1/14 – no response Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Rhoads et al, JAVMA 2016 20 dogs with IMPA randomly assigned to receive either pred or cyclosporine 7/10 in both groups achieved treatment success Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Colopy et al, JVIM 2010 Rhoads et al, JAVMA 2016 NSAIDS, tramadol, and gabapentin used for anti-inflammatory and analgesic support when steroids not used Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Colopy et al, JVIM 2010 Rhoads et al, JAVMA 2016 Consider cyclosporine or leflunomide as monotherapy in cases where steroids may be too risky a choice Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Cyclosporine, mycophenolate, azathioprine, and leflunomide are all appropriate choices if ADDING a second agent to prednisone therapy Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Neuropathic pain (e.g. gabapentin) NMDA Antagonist (e.g. amantadine) Opioid medications, if needed (e.g. fentanyl) Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Support hydration during first few days if nonambulatory Limit activity during the first 2-4 weeks of treatment – important cause of relapsing signs Immune-Mediated Polyarthritis GOALS OF THERAPY Monitoring Resolution of inflammation Control pain Supportive care & monitoring Clinical signs! Repeat joint taps can confirm normal cytology/remission Risk vs benefit Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Monitoring Consider plasma CReactive Protein Immune-Mediated Polyarthritis GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring C-Reactive Protein Non-specific inflammatory marker Reliably increased in IMPA Immune-Mediated Polyarthritis C-Reactive Protein GOALS OF THERAPY Resolution of inflammation Control pain Supportive care & monitoring Foster et al, JVIM 2014 Plasma CRP was increased in dogs with lMPA • Decreased by 2 weeks • Correlated with joint fluid cellularity and joint mobility Nitro’s IMPA Prognosis • Good • Mortality rate LOW • Quality of Life most important factor for prognosis – EROSIVE disease associated with more severe and longlasting orthopedic issues Relapse ~20% www.dogcare.com Thank You!