Systemic Lupus & Immune Mediated Polyarthropathies Flashcards
What are the most commonly reported manifestations for SLE?
- Polyarthropathy (pain in multiple joints)
- Skin lesions (mucocutaneous jxn)
- Renal GLN or PLN
- Blood dyscrasia
(must have atleast 2 to say its SLE)
What dog breeds are slightly more overrepresented with SLE?
- GSD
- Sheltie
- Collies
- Poodles
How can SLE be definitely diagnosed?
- Positive anti-nuclear antibody (ANA) test from serum with at least 2 body systems affected
(Renal GLN or PLN, IMPA, immune mediated skin disease, IMHA, etc)
What is the treatment protocol for SLE?
- Prednisone
- Azathioprine
- Levamisole? (sheep dewormer)
What is the prognosis of SLE?
- Guarded, relapses occur
- Long term therapy with Pred +/- Azathioprine, months or longer is needed
What are non inflammatory causes of polyarthropathy?
- Osteoarthritis / DJD
- Traumatic injury
(would see mononuclear plasma cells and macs in synovial fluid)
What are inflammatory causes of polyarthropathy?
- Infectious (septic joint)
- Rheumatoid arthritis (erosive IMPA)
- Non erosive IMPA
List non erosive causes of IMPA
- Idiopathic (Primary IMPA) most common
- Type II: secondary to infection elsewhere (UTI, endocarditis)
- Type III: Hepatic / GI associated
- Type IV: Distant neoplasia
- Misc tick borne disease, vaccine induced, drug induced, SLE
What are the most suggestive exam findings for Idiopathic/Primary IMPA?
- Lameness/gait abnormalities
- Fever
- Joint pain and swelling affecting multiple limbs
How would you work up a middle age dog presenting with multiple limb lameness and evidence of joint pain and swelling on PE?
- CBC, Chem, UA
- Rads
- Arthrocentesis of multiple joints for direct smear, cell counts, and bacterial culture of synovial fluid
- 4DX for tick borne dz
What is seen in synovial fluid with IMPA?
- Non degenerate neutrophils
- Increased NCC > 3000
(Good diagnostic for IMPA but doesn’t determine the underlying cause)
What is seen in synovial fluid with osteoarthritis / DJD?
- Mononuclear plasma cells and macs (Reactive joint)
(No neuts!!! Use arthrocentesis of synovial fluid to differentiate IMPA vs Rheumatoid Arthritis vs Reactive joint disease)
What is the treatment protocol for a patient diagnosed with Primary IMPA
- Prednisone at immunosuppressive dose of 2mg/kg/day
- Repeat arthrocentesis q 2-3 weeks
- +/- Azathioprine, cyclosporine, etc
- Some cases meds can be tapered off
What is the treatment protocol for a patient diagnosed with Secondary IMPA?
- Short term NSAIDs and Doxy for Tick borne disease
- Short term NSAIDs for drug/vaccine induced which resolves quickly
- Treat neoplasia if IMPA secondary to LSA, OSA, HSA
What neoplasia can cause secondary IMPA?
- LSA
- OSA
- HSA
What is the preferred treatment protocol for a patient with secondary IMPA due to Lyme disease?
- Short term NSAIDs and Doxycycline
(no Pred for secondary IMPA!)
What are common causes of non erosive secondary IMPA?
- Chronic infection (UTI, endocarditis)
- Drug induced (TMS, Carprofen)
- Vaccine induced (Calicivirus in cats)
- GI disease
- Hepatic disease
- Neoplastic disease (LSA, OSA, HSA)
- SLE
What is the prognosis for primary IMPA?
- Responds well to Prednisone and relapse is uncommon
- Possibility of life long meds
What is the prognosis for secondary IMPA?
Depends on underlying cause!
(Tick borne vs neoplasia vs drug induced)
What drugs are at risk of causing secondary IMPA?
TMS, Carprofen
Which immune mediated polyarthropathy has the worst prognosis?
Rheumatoid arthritis - erosive bony lesions, aggressive with no definitive tx
What is seen in synovial fluid with Rheumatoid arthritis?
High NCC > 3000 with Non degenerate neutrophils
What is seen in synovial fluid with septic joint polyarthropathy?
Bacteria / septic joint with degenerative neutrophils
What is rheumatoid arthritis?
- Chronic, progressive inflammatory joint disease characterized by erosive and destructive changes within multiple joints
