Inflammatory Arthritis Flashcards
What is the diagnostic plan for dogs with septic arthritis?
Radiograph affected joints with perpendicular joints
Arthrocentesis to differentiate between septic and IMPA
Synovial investigation
Systemic investigation with thorough PE, history and CBC/biochem
What is the clinical presentation of septic arthritis?
Severe lameness, generalised stiffness, pyrexic, lethargic, inappetant, multiple painful swollen joints, stilted/crouched, arthralgia ranging from subtle to severe, may present as ataxic
What are the key diagnostic findings for septic arthritis?
Arthrocentesis = increased number of degenerate neutrophils
Radiography if acute may be normal or see primary disease but if subacute/chronic = erosion of cartilage/bone
What are the causes of septic arthritis?
Haematogenous spread from focus elsewhere
Lacerations or puncture wound
Iatrogenic from IA injections or surgery
What is the treatment for small animals with septic arthritis?
Antibiotics (amoxy-clav), no difference between medical ad surgical treatment, 94% infections resolve, may need to remove implants, 6 weeks of antibiotics based on culture and sensitivity
What is the treatment for horses with septic arthritis?
Antibiotics, through and through lavage and arthrotomy, intra-articular and IV antibiotics (penecillin and gentamycin)
Resample joint fluid every 48 hours to ensure treatment is effective
What management is necessary for septic arthritis cases?
Antibiotics
Daily bandage dressings for wounds
Early stages rest and then physio/hydrotherapy to prevent adhesions and periarticular fibrosis
What is the prognosis for septic arthritis?
Good with prompt recognition and aggressive treatment and local antibiotics
Intended use, structures involved and concurrent bone involvement play a part
What is the aetiology of immune-mediated polyarthritis?
Antigen-antibody complex leads to formation of inflammatory products
Host IgG and IgM bind to altered autologous IgG
Antigen-antibody complex deposited on synovium leading to neutrophil/macrophage chemotaxis
What additional pathology occurs in erosive form of immune-mediated polyarthritis?
Cellular or humoural immunopathogenic factors
Release of chondrodestructive collagenases/proteases
Failure of self tolerance or production of immunogenic immunoglobulins
What are the risk factors for immune-mediated polyarthritis?
Hereditary in Beagles, GpA streptococcal pharyngitis can lead to rheumatic fever, bacterial endocarditis, discospondylosis, immune-mediated bowel disease, certain neoplasias (pancreatic adenocarcinoma, SCC, lymphoma), chronic hepatitis
What type of hypersensitivity is behind immune-mediated hypersensitivity?
Type III hypersensitivity reaction and chronic disease due to continual/recurrent presence of inciting antigens, failure of normal down regulation and exposure of self antigens due to initial damage
How do animals with immune-mediated polyarthritis present?
35% are lame and 40% have joint effusions
Ligamentous laxity causes plantigrade stance
Symmetrical swollen joints +/- painful joints
Multiple joints affected
What are the different types of non-erosive arthritis?
Type I = 50%, type II = 25%, type III = 15% and type IV = <10%
How is non-erosive arthritis investigated?
Arthrocentesis, joint radiography and synovial biopsy
Underlying disease hunt using haematology, biochemistry, urinalysis, thoracic radiographs, abdominal ultrasound and CSF/serology/PCR/echo
What are some examples of non-erosive arthritis?
Systemic Lupus Erythematosus (SLE), Lyme disease, Drug associated in Dobermanns with sulphonamides, Caliciviral in kittens, Steroid-responsive meningitis arteritis (SRMI) in adolescent dogs, IBD, Vaccine induced
How do you manage a pet with non-erosive arthritis?
Opioids as may want to give steroids later which are contra-indicated with NSAIDs
What is the pathogenesis of erosive arthritis?
Chronic synovitis leads to production of proliferative granulation tissue or pannus which invades articular cartilage and can erode sub-chondral bone leading to collapse of the joint
Pannus and inflamed synovium produce enzymes which cause further joint destruction
What are some examples of erosive joint diseases?
Rheumatoid arthritis
Periosteal proliferative polyarthritis in cats
Polyarthritis of Greyhounds (Felty’s syndrome) = PA, splenomegaly and neutropenia
What classically needs to be present to diagnose a person with rheumatoid arthritis?
Need 7/11 to be present
Stiffness after rest, pain, swelling of one joint, swelling of another joint recently (<3 months), symmetric joint swelling, subcutaneous nodules, radiographic erosion, RF +ve serology, abnormal synovial fluid, synovial histology, nodule histology
What radiographic changes occur in erosive arthritis?
Sub-chondral bone erosions
Destructive symmetric multi-joint arthropathy
Early may only be soft-tissue changes
Chronic = joint collapse, joint deformity/subluxation, peri-articular new bone formation, calcification of peri-articular soft tissues
What can serology tell you about erosive arthritis?
75% of dogs will have high levels of RF not specific for RA in circulation even though they have RA
Differentiate from SLE with ANA test
What is the therapy for erosive arthritis?
Remove/treat inciting factor and modify lifestyle to decrease joint stress
Suppress immune response/control inflammation using prednisolone initially at 2-4 mg/kg/day in divided doses then gradually taper
Can include cytotoxic drugs e.g. cyclophosphamide or disease modifying antirheumatic drugs e.g. leflunomide/methotrexate or biological agents such as anti-TNF alpha or IL-1 blockers
What monitoring is necessary for treating erosive arthritis?
Response in 7 days with substantial decrease in WBCs and neutrophils is a good prognostic indicator
