Inflammatory Arthritis

Question 0

What is the diagnostic plan for dogs with septic arthritis?

Answer 0

Radiograph affected joints with perpendicular joints
Arthrocentesis to differentiate between septic and IMPA
Synovial investigation
Systemic investigation with thorough PE, history and CBC/biochem

Question 1

What is the clinical presentation of septic arthritis?

Answer 1

Severe lameness, generalised stiffness, pyrexic, lethargic, inappetant, multiple painful swollen joints, stilted/crouched, arthralgia ranging from subtle to severe, may present as ataxic

Question 2

What are the key diagnostic findings for septic arthritis?

Answer 2

Arthrocentesis = increased number of degenerate neutrophils

Radiography if acute may be normal or see primary disease but if subacute/chronic = erosion of cartilage/bone

Question 3

What are the causes of septic arthritis?

Answer 3

Haematogenous spread from focus elsewhere
Lacerations or puncture wound
Iatrogenic from IA injections or surgery

Question 4

What is the treatment for small animals with septic arthritis?

Answer 4

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

Question 5

What is the treatment for horses with septic arthritis?

Answer 5

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

Question 6

What management is necessary for septic arthritis cases?

Answer 6

Antibiotics
Daily bandage dressings for wounds
Early stages rest and then physio/hydrotherapy to prevent adhesions and periarticular fibrosis

Question 7

What is the prognosis for septic arthritis?

Answer 7

Good with prompt recognition and aggressive treatment and local antibiotics
Intended use, structures involved and concurrent bone involvement play a part

Question 8

What is the aetiology of immune-mediated polyarthritis?

Answer 8

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

Question 9

What additional pathology occurs in erosive form of immune-mediated polyarthritis?

Answer 9

Cellular or humoural immunopathogenic factors
Release of chondrodestructive collagenases/proteases
Failure of self tolerance or production of immunogenic immunoglobulins

Question 10

What are the risk factors for immune-mediated polyarthritis?

Answer 10

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

Question 11

What type of hypersensitivity is behind immune-mediated hypersensitivity?

Answer 11

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

Question 12

How do animals with immune-mediated polyarthritis present?

Answer 12

35% are lame and 40% have joint effusions
Ligamentous laxity causes plantigrade stance
Symmetrical swollen joints +/- painful joints
Multiple joints affected

Question 13

What are the different types of non-erosive arthritis?

Answer 13

Type I = 50%, type II = 25%, type III = 15% and type IV = <10%

Question 14

How is non-erosive arthritis investigated?

Answer 14

Arthrocentesis, joint radiography and synovial biopsy
Underlying disease hunt using haematology, biochemistry, urinalysis, thoracic radiographs, abdominal ultrasound and CSF/serology/PCR/echo

Question 15

What are some examples of non-erosive arthritis?

Answer 15

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

Question 16

How do you manage a pet with non-erosive arthritis?

Answer 16

Opioids as may want to give steroids later which are contra-indicated with NSAIDs

Question 17

What is the pathogenesis of erosive arthritis?

Answer 17

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

Question 18

What are some examples of erosive joint diseases?

Answer 18

Rheumatoid arthritis
Periosteal proliferative polyarthritis in cats
Polyarthritis of Greyhounds (Felty’s syndrome) = PA, splenomegaly and neutropenia

Question 19

What classically needs to be present to diagnose a person with rheumatoid arthritis?

Answer 19

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

Question 20

What radiographic changes occur in erosive arthritis?

Answer 20

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

Question 21

What can serology tell you about erosive arthritis?

Answer 21

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

Question 22

What is the therapy for erosive arthritis?

Answer 22

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

Question 23

What monitoring is necessary for treating erosive arthritis?

Answer 23

Response in 7 days with substantial decrease in WBCs and neutrophils is a good prognostic indicator

Question 24

When is surgery used in erosive arthritis? What surgery can be performed?

Answer 24

For management of pain in chronic disease as persistent inflammation may cause joint subluxation
Synovectomy, arthrodesis, excision arthroplasty or total joint replacement possible

Question 25

What must be considered before performing surgery on animals with erosive arthritis?

Answer 25

Cost, morbidity and surgical failure rates due to ongoing disease in other joints and effects of therapeutic agents on healing

Question 26

In which species does gout occur?

Answer 26

Humans, birds and reptiles as they don’t have enzyme uricase

Question 27

What causes gout in reptiles?

Answer 27

Renal damage leading to decreased excretion of urate

Question 28

How is gout diagnosed?

Answer 28

White peri-articular deposits (urate crystals) causing an inflammatory reaction

Question 29

What is the treatment for gout?

Answer 29

Fluid therapy and avoidance of medication that increases renal excretion