Chapter 68 – Arthritis

Question 1

Fill in the chart

Answer 1

Question 2

Name three predisposing factors to OA

Answer 2

Genetics (The genes that control this susceptibility to osteoarthritis have not yet been identified in dogs)
Age
- Overall, aging is associated with multiple changes in articular cartilage such that cellular activity and responsiveness, repair mechanisms, and extracellular matrix features favor the loss of tissue.
Systemic factors such as obesity
- Canine obesity is associated with a systemic subclinical proinflammatory state with increased concentrations of circulating adipokines such as tumor necrosis factor (TNF), interleukin (IL)-6, and leptin

Question 3

How does neutering effect the risk of developing OA?

Answer 3

Neutering may increase the risk of OA in dogs (although the data on effect of gender is sparse)

Question 4

Describe the three overlapping phases of the pathophysiologic process of OA

Answer 4

• Initially the extracellular matrix degrades, the water content increases, the size of aggrecan molecules within the tissue decreases, and the structure of the collagen network is damaged, all of which leads to reduced stiffness of the cartilage
• Second, chondrocytes try to compensate for the damage through enhanced proliferation and metabolic activity—cell clusters, appear surrounded by newly synthesized matrix molecules. This condition can remain for several months to years.
• In the third stage, the chondrocytes are not able to keep up their repair activity, and complete loss of cartilage tissue is the consequence

Question 5

Give examples of inflammatory mediators effecting the articular cartilage in the OA process

Answer 5

• Inflammatory cytokines upregulate the synthesis of certain matrix metalloproteinases and other proteolytic enzymes leading to degradation of the components of the extracellular matrix of articular cartilage and cell death which is a key processes in osteoarthritis
• Prostaglandins E2 - decreased proteoglycan synthesis and enhanced the degradation of both aggrecan and type II collagen
• Reactive oxygen species such as superoxide anion, hydrogen peroxide, and hydroxyl radicals directly promote chondrocyte apoptosis
• Nitric oxide- inhibition of matrix synthesis, activation of matrix metalloproteinases, and apoptosis.
• Matrix metalloproteinases such as MMP-13, but the “aggrecans” also known as ADAMTS-4 and ADAMTS-5 – causes degradation of aggrecan which appears to be a very early event in canine osteoarthritis

Question 6

What are some key features that can be seen on x-ray indicating OA?

Answer 6

• Osteophyte formation and subchondral sclerosis
  (Osteophyte formation is highly associated with cartilage damage, but osteophytes can develop without explicit cartilage damage)

COMPLETE?

Question 7

List the radiologic features of OA

Answer 7

Osteophytosis
Enthesophytosis
Effusion
Soft tissue swelling
Subchondral sclerosis
Intra-articular mineralization
Subchondral cyst

Question 8

Describe the x-rays

Answer 8

A. Osteophyte formation on the proximal boarder of the anconeal process and the cranial aspect of the redial head
B. Marked osteophyte formation of the acetabulum and femoral neck with extensive remodeling
C. Osteophyte formation at the proximal and distal poles of the patella, the proximal boarder of the trochlear ridge and the caudal tibial margin as well as increased soft tissue opacity within the joint (joint effusion)
D. Osteophyte formation and enthesophytosis of the talocrural joint.

Question 9

what is the typical finding in synovial fluid of an OA joint vs in septic arthritis?

Answer 9

Synovial fluid: mild to moderate increase in cell count, mainly mononuclear cells. (cellcount 2-5 x 109)

Septic arthritis: marked increase in cell count (40-267 x 109) with mainly neutrophils

(< 2 x 109 is the normal synovial fluid)

Question 10

Briefly describe the management of OA

Answer 10

Weight management
Some evidence indicates that reduction in obesity of dogs with clinical signs of osteoarthritis can lead to improvement in clinical signs such as lameness and multiple studies in human beings show that treatment of overweight and obesity can improve symptom
Exercise
Regular, moderate, controlled exercise may be beneficial for osteoarthritis patients
Medical management
NSAID
Other pain medications eg. Gabapentin, paracetamol
Nutritional management
Glucosamine
Essential fatty acids
Mesenchymal stem cell therapies
Joint debridement and micropick surgery
The aim of such surgeries is to stimulate fibrocartilage repair mechanisms.
Joint replacement surgery
Often the ideal surgical treatment
Arthrodesis ans salvage procedures
Euthanasia
Last choice if none of the above leads to a good quality of life

Question 11

What are the positive and negative effects of using corticosteroids i.a?

Answer 11

It suppresses the local inflammation rapidly with minimal systemic effect. Although the effect is usually only temporary
There’s a risk for cartilage damage and progressive joint destruction caused by the suppression of cartilage matrix synthesis
Injection info the same joint should be limited, not more than 3-4 injections a year (based ion human studies)

Question 12

What are the clinical signs of immune mediated polyarthritis?

Answer 12

Multiple joint pain and swelling
Generalized stiffness
Moderate pyrexia (In fact, immune-mediated polyarthritis is the most common diagnosis in dogs presenting with pyrexia of unknown origin.)
Can be any age, breed and gender

Question 13

How should you collected the synovial fluid in the diagnosis of IMPA?

Answer 13

It is recommended to sample at least four joints and to continue sampling until a minimum of three acceptable samples are obtained

Question 14

What hematological and biochemical changes can you have in IMPA?

Answer 14

Anemia
Leukocytosis or leukopenia
Neutrophilia with a left shift
Thrombocytopenia
- Thrombocytopenia and leukopenia are especially seen in systemic lupus erythematosus

Serum biochemistry may reveral

Elevated crea, urea, ALAT, ALP
Protein-losing nephropathy or enteropathy may occasionally be encountered due to immune complex deposition; this may lead to decreased serum albumin concentrations.
Globulins may be increased as the result of autoantibody production.
Urinalysis may demonstrate proteinuria that may be detected as a result of glomerulonephropathy.

Question 15

What serological findings can you have in IMPA?

Answer 15

Rheumatoid factors (anti-immunoglobulin (Ig) antibodies of IgM and IgA classes against the Fc portion of IgG., however, the appearance of rheumatoid factors in serum is not specific for canine rheumatoid arthritis; they can be a feature of other chronic inflammatory conditions)
Antinuclear antibodies, however, raised antinuclear antibody titers are also noted in a variety of chronic inflammatory diseases in human patients. The authors of one study suggest that measurement of antinuclear antibody titer was not a useful diagnostic test in dogs with no major clinical or clinicopathologic abnormalities suggestive of systemic lupus erythematosus. In contrast, there was a good chance that results of the antinuclear antibody assay would be positive and that the dog would be found to have systemic lupus erythematosus if at least two major signs (for major signs, see the section on systemic lupus erythematosus) were present

Question 16

What are the classification of non-erosive immunmediated polyarthritis?

Answer 16

Idiopathic immune-mediated polyarthritis groups I to IV
Polyarthritis-polymyositis syndrome
Systemic lupus erythematosus and systemic lupus erythematosus–related disorders
Drug-induced immune-mediated polyarthritis
Breed-associated immune-mediated polyarthritis

Question 17

Define typ I to IV immunomediated polyarthritis

Answer 17

Type 1: idiopathic immune-mediated polyarthritis. The most common one of all non-erosive (accounts for ca 50 %). Don’t have a multisystem involvement. Diagnosed by exclusion of other diseases.
Type 2: immune-mediated polyarthritis associated with infection remote from the joint (account for approximately 25%). Sites of infection include endocarditis, respiratory infection, genitourinary tract infection, pyoderma, and abscessation.
- Treatment of the initiating infection can bring about resolution of the immune-mediated polyarthritis. However, this is not necessarily the case, and chronic or recurrent immune-mediated polyarthritis can persist.
Type 3: Immune-mediated polyarthritis associated with some form of gastrointestinal disease (approximately 15%)
- The most common gastrointestinal signs were vomiting and diarrhea
Type 4: Immune-Mediated Polyarthritis Associated With Neoplasia (paraneoplastic arthritis). Only a few reports have described paraneoplastic immune-mediated polyarthritis in dogs

Question 18

Give examples of medicines that can give drug induced polyarthritis

Answer 18

Often antibiotics, such as sulfonamides (mainly), penicillin derivatives, erythromycin, lincomycin, and cephalosporins. More common in large breeds (Doberman overrepresented)

Question 19

What is the criteria’s for diagnosis of definite systemic erythematosus?

Answer 19

The appearance of at least two major signs (i.e., skin lesions, polyarthritis, hemolytic anemia, glomerulonephritis or substantial proteinuria, polymyositis, leukopenia, and thrombocytopenia) or
is made if the dog has an antinuclear antibody titer ≥160, one major sign, and at least two minor signs (i.e., pyrexia of unknown origin with central nervous system signs including seizures, oral ulceration, lymphadenopathy, pericarditis, and pleuritis)

Question 20

How is rheumatoid arthritis distinguished from other immune-mediated polyarthritis?

Answer 20

By the erosive changes in the joint seen of x-ray (not always present in the early stage) and the appearance of rheumatoid factor in serum (but it is not specific for rheumatoid arthritis and should never be used as a sole diagnostic test, as well as you can have rheumatoid arthritis without being positive for rheumatoid factor)

Question 21

How many of the criteria’s of canine rheumatoid arthritis has to be present to have a define diagnosis?

Answer 21

Five

Question 22

Which criteria’s are the most specific for canine rheumatoid arthritis?

Answer 22

Destructive radiographic changes typical of rheumatoid arthritis
Positive agglutination test for serum rheumatoid factor
Characteristic histopathologic changes in the synovial membrane with three or more of the following: marked villous hypertrophy, proliferation of superficial synovial cells, marked infiltration of chronic inflammatory cells (lymphocytes and plasma cells predominating) with tendency to form lymphoid nodules, deposition of fibrin, foci of cell necrosis

Question 23

Which joints are more commonly affects by feline chronic progressive polyarthritis?

Answer 23

carpal and tarsal joints

Question 24

which is the most commonly isolate bacteria in septic arthritis in dogs and in cats?

Answer 24

Dogs: Staphylococcus intermedius, Staph. Aureus and beta-hemolytic Streptococci
Cats: Pasturella multocida and bacteroides spp.

Question 25

which is the most common bacteria isolated for in bacterial arthritis resulting form congenital or neonatal exposure?

Answer 25

Staphylococcus canis

Question 26

What changes on synovial fluid cytology should raise suspicion of bacterial infective arthritis?

Answer 26

An automated cell count greater than 50 × 109 cells/L and greater than 40% neutrophils
(In acute cases, cell counts are usually very high and range from 100 to 250 × 109/L with 98% neutrophils. However, in chronic cases, cell counts may be lower, in the region of 40 to 100 × 109/L.)

Question 27

What is the recommended treatment of septic arthritis?

Answer 27

Systemic antibiotic treatment for a minimum of 28 days or until clinical signs have resolved, whichever is longest.
Repeated arthrocentesis after 7-14 days of treatment and compare the cell count to the initial sample. If no change in cell count consider changing antibiotics.
An additional repeated synovial fluid analysis should be done before withdrawal of antibiotic therapy. The antibiotics is withdrawal when the cell count is normal and the neutrophils is under 3%

Question 28

Among 95% of dogs infected with Borrelia Burdorferi will remain without clinical signs. What is the most common clinical sign in the remining 5 %

Answer 28

Inflammatory nonerosive arthropathy with shifting lameness and swollen joints.
In addition, chronically infected dogs may develop a glomerulonephritis syndrome referred to as Lyme nephropathy (always suspect borrelia if you have proteinuria and joint stiffness)

Question 29

What is the ACVIMs consensus statement for presumptive diagnosis of Lyme disease?

Answer 29

evidence of exposure to B. burgdorferi
clinical signs consistent with Lyme disease
consideration of other differentials, and, it is hoped
response to treatment