3 Disorders of the Joints

Noninflammatory

Developmental and degenerative joint disease (DJD) are examples of what type of joint disease?

Inflammatory

Infectious and immune mediated (like primary idiopathic and reactive polyarthritis) are examples of what type of joint disease?

Degenerative Joint Disease

• remember: insidious onset

Which disease is confined to the musculoskeletal system with no systemic signs? Animals have lameness, stiffness and muscular atrophy, where joint instability, trauma, and developmental orthopedic disease are the MOST common underlying causes?

hips

Where is the most common location for DJD?

Multi-modal!

• Weight management

• exercise and physical fitness

• pharmaceuticals

• physical rehabilitation

• complementary therapies

How can you prevent and treat DJD?

COX2 --> inflammatory PGs --> inflammation = chronic cycle of degradation and pain with DJD

Which COX pathway do you want to inhibit with NSAIDs?

Spare COX 1 (also associated with 50% less GI ulceration if you use COX 1 sparing)

Which COX do you ideally want to spare with NSAIDs?

The most selective because >1 = COX2 selective

1. Firocoxib

2. Robenacoxib

3. deracoxib

Which NSAIDs are the best for COX2 selectivity?

Minimum of 72 hours washout period between NSAIDs

What is the minimum washout period between NSAIDs?

All NSAIDs have potential to cause gastric ulceration to erosion

What is the problem with NSAIDs? What side effect can they have?

Grapiprant --> PGE2 EP4 receptor antagonist

Which NSAID does NOT inhibit COX?

Blood in vomit, black stool, inappetence, anemia

If GI ulceration is occurring in dogs, what kinds of symptoms would you see?

1. Dehydrated

2. Hypotensive (addison's patients)

3. Concurrent Steroids

4. Geriatrics with co-morbidities (renal disease, gi issues)

   1. Reach for opioids first

Note: you avoid in hypotensive dogs because there is already low blood pressure and NSAIDs inhibit prostaglandins which play a role in maintaining blood flow to kidneys. When NSAIDs inhibit prostaglandins, blood flow to the kidneys is lowered even more

Which patients do you have to be cautious of using NSAIDs in? What should you reach for first instead?

They have limited hepatic glucuronidation

Why should NSAIDs be used with extreme caution in cats?

Robenacoxib and Meloxicam (but try and go for supplements first)

• 2 FDA approved NSAIDs

• Meloxicam has a block box warning

Which NSAIDs can you use in cats to attempt to manage OA? What should you go for first?

Linoleic Acid and Arachidonic Acid (spiders are bad, this is the inflammatory omega)

Name the Omega 6's

alpha Linoleic Acid (ALA), Eicosapentanoic acid (EPA), Doxosahexanoic Acid (DHA)

Name the Omega 3's

Omega 3

Which Omega is minimally inflammatory with eicosanoids and is inflammation resolving?

Omega 6

Which Omega is PRO inflammatory with prostaglandins, leukotrienes, and thromboxanes?

Omega 6: Omega 3

3:1

What is the good ratio between Omega 3 and 6

Glucosamine, chondroitin, pentosan, green lipped mussel

Name some oral disease modifying OA agents

Polysulfated glycosaminoglycans, hyaluronic acid

Name some injectable disease modifying formulations for OA

Hydromorphone, buprenorphine, tramadol (oral & not used alone for dogs)

Name some opioids best for OA analgesic

Gabapentin

Note: (ketamine also associated with NMDA)

Which novel adjunct analgesic is associated with NMDA receptors

Synovetin

Which OA treatment uses radio-synovi-orthesis to break the cycle of pain and inflammation for chronic OA patients with 92% success rate?

Frunevetmab for cats (Solensia) and Bedinvetmab for dogs (Librela)

Name the newest OA treatments for cats and dogs but has serious side effects

1. Hematogenous

2. *Direct inoculation* (specifically penetrating joint wounds are COMMON)

• results in single joint infection

3. spread from local, adjacent tissue

What are the routes of infection for septic arthritis?

Staphylococcus, Streptococcus, and coliform organisms

What are the most common organisms that cause septic arthritis in dogs?

Pasteurella

What are the most common organisms that cause septic arthritis in cats?

Chronic infections, foreign bodies, immature animals with open growth plates

Which causes of septic arthritis should you treat immediately with surgery?

• Dogs » cats

• large breed dogs

• males

Who is septic arthritis more common in?

Acute cases

Which causes of septic arthritis can you manage medically with caution?

Borrelia burgdorferi

What causes tick borne polyarthritis or Lyme?

Most commonly asymptomatic. May have lameness or joint swelling in one or more joints that are painful on palpation

Describe the typical presentation of a dog with Lyme

Distemper, bacteria (Staphylococcus and Streptococcus, most common), Mycoplasma, Borrelia burgdorferi, Leishmania, Tick borne (Ehrlichia, RMSF, Anaplasma)

Give some differentials for infectious causes of arthropathy in canine patients

Calicivirus, bacteria (Pasteurella multocida), mycoplasma

Give some differentials for infectious causes of arthropathy in feline patients

Spirochetes colonize synovial membrane --> IL 8 --> neutrophil chemotaxis = fibrin effusion, neutrophil infiltration, thick synovial membranes

How does Lyme disease cause polyarthritis?

Renal homeostasis, gastric mucosal protection, platelet function

What are some effects COX 1 has on the body in health?

ELISA to test for C6 peptide surface protein

What is the most common diagnostic tool for tick borne polyarthritis or lyme?

Tetracycline like doxycycline and lactams

How do you treat dogs with acute infections of Borrelia burgdorferi Lyme?

Avoid steroids = immunosuppressive doses can exacerbate infection

What should you probably avoid using to treat dogs with Lyme infections? Why?

Rickettsia rickettsii

What causes Rocky Mountain Spotted Fever (RMSF)?

Tick borne polyarthritis, but rickettsia does it thru RMSF and Borrelia does it thru Lyme

Both rickettsia and Borrelia have the ability to cause what?

Lyme: no CBC change

Rickettsia: thrombocytopenia (low platelets)

What is the difference in the CBC between lyme and rickettsial polyarthropathy?

Tetracycline (antibiotics) and glucocorticoids

How can you treat RMSF?

PCR, ELISA

How can you diagnose RMSF?

Mycoplasma gatea and Mycoplasma felis

What causes feline polyarthropathy?

Secondary to bite wounds OR may get transient polyarthropathy associated with calicivirus following vaccination

How do felines get polyarthropathy (Mycoplasma)?

Reactive polyarthritis

What accounts for 25% of all nonerosive immune mediated polyarthritis cases, which is a form of inflammation affecting multiple joints, triggered by an infection or inflammation elsewhere in the body?

ONLY by ruling out other causes of polyarthritis

What is the ONLY WAY to diagnose idiopathic immune mediated nonerosive polyarthritis?

Idiopathic immune mediated nonerosive polyarthritis

What is the most common form of polyarthritis in dogs but NOT in cats?

You are probably dealing with idiopathic immune mediated nonerosive polyarthritis (IMPA). This means antibiotics will probably not have any effect. Do prednisone

A dog comes in with cyclic fever, stiffness and lameness, with multiple joints affected. You have ruled out Rickettsial disease and Lyme in addition to septic arthritis and osteoarthritis. Where do you go from here?

NOT WORK: antibiotics

WILL WORK: prednisone

What treatment is NOT likely to work for idiopathic immune mediated polyarthritis? What WILL work?

DJD (degenerative), trauma, neoplasia, developmental

A dog is having joint pain. You decide to look at the synovial fluid and see it is noninflammatory. Give some differentials

Bacterial, fungal, Rickettsial, Borrelia

A dog is having joint pain. You decide to look at the synovial fluid and see it is inflammatory. Upon radiographs, you see it is nonerosive. You culture synovial fluid and find it infected. Give some differentials

Reactive polyarthritis

A dog is having joint pain. You decide to look at the synovial fluid and see it is inflammatory. Upon radiographs, you see it is nonerosive. You culture synovial fluid and find it noninfected. So, you decide to evaluate for systemic disease and find it present. Give some differentials

"erosive" means that the condition causes damage and destruction, often leading to visible lesions or erosions (breaks or ulcers) in the affected tissue. "Nonerosive" means the disease is present but does not cause these types of visible tissue damage or erosions

What is the difference between erosive and nonerosive noninfectious inflammatory diseases?