EQ Arthritides Flashcards
What is an arthritide?
A condition causing pain and dysfunction related to joints
Define arthritis
Inflammation/ degeneration of the joint
What is osteoarthritis?
A degenerative condition which leads to cartilage breakdown and loss of joint function
Describe the structure of articular cartilage.
- Mainly ECM
- Collagen (mainly type 2) - shear resistance
- Proteoglycans (compressability
- Chondrocytes - maintain ECM
- Avascular
- Aneural
- Hypoxic
- Limited repair
Name some possible predisposing factors to osteoarthritis.
- Exercise/ trauma
- Developmental orthopedic disease
- Obesity
- Genetics
- Sepsis
- Ageing
- Medication - steroids
What radiographic signs are seen with osteoarthritis?
- Soft tissue swelling
- Osteophytosis
- Enthesiophytosis
- Subchondral bone sclerosis
- Intra-articular mineralisation
- Fragmentation/joint mice
- Collapsed joint space
- Subchondral bone cysts
Osteophyte
A boney protrusion of new tissue
Enthesiophyte
Abnormal boney projection at the site of muscle attachment
How can osteoarthritis be managed?
- Rest/restricted activity
- Weight loss if necessary
- Exercise
- Block joint
What is the mechanism of action of NSAIDS?
COX inhibition - reduce PGE2 and NO levels in chondro and synoviocytes
Also inhibit PMN migration
Central analgesia effects
Name three NSAIDs used in small animal and equine practice.
- Small animal
- Carprofen
- Meloxicam
- Firocoxib
- Equine/LA
- Phenylbutazone
- Flunixin
- Ketoprofen
Outline the mechanism of action of corticosteroids.
Bind to cytoplasmic and nuclear receptors and hence inhibit IL1 , TNFa and prostaglandin release.
Name two corticosteroids which are popular for use in equine practice.
Methylprednisolone acetate
Triamcinolone acetonide
What is the mechanism of action of Cartrophen?
Enhances proteoglycan synthesis
Reduce articular cartilage fibrillation
Improves synovial fluid viscosity
Increased free radical scavengers
What is the mechanism of action of hyaluronic acid?
Reduces PGE release and chemotaxis
Steric hinderance
What is the mechanism of action of IRAP?
Upregulation of IL-1 receptor antagonists
What is the mechanism of action of Bisphosphonates?
Potent inhibitors of bone resorption by:
- inhibiting osteoclasts
- inhibits NO and IL-1 induced collagenase release
Name a polyunsaturated fat. What substance are they a precursor of?
What is their mechanism of action?
Omega-3
Eicosapentaenoic acid analogues of arachidonic acid
They are anti-aggrecanases and stabilise cell membranes. They also reduce MMPs COX-2 IL1b and TNFa levels
What is the proposed mechanism of action of Glucosamine/ chondroitin sulphate?
- Reduced PGE2 and NO
- Reduced PG loss
- Increased joint motility
How can surgical methods be used to treat OA?
- Arthroscopy
- Assess, debride and flush inflammatory mediators
- Joint replacement
- Arthrodesis - artificial induction of joint fusion
What is the pathophysiology of immune-mediated joint disease?
Early changes to synovium
Chronic antigenic stimulation
Inappropriate immune response
Clinical signs associated with IMPA.
- Multiple limb joint pain/ swelling
- Generalised stiffness
- Shifting lameness
- Neck pain
- Lethergy
- Pyrexia of unknow origin
- Secondary OA/ fibrosis of joints
Which diagnostic techniques are used in the diagnosis of IMPA?
- Synoviocentesis
- Full clinical exams
- Bloods - anaemia, leucopenia, thrombocytopenia, raised globulins, low albumin
- Urinalysis - proteinuria
- Diagnostic imaging
Name pharmacological agent which are used in the treatment of IMPA.
- Corticosteroids
- Azathioprine
- Cyclosporine
- Apaquel
Name three aetiological agents involved in infective arthritis.
- Staph. intermedius
- Pateurella multocida
- Truperella pyogenes
- Mycoplasma
- Salmonella
Outline the pathophysiology of of infective arthritis.
- Marked inflammatory response
- Vasodilation
- Neutrophil influx
- Cytokine release - IL1/ TNFa
- Fibin clots trap bacteria
- Cartilage destruction and extension to subchondral bone
What clinical signs are associated with infective arthritis?
- Acute, severe lameness
- Stiffness
- Lying down
- Pyrexia
- Wound near/over joint
- Pain on palpatoin
- Articular swelling
Ddx. for infective arthritis
Traumatic joing/ soft tissue injury
Osteochondritis
Bursitis
Hygroma
Cellulitis
How would synovial fluid from an infected joint compare to that of a normal, healthy one?
- Normal
- Pale yellow
- Highly viscous
- WBC <1X10^9, TP <20g/L
- Septic synovial fluid
- Serosanguinous
- Turbid
- Reduced viscosity
- wbc >10-20x10^9, TP >30-40g/L
Outline the treatment plan for infective arthritis.
- Antibiotics - dependant on aetiological agent
- Sytemic
- Intra-articular - gentamycin
- Joint lavage - ensure environment is sterile
- Arthroscopy - remove debris/ fb
Lyme disease is caused by which tick-borne spirochaete?
Borrelia burgdorferi
Clinical signs associated with lyme disease in dogs.
- Inflammatory non-errosive arthropathy
- Shifting lameness
- Swollen lameness
What antibiotic is used in treatment of lyme disease?
Doxycycline
