- No causative agent has been found
- Seem to be immune-mediated diseases
Erosive
Rheumatoid Arthritis
Non-erosive
Systemic lupus erythematosus (SLE)
- Occurs in dogs
- Clinical signs:
- Anaemia
- Thrombocytopaenia
- Polymyositis
- Glomerulonephritis
In chronic diseases
- E.g. pyometra, otitis externa, endocarditis, enteritis
- Can lead to immune complex deposition in joints
Gout
- Occurs in humans, reptiles and birds (have no uricase enzyme)
- The urate triggers inflammation