Describe the pathology of osteoarthritis.
Fragmentation and loss of cartilage denuge the subchondral bone, which undergoes sclerosis (eburnation) and cystic change. Osteophytes form on the lateral sides and protrude into the adjacent soft tissues, causing irritation, inflammation, and fibrosis.
What are the main clinical signs and symptoms of osteoarthritis?
most common symptom = pain
- reduced mobility
- crepitus (rough articular surfaces
- muscle spasm and contractures
What is rheumatoid arthritis?
A disease characterized by systemic inflammation of the joints. An autoimmune disease that primarly involves the synovial joints.
What are the roles of hormones, genes, and autoimmunity in the pathogenesis of rheumatoid arthritis?
Hormones: affects w > m
Familial predisposition: HLA loci on chromosome 6
Autoimmunity: increased incidence of autoimmune diseases
What is pannus, and how does it evolve?
Pannus is caused by exuberant synovial fronds that transform into granulation tissue. The pannus cover ths articular surfaces like a sheet. It is rich in inflammatory cells that secrete lytic enzymes and various mediators of inflammation.
Describe the pathology of rheumatoid arthritis.
Inflammation leads to pannus formation, obliteration of the articular space, and finally ankylosis (collagenous scar). The periatricular bone show disuse atrophy in the form of osteoporosis.
Whare are the clinical features of rheumatoid arthritis?
Nonspecific: low-grade fever, fatigue, loss of appetite, anemia
Rheumatoid subcutanous nodules
What are the main causes of infectious arthritis?
Most common = Lyme
pyogenic = staph or strep (rare)
What is gout?
Group of diseases characterized by hyperuricemia and the deposition of uric acid crystals in the joints, subcutaneous tissues, and kidneys.
Hyperuricemia (>7mg/dL) is a prerequisite, but only 5% of these patients develop gout.
How common is gout in men and women?
95% are male, many have family history
Compare primary and secondary gout.
Primary gout: metabolic or renal
Secondary gout: hematopoietic malignant disease, chronic hemolysis, obestiy, alcoholism, kidney disease, drugs (diuretics), lead poisoning
How does hyperuricemia lead to podagra.
Most uric acid crystals form deposit as insoluble monosodium urate . . . esp in the joints and periarticular connective tissue.
Tarsometatarsal joint of the big toe in 90%: podagra "foot seizure"
Likely because the feet are colder and reduces uric acid solubility >> crystalization inside joint. Activates complement and recruits leukocytes. Because the crystals are sharp, they pierce the lysosomes and release acid hydrolases.
Compare the clinical features of acute and chronic gout.
Acute = joint is swollen, hyperemic, warm, excruciating pain
Chronic = less inflammation, but more bone deformities
What are tophi?
Painless subcutaneous deposits of uric acid.
Most commonly on the ears, extensor sites of the arms, over the olcranon, and patella.
Encapsulated, birefringent urate crystals, surrounded by macrophages, lymphocytes, and giant cells.
What kind of urinary stones are found in persons who have gout?
Uric acid stones
Also predisposes to the formation of calcium stones.