pathology of joints part 1

<<Rheumatoid Arthritis<<

• A chronic systemic inflammatory disorder.
• It can affect numerous tissues and organs, but it primarily affects the joints, causing a non-suppurative proliferative and inflammatory synovitis that frequently proceeds to articular cartilage degradation and joint ankylosis.

<<INCIDENCE<<

•Involves about 1% of the population

•Females are 3-5 times more affected than males

•Less common in African and Asian individuals but tends to be more aggressive.

•Majority of patients affected are 40-70 years old.

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==Genetic susceptibility==
• HLA-DRB 1 alleles

==Environmental arthritogen(==Causing or caused by arthritis)

• Microbial agents (i.e viral infections) have been implicated

• Citrullinated proteins (CCP)

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<<Cause and pathogenesis<<

==Autoimmunity== • There is evidence for both abnormal humoral and cell-mediated immunity.

• These antibodies (usually IgM), which react with the Fc components of the IgG, can be detected in the blood as rheumatoid factor
• Approximately 25 % of patients have antinuclear antibodies.

\n CLINICAL FEATURES

Swollen, tender and warm joints Symmetrical involvement ‘Morning stiffness’ is a common complaint .Any joint may be affected, mostly Small hand joints Feet joints Wrists, elbows and ankles are often involved. Insidious onset, chronic disease

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==Typical findings:==

•chronic inflammation of the synovium

•exudation of cells, fluid, and fibrin (rice bodies) into the articular cavity

•erosion of cartilage

•juxta-articular osteoporosis

•bony ankylosis

•deformities of the joints

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==Extra-articular manifestations:==

•subcutaneous rheumatoid nodules

•lymphadenopathy

•Splenomegaly and neutropaenia (Felty’s syndrome)

•anaemia

•dry mouth and dry eyes

•pneumonitis with interstitial fibrosis and nodules

•pericarditis

•uveitis and scleritis

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^^morphology^^

symmetric athritis

• Synovium-oedematous, thickened, hyperplastic

-Main histologic features:

==•synovial cell hyperplasia and proliferation==

==•dense inflammatory infiltrate==

==•increased vascularity due to angiogenesis==

==•fibrinopurulent exudate on synovial and joint surfaces==

==•osteoclastic activity in underlying bone==

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^^Pannus^^ is A mass of oedematous synovium, inflammatory cells, granulation tissue that grows over the articular surface and causes its erosion

^^Fibrosing ankylosis^^ is When cartilage has been destroyed and the pannus bridges the apposing bones

^^Bony ankylosis^^ is Fusion of bones

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h ![Early rheumatoid dâease. A byer of chronic inflammatory tisue (’pannus', arrowed) has eroded the a1!cuIar„ surface of the ferroral condyb.

](https://knowt-user-attachments.s3.amazonaws.com/a2753612460a4694a2b29c712380a766.jpeg)

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^^Rheumatoid Nodules^^
• Develop in about 30% of patients with RA
• Not diagnostic of RA

Gross morphology
Firm, non-tender, round to oval
• Located on ulnar surface of the forearm, elbow, lumbosacral area
• Arise in subcutaneous tissue
• Less commonly may be found in the lungs, spleen, pericardium,
myocardium, heart valves and aorta

^^Histopathology^^
• central area of fibrinoid necrosis
• surrounding rim of macrophages, lymphocytes and plasma cells

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^^MORPHOLOGY^^

Blood vessels

• Acute necrotising vasculitis (small and large arteries)

• Can involve pleura, pericardium, lung

• Obliterans endarteritis can occur obstructing digital arteries causing peripheral neuropathy.,ulcers, gangrene

• Leukocytoclastic vasculitis -produces purpura, cutaneous ulcers, nail bed infarction

• Ocular changes:uveitis, keratoconjuctivitis may be prominent.

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^^RADIOLOGICAL FEATURES^^

• Osteopaenia

• Prominent radial deviation of the wrist

• Radial deviation of the fingers

• Flexion-hyperextension abnormalities of the fingers ( swan neck, botonniere)

• Marked loss of the joint spaces

• Erosions of the metacarpal and carpal bones

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^^LABORATORY INVESTIGATIONS^^
• Rheumatoid factor
• Anti-CCP antibody
• Normocytic normochromic anaemia
• Raised ESR and CRP
• Auto-antibodies such as ANF may be present

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^^Rheumatoid factor^^
• Found in only 75 % of patients with RA.
• May be present in the serum of patients who do not
have RA but who do have :
• Systemic Lupus Erythematosus
• Sjogren syndrome
• infectious mononucleosis
• viral hepatitis

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^^Juvenile Idiopathic Arthritis^^

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• Variant of RA

• Begins before the age of 16 years

• There are several forms which correspond toseparate diseases and different backgrounds

• Long term prognosis is variable and 10 % of patients develop a serious functional disability

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^^Several forms^^
• systemic arthritis
• oligoarthritis
• rheumatoid factor-positive polyarthritis
• rheumatoid factor-negative polyarthritis
• rheumatoid factor polyarthritis
• enthesitis
• psoariatic arthritis
• undifferentiated arthritis

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^^Differences between JIA and adult RA^^

• Systemic disease is more frequent

• Large joints are affected more often than small joints

• Rheumatoid nodules and rheumatoid factor are usually absent

• Anti-nuclear antibody (ANA) seropositivity is common

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^^Juvenile^^
Stills disease / systemic arthritis

• Variant of JIA

• Abrupt onset

• Features include :

-high spiking fevers

-migratory and transient skin rash

-hepatomegaly

-serositis

• Associated with recurrent flares or persistent disease with significant morbidity