Download - RHEUMATOID ARTHRITIS. Chronic multisystem disease of unknown cause Characteristic features: Persistent inflammatory synovitis Involves peripheral joints

RHEUMATOID ARTHRITIS

Chronic multisystem disease of unknown cause

Characteristic features:Persistent inflammatory synovitisInvolves peripheral jointsSymmetric distribution

Hallmark of the disease:Synovial inflammation causes cartilage damage and bone erosions and subsequent changes in bone integrity

Source: Harrison’s Principles of Internal Medicine, 17th edition

PATHOLOGY AND PATHOGENESIS

Earliest lesions in rheumatoid synovitis:

- Microvascular injury- Increase in the # of synovial lining cells

o Seen along with perivascular infiltration w/ mononuclear cells



Characteristic constellation of features (light microscopy):

- Hyperplasia and hypertrophy of synovial lining cells- Focal or segmental vascular changesoMicrovascular injuryoThrombosisoNeovascularisation

- Edema - Infiltration w/ mononuclear cells



Source: http://www.bio.davidson.edu/Courses/Immunology/Students/Spring2003/Super/jointandcells.gif



Collagenase and cathepsins- Degrade components of the articular matrix

Osteoclasts - Prominent at sites of bone erosion

DIAGNOSIS OF RA


1. Morning stiffness: stiffness in and around the joints lasting 1 hr before maximal improvement

DIAGNOSIS OF RA


2. Arthritis of 3 or more joint areas: At least three joint areas have soft tissue swelling or joint effusions, not just bony overgrowth. The 14 possible joint areas involved are right or left PIP, MCP, wrist, elbow, knee, ankle, and MTP joints.

DIAGNOSIS OF RA


3. Arthritis of hand joints: Arthritis of wrist, MCP joint,or PIP joint

DIAGNOSIS OF RA


4. Symmetric arthritis: Simultaneous involvement of the same joint areas on both sides of the body.

DIAGNOSIS OF RA


5. Rheumatoid nodules: Subcutaneous nodules over bony prominences, extensor surfaces, or juxtaarticular regions.

DIAGNOSIS OF RA


6. Serum rheumatoid factor: Demonstration of abnormal amounts of serum rheumatoid factor by any method for which the result has been positive in less than 5% of normal control subjects.

7. Radiographic changes: Typical changes of RA on posteroanterior hand and wrist radiographs that must include erosions or unequivocal bony decalcification localized in or most marked adjacent to the involved joints.

STAGES OF RHEUMATOID ARTHRITIS

Source: http://nihseniorhealth.gov/rheumatoidarthritis/faq/faq1c_popup.html

STAGE I: - Represents synovitis - Synovial membrane becomes hyperemic and edematous

with foci of infiltrating small lymphocytes - Joint effusions w/ high cell count (5,000 to 60,000 per mm3) - X-rays will not yet show destructive changes, but soft tissue

swelling or osteoporosis may be seen

STAGE II: - Inflamed synovial tissue now proliferates & begins to grow

into joint cavity across articular cartilage, which it gradually destroys

- Narrowing of joint due to loss of articular cartilage


Source: Wheeless' Textbook of Orthopaedics from http://www.wheelessonline.com/ortho/stages_of_rheumatoid_arthritis

STAGE III: - Pannus of synovium - Eroded articular cartilage & exposed sub-chondral bone - X-rays will show extensive cartilage loss, erosions around the margins of joint, and deformities may have become apparent

STAGE IV: - End stage disease - Inflammatory process is subsiding - Fibrous or bony ankylosing of joint will end its functional life - Subcutaneous nodules associated w/ severe disease


Source: Wheeless' Textbook of Orthopaedics from http://www.wheelessonline.com/ortho/stages_of_rheumatoid_arthritis

Class I Completely able to perform usual activities of daily living (self-care,

vocational, and avocational)

Class II Able to perform usual self-care and vocational activities, but limited in

avocational activities

Class III Able to perform usual self-care activities, but limited in vocational and


Class IV Limited in ability to perform usual self-care, vocational, and


CLASSIFICATION OF GLOBAL FUNCTIONAL STATUS IN RHEUMATOID ARTHRITIS

Source: American College of Rheumatology from http://www.rheumatology.org/publications/classification/ra/raclass.asp

EXTRAARTICULAR COMPLICATIONS OF RA


Occur in those with high titers of autoantibodies to the fc component of immunoglobulin G or with antibodies to CCP

Rheumatoid nodules

- Found on periarticular structures, extensor surfaces, or other areas subjected to mechanical pressure- Common locations: olecranon bursa, proximal ulna, achilles tendon, and occiput- Has a central zone of necrotic material including collagen fibrils, noncollagenous filaments and cellular debris



Clinical weakness and skeletal muscle atrophy

-May be evident within weeks of onset of RA- Most apparent in musculature approximating affected joint Type II fiber atrophy and muscle fiber necrosis with or without mononuclear cell infiltrate

Cutaneous vasculitis

- Crops of small brown spots in the nail beds, nail folds, and digital pulp



Pleuropulmonary manifestations

- More common in men- Found during autopsy (symptomatic disease during lifetime is infrequent)- Include: pleural disease, interstitial fibrosis, pleuropulmonary nodules, pneumonitis, arteritis

Pericarditis

- Pericardial fluid has a low glucose level and is frequently associated with the occurrence of pleural effusion- Increased incidence of congestive heart failure and death from CV disease



Neurologic manifestations

-RA tends to spare the CNS directly, although vasculitis can cause peripheral neuropathy

- May result from atlantoaxial or midcervical spine subluxation

- Nerve entrapment secondary to proliferative synovitis or joint deformities may produce neuropathies of median, ulnar, radial (interosseous branch) or anterior tibial nerves



Eye manifestations

- EpiscleritisUsually mild and transient

- Scleritis Involves deeper layers of the eye Histologically, the lesion is similar to a rheumatoid nodule and may result in thinning and perforation of the globe (scleromalacia perforans)



Felty’s syndrome

- Consists of:- Chronic RA- Splenomegaly- Neutropenia- Anemia

- Patients have high titers of rheumatoid factor, subcutaneous nodules, and other manifestations of systemic rheumatoid disease

- May develop after joint inflammation has regressed



Osteoporosis

- May be aggravated by glucocorticoid therapymay cause significant loss of bone mass, especially early in the course of therapy

-Osteopenia in RA involves both juxtaarticular bone and long bones distant from involved joints

- Modest decrease in mean bone mass and moderate increase in the risk of fracture

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