PATHO CH52 - Rhemumatic Disorders

most common disabling musculoskeletal disorder in the US

arthritis

almost 2/3 of adults in the US w/ arthritis are

• of working age

• 18-64 years old

local disorders of joint function

• osteoarthritis (know for test)

• infectious arthritis

• lyme disease

systemic disorders of joint function

• immune-mediated (know for test)

• post infectious

joint dysfunction secondary to other diseases

• psoriatic

• gout (know for test)

most common arthritis in the world

osteoarthritis

osteoarthritis

• progressive disease of DIARTHROIDAL JOINTS

• local degenerative joint disorder (DJD) associated w/

  • aging ( > 70 y/o)

  • wear & tear from repetitive stress

osteoarthritis is characterized by

• LOSS OF ARTICULAR CARTILAGE

• cartilage calcifies

• wear of underlying bone

• formation of bone spurs (osteophytes)

• noninflammatory

• weight-bearing joints

reason that osteoarthritis is noninfammatory

no immune system involvement; only mechanical damage

[osteoarthritis] factors that increase the likelihood of abnormal “wear & tear” on joins

• obesity

• joint trauma

• congenital disorders

  • genu valgus/varus

  • hip dysplasia

etiology of osteoarthritis

• lifestyle & occupation

  • abnormal stress to joins

• genetic predispositions

• hormonal status

  • postmenopausal

pathogenesis of osteoarthritis via initial injury causes

• chondrocytes to release enzymes that breakdown matrix of proteoglycan & collagen

  • proteolytic

  • collagenolytic

• collagen fatigue & microfractures

pathogenesis of osteoarthritis via progressive injury causes

• structural breakdown of cartilage

• osteophyte/spur formation

• joint effusion

• inflammation of synovial membrane = joint distention

clinical manifestations of osteoarthritis

localized

• joint pain w/ function; relieved by rest but not at night

• crepitus (creaking) w/ movement

• bony enlargement

• morning stiffness

• hand deformity

morning stiffness in osteoarthritis

• lasts < 30 minutes

• improves w/ joint mobility

hand deformities related to osteoarthritis

• Heberden (DIP joint involvement) = top joint in finger

• Bouchard nodes (PIP joint involvement) = middle joint in finger

PIP

proximal interphalangeal (top joint in finger)

DIP

distal interphalangeal (middle joint in finger)

MCP

metacarpophalangeal

radiologic changes in osteoarthritis

• bony proliferation at the joint margins (bony spurs/osteophytes)

• ASYMMETRIC narrowing of joint space

• subchondral bone sclerosis

• malalignment of joints

• cyst formation

mnemonic for radiologi changes in osteoarthritis

LOSS

• Loss of joint pain

• Osteophytes

• Subchondral cysts

• Subchondral sclerosis

treatment for osteoarthritis is aimed at

decreasing stress on the joint & protecting from additional trauma

treatment for osteoarthritis

• acetaminophen (reduces pain)

• nonsteroidal anti-inflammatory (NSAID) drug therapy

• intraarticular injection of hyaluronan (joint lubrication)

• physical therapy

• surgery

most common cause for total hip & knee replacement

osteoarthritis (OA)

rheumatoid arthritis

systemic autoimmune inflammatory disease that involves synovial membranes, cartilage, joint capsule, & surrounding ligaments & tendons

characteristics of rheumatoid arthritis

• greater in women

• premenopausal age (40-50 y/o)

• cause unknown

• all races

• caused by abnormal autoimmune response

rheumatoid arthritis is triggered by

bacterial or viral antigen in GENETICALLY susceptible individuals

• HLA-DR4 in whites

• HLA-DRB1

factors that increase the risk of rheumatoid arthritis

• smoking

• women who have never given birth

pathogenesis of rheumatoid arthritis (3 phases)

• initial phase

• inflammatory phase

• destruction phase

initial phase of rheumatoid arthritis

• immune response localizes in synovial tissue

• activation of B cells, T cells, macrophages

• B cells produce auto-antibodies

  • anti-IgG antibody (RF factor)

  • anti-Cyclic polypeptid antibodies antibodies (anti-CCP)

inflammatory phase of rheumatoid arthritis

• immune cells activate the complement

• cytokines & other immune mediators produced

• STIMULATE & SPREAD INFLAMMATION IN THE JOINT

destruction phase of rheumatoid arthritis

• escalating inflammatory response leads to PANNUS FORMATION

• erode & destroy articular cartilage; results in

  • inflammation

  • subluxations (partial separation/displacement)

  • contractures (tightening of tissue around joint)

  • & deformities

pannus formation

vascularized tissue made up of lymphocytes, macrophages, histiocytes, fibroblasts, & mast cells

clinical manifestations of rheumatoid arthritis

• BILATERAL SYMMETRIC polyarthritis involving smaller joints

• malaise, fatigue

• diffuse musculoskeletal pai

• hands, wrists, knees, & feet are most commonly involved

• swelling in hands (nodule)

• joint deformity

• abnormalities in gait & limitation of movement (hip involvement)

joint deformities in rheumatoid arthritis

• ONLY MCP & PIP joint involvement

• swan-neck deformity

• boutonniere deformity

• ulnar deviation

swan-neck joint deformity in rheumatoid arthritis

• hyperextension of PIP

• flexion of MCP & DIP due to contraction of muscle & tendon

boutonniere joint deformity

• flexion of PIP

• hyperextension of DIP due to excess laxity of extensor tendon

• ex: top joint in finger makes u shape

clinical manifestations of rheumatoid arthritis

• pericarditis

• myocarditis

• mitral valve disease

• complete heart block

• pulmonary manifestations

• ophthalmic manifestations

pulmonary manifestations of rheumatoid arthritis

• pleuritis

• pulmonary effusion

ophthalmic manifestations of rheumatoid arthritis

• scletitis

• 2˚ sjogren syndrome (dry eyes & mouth)

diagnosis of rheumatoid arthritis

• at least one documented swollen joint

• absence of alternative diagnosis that better explains the joint swelling

• a total score on the criteria scale of ≥ 6

treatment goal for rheumatoid arthritis

• alleviation of pain & swelling

• prevention of structural damage

• preservation of function

treatment for rheumatoid arthritis

• anti-inflammatory medication

  • corticosteroids

• disease-modifying antirheumatic drugs

  • biological agents – achieve long term control; recommended very early to minimize later damage

joint dysfunction secondary to other diseases

• neurovascular, hematologic, & metabolic disorders associated disorders of joint function

• most related to chronic diseases

gout

• heterogenous disorder in which there is a disturbance of uric acid metabolism

• deposition of uric acid crystals in joints

• risk increases w/ age

characteristics of gout

• hyperuricemia

• urate crystal = induced arthritis

• recurrent attacks of articular & periarticular inflammation

• accumulation of tophi (urate crystal stones)

• renal impairment / uric acid calculi

gouty arthritis is most common in

• middle aged men

• postmenopausal women

a diet involving food rich in purines can lead to

gout

clinical manifestations of gout

• hyperuricemia

• elevated serum urate levels

four phases of gout

• asymptomatic hyperuricemia

• acute gouty arthritis

• intercritical goat

• chronic tophaceous gout

acute gouty arthrits

• weight bearing joints most commonly affected

• warm, red, & tender joints

• great toe

• intitial attacks can last 1-14 days

• later attacks become more frequent

intercritical gout

• intervals between acute attacks

• no symptoms

chronic tophaceous gout

• advanced deforming gout

• tophi develops

• tophi appear 10yrs after initial onset of gout

• tophi appear in synovium, bone, & tendons

• can develop renal malfunction

diagnosis of gout

• joint fluid test

• blood test (uric acid / creatinine)

• xray imaging to rule out other causes of joint inflammation

• ultrasound to detect urate crystals in joint or tophus

treatment of gout

• for acute gouty attack

  • colchicine

  • NSAIDs

  • corticosteroids

• uricosuric agents / probenecid (increase uric acid secretion by kidneys)

• block uric acid production / allopurinol