Rheumatoid Arthritis
It is one of the common multisystemic inflammatory disease. The characteristic feature of RA is persistent synovitis of diarthrodial joints " synovial joints". It is deforming, usually symmetrical polyarthritis affecting small & large joints, causing structural damage of cartilage, bone & ligaments with subsequent changes in the joints, with extra articular systemic manifestations affecting variety of organs, with intermittent exacerbation and remission, with high variable in severity.
Epidemiology: RA has a world wide distribution and affect all ethenic groups, the disease can occur at any age but its prevalence increase with age, the peak incidence is between 4th and 5th decades. The prevalence is approximately 3 times higher in women than in men. The sex differences diminishes in older ages.
Aetiology: No single factors has been identified to date. RA can be considered as a disease of an aberrant immune response in genetically predisposed host that leads to chronic progressive synovial inflammation & destruction of involved joint.
The support for a genetic predisposition for RA has come from:
1/ The frequency of the disease is increased in first-degree relatives of patients with RA.
2/ Studies in monozygotic twins has shown a concordance rate of about (15%) than in dizygotic twins (3%).
3/ The main genetic susceptibility is due to genes in HLA region. HLA-DR4 is the major susceptibility haplotype in most ethenic group (for ex: occurring in Caucasian patients with RA in 50%-75% comparing to 20-25% of normal population), also DR4 usually associated with severe erosive disease.
Non genetic risk factors:
· Female gender is also considered as a risk factor for disease susceptibility .
· Bacterial products as peptidoglycan can be present in RA joint in the absence of active infection.
Studies showed patients with RA have increase EBV load and their synovium can express viral RNA.
In general infectious theory is not due direct bacterial or viral active infectious process and no infectious agents have been consistently isolated and there is no evidence of disease clustering, but may participate indirectly to arthritis in genetically susceptible individual by stimulating their innate immune system.
· Studies shows clear association of RA development with cigarette smoking. Smoking may enhance the risk of developing anti-ccp Ab and other Abs like RF.
Pathology:
RA is characterized by persistent cellular activation, auto immunity and the presence of the immune complexes at sites of articular and extra articular lesions leading to chronic inflammation, granuloma formation and joint destruction.
* Earliest changes are swelling and congestion of synovial membrane and underling connective tissue.
* Cellular infiltration with lymphocytes (mainly CD4 T-cells) , plasma cells & macrophages.
* Effusion of synovial fluid into joint cavity, during active phases of the disease.
* Hypertrophy of synovial membrane.
* Inflammatory granulomatous tissue (panus) spread over and under articular cartilage, it actively erodes and destroys the periarticular bone and cartilages.
* Later fibrous or even bony ankylosis may occur.
* Muscles adjacent to inflamed joint get atrophy and may be focally infiltrated by lymphocyte.
* Rheumatoid nodules, which consist of central area of fibrinoid material, surrounded by proliferating mononuclear cells. It occur subcutenously, at extensor surfaces, friction site, also similar lesion occur in pleura, lung,
pericardium and sclera.
* Rheumatoid factor is synthesized by plasma cells in synoviam and lymph nodes.
* Tenosynovitis is present in majority of patients, less frequently the formation of characteristic nodules with central necrosis.
Clinical Manifestations:
Pattern of presentation: ( incidious ) presentation is more common begins with fatigue, anorexia, generalized weakness, till gradual synovitis becomes apparent in symmetrical fashion. The incidious onset is traditionally considered as poor prognosis, this may due to delay in diagnosis and treatment.
The onset may be (acute), with rapid development of poly-arthritis "over a few days, or explosively over night” often accompanied by constitutional symptoms as fever, florid morning stiffness, pitting edema, occur more commonly in elderly.
In some elderly patient presented as (polymyalgic) pain, with marked morning proximal muscle stiffness, synovitis can appear several months, after steroid withdrawal.
Occasionally the onset is (palindromic), with recurrent acute onset of mono or symmetrical polyarthritis lasting only few hours or days, in some cases (up to 50%) of this palindromic presentation, the interval b/t attacks decreases, till no more resolution of an attack, evolving into RA.
In some patients symptoms may be confined to (mono, oligo) articular, the arthritis may remain asymmetrical, anyhow the symmetrical pattern is typical one in RA.
Whatever the mode of presentation, the clinical hall mark is persistent synovitis, involvement of other synovial structure (teno synovium, bursae) is common, while entheses involvement (enthesitis) is not a target.
Constitutional features
The majority of patients will experience constitutional symptoms such as weakness, fatigue, anorexia and wt. loss. Although high fever may occur, but temperature more than 38 c? is unusual and should rise the possibility of inter current problem such as sepsis.
Articular manifestations:
Pain, swelling, and tenderness of affected joint.
RA can affect any of the synovial joints. Most commonly, the disease start in the wrist, MCP, PIP, interphalangeal joint of the thumb and MTP joints followed by the knees, elbows, hips and shoulders. Of particular importance, RA usually spares the distal interphalangeal joints. RA may involve the tempromandibular joints, cricoarytenoid and sternoclavicular joints, but less commonly and usually in more advanced cases. RA may involve the upper part of the cervical spine, particularly the C1-C2 articulation, but , unlike the spondyloarthropathies rarely, if not, involves thoraco lumbar spine.
Pain is aggravated by initiation of movement is the most common manifestation of established RA , pain originate from capsule, which is very sensitive to distention and stretching.
Morning stiffness, is an almost universal feature of synovial inflammation, in RA and other systemic inflammatory rheumatic disorders. In contrast to brief (usually several minutes) period of gelling seen in osteoarthritis, morning stiffness in RA is prolonged, usually lasting more than two hours. The duration tends to correlate with the degree of synovial inflammation and diminishes or disappears when a remission occur. For this reason , the presence and length of morning stiffness is useful in following the disease course and should be reported in the patient s data base.
Joint swelling results from accumulation of synovial fluid, hypertrophy of synovium and thickening of joint capsule.
Joint motion:. Initially, motion is limited by pain. The joint usually is held in flexion to maximize joint volume and minimize distention of capsule.
Then persistent synovitis causes cartilage damage and bone erosions and subsequent changes in joint integrity and motion is the hall mark of the disease.
Later, the motion, is limited by fibrous or bony ankylosis, or soft tissue contracture leading to fixed deformities "structural damage".
Specific Joints:
Hand joint: The degree in which hand is involved and subsequent impairment of function , usually reflect the disease activity.
Symmetrical synovitis usually involve proximal interphalangeal (fusiform appearance) and metacarpophalangeal joints. The distal interphalangeal joints are usually spared.
Synovitis of the wrist usually uniform feature of RA, may lead to limitation of movement. Dorsal subluxation of ulnar styloid is common and may contribute to rupture of the 4th and 5th extensor tendon. Median nerve entrapment can be occur.
Radial deviation at the wrist. Ulnar deviation of MCP joints.
Swan neck deformity (hyperflexion of DIP joint and hyperextension of PIP joint).
Boutonniere deformity (hyperextension of DIP joint and hyperflexion of PIP joint).
(Z) deformity of the thumb.
Triggering of finger may occur due to nodules formation in flexor tendon sheath.
The Knee Joint: is commonly involved with synovial hypertrophy, chronic effusion , ligmentous laxity. Pain and swelling behind the knee may be caused by posterior herniation of the capsule creating a popliteal (Baker s) cyst, the synovial fluid is communicating with cyst but being prevented from returning to the joint by a valve – like mechanism. Dissection or rupture of the cyst into the calf, often can occur by knee flexion in the presence of large effusion, causing pain and swelling in calf and pitting edema producing picture similar to DVT , however the {A} characteristic pre-existing history of joint problem. {B} Doppler ultrasound study are required to establish the diagnosis, since DVT and Baker s cyst can coexist and it is essential to aware of this differential diagnosis, because anticoagulation of the ruptured cyst cause more leg swelling which might lead to compartment syndrome.
Cervical spine: Axial involvement is usually limited to the upper cervical spine. Atlanto-axial subluxation can occur in long standing RA, due to destruction of the transverse ligament (C1) around the posterior aspect of the odontoid peg (C2). On neck flexion this can lead to the movement of the odontoid posteriorly causing indentation of spinal cord, so if this instability unrecognized, it may lead to cord compression or even sudden death following minor trauma or manipulation. So atlanto-axial subluxation should be suspected in patient who, describes occipital headache, parasthesia, electrical shock in the arms or it could be incidious therefore the sensory and upper motor signs are important signs to be checked.
Foot: Arthritis in the forefoot, ankles, and subtalar joint produce severe pain with ambulation as well as number of deformities, including eversion at the hind foot. Rupture of posterior tibialis tendon, result in drop arch "pes planus".
Planter subluxation of MT heads, causing pain on walking, with development of bursae, callosities, widening of the forefoot, hallux valgus, and lateral deviation and dorsal subluxation of the toes [ cock-up toe deformity ].
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .