Rheumatoid arthritis (RA) is a chronic, predominantly inflammatory synovitis systemic disease of unknown etiology. It is characterized by polyarticular, symmetric, aggressive joint inflammation of the small joints of the hands and feet, often associated with extra-articular organ involvement and positive serum rheumatoid factor, which can lead to joint deformity and loss of function.
I. Etiology
The pathology of RA arthritis is mainly composed of synovial lining cell proliferation, massive interstitial inflammatory cell infiltration, as well as microvascular neovascularization, formation of vascular opacities and destruction of cartilage and bone tissue.
Clinical manifestations
1.Population
The incidence is 2 to 3 times higher in women than in men. It can occur at any age, with a high incidence at the age of 40-60.
2.Signs and symptoms
It may be accompanied by general symptoms such as weight loss, low fever and fatigue.
(1) Morning stiffness is a subjective feeling of inflexible joint movement when waking up in the morning, which is a non-specific manifestation of joint inflammation, and its duration is proportional to the severity of inflammation.
(2) Manifestations of joint involvement
(1) Polyarticular involvement is symmetric polyarthritis (often ≥5 joints). The easily involved joints are hand, foot, wrist, ankle and temporomandibular joints, etc. Other joints may include elbow, shoulder, cervical spine, hip and knee joints.
The deformities of the hand include pike swelling, ulnar deviation, swan neck-like deformity, and buttonhole flower-like deformity. Foot deformities include supination deformity caused by metatarsal head downward subluxation, valgus deformity, metatarsophalangeal joint subluxation, curved hammer toe and foot valgus deformity.
Other deformities include carpal tunnel and tarsal tunnel syndrome caused by compression of the median nerve/posterior tibial nerve, knee cavity effusion into the posterior aspect of the joint to form N-fossa cyst (Baker cyst), cervical spine involvement (2nd and 3rd cervical vertebrae are common) with neck pain, neck weakness and difficulty in maintaining its normal position, and atlantoaxial joint subluxation with corresponding spinal cord compression and insufficient blood supply to the basilar artery.
(3) Extra-articular manifestations
(1) General manifestations may include fever, rheumatoid nodules (rheumatoid granulomas, associated with high titers of RF, severe joint destruction and RA activity, most often found in the elbow, joint eminence, sacrum and other joint prominence and often under pressure), rheumatoid vasculitis (necrotizing small arteritis, mainly involving small arteries, may be manifested as finger and toe end necrosis, skin ulcers, peripheral neuropathy, etc.) and lymph node enlargement.
Cardiac involvement may include pericarditis, pericardial effusion, epicardial, myocardial and valvular nodules, myocarditis, coronary arteritis, aortitis, conduction disorders, chronic endocarditis and valvular fibrosis.
③ Respiratory system involvement may include pleurisy, pleural effusion, pulmonary arteritis, interstitial lung disease, nodular lung disease, etc.
④Renal manifestations mainly include primary glomerular and tubulointerstitial nephritis, renal amyloidosis and renal damage secondary to drug therapy (gold agents, penicillamine and NSAIDs).
⑤ In addition to symptoms of peripheral nerve compression, neurological disease, myelopathy, peripheral neuropathy, ischemic neuropathy secondary to vasculitis, muscle hypertrophy, and drug-induced neuropathy may be induced in the nervous system.
(6) Anemia is the most common extra-articular manifestation of RA and is chronic disease anemia, often mild to moderate.
(7) Digestive system can be due to RA vasculitis, complications or drug therapy.
(viii) The eyes may have uveitis in young patients and sclerositis in adults, which may be caused by vasculitis. There may also be dry conjunctival keratitis, scleral softening, scleral softening perforation, and corneal lysis.
(4) Felty syndrome 1% of RA patients may have splenomegaly, neutropenia (and thrombocytopenia, decreased red blood cell count), often severe arthropathy, high titers of RF and positive ANA, which is a severe type of RA.
(5) Relieving seronegative, symmetric synovitis with sunken edema syndrome (RS3PE) is more common in men, often after 55 years of age, with acute onset, symmetric inflammation of the wrist, flexor tendon sheaths and small joints of the hand, and sunken edema may be present on the back of the hand. Morning stiffness is prolonged (0.5 to 1 day), but RF is negative and X-rays are mostly without bone destruction. Fifty-six percent of patients are HLA-B7 positive. Treatment is poorly responsive to NSAIDs alone, while low-dose glucocorticoids are highly effective. Spontaneous remission often occurs after 1 year and the prognosis is good.
(6) Adult Still disease (AOSD) is a rare type of RA that alternates acute attacks and remissions with hyperthermia, arthritis, and rash. It is named because the clinical manifestations resemble juvenile rheumatoid arthritis (Still’s disease) with generalized onset. Some patients develop typical RA after several episodes.
(7) The onset of RA in the elderly is often >65 years of age, with small gender differences, mostly with acute onset and rapid development (some have OA as the initial manifestation, with typical RA manifestations appearing a few years later). It is often characterized by hand and foot edema, carpal tunnel and tarsal tunnel syndrome and polymyalgia, with significant morning stiffness. 60%-70% of RF is positive, but the titer is mostly low. Patients often die due to comorbidities such as cardiovascular, infection and impaired renal function. NSAIDs should be selected with caution, and small doses of hormones can be applied, which respond better to slow-acting antirheumatic drugs (SAARD).