Psoriatic arthritis (PsA) is an inflammatory arthropathy associated with psoriasis that has a psoriatic rash and causes pain, swelling, tenderness, stiffness, and impaired motion in the joints and surrounding soft tissues, and some patients may have sacroiliac arthritis and/or spondylitis. About 75% of patients with PsA have a rash that appears before arthritis, about 15% have it at the same time, and about 10% have it after arthritis. The disease can occur at any age, with a peak age of 30-50 years, with no gender differences, but spinal involvement is more common in men. In the United States, the prevalence of PsA is 0.1%, and arthritis occurs in about 5-7% of patients with psoriasis. Initially, the prevalence of PsA in China is about 1.23‰.
Clinical manifestations
The disease starts insidiously, and about 1/3 of them have acute attacks, and there is often no cause before the onset of the disease.
1, joint manifestations: joint symptoms are diverse, in addition to peripheral joint lesions of the extremities, some can involve the spine. Pain, pressure, swelling, morning stiffness and dysfunction of the affected joints are divided into five types according to clinical features, and 60% of the types can be transformed into each other and exist together.
(1) Monoarthritis or oligoarthritis: 70% of the joints involved are mainly the distal or proximal interphalangeal joints of the hands and feet, while the knee, ankle, hip and wrist joints can also be involved, with asymmetric distribution. Due to synovitis and tenosynovitis of the distal and proximal interphalangeal joints, the damaged fingers (toes) may appear as typical salami fingers (toes), often accompanied by finger (toe) nail lesions. Approximately 1/3-1/2 of patients with this type may evolve into a polyarthritic type.
(2) Distal interphalangeal joint type: 5-10% of patients have lesions involving the distal interphalangeal joints, typical of PsA, usually associated with psoriatic nail lesions.
(3) Destructive joint type: accounting for 5% of the cases, it is a serious type of PsA, with a predilection for age 20-30 years. The affected finger, metacarpal and metatarsal bones may have osteolysis, the knuckles may be telescopically overlapping, and the joints may be tonic and deformed. It is often associated with fever and sacroiliac arthritis, and severe skin lesions.
(4) Symmetrical polyarthritis: 15% of the cases are mainly in the proximal interphalangeal joints, but the distal interphalangeal joints and large joints such as wrist, elbow, knee and ankle joints may be involved.
(5) spondylosis type: about 5%, male, older, mainly spine and sacroiliac joint lesions, often unilateral, symptoms such as lower back pain or chest wall pain can be absent or very mild, spondylitis manifested as ligamentous bone formation, in severe cases can cause spinal fusion, sacroiliac joint blurring, joint space narrowing or even fusion, can affect the cervical spine leading to atlantoaxial and subaxial incomplete dislocation.
In recent years, some scholars have classified PsA into three types.
(i) mono- and oligoarthritic types resembling reactive arthritis with attachment point inflammation.
(ii) symmetric polyarthritic type similar to rheumatoid arthritis.
③ Spondylosis type similar to ankylosing spondylitis with predominantly mid-axis joint lesions (spondylitis, sacroiliac arthritis and hip arthritis), with or without peripheral joint lesions.
2.Skin manifestation: skin psoriasis is usually found on the scalp and the extremities, especially the elbows and knees, with scattered or generalized distribution, paying special attention to the lesions in hidden areas such as hair, perineum, buttocks, umbilicus, etc.; the lesions appear as papules or plaques, garden-shaped or irregular-shaped, with abundant silvery-white scales on the surface, shiny film after removing the scales, and dotted bleeding (Auspitz sign) after removing the film. The features have diagnostic significance for psoriasis. The presence of psoriasis is an important distinction from other inflammatory arthropathies, and there is no direct relationship between the severity of skin lesions and the degree of joint inflammation, and only 35% of the two are related.
3, finger (toe) nail performance: about 80% of PsA patients have finger (toe) nail lesions, while 20% of psoriasis patients without arthritis have nail lesions, so finger (toe) nail lesions are a characteristic of PsA. The common manifestation is thimble-like depressions, and multiple depressions in the nails of the distal interphalangeal joints of inflammation are characteristic changes of PsA. Other changes include thickened and cloudy nail plate, darkened or white nail, uneven surface, transverse grooves and longitudinal ridges, often with subcutaneous nail hyperplasia, and in severe cases, nail peeling. Sometimes spatulate nail is formed.
4.Other manifestations.
(1) Systemic symptoms: a few have fever, weight loss and anemia, etc.
(2) Systemic damage: 7%-33% of patients have ocular lesions such as conjunctivitis, uveitis, iritis and dry keratitis; <4% of patients have aortic valve insufficiency, which is common in the late stage of the disease, as well as cardiac hypertrophy and conduction block; upper lung fibrosis is seen in the lungs; inflammatory bowel disease may be present in the gastrointestinal tract; amyloidosis is rare.
(3) Adhesion point inflammation: especially in the Achilles tendon and metatarsal tendon membrane attachment site. Heel pain is a manifestation of attachment point infection.
Diagnostic points
1.Symptoms and signs
(1) skin manifestations: skin psoriasis is an important diagnostic basis for PsA, skin lesions appear in arthritis latter diagnosis is difficult, meticulous medical history, family history of psoriasis, drop psoriasis in childhood, examination of hidden areas of psoriasis (such as scalp, umbilicus or perianal) and characteristic radiological manifestations can provide important clues, but other diseases should be excluded, and should be followed up regularly.
(2) Finger (toe) nail manifestations: thimble-like depressions (>20), nail detachment, discoloration, thickening, roughness, transverse ridges, and hyperkeratosis under the nail. Finger (toe) nail lesions are an important clinical manifestation of psoriasis that may develop into PsA.
(3) Joint manifestations: Involvement of one or more joints, mainly the finger joints, metatarsophalangeal joints and other small joints of the hands and feet, the distal interphalangeal joints are most easily involved, often asymmetrical, with joint stiffness, swelling, pressure pain and dysfunction.
(4) Spinal manifestations: spinal lesions may have symptoms such as low back pain and spinal ankylosis.
2.Auxiliary examination
(1) Laboratory tests: There are no specific laboratory tests for this disease. When the disease is active, blood sedimentation is accelerated, C-reactive protein is increased, IgA and IgE are increased, and complement levels are increased; synovial fluid shows non-specific reaction, and white blood cells are mildly increased, mainly neutrophils; rheumatoid factor is negative, and a few patients may have low titer rheumatoid factor and anti-nuclear antibody. HLAB27 is positive in about half of the patients and is significantly associated with sacroiliac joint and spine involvement.
(2) Imaging.
(1) Peripheral arthritis: there are signs of destruction and hyperplasia of peripheral joint bones. The distal end of the terminal phalanx has osteolysis and resorption while the base has osteophytes; the distal end of the middle phalanx may become pointed due to erosion and the distal phalanx has osteophytes, both of which cause a “pencil-in-cup”-like deformity; or a “telescope Both result in a “pencil-in-cup” deformity; or “telescope” deformity; narrowing, fusion, ankylosis and deformity of the affected interphalangeal joint space; and choroidal osteochondritis of the long bone stem.
(2) Mesial arthritis: manifests as asymmetric sacroiliac arthritis with blurring, narrowing, and fusion of the joint space. Narrowing and straightening of the vertebral space, asymmetric ligamentous osteoid formation, and paravertebral ossification, which is characterized by ligamentous ossification forming a bone bridge between the middle of adjacent vertebrae with asymmetric distribution.
3.Diagnosis basis.
Psoriasis patients with inflammatory arthritis manifestations can be diagnosed. Because some PsA patients with psoriatic lesions appear after arthritis, the diagnosis of such patients is more difficult. Clinical and radiological clues, such as family history of psoriasis, searching for psoriatic lesions in hidden areas, paying attention to affected joint sites and the presence of spondyloarthropathy, should be noted to make the diagnosis and exclude other diseases.
Differential diagnosis
1, rheumatoid arthritis: both have small arthritis, but PsA has psoriatic lesions and special nail lesions, finger (toe) inflammation, attachment point inflammation, often invading the distal interphalangeal joints, rheumatoid factor negative, special X performance such as pencil cap-like changes, some patients have spine and sacroiliac joint lesions, while rheumatoid arthritis is mostly symmetrical small arthritis, with proximal interphalangeal joints and metacarpophalangeal joints, wrist joint involvement is common The rheumatoid factor is positive, and X-rays are dominated by erosive joint changes.
2, ankylosing spondylitis: PsA invasion of the spine, the spine and sacroiliac joint lesions are asymmetrical, can be “jump” lesions, the onset is often in older men, the symptoms are mild, there are psoriatic lesions and nail changes. The age of onset of ankylosing spondylitis is younger, without skin and nail lesions, and the spine and sacroiliac joint lesions are often symmetrical.
3, osteoarthritis: both erode the distal interphalangeal joints, but osteoarthritis without psoriatic lesions and nail lesions, may have Heberden nodes, Bouchard nodes, without the typical X-ray changes of PsA, the age of onset is mostly older than 50 years.
Treatment options and principles]
PsA treatment aims at relieving pain and delaying joint destruction, and should take into account the treatment of arthritis and psoriatic lesions, and the treatment plan should vary from person to person.
1.General treatment: take proper rest, avoid overexertion and joint damage, pay attention to joint function exercise, avoid smoking, alcohol and stimulating food.
2.Medication: refer to the medicine for rheumatoid arthritis.
(1) non-steroidal anti-inflammatory drugs (NSAIDs): for mild to moderate active arthritis, with anti-inflammatory, analgesic, antipyretic and anti-swelling effects, but not effective for skin lesions and joint destruction. The therapeutic dose should be individualized; change to another NSAID only after 1-2 weeks of ineffective use of one NSAIDs in full dose; avoid two or more NSAIDs taken at the same time, because the efficacy does not superimpose, and the adverse effects increase; the elderly should choose NSAIDs with short half-life drugs, for patients with a history of ulcers, it is appropriate to take selective COX-2 inhibitors to reduce the adverse effects of the gastrointestinal tract. The adverse reactions of NSAIDs mainly include gastrointestinal reactions: nausea, vomiting, abdominal pain, abdominal distension, poor appetite, serious peptic ulcer, bleeding, perforation, etc.; renal adverse reactions: reduced renal perfusion, water and sodium retention, hyperkalemia, hematuria, proteinuria, interstitial nephritis, and renal necrosis leading to renal insufficiency in severe cases. NSAIDs can also cause peripheral blood cell reduction, coagulation disorders, aplastic anemia, hepatic impairment, allergic reactions (rash, asthma) and tinnitus, hearing loss, aseptic meningitis, etc. in a few patients.
(2) Slow-acting anti-rheumatic drugs (DMARDs): prevent the deterioration of the disease and delay the destruction of joint tissues. If a DMARDs alone is ineffective, it can also be combined with methotrexate as the basic drug of the combination therapy, such as methotrexate plus salbutamol.
Methotrexate (MTX): It is effective for both skin lesions and arthritis, and can be the drug of choice. It can be administered orally, intramuscularly or by sedation, starting at 10mg once a week, and gradually increasing the dose to 15-25mg once a week if there are no adverse reactions and symptoms worsen, and gradually decreasing the dose after the disease is controlled. Common adverse reactions include nausea, stomatitis, diarrhea, alopecia, rash and, in a few cases, bone marrow suppression, hearing impairment and interstitial lung changes. It can also cause miscarriage, malformation and affect fertility. Blood tests and liver function should be checked regularly during the drug administration.
②Sulfasalazine (SSZ): Effective for peripheral arthritis. The main adverse effects include nausea, anorexia, dyspepsia, abdominal pain, diarrhea, rash, asymptomatic aminotransferase and reversible spermopenia, occasionally leukocyte and plateletopenia, and hypersensitivity to Sulfanilamide is contraindicated in patients with allergy. Blood test and liver function should be checked regularly during the drug administration.
Auranofin: Effective for arthritis of the extremities, with an initial dose of 3mg/day, increasing to 6mg/day after 2 weeks. Common adverse reactions include diarrhea, pruritus, dermatitis, tongue inflammation and stomatitis, others include hepatic and renal injury, leukopenia, eosinophilia, thrombocytopenia and pancytopenia, aplastic anemia. Peripheral neuritis and encephalopathy may also occur. To avoid adverse reactions, blood and urine routine and liver and kidney functions should be checked regularly. Pregnant and lactating women should not use it.
D-penicillamine: 250-500mg/day, can be gradually reduced to maintenance 250mg/day after oral effect. Penicillamine adverse reactions are more, long-term high dose can appear renal damage (including proteinuria, hematuria, nephrotic syndrome) and bone marrow suppression, such as timely discontinuation of most of the drug can be recovered. Other adverse reactions include nausea, vomiting, anorexia, rash, oral ulcers, loss of smell, swollen lymph nodes, arthralgia, occasionally can cause autoimmune diseases, such as myasthenia gravis, polymyositis, systemic lupus erythematosus and aspergillosis. Blood, urine and liver and kidney functions should be checked regularly during treatment.
⑤ Azathioprine (AZA): It is also effective for skin lesions. The commonly used dose is 1-2mg/kg/day, usually 100mg/day, with a maintenance dose of 50mg/day. Adverse reactions include alopecia, rash, bone marrow suppression (including leukopenia, thrombocytopenia, anemia), gastrointestinal reactions including nausea, vomiting, may have liver damage, pancreatitis, some damage to sperm and eggs, appear teratogenic, long-term application of carcinogenic. Blood tests and liver function should be checked regularly during the drug administration.
(6) Cyclosporin (Cyclosporin, Cs): The U.S. FDA has passed its use in the treatment of severe psoriasis, effective for skin and joint psoriasis, the FDA believes that maintenance treatment within one year and more long-term use is prohibited for psoriasis. The usual dosage of 3-5 mg/kg/day maintenance is 2-3 mg/kg/day. the main adverse effects of Cs are hypertension, hepatic and renal toxicity, neurological damage, secondary infections, tumor and gastrointestinal reactions, gingival hyperplasia, and hypertrichosis. The severity and duration of adverse reactions are related to the dose and blood concentration. Blood test, blood creatinine and blood pressure should be checked during the drug administration.
(7) Leflunomide (LEF): It is used for moderate and severe patients at 20mg/day. The main adverse effects include diarrhea, pruritus, hypertension, increased liver enzymes, rash, hair loss and transient white blood cell drop. It is prohibited for pregnant women because of its teratogenic effect. Blood tests and liver function should be checked regularly during the drug administration.
There are reports that 31% of psoriasis with antimalarials suddenly relapsed, usually after 2-3 weeks of use, and the chance of hydroxychloroquine is 19%, which is much safer than chloroquine. However, antimalarials have also been applied to treat PsA and are considered effective. Hydroxychloroquine 200-400mg/day, this drug has accumulation effect, easy to precipitate in the pigment epithelial cells of retina, causing retinal degeneration and blindness, about six months after taking the drug should check the fundus of the eye. In addition, in order to prevent heart damage, electrocardiogram should be checked before and after the use of the drug. Patients with heart disease such as sinus node insufficiency, slow heart rate and conduction block should be prohibited. Other adverse reactions include dizziness, headache, skin rash, itching and tinnitus.
(3) Etretinate: aromatic retinoid. It should be started at 0.75-1mg/kg/day and gradually reduced after remission for 4-8 weeks. Pay attention to liver function and blood lipids during the use of the drug. Long-term use may cause calcification of the spinal ligaments, so it should be avoided in medial lesions.
(4) Glucocorticosteroids: Used when the condition is serious and cannot be controlled by general drug therapy. Because of the large adverse reactions, sudden discontinuation may induce serious types of psoriasis and easy relapse after discontinuation, so they are generally not chosen and not used for a long time. However, some scholars now believe that small doses of glucocorticoids can relieve patients’ symptoms and act as a “bridge” before DMARDs take effect.
(5) Botanical preparations: Radix Polygoni, 30-60mg/day, divided into 3 doses after meals. The main adverse effects are gonadal suppression, resulting in reduced sperm production, male infertility and female amenorrhea. It can also cause poor appetite, nausea, vomiting, abdominal pain and diarrhea. There can be bone marrow suppression, anemia, leukopenia and thrombocytopenia, and reversible elevation of liver enzymes and decrease in blood creatinine clearance. Other adverse reactions include rash, hyperpigmentation, oral ulcers, nail softening, hair loss, dry mouth, palpitation, chest tightness, headache and insomnia.
(6) Local administration.
(1) Long-acting corticosteroids by injection into the joint cavity. It is suitable for patients with acute monoarticular or oligoarticular arthritis, but should not be used repeatedly, and should not be used more than 3 times in a year, and should avoid injection at the skin lesion.
②Local medication for skin lesions. Depending on the type of lesion and the condition, different drugs are used. For example, topical glucocorticosteroids are generally used for mild to moderate psoriasis and can be used daily, every other day or 1-2 times a week. Improper use or abuse, especially in large doses, can lead to skin relaxation, thinning and atrophy. Tar preparations are easy to contaminate clothing and have an unpleasant odor. They can generally be taken during sleep and have few adverse effects other than skin irritation. Anthralin is effective for mild to moderate psoriasis, but inconvenience and adverse reactions limit its widespread use, but there are improved preparations. Topical vitamin D3 and calcipotriol (Darex) are used for the treatment of moderate psoriasis with some side effects, but they are free from contamination and odor and are not recommended for facial and genital skin and for women and children during pregnancy. Tazarotene (Tazorac), a topical retinoid or vitamin A derivative used for psoriasis, has the most obvious adverse effect of turning the skin bright red, which is often mistaken for worsening, and is generally not used in skin folds such as the groin and around the eyes. Other products include black distillation oil ointment, tincture of hippophae solution, etc.
3.Physical therapy
(1) Closed treatment: after using topical hormones or wetting the skin will be a layer of impermeable, impermeable paste covered in the affected area. It is mostly used for stubborn, limited psoriasis lesions and scalp psoriasis, not for wide range of lesions.
(2) Moistening treatment: Keeping the skin moist reduces the incidence of infection and itching, makes the skin more pliable and increases defensibility.
(3) Water baths: It has been found that baths with coal tar solution, cereal oil, EPSOM salt or Dead Sea salt can also help clear the rash and relieve itching, usually by moistening the skin with an oil immediately after the bath for at least 15 minutes.
(4) Photochemotherapy (Psoralen long-wave UV therapy PUVA): Taking psoralen and exposure to the first letter of A-wave UV constitutes PUVA. it is effective and even achieves long-term remission in 1/3 of psoriasis patients. However, because of its side effects, it is generally used only for patients with moderate to severe psoriasis or for those for whom other treatments have failed and only in hospital. Adverse effects include nausea, headache, dizziness, itching and redness of the skin. Long-term side effects include skin aging, which manifests as dry wrinkles and orange peel-like changes in the skin. Patients treated with PUVA wear goggles to protect their eyes during and 12-24 hours after treatment. Patients with multiple treatments have an increased chance of developing skin cancer.
4.Surgical treatment: Consider surgical treatment, such as arthroplasty, for patients who have developed joint deformity with functional impairment.
Prognosis
Generally the course of the disease is good, only a few patients (<5%) have joint destruction and deformity. Family history of psoriasis, onset before the age of 20, positive HLADR3 or DR4, erosive or polyarticular disease, and extensive skin lesions suggest a poor prognosis.
Warm tip: Please combine the specific medication with the clinical and be guided by the doctor’s face-to-face consultation.