Psoriatic arthritis (PsA) is an inflammatory arthropathy associated with psoriasis, with a psoriatic rash, pain, swelling, tenderness, stiffness and dyskinesia of the joints and surrounding soft tissues, and in some patients, sacroiliac arthritis and/or spondylitis. The rash appears before arthritis in about 75% of patients with PsA, after arthritis in about 10%, and at the same time in about 15%. The disease can occur at any age, with a peak age of 30 to 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% to 7% of patients with psoriasis. Preliminary statistics show that the prevalence of PsA in China is about 1.23 per 1,000.
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 knee, ankle, hip and other large joints, and one or two interphalangeal joints may be involved at the same time. Due to synovitis and tenosynovitis in the distal and proximal interphalangeal joints, the damaged finger (toe) may appear as a typical waxy finger (toe), often accompanied by finger (toe) nail lesions. Approximately 1/3 to 1/2 of patients with this type may evolve into a polyarthritic type.
(2) Distal interphalangeal joint type: 5% to 10% of patients have lesions involving the distal interphalangeal joints, typical of PsA and usually associated with psoriatic nail lesions.
(3) Destructive joint type: accounting for 5%, 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 are 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) spondyloarthropathy type: about 5%, male, older people are more common, mainly spine and sacroiliac joint lesions, often unilateral, lower back pain or chest wall pain and other symptoms can be absent or very light, spondylitis manifested as ligamentous bone superfluous formation, in severe cases can cause spinal fusion, sacroiliac joint blurring, joint space narrowing or even fusion.
2, skin manifestations: skin psoriasis lesions tend to occur on the scalp and extremities, especially elbows and knees, with scattered or generalized distribution, paying special attention to the hidden parts of the lesions such as hair, perineum, buttocks, umbilicus, etc.; the lesions appear as papules or plaques, round or irregular in shape, with abundant silvery-white scales on the surface, shiny film after removing the scales, and dotted hemorrhage (Auspitz sign) is visible after removing the film, which 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 depression, inflammation of the distal interphalangeal joints of the nail with multiple depressions is the characteristic changes of PsA, other thickening of the nail plate, turbidity, dark or white nail, the surface is uneven, there are transverse grooves and longitudinal ridges, there is often under the nail keratin hyperplasia, heavy nail peeling, sometimes the formation of spatulate nail.
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 incompetence, 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 inflammation.
Diagnostic points
1.Symptoms and signs
(1) Skin manifestations: skin psoriasis is an important diagnostic basis for PsA, the skin lesions appear in arthritis latter diagnosis is difficult, meticulous questioning of medical history, family history of psoriasis, droplet psoriasis in childhood, examination of psoriasis in hidden areas (such as scalp, umbilicus or perianal area) 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 crest and hyperkeratosis under the nail, etc. Finger (toe) nail lesions are an important clinical manifestation of psoriasis that may develop into PsA.
(3) Joint manifestations: one or more joints are involved, mainly small joints of hands and feet such as finger joints and metatarsophalangeal joints, and distal interphalangeal joints are most easily involved, often asymmetrically, 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 a 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 antinuclear antibody. HLA-B27 is positive in about half of the patients and is significantly associated with sacroiliac joint and spine involvement.
(2) Imaging
Peripheral arthritis: there are signs of destruction and hyperplasia of peripheral joint bones. There is osteolysis and resorption of the distal end of the terminal phalanges and osteophytes at the base; the distal end of the middle phalanges may become pointed due to erosion and destruction and the distal phalanges may become osteophytic, both of which result in a “pencil-in-cup”-like deformity or a “telescope “pencil-in-cup” deformity; narrowing, fusion, ankylosis, and deformity of the affected interphalangeal joint space; and villonodular osteochondritis of the long bones.
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 osteophyte formation, and paravertebral ossification characterized by ligamentous ossification forming a bone bridge between the middle of adjacent vertebrae with an asymmetric distribution.
3.Diagnosis basis
Psoriasis can be diagnosed when there are manifestations of inflammatory arthritis. Because some PsA patients with psoriasis appear after arthritis, the diagnosis of such patients is more difficult. Clinical and radiological clues, such as family history of psoriasis, looking for psoriatic lesions in hidden areas, paying attention to affected joint sites and the presence of spinal arthropathy, should be noted to make the diagnosis and exclude other diseases.
4.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 manifestations 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, metacarpophalangeal joints and wrist joints involved The rheumatoid arthritis is mostly symmetrical small arthritis, with proximal interphalangeal joints, metacarpophalangeal joints and wrist joints involved.
(2) Ankylosing spondylitis: PsA invading the spine, asymmetric lesions of the spine and sacroiliac joints, may be “jumping” lesions, often in older men, with mild symptoms, psoriatic lesions and nail changes. Ankylosing spondylitis has a younger age of onset, no skin or nail lesions, and the spine and sacroiliac joint lesions are often symmetrical.
(3) Osteoarthritis: Both erode the distal interphalangeal joints, but osteoarthritis does not have psoriatic lesions and nail lesions, and may have Heberden nodes and Bouchard nodes, without the typical X-ray changes of PsA.
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, and avoid smoking, alcohol and stimulating food.
2.Medication: refer to the medicine for rheumatoid arthritis.
(1) Non-steroidal anti-inflammatory drugs (NSAIDs): suitable 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 one NSAIDs is ineffective in full dose for 1 to 2 weeks; avoid taking two or more NSAIDs at the same time, because the efficacy does not superimpose and the adverse effects increase; it is advisable to use NSAIDs with short half-life for the elderly, and for patients with a history of ulcers, it is advisable to take selective COX-2 inhibitors to reduce the adverse effects in 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 cytopenia, coagulation disorders, aplastic anemia, hepatic impairment, allergic reactions (rash, asthma) and tinnitus, hearing loss, and aseptic meningitis in a few patients. NSAIDs are commonly used in rheumatoid arthritis.
(2) Slow-acting anti-rheumatic drugs (DMARDs): prevent the deterioration of the disease and delay the destruction of joint tissue. If a DMARDs alone is not effective, it can also be used in combination, with methotrexate as the basic drug for 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 with 10mg once a week, and gradually increasing the dose to 15-25mg once a week if there are no adverse reactions and the symptoms worsen. 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.
Sulfasalazine (SSZ): Effective for peripheral arthritis. The main adverse effects include nausea, anorexia, dyspepsia, abdominal pain, diarrhea, rash, asymptomatic transaminase increase and reversible spermopenia, occasionally leukocytosis, thrombocytopenia. Sulfanilamide is contraindicated in patients who are allergic to sulfanilamide. Blood test and liver function should be checked regularly during the drug administration.
Auranofin: Effective in arthritis of the extremities at an initial dose of 3 mg/d, increasing to 6 mg/d after 2 weeks. common adverse reactions include diarrhea, pruritus, dermatitis, tongue inflammation and stomatitis, others include liver and kidney damage, leukopenia, eosinophilia, thrombocytopenia, allohemocytopenia and 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. It should not be used in pregnant and lactating women.
Penicillamine (D-penicillamine): 250-500mg/d, can be gradually reduced to maintenance 250mg/d after oral effect. penicillamine adverse reactions, long-term high dose may appear renal damage (including proteinuria, hematuria, nephrotic syndrome) and bone marrow suppression, etc., 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, and occasionally autoimmune diseases, such as myasthenia gravis, polymyositis, systemic lupus erythematosus and aspergillosis. Blood and urine tests and liver and kidney function should be checked regularly during treatment.
Azathioprine (AZA): It is also effective for skin lesions, commonly used dose 1~2mg/(kg?d), generally 100mg/d, maintenance dose 50mg/d. Adverse effects include alopecia, rash, bone marrow suppression (including leukopenia, thrombocytopenia, anemia), gastrointestinal reactions including nausea, vomiting, liver damage, pancreatitis, sperm and egg damage, and teratogenic. It may cause damage to sperm and eggs, teratogenic and carcinogenic in long-term application. Blood test and liver function should be checked regularly during the drug administration.
Cyclosporin (Cs): The U.S. FDA has approved its use for the treatment of severe psoriasis, which is effective for skin and joint psoriasis, and the FDA approved maintenance treatment within one year, and more long-term use is prohibited for psoriasis. The usual dosage is 3-5 mg/(kg?d), and the maintenance dosage is 2-3 mg/(kg?d). The major adverse reactions to Cs include hypertension, hepatic and renal toxicity, neurological damage, secondary infection, tumor and gastrointestinal reactions, gingival hyperplasia, and hypertrichosis. The severity and duration of adverse reactions are related to the dose and blood concentration. Blood count, creatinine and blood pressure should be checked while taking the drug.
Leflunomide (LEF): Leflunomide, 20mg/d, is used for moderate and severe patients, with the same treatment method as rheumatoid arthritis.
Antimalarials: The application of antimalarials is controversial. It has been reported that 31% of psoriasis with antimalarials suddenly relapsed, usually occurring after 2-3 weeks of medication, and the chances of hydroxychloroquine are minimal at 19%, which is relatively much safer than chloroquine. However, antimalarials have also been applied to treat PsA and are considered effective. Hydroxychloroquine 200-400mg/d, this drug has accumulation effect, easy to precipitate in the pigment epithelial cells of the 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. Start 0.75~1mg/(kg?d), gradually reduce the dosage after the condition is relieved, the course of treatment is 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 to 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 play a “bridging” role before DMARDs take effect.
(5) Botanical preparations: Radix Polygonatum multiflorum 30-60mg/d, divided into 3 doses after meals. The main adverse effect is gonadal suppression, resulting in reduced sperm production, male infertility and female amenorrhea. Other adverse reactions include rash, hyperpigmentation, oral ulcers, nail softening, hair loss, dry mouth, palpitation, chest tightness, headache, insomnia, etc.
(6) Local administration
Joint cavity injection of long-acting corticosteroids is suitable for patients with acute mono- or oligoarthritis type, but should not be used repeatedly, and should not be used more than three times in a year, while avoiding injection at the skin lesion, too many joint cavity puncture in addition to easy complication of infection, but also can occur steroid crystal arthritis.
Topical drugs for topical treatment of psoriasis are based on reducing agents, keratolytic exfoliators and cytostatic agents. The choice is based on the type of lesion and the condition. In the acute phase of the disease, and in lesions occurring in folds, irritating drugs are avoided. In the stable stage, stronger drugs can be used, such as 5% salicylic acid ointment, tar-based ointment, 0.1% to 0.5% anthralin ointment, etc. Other drugs that can be used for stable lesions are calcipotriol (a derivative of vitamin D3) and tazarotene (tazarotene). Stable and stubborn limited lesions can be combined with topical corticosteroids, which can be added after the topical application of drugs to promote the efficacy of the treatment, which can make the lesions fade faster, but attention should be paid to the local adverse reactions of the hormone when applying this drug, as well as the systemic absorption that may occur when the application is extensive.
(7) Biological agents: When the effect of conventional drug treatment is not good, biological agents such as Yicep should be used as soon as possible to reduce bone destruction and disability while controlling the psoriasis rash.
3.Physical therapy.
(1) UV therapy: mainly B-wave UV therapy, which can be applied alone or irradiated with B-wave UV after taking photosensitive drugs and topical tar-like preparations, and then add hydrotherapy (triple therapy).
(2) PUVA therapy: photochemotherapy, including oral administration of photosensitizing drugs (usually 8-methoxypsoralen, 8-MOP), followed by long-wave ultraviolet (UVA) irradiation. Care should be taken during the administration of 8-MOP to avoid sun exposure causing photosensitive dermatitis. It is thought that long-term use of PUVA may increase the chance of skin squamous carcinoma.
(3) Water bath treatment: including hot spring bath, bran bath, herbal bath, Dead Sea salt mud bath treatment, etc., which can help moisten the skin, get rid of scales and relieve dry and itchy symptoms.
4. Surgical treatment
Consider surgical treatment, such as arthroplasty, for patients who have developed joint deformities with functional disorders.
Psoriatic arthritis generally has a good course, and only a small number of patients (<5%) have joint destruction and deformity. Family history of psoriasis, onset before the age of 20, HLA-DR3 or DR4 positivity, erosive or polyarticular disease, and extensive skin lesions suggest a poor prognosis.