I. What is psoriatic arthritis?
Psoriasis, commonly known as psoriasis, is a disease that occurs in young adults, with clinical manifestations based on erythema and scaling, and can develop all over the body, with scalp and extremities more common, mostly aggravated in winter. In addition to skin damage, some patients also experience pain, swelling, tenderness, stiffness, and movement disorders in the joints and surrounding soft tissues. These patients are called “arthritic psoriasis” by dermatologists and “psoriatic arthritis” by rheumatologists. The rash appears before the arthritis in about 75% of patients, and the rash appears after the arthritis in about 15% of patients.
The clinical manifestations of psoriatic arthritis are complex and can involve large and small joints throughout the body, and some can involve the spine, but the most characteristic lesions are in the interphalangeal joints of the terminal fingers (toes). According to the clinical characteristics, there are five types of arthritis: ① asymmetric monoarthritis, which accounts for 5% to 10%, mainly manifests as inflammation of the distal interphalangeal joints of the fingers and toes, showing diffuse finger (toe) swelling and a salami shape, accompanied by nail damage. ② Asymmetric oligoarthritis, this type accounts for 50% to 70% of cases and can affect 2 to 3 joints at the same time. (③) Symmetric polyarthritis, which accounts for 15% to 25% of cases, has clinical manifestations similar to rheumatoid arthritis, but is negative for serum rheumatoid factor. ④Spondyloarthritis, this type accounts for 20% to 30% of patients, mostly in males, typically presenting as sacroiliac arthritis, with or without spondylitis, and closely related to HLA-B27 antigen. Because of these features, psoriatic arthritis is also often classified as a form of spondyloarthropathy. ⑤ Disfiguring arthritis, this type accounts for about 5% of cases, and the arthritis presents with continued progression and leads to osteolysis, severe deformity and joint ankylosis.
Second, in the treatment process of psoriatic arthritis, what are the issues that patients often care about?
1. Are immunosuppressive drugs used to improve skin lesions or joint symptoms?
For psoriatic arthritis, in addition to anti-inflammatory and pain-relieving drugs, slow-acting anti-rheumatic drugs are generally needed to prevent the deterioration of the disease and delay the destruction of joint structures. If a DMARD alone is not effective, a combination of drugs can be used, such as methotrexate as the basic drug, plus salbutamol.
The following is a brief description of several commonly used.
①Methotrexate: It is effective for both skin lesions and arthritis, and can be the drug of choice. It can be taken orally, intramuscularly or by static injection, starting with 7.5-10mg once a week. If there is no adverse reaction, the dose can be gradually increased to 15-25mg per week for those with severe symptoms, and gradually reduced to maintenance after the disease is controlled. Blood test and liver function should be checked regularly during the drug administration.
②Lyuzosulfapyridine: Effective for peripheral arthritis but not for skin rash. Gradually increase the dosage from small dose to help reduce adverse reactions, the use of small daily dose (0.75-1.0g) to start, and then increase the appropriate dose every week, if the efficacy is not obvious can be increased to the maximum amount (2.0-3.0g per day), during the drug should be regularly checked blood routine and liver function.
(③) Radix Polygoni: It has the dual effect of anti-inflammation, pain relief and immunosuppression, and is effective for both skin lesions and arthritis. Because of its gonadal toxicity, it should not be used by young and strong patients, especially premenopausal women.
Cyclosporine: The US FDA has approved its use for the treatment of severe psoriasis, and it is effective for both psoriatic lesions and arthritis. It is effective for psoriasis lesions and arthritis. Blood count, blood creatinine and blood pressure should be monitored during the drug administration.
Leflunomide: It is effective for both skin lesions and arthritis, and is indicated for patients with moderate to severe disease. Adverse effects include hair loss, diarrhea, itchy skin, etc.
2.The disease keeps recurring after taking the medicine, and the joints are still swollen and painful, should I change the medicine or increase the dosage?
For stubborn psoriatic rash or psoriatic arthritis, immunosuppressive drugs such as methotrexate, leflunomide, tretinoin and cyclosporine A can be used for treatment. The onset of action of these drugs is about 1-2 months, and the efficacy will gradually appear within 6 months, so there is no need to hurry at this time. If you continue to use the drug for more than 6 months still have joint swelling and pain, you should adjust the treatment plan, if the original dose is small can be increased; if the dose has been used to the maximum amount can be considered to change another; such as the original only one can also be changed to two kinds of combination, but need to pay attention to the risk of adverse reactions may increase.
3.How to monitor and protect the immunosuppressant if I am worried about liver damage? Can it be used in patients with poor liver function?
Most drugs (including alcoholic beverages) will be metabolized by the liver after entering the body and may cause liver damage. Immunosuppressants are no exception and may induce liver function damage in a small number of patients. Therefore, monthly liver function tests are required during the first 3 months of taking immunosuppressants, and thereafter every 3 months or when you feel uncomfortable. Immunosuppressants should be used with caution in patients with hepatitis B virus. Immunosuppressants should be prohibited for patients with active hepatitis or with an abnormal increase in transaminases of more than 3 times.
4.Is the use of immunosuppressants easy to cause infection? How to protect?
As the name suggests, immunosuppressants have an immunosuppressive effect, i.e. they reduce a person’s resistance, and therefore increase the risk of infection. However, at commonly used doses, the risk of secondary infections with methotrexate, leflunomide, and ralston is small, while the risk of secondary infections with cyclosporine is increased. The best protection is to reduce the dose of the drug (but it will reduce the efficacy), and to avoid contact with the source of infection.
5.How should I treat leukocytes below 4.0 after medication? Should I use leukostatic drugs or discontinue immunosuppressive drugs?
If the blood leukocyte is slightly below 4.0 and relatively stable, it can be left untreated. If the blood leukocytes are declining, the drug should be stopped or its dose should be reduced, and the specific measures should be decided by an experienced doctor.
6.After taking immunosuppressant drugs with severe gastrointestinal reaction, can I change the drug? Or use drugs that improve gastrointestinal function?
Any drug may cause abdominal discomfort, nausea and other adverse reactions, if it is very mild, it will disappear after a period of time with the drug. If the gastrointestinal reaction is severe, you can change to a smaller dose and gradually increase the dose after getting used to it. Other drugs are not recommended to improve the gastrointestinal symptoms to avoid other adverse reactions (each drug may have adverse reactions).
7.Is it normal to be weak after taking immunosuppressants and is it normal to lose hair?
After taking immunosuppressants, hair loss is more common, and usually new hair can grow back. But the phenomenon of malaise is not common.
8.Do immunosuppressants need to be used for life, or can they be stopped when the condition improves?
For psoriatic arthritis, lifelong treatment is generally required, but not the same drug for life. When the disease improves, the dose can be reduced. After remission, maintenance can be changed to one with fewer adverse effects.
9.When the blood sedimentation, CRP, liver and kidney function indicators reach what level can stop the drug?
Elevated blood sedimentation or CRP generally indicates that the disease is still active, but normal blood sedimentation or CRP does not completely mean that the disease is in remission. We should observe whether there is swelling, pain and rash in the joints to determine the activity of the disease. The liver function or kidney function is mainly used to monitor the adverse drug reactions and is not related to the assessment of the disease.
10.Do I need to reduce the dosage before stopping the drug and what problems may occur if I stop the drug hastily?
Unlike glucocorticosteroids, sudden discontinuation of immunosuppressants will not cause deterioration of the disease, but relapse of the disease may occur after discontinuation for a longer period of time. When the disease is well controlled, the dose of immunosuppressant can be reduced or replaced with maintenance therapy without immunosuppressive effect.