Rheumatoid arthritis is a chronic, systemic, progressive, autoimmune disease that preferentially attacks the joints. Because it is a systemic condition, it may also affect the eyes, skin, lungs, blood, and central nervous system.
Rheumatoid arthritis affects more than 2.1 million Americans and though there is no cure, there are medicines that are currently available that can put the condition into remission.
The combination that seems to work the best for most patients is to use both methotrexate, a disease-modifying anti-rheumatic drug (DMARD), along with a TNF-inhibitor. These are drugs that block the effect of tumor necrosis factor, a protein that is largely responsible for the inflammation and destruction seen in rheumatoid arthritis. Examples of these drugs are etanercept (Enbrel), infliximab (Remicade), and adalimumab (Humira).
Because of the mode of action of these drugs which is to interfere with immune function, there has been concern regarding side effects. Chief among these side-effects is infection.
There is an increased incidence of infection in patients with rheumatoid arthritis by itself. Certain factors such as severe disease, diabetes, involvement of organ systems besides the joints, chronic lung disease, and older age all contribute to this increased risk.
In addition, concomitant use of corticosteroids such as prednisone also appear to add to the increased risk of infection. The relationship between this increased incidence and the use of TNF inhibitors is still unclear.
Package inserts for all the TNF inhibitors indicates there is an increased incidence of non-serious infections such as upper respiratory infections, urinary tract infections, sinusitis, pharyngitis, bronchitis, and rhinitis (runny nose").
From clinical trial results, the most commonly reported non-serious infections in patients receiving TNF inhibitors are upper respiratory tract infections, skin infections, and urinary tract infections.
To deal with infections in rheumatoid arthritis patients, it's important first, to institute preventative measures. These include general infection control such as avoidance of crowds, frequent hand washing, disinfection of frequently handled surfaces, etc.
Co-morbidities meaning other medical problems- such as diabetes, cigarette smoking, excessive alcohol use, and chronic corticosteroid therapy also should be addressed.
Vaccinations including influenza and pneumonia are highly recommended and meningococcus (meningitis), and hepatitis B are suggested if a patient is in a high risk environment. Patients receiving either methotrexate or TNF inhibitors should avoid live virus vaccines such as oral polio, measles, mumps, rubella, and varicella (shingles).
There is no hard data available to guide decision making. However, there are common sense approaches. If a patient develops a fever or has signs and symptoms of severe respiratory tract illness such as bronchitis or pneumonia, cellulitis (skin infection), or bone or joint infection, both methotrexate and TNF inhibitor medicines should not be administered. Also, if major surgery is contemplated, these medicines should also be held until after surgery.
Higher doses of TNF inhibitors seem to increase risk of infection.
The risk of pneumonia is increased in patients who have at least three of the following factors: congestive heart failure, diabetes, age greater than 65, history of pneumonia, history of chronic lung disease, steroid use equivalent to more than 10 mgs of prednisone per day.
Patients who are started on TNF inhibitors should be screened for hepatitis B. Prior history of invasive fungus infection should prompt an infectious disease consultation. Patients may need anti-fungal therapy.
Patients should be screened for tuberculosis with properly administered tuberculin skin tests before TNF inhibitor therapy is instituted.
