The effects of rheumatoid arthritis (RA) on the joints have long been recognised, but its potential for causing lung disease is perhaps less well known. However, after heart disease, lung disease is the second most common cause of death in RA.1
Interstitial lung disease (ILD) was the only internal organ disorder found to have increased in frequency among RA patients in a recent large survey.2
Many patients with RA are more mobile because of effective treatment of their joint disease; some are noticing that they are limited by breathlessness.
This article will deal with the common forms of lung disease found in RA, the risk of pneumonia in RA and the different effects that some drugs have on the lung in RA.
The airways can become inflamed in RA, causing a dry cough and breathlessness. This is common3 and more often seen in smokers, especially if they have dry eyes and mouth (secondary Sjogren's syndrome).
The condition may mimic asthma and often responds to steroid inhalers. It is rarely serious or rapidly progressive, unless patients continue to smoke.
Interstitial lung disease
The alveolar structure can be altered as a result of inflammation, leading to fibrosis and ultimate destruction of lung tissue. This may cause a cough, breathlessness and fatigue as oxygen levels fall.
Although ILD has been found in up to 25% of RA patients by high resolution CT (HRCT),4 many are unaware of any related symptoms and only about 5% develop symptoms.5 Male smokers are especially likely to develop ILD.6
Patients who are seropositive for rheumatoid factor and/or cyclic citrullinated peptides are also at increased risk of ILD.6 Diagnosis is based on a combination of symptoms and bibasal lung crackles.
In such patients, chest X-ray may be normal and HRCT is required to confirm the diagnosis and define the nature and extent of the disease. The subtype and degree of lung involvement are major determinants of survival. Breathing tests are used to assess severity and response to therapy.
Other forms of lung disease have become much more rare in RA, with pleural effusions and nodules both declining rapidly, probably as a result of the earlier treatment of RA.
Risk of pneumonia
The risk of lung infection is generally agreed to be about twice that seen in patients without RA.7
This relates predominantly to the activity of the disease itself, although certain drugs, such as long-term oral steroids, also substantially increase the risk.
This risk may be reduced by ensuring that patients receive annual influenza vaccines and pneumonia vaccination every 10 years. We recommend drugs such as methotrexate are suspended during an infection requiring antibiotics, to allow the immune system to recover.
Smoking increases the risk of developing RA and the risk of pneumonia, and reduces the chances of responding to treatment. All smokers with RA should be actively encouraged to stop smoking.
Effects of RA drugs on lungs
Methotrexate may cause an acute pneumonitis, but this only occurs in about 1% of patients.8 It can occur in patients with normal lungs, but those with existing lung disease appear to be at higher risk. Pretreatment lung function tests are often used to screen out highest-risk patients.
Anti-TNF agents have a complex effect on the lung, but have been reported to precipitate progression in patients with established ILD, often irreversibly.9
By contrast, the use of the anti-B cell drug rituximab, advocated by NICE for patients who fail anti-TNF drugs, may be associated with stabilisation or even improvement in some patients with ILD.10 There have been mixed reports on the effect of the newly released I-L6 antagonist, tocilizumab, on ILD in RA patients.
Other drugs used in the treatment of ILD in RA include steroids and azathioprine. Neither of these has a good evidence base and they are being superseded by newer agents, such as mycophenolate mofetil.
- Dr Kelly is a consultant physician and rheumatologist, department of acute medicine, Queen Elizabeth Hospital, Gateshead, Tyne and Wear, and co-wrote 'Interstitial lung disease in rheumatoid arthritis: a review' (arthritisresearchuk.org)
CPD IMPACT: EARN MORE CREDITS
These further action points may allow you to earn more credits by increasing the time spent and the impact achieved.
- Discuss the significance of ILD in RA patients at a practice meeting.
- Invite the local rheumatologist to your practice to discuss the effects of RA treatments on the lungs.
- Ask your patient participation group to organise a meeting where conditions such as ILD in RA can be presented and discussed.
Save this article and add notes with your free online CPD organiser at gponline.com/cpd Take clinical tests and claim certificates for CPD at myCME.com/gp
1. Young A, Koduri G, Batley M et al. Mortality in rheumatoid arthritis. Increased in the early course of disease, in ischaemic heart disease and in pulmonary fibrosis. Rheumatology (Oxford) 2007; 46: 350-7.
2. Bongartz T, Nannini C, Medina-Velasquez YF et al. Incidence and mortality of interstitial lung disease in rheumatoid arthritis: a population-based study. Arthritis Rheum 2010; 62: 1583-91.
3. Kim EJ, Collard HR, King TE. Rheumatoid arthritis-associated interstitial lung disease: the relevance of histopathologic and radiographic pattern. Chest 2009; 136: 1397-405.
4. Dawson J, Fewins H, Desmond J et al. Fibrosing alveolitis in patients with rheumatoid arthritis as assessed by high resolution computed tomography, chest radiography, and pulmonary function tests. Thorax 2001; 56: 622-7.
5. Rajasekaran BA, Shovlin D, Lord P et al. Interstitial lung disease in patients with rheumatoid arthritis: a comparison with cryptogenic fibrosing alveolitis. Rheumatology 2001; 40: 1022-5.
6. Solomon JJ, Brown KK. Rheumatoid arthritis-associated interstitial lung disease. Open Access Rheumatology: Research and Reviews 2012; 4: 21-31.
7. Doran MF, Crowson CS, Pond GR et al. Frequency of infection in patients with rheumatoid arthritis compared with controls: a population-based study. Arthritis Rheum 2002; 46: 2287-93.
8. Kramer N, Chuzhin Y, Kaufman LE et al. Methotrexate pneumonitis after initiation of in?iximab therapy for rheumatoid arthritis. Arthritis Rheum 2002; 47: 670-1.
9. Dixon WG, Hyrich KL, Watson KG et al. Influence of anti-TNF therapy on mortality in patients with rheumatoid arthritis-associated interstitial lung disease: results from the British Society for Rheumatology Biologics Register. Ann Rheum Dis 2010; 69: 1086-91.
10. NICE. Rheumatoid arthritis. The management of rheumatoid arthritis in adults. CG79. London, NICE, 2009. Available from: http://www.nice.org.uk/nicemedia/pdf/CG79NICEGuideline.pdf