Rheumatoid arthritis (RA) is a common inflammatory disease of the joints. It affects multiple joints, mainly small joints of the hands and wrists but also larger ones. It causes painful joints with stiffness that is typically more in the morning and progresses with time causing joint deformities and, ultimately, a crippling state. Effective treatments are available and therefore, early diagnosis and regular treatment with monitoring of disease activity are important to limit or prevent permanent damage.
Can Rheumatoid Arthritis cause lung disease?
RA is more than just a joint disease. The inflammatory process also affects several other parts of the body. The most frequently affected are the lungs, besides skin, eyes, digestive system, heart, and blood vessels. The lung conditions that occur in patients with RA are of several types. More than 25 per cent of patients with RA will eventually develop lung conditions and diseases in their lifetime. If all patients with RA are screened for lung disease, even when there are no lung symptoms, more than half are found to have evidence of lung involvement.
Lung disease is next only to cardiac disease and cancer as the cause of death in patients with RA. Lung disease due to RA is a major contributor to a poorer quality of life besides mortality. Most often, lung disease follows joint involvement but rarely, RA may start as a lung disease and joint manifestations may follow later.
What are the different lung diseases caused by Rheumatoid Arthritis?
The most common lung disease caused by rheumatoid arthritis is a shrinkage of the lungs, called Interstitial Lung Disease (ILD). Other lung conditions and diseases that can occur in RA include pulmonary nodules (one or more rounded masses of tissue, of various sizes, confusing the possibility of lung cancer), pleural effusion (protein-rich fluid in the sac around the lungs), pleural thickening, bronchiectasis (dilatation of lung airways causing pooling of secretions and lung infections), bronchiolitis (narrowing of airways deep in the lung), pulmonary hypertension (high blood pressure in lung arteries) and increased tendency for lung infections like pneumonia. The drugs that are used to treat RA in general suppress immunity increasing the risk of lung infections.
What is an Interstitial Lung Disease?
ILDs are a group of conditions with diverse causations having in common a reduction in lung size due to fibrosis that usually worsens with time. RA is one of the more common causes of an ILD. There are several types of ILD patterns and treatment, prognosis and natural history differ according to the ILD pattern.
A patient with ILD develops breathlessness on exertion, initially on running or walking fast, especially up an incline. It progresses with time and, ultimately, even activities of daily living such as dressing, taking a bath, or even taking food cause breathlessness. The oxygen levels in the blood decrease, in the early stages of exertion, and later, even at rest. These patients require home oxygen to keep their oxygen in the normal range. Dry cough is the other major symptom. Patients with ILD sometimes get sudden flare-ups, called acute exacerbations, that acutely worsen respiratory failure and carry a high risk of mortality.
Males, smokers, those with a long history of joint disease, more active joint disease, and older age are more prone to develop ILD but many patients of RA with none of these risk factors can also develop ILD.
How is an ILD diagnosed and treated?
ILD is diagnosed by features on chest examination, breathing tests called spirometry and diffusion capacity, and imaging including a plain chest radiograph and a high-resolution computed tomogram (HRCT) of the chest that provides the clue to the pattern of ILD. In a case where the diagnosis of RA is already established by clinical features and characteristic blood tests, a lung biopsy is not required. Some of these tests are required from time to time after treatment is started to evaluate for a response as well as the progress of the disease.
Treatment of ILD due to RA has variable effectiveness and may produce relief in symptoms.
This is in addition to drugs that are being given for other symptoms of RA including joint disease. While effective treatments are now available for RA according to the severity and extent of the disease, treatment of lung diseases like ILD is more difficult. The drugs that work for the joints do not seem to work for the lungs in general. Drugs like corticosteroids that suppress immunologically mediated immune damage have a variable response. For those who have increased lung fibrosis, a newer class of drugs called antifibrotics may help in slowing down the increasing shrinkage. The fibrosis is not reversible.
What are the treatments for other lung diseases due to Rheumatoid Arthritis?
Management of a large pleural effusion would require drainage with a chest tube or a video-assisted thoracoscopy which is a minimal-access surgery. Treatment of lung infections requires appropriate antibiotics. Narrowing of lung airways requires inhaled medicines.
What are the other treatment modalities for Interstitial Lung Disease?
Apart from drugs, breathing exercises, and nutritional supplementation as required are given as part of what is called pulmonary rehabilitation. This reduces breathlessness and improves exercise tolerance. Patients who are unable to maintain normal blood oxygen, which can easily be measured by pulse oximeter and blood gas analysis, require oxygen therapy round the clock. This can be given using oxygen concentrators. Portable machines are also available.
The last resort for extensively scarred lungs is lung transplantation, a highly specialiSed and expensive surgery, now increasingly available in different cities in India.
What other measures are advised in Rheumatoid Arthritis ILD?
It is very important to give up smoking as well as avoid passive exposure and avoid exposure to air pollution. These patients are advised to get timely vaccination against influenza and pneumonia. Patients are encouraged to talk with their physician to make sure that the medications are optimal for their joint symptoms, side effects are managed, and that their lung health is monitored for early diagnosis and prompt action.
How can patients with Rheumatoid Arthritis detect that they have a lung problem?
Once you are diagnosed to have RA, an assessment for the presence of lung disease is advisable as early lung disease may not produce any symptoms. Subsequently, any occurrence of prolonged cough, expectoration, and, most importantly, breathlessness with reduced exercise tolerance calls for an evaluation of a possible lung complication. Early diagnosis holds the best promise for a good response.
(Dr SK Chabra, Senior Consultant, Pulmonary Medicine, Primus Superspeciality Hospital, Chanakyapuri, New Delhi)