Pulmonary manifestations of the rheumatic diseases

The risk of asthma in patients with ankylosing spondylitis: a population-based cohort study

Background

The relationship between asthma and ankylosing spondylitis (AS) is controversial. We examined the risk of asthma among AS patients in a nationwide population.

Methods

We conducted a retrospective cohort study using data from the National Health Insurance (NHI) system of Taiwan. The cohort included 5,974 patients newly diagnosed with AS from 2000 to 2010. The date of diagnosis was defined as the index date. A 4-fold of general population without AS was randomly selected frequency matched by age, gender and the index year. The occurrence and hazard ratio (HR) of asthma were estimated by the end of 2011.

Results

The overall incidence of asthma was 1.74 folds greater in the AS cohort than in the non-AS cohort (8.26 versus 4.74 per 1000 person-years) with a multivariable Cox method measured adjusted HR of 1.54 (95% confidence interval (CI), 1.34–1.76). The adjusted HR of asthma associated with AS was higher in women (1.59; 95% CI, 1.33–1.90), those aged 50–64 years (1.66; 95% CI, 1.31–2.09), or those without comorbidities (1.82; 95% CI, 1.54–2.13).

Conclusion

Patients with AS are at a higher risk of developing asthma than the general population, regardless of gender and age. The pathophysiology needs further investigation.

Pulmonary manifestations of ankylosing spondylitis

Ankylosing spondylitis, a chronic multisystem inflammatory disorder, can present with articular and extra-articular features. It can affect the tracheobronchial tree and the lung parenchyma, and respiratory complications include chest wall restriction, apical fibrobullous disease with or without secondary pulmonary superinfection, spontaneous pneumothorax, and obstructive sleep apnea. Ankylosing spondylitis is a common cause of pulmonary apical fibrocystic disease; early involvement may be unilateral or asymmetrical, but most cases eventually consist of bilateral apical fibrobullous lesions, many of which are progressive with coalescence of the nodules, formation of cysts and cavities, fibrosis, and bronchiectasis. Mycobacterial or fungal superinfection of the upper lobe cysts and cavities occurs commonly. Aspergillus fumigatus is the most common pathogen isolated, followed by various species of mycobacteria. Prognosis of patients with fibrobullous apical lesions is mainly determined by the presence, extent, and severity of superinfection. Pulmonary function test results are nonspecific and generally parallel the severity of parenchymal involvement. A restrictive ventilatory impairment can develop in patients with ankylosing spondylitis because of either fusion of the costovertebral joints and ankylosis of the thoracic spine or anterior chest wall involvement. Chest radiographic findings may mirror the severity of clinical involvement. Pulmonary parenchymal disease is typically progressive, and cyst formation, cavitation, and fibrosis are seen in advanced cases. No treatment has been shown to alter the clinical course of apical fibrobullous disease. Although several antiinflammatory agents, such as infliximab, etanercept, and adalimumab, are being used to treat ankylosing spondylitis, their effects on pulmonary manifestations are unclear.

Pulmonary Tuberculosis and Disease-Related Pulmonary Apical Fibrosis in Ankylosing Spondylitis

Objective.

We investigated the etiological association and clinical characteristics of apical pulmonary fibrosis in ankylosing spondylitis (AS).

Methods.

We reviewed medical records of 2136 consecutive patients diagnosed with AS at a tertiary medical center. Clinical and radiographic characteristics were analyzed for evidence of apical lung fibrosis on chest radiographs.

Results.

Of 2136 patients with AS, 63 (2.9%) developed apical lung fibrosis, of which chronic infections were the cause in 41 and AS inflammation predisposed the fibrosis in 22 patients. Tuberculosis (TB) infection was considered to be the cause of apical lung fibrosis in 40 patients (63.5%) including 19 with bacteriologically-proven TB and 21 with chest radiographs suggestive of TB. Two were identified as having non-TB mycobacterial infection and one as Aspergillus infection. Lung cavity lesion appeared to be a crucial differentiator (p = 0.009, odds ratio 7.4, 95% CI 1.5–36.0) between TB infection and AS inflammation-induced apical fibrosis.

Conclusion.

Our study suggests that TB, instead of Aspergillus, is the most common pulmonary infection in patients with AS presenting with apical lung fibrosis. AS-associated apical lung fibrosis may mimic pulmonary TB infection. Thus, bacteriological survey and serial radiological followup of lung fibrocavitary lesions are critical for accurate diagnosis and treatment.

Collagen Vascular Diseases and Disorders of Connective Tissue

The collagen vascular diseases, also referred to as connective tissue diseases, are a diverse group of systemic inflammatory disorders thought to be immunologically mediated. The concept of collagen vascular disease began to take shape in the 1930s, when it was recognized that rheumatic fever and rheumatoid arthritis can affect connective tissues throughout the body.1,2 During the following decade, as conditions such as systemic lupus erythematosus (SLE) and scleroderma came to be viewed as systemic diseases of connective tissue, the terms diffuse connective disease and diffuse collagen disease were proposed.3,4 During the same period, the designation of diffuse vascular disease was proposed for diseases such as scleroderma, polymyositis, SLE, and polyarteritis nodosa, which featured widespread vascular involvement.5 With the realization that many of these entities can exhibit both systemic connective tissue manifestations and vascular abnormalities, the unifying designation of collagen vascular disease was introduced.6

Clinical significance of ventilation/perfusion scans in collagen disease patients

The purpose of this study was to detect disturbances in pulmonary circulation in collagen disease patients by means of a non-invasive technique.

METHODS

Ventilation/perfusion scans with 133Xe gas and 99mTc-macroaggregated albumin (MAA) were performed in 109 patients with various collagen diseases. Functional images of V, Vol, Q and V/Q ratio were obtained at total lung capacity. Wash-out time was calculated from the wash-out curve. Whole body scans were performed in 65 patients to evaluate intra-pulmonary shunts.

RESULTS

Increased V/Q areas were observed in 74 patients (67.9%), suggesting some impairment of pulmonary perfusion. Decreased perfusion, probably due to vasculitis or intravascular microcoagulation, was observed often, even in patients without pulmonary fibrosis. Shunt ratios over 10% were observed in 8 of the 65 patients (12.3%), indicating formation of PA-PV shunts secondary to peripheral vascular impairment. Wash-out time was prolonged in 37 patients (33.9%), shortened in 18 (16.5%), and within the normal range in 54 (49.6%). The prolonged and normal wash-out times in the patients with pulmonary fibrosis may represent obstructive changes in the small airways superimposed on the fibrosis.

CONCLUSION

Ventilation/perfusion scans are a very useful tool for evaluating collagen lung diseases, and they might contribute to treatment decisions for the patients.

Pulmonary manifestations of ankylosing spondylitis and relapsing polychondritis

Ankylosing spondylitis is a chronic inflammatory disease that affects chiefly the joints of the axial skeleton. It is a multisystem disease. Several extra-auricular manifestations of ankylosing spondylitis have been described including ocular, cardiovascular, renal, and neurologic complications. Pulmonary involvement consists principally of upper lobe fibrocystic changes and chest wall restriction. Relapsing polychondritis, on the other hand, is a rare disorder characterized by progressive inflammation and degeneration of the cartilaginous structures and other connective tissues throughout the body. Involvement of the respiratory tract is identified in more than one-half of patients with relapsing polychondritis.

Pulmonary manifestations of rheumatic disease

The lungs are a common target in many rheumatic diseases. Treatment of the primary rheumatic disease is often all that is required to control lung involvement. Physicians must be careful not to attribute lung disease to the underlying rheumatic disorder, because interstitial lung disease can be a complication of drug therapy.