Definition

Generalized inflammatory joint disorder of uncertain etiology.

Epidemiology

Most common collagen vascular disease Extraarticular manifestations are rare More common in men than women Rarely occurs before joint symptoms Occurs in middle age.

Etiology, pathophysiology, pathogenesis

Etiology is unclear Pleuropulmonary manifestations include pleural involvement and, less pronounced, fibrosing alveolitis, rheumatoid nodules, airway changes (bronchitis, bronchiolitis, bronchiectasis).

Imaging Signs

Modality of choice

CT.

Radiographic findings

Low sensitivity Severe cases show predominantly basal reticulonodular shadowing and linear, nonseptal opacities Honeycombing Pleuritis (pleural effusion Rheumatoid nodules (< 5% of cases).

CT findings

Pathologic findings are visualized in about 30% of cases.

– Pleural findings (most common): Include slight pleural effusion Pleural thickening.

– Parenchymal findings (predominantly basal and subpleural): Include finely to coarsely reticular and nodular opacities with honeycombing, similar to idiopathic pulmonary fibrosis or nonspecific interstitial pneumonitis Ground-glass opacities Rheumatoid nodules (solitary or multiple, peripheral, sharply demarcated, 50% showing cavitation, rarely calcified).

– Airway findings: Include bronchiolitis Bronchiectasis.

Pathognomonic findings

Coarsely reticular and nodular interstitial changes in combination with joint symptoms.

Clinical Aspects

Typical presentation

Presentation is variable; patients may be asymptomatic Dyspnea with nonproductive Pleuritis Lung function is restricted with impaired diffusion capacity and reduced vital capacity Positive rheumatoid factor in 80% of cases Pleural exudate is high in protein and low in glucose with a high level of lactate dehydrogenase and low pH and contains lymphocytic, neutrophilic, and eosinophilic cells.

Therapeutic options

Anti-inflammatory treatment of the underlying disorder (anti-inflammatory agents, steroids, TNF-α blockers, immunosuppressives).

Fig. 6.1 Plain chest radiograph of a 70-year-old man with a long history of rheumatoid arthritis. Relatively nonspecific bilateral basal finely reticular streaky shadowing consistent with pulmonary interstitial changes.

Course and prognosis

Depend on the underlying disorder.

What does the clinician want to know?

Characterize and ascertain the extent of findings.

Differential Diagnosis

Tips and Pitfalls

In the presence of a known underlying disorder, the diagnosis is straightforward However, the findings themselves are nonspecific Focal lesions require histologic evaluation.

Fig. 6.2 Rheumatoid nodules in a 70-year-old woman.

a The plain chest radiograph shows bilateral focal lesions, the largest of which occur in the left laterobasal pleural region.

b Findings on CT include isolated eccentric cavities and bronchiectatic changes.

Selected References

Biederer J et al. Correlation between HRCT findings, pulmonary function tests and bronchoalveolar lavage cytology in interstitial lung disease associated with rheumatoid arthritis. Eur Radiol 2004; 14: 272–280

Remy-Jardin M et al. Lung changes in rheumatoid arthritis: CT findings. Radiology 1994; 193: 375–382

Definition

Epidemiology

Systemic autoimmune disorder, a member of the group of collagen diseases.

Etiology, pathophysiology, pathogenesis

Antinuclear antibodies are present in 95% of cases Genetic disposition 90% of patients are women Pleuropulmonary involvement in about 50% of cases, usually in the form of pleural effusions, less often as acute lupus pneumonitis with damage to the alveolar-capillary membrane and alveolar hemorrhages Pulmonary fibrosis rarely develops.

Imaging Signs

Modality of choice

CT is preferable to plain radiography.

Radiographic and CT findings

Pleuritis or pleural effusion in 70% of cases, pericardial effusion in 35% (usually slight and bilateral) Lupus pneumonitis in 5% with nodular consolidations, ground-glass opacities, alveolar hemorrhages, predominantly basal “Shrinking lung” syndrome: increasing volume loss without significant parenchymal changes (from diaphragmatic dysfunction or pleuritis) Fibrosis, thickening of the bronchial wall, or bronchiectasis are rare Note: Pneumonia is common in immunosuppression (whether pathologic or drug-induced).

Pathognomonic findings

There are no pathognomonic findings. Pleural and pulmonary changes tend to be nonspecific.

Clinical Aspects

Typical presentation

Presence of at least four of the following symptoms is diagnostic: butterfly erythema, discoid lupus, photosensitivity, oral ulcerations, arthritis, serositis, renal involvement, CNS involvement, antinuclear antibodies With pulmonary involvement, symptoms include fever, dyspnea, cough, chest pain, and hemoptysis.

Therapeutic options

Immunosuppressives.

Course and prognosis

Depend on the organs involved.

Fig. 6.3

a     Pleuritis with systemic lupus erythematosus. The plain chest radiograph of a patient with reduced depth of inspiration shows a left pleural effusion with strips of dystelectasis on the right.

b, c The CT scans show pericardial involvement in addition to the pleural effusion but no interstitial or parenchymal changes.

Fig. 6.4 CT in systemic lupus erythematosus showing discrete inter-stitial changes resembling ground-glass opacity.

Differential Diagnosis

Tips and Pitfalls