Introduction
When the immune system’s usual process of self-tolerance breaks down, it results in immunologic lung disorders. The primary cells involved in initiating and maintaining acquired immune response in the lung are macrophages and lymphocytes. The macrophages that serve as scavenger cells consume and degrade the inhaled antigenic load. The macrophages have another role in acting as antigen-presenting cells for the T lymphocytes. However, the normal parenchyma of the normal lung contains a few lymphocytes.
What Are Systemic Autoimmune Diseases?
Systemic autoimmune diseases are a group of inflammatory diseases mediated by the immune system that may affect multiple organs. The entire pulmonary system may be vulnerable, as multiple organs are affected. The sections of the pulmonary system would be affected independently or simultaneously. The true prevalence of pulmonary illness in systemic autoimmune diseases can be challenging to determine.
What Are the Pulmonary Manifestations in Rheumatoid Arthritis?
Since rheumatoid arthritis is so widespread, rheumatoid lung disease is most likely the most typical autoimmune lung disorder. Clinical lung disease affects at least ten percent of people on average, with risk factors including advanced age, severe joint pain, and male gender. The prevalence of lung anomalies who undergo high-resolution computed tomography screening ranges from twenty percent to forty-four percent. Even the possibility that up to two-thirds of people with rheumatoid arthritis will get interstitial lung disease has been raised.
The clinical symptoms can range from coughing, exercise intolerance and symptoms of pleural inflammation. Testing the pulmonary functions might reveal obstructive disease, which can lead to airway disease, restrictive disease, or a mixture of both if fibrosis is present. Rheumatoid nodules are the characteristic features of rheumatoid arthritis, which is uncommon in the lung.
Rheumatoid pneumoconiosis, also called Calpan syndrome, is an uncommon reaction to mineral, coal, or silica dust that causes many rheumatoid nodules and lung fibrosis in people with rheumatoid arthritis. A variety of diseases also occur in rheumatoid lung disease. Different types of bronchiolitis (like follicular and constrictive bronchiolitis) are seen in rheumatoid arthritis. An infection of the respiratory tract is called bronchiolitis. Pulmonary vascular disease is rarely seen as a manifestation of this condition.
What Are the Pulmonary Manifestations in Systemic Lupus Erythematosus?
About five percent of the patients are clinically diagnosed with acute lupus pneumonitis during the illness. Its symptoms include fever, coughing, and bibasilar fluffy reticular densities (the presence of many small linear opacities, when observed together, appears as a net). In about fifty percent of cases, acute lung illness is one of the first symptoms seen in lupus.
Acute alveolar injury (also known as diffuse alveolar damage), cellular interstitial inflammation (also called cellular interstitial pneumonia), and arterial thrombosis (blood clots in the arteries) were among the findings that were first published more than fifty years ago. Some authors solely associate acute lupus pneumonitis with diffuse alveolar destruction and hyaline membranes.
Acute lupus pneumonitis also includes capillaritis (inflammation of the capillaries) with pulmonary bleeding in its spectrum of symptoms. Pleuritis is another most common pulmonary sign of SLE, seen in about forty to sixty percent of cases. Diaphragmatic dysfunction, pulmonary hypertension, and pulmonary thromboembolism are other pulmonary complications of the condition.
What Are the Pulmonary Manifestations of Sjogren's Syndrome?
Pulmonary involvement is the most common sign of Sjogren’s disease when checked radiologically or functionally. Airways problems may affect the trachea, bronchi, and bronchioles. They may be caused by cell infiltration (extra glandular involvement) or Sicca syndrome (an immune disorder characterized by dry eyes and dry mouth). CD4+ T lymphocytes are seen in the tissue infiltrate. Eight to twelve percent of patients with Sjogren's syndrome show large airway involvement during pulmonary function tests. This was notably shown by decreased mucociliary clearance. Bronchiolitis is the most common airway disease observed.
What Are the Pulmonary Manifestations in Systemic Sclerosis?
The pulmonary manifestation in systemic sclerosis is rare compared to other systemic autoimmune diseases. Although autopsy results of systemic sclerotic lungs revealed atrophic and fibrotic lesions in the bronchial wall's elastic, adventitial, and muscular layers, a distinct obstructive pattern on pulmonary function tests is uncommon in systemic sclerosis. Small airway dysfunctions are seen in about twenty percent of patients.
What Are the Pulmonary Manifestations in Mixed Connective Tissue Disease?
Mixed connective tissue disease is a separate clinicopathological condition that is an overlap syndrome. The main characteristics of this disease are the symptoms of SLE, scleroderma, and dermatomyosis, which may occur concurrently or evolve gradually over observation and antibodies to an extractable nuclear antigen. About two-thirds of the people with this condition have infiltrative lung disease, making pulmonary involvement prevalent. Pulmonary hypertension and esophageal dysmotility are the other complications of this condition.
What Are the Pulmonary Manifestations in Wegeners Granulomatosis?
Most cases of Wegener’s granulomatosis have shown lung diseases. The clinical signs may vary from asymptomatic nodules in the lungs to alveolar hemorrhage. Multiple nodules with irregular margins that can be cavitated in some cases are seen in this condition. Pleural effusion (accumulation in the layers between the chest and the lungs) is rare.
What Are the Pulmonary Manifestations in Churg Strauss Syndrome?
Lung involvement is the most common symptom of Churg-Strauss syndrome. More than ninety percent of people with this condition have been shown to have a history of asthma. Churg-Strauss syndrome is a disorder characterized by inflammation in the blood vessels. Most patients with this condition are generally asthmatic and have eosinophilia (increased number of eosinophils in the blood), fever, and allergic rhinitis (an allergic reaction with itchy nose, watery eyes, and sneezing).
Conclusion
A variety of pulmonary manifestations can be seen in various systemic autoimmune diseases. Bronchiectasis, bronchiolitis, pleural effusion, pulmonary fibrosis, pulmonary hypertension, etc, can be some of the symptoms seen. These can be diagnosed by imaging modalities like Computerised Tomography (CT). However, the imaging results should be correlated with clinical findings to find other systemic involvements. Rheumatoid arthritis and systemic lupus erythematosus are the most common autoimmune diseases affecting the pleural cavity.
