Pulmonary Manifestations of Systemic Diseases - An Overview

Introduction

Systemic illnesses are identified by examining the symptoms of respective organ systems. Clinical features are usually consistent with serologic abnormalities, radiologic findings, and histology. Systemic diseases may impact the lungs; the membranes between the lungs and the cardiac tissue are anatomical structures, lymph nodes, arteries, and the heart. While this discussion will focus on lung symptoms, extrapulmonary indications can often provide important diagnostic information. Systemic diseases such as sarcoidosis are disorders in which lumps or nodules (granulomas) grow in the lungs, lymph nodes, skin, eyes, and other body regions. Granulation disease is an unusual ailment that causes inflammation of blood vessels in the nose, sinuses, throat, lungs, and kidneys, which are more likely to cause lung involvement.

The role of imaging in systemic illnesses varies depending on the condition. Diagnostic imaging, particularly CT, may be beneficial. Typical CT findings for sarcoidosis (a disorder in which lumps or nodules (granulomas) grow in the lungs, lymph nodes, skin, eyes, and other body regions) are critical for diagnosis. Imaging is less important in diagnosing connective tissue illness, largely determined clinically and through serology. In clinical practice, CT abnormalities such as lung fibrosis (especially the NSIP pattern) prompt further investigation for underlying systemic disease. Despite not being critical for diagnosis, imaging can help detect lung disease's existence, pattern, and severity, which influences therapeutic decisions. Imaging aids in evaluating patients with deteriorating or acute symptoms and serial monitoring of lung anomalies.

What Symptoms of Sarcoidosis Manifest in the Lungs?

Sarcoidosis, connective tissue disorders, and vasculitis are common systemic illnesses that induce lung abnormalities.

• There is a genetic tendency towards sarcoidosis; it causes granulomas composed of noncaseating epithelioid noncaseating granulomas that can cause an inflammatory disorder, vasculitis, or exposure to foreign particles. Granulomas form as a result of specific disorders. In numerous organs, pulmonary symptoms cause clinical cases and mortality.

• Pulmonary sarcoidosis' CT appearance varies often and can mimic several diffuse infiltrative lung disorders.

• Diagnostic criteria include typical clinical and radiographic symptoms, noncaseating granulomas, and exclusion of other illnesses.

• While typical chest radiograph findings can be sufficient in the correct context for some suspected sarcoidosis patients, a classic nodular pattern on CT is necessary for others, and controversial or nonspecific clinical and radiological findings require histological proof for others.

• Traction bronchiectasis (abnormal and permanent dilation of the bronchi in the lungs due to the pulling or stretching of the surrounding lung tissue) and airway compression from surrounding lymphadenopathy (characterized by the enlargement of lymph nodes, can occur as a result of bacterial, viral, or fungal infections, autoimmune disorders, or malignancies) and fibrosis are airway disorders. Granulomas thicken the bronchial walls irregularly, restricting the major and small airways. Expiratory CT scans show lobular air trapping better when tiny airways are involved.

• Sarcoidosis can be diagnosed without invasive procedures using HRCT characteristics with unusual symptoms and aspergilloma (a fungus ball made of aspergillus hyphae, cellular detritus, and mucus). It is a non-invasive form of chronic pulmonary aspergillosis. Aspergillus species colonize the existing reservoir in the lung parenchyma, forming a fungal cavity) and pulmonary hypertension as complications.

• Life-threatening hemoptysis (coughing up blood from the respiratory tract) may necessitate emergency bronchial artery embolization.

• End-stage fibrosis, a rare etiology of pulmonary hypertension that predominantly affects the venous system, mediastinitis (the inflammation and swelling of the mediastinum, which is the region between the lungs in the chest area), lymph node disease, and intrinsic sarcoid vascular disease are all components of this condition. It can induce pulmonary hypertension.

• Before CT, chest radiography staging was devised decades ago. It is descriptive but does not reflect disease activity.

An integrated clinicopathological staging system is used to identify patients with poor prognoses and at risk for mortality.

What Are the Pulmonary Manifestations of Connective Tissue Disease?

Connective tissue illness is a collection of conditions characterized by the involvement of protein-rich tissue responsible for supporting various organs and bodily structures that affect the lungs, pleura, pericardium, lymphatics, vascular, and heart; it has common symptoms and physical exam findings. Certain antibodies aid in diagnosing the condition, as the imaging can only detect lung disease. Multiple compartments are normal; the respiratory system produces substantial morbidity and mortality. Most of the CTD lung symptoms resemble idiopathic interstitial pneumonia.

CTD patients rarely have lung biopsies; therefore, high-resolution CT often determines the main damage pattern. This pattern impacts treatment and prognosis. CTDs have diverse damage patterns, but some are more common. Organizing pneumonia commonly involves polymyositis and dermatomyositis, which are autoimmune disorders characterized by muscular inflammation, primarily affecting the upper arms and thighs, leading to muscle weakening.

What Are the Pulmonary Symptoms of Rheumatoid Arthritis (RA)?

Rheumatoid arthritis (RA) is a chronic autoimmune disease that mostly affects the joints and is characterized by inflammation and pain. The majority of individuals diagnosed with rheumatoid arthritis (RA) exhibit irregularities on high-resolution chest CT scans, although they frequently do not experience any accompanying symptoms. The lungs commonly exhibit various computed tomography (CT) abnormalities, such as thickening of the bronchial walls and dilatation of the bronchial passages. The terms "reticulation (a network of intersecting lines that form a pattern or arrangement like a net.)," "ground-glass opacity," "honeycombing," and "consolidation" are used to describe specific patterns seen in medical imaging.

• The lung is believed to be the initial site of manifestation for rheumatoid arthritis, with airway disease being the earliest observed manifestation. Bronchiectasis and air trapping are often observed phenomena.

• An established correlation has been observed between rheumatoid arthritis (RA) and obliterative bronchiolitis, a condition characterized by the destruction of bronchioles and subsequent replacement by fibrotic tissue.

• The primary computed tomography (CT) observation is the presence of mosaic perfusion, accompanied by expiratory air trapping and frequently accompanied by bronchial dilatation. Follicular bronchiolitis is an additional subtype of small airway condition that has been identified in the context of rheumatoid lung disease.

• The prevalence of pulmonary fibrosis associated with rheumatoid arthritis (RA) is much higher in males than in females.

• Therapeutic interventions may give rise to many complications, including the development of infections such as pneumocystis pneumonia.

Conclusion

Chest symptoms might vary greatly depending on the underlying cause of the systemic condition. Imaging, including computed tomography, plays a critical role in identifying these disorders; however, the imaging findings must be associated with the typical clinical symptoms that impact various organ systems. Imaging plays a crucial role in the diagnosis of these disorders. It is essential for the interdisciplinary assessment and follow-up of patients suffering from these disorders to understand the typical and atypical imaging characteristics.