SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS-SSTRSDO-QAA 025

1. What is the pathogenesis of pleural effusion?

Pleural effusion is the abnormal accumulation of fluid within the pleural cavity due to imbalance between pleural fluid formation and absorption. Increased hydrostatic pressure, as in congestive heart failure, produces transudative effusions.

Reduced plasma oncotic pressure due to nephrotic syndrome, liver cirrhosis, or malnutrition also causes transudates. Increased vascular permeability from infections, malignancy, pulmonary embolism, or inflammatory diseases results in exudative effusions.

Obstruction of lymphatic drainage by tumors impairs fluid removal. Hemothorax and chylothorax represent specialized forms of pleural effusion. Progressive fluid accumulation compresses the lung and causes dyspnea.

Thoracentesis and pleural fluid analysis help determine the underlying cause. Treatment is directed at correcting the primary disease.

2. Which forms of pleuritis do you know?

Pleuritis is inflammation of the pleura resulting from infections, autoimmune diseases, malignancy, or pulmonary disorders. Acute fibrinous pleuritis is characterized by deposition of fibrin on the pleural surfaces and often produces pleuritic chest pain with a pleural friction rub.

Serous pleuritis results in accumulation of clear inflammatory fluid. Suppurative pleuritis (empyema) contains purulent exudate due to bacterial infection.

Hemorrhagic pleuritis occurs in tuberculosis, malignancy, or trauma. Chronic fibrous pleuritis produces pleural thickening and adhesions. Tuberculous pleuritis is an important granulomatous form.

Chronic inflammation may lead to pleural fibrosis and restriction of lung expansion. Identification of the underlying cause guides treatment.

3. What are the main types of non-inflammatory pleural effusions?

Non-inflammatory pleural effusions are mainly transudative and result from systemic disorders rather than pleural inflammation. Hydrothorax is a transudative pleural effusion caused by congestive heart failure, nephrotic syndrome, or liver cirrhosis.

Hemothorax is the accumulation of blood in the pleural cavity following trauma, surgery, or rupture of blood vessels. Chylothorax results from leakage of lymph due to thoracic duct injury or obstruction by tumors. Urinothorax occurs rarely after urinary tract injury. These effusions usually lack significant inflammatory cells.

Large effusions compress the underlying lung and impair ventilation. Pleural fluid analysis distinguishes transudates from exudates. Management depends on treatment of the underlying condition.

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 DR.C.GANESAN M.D

PROFESSOR OF MEDICINE

 

SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS-SSTRSDO-QAA 024

1. What are the most frequent pleural tumors?

Pleural tumors may be primary or secondary. Metastatic involvement of the pleura from lung, breast, ovarian, or gastrointestinal cancers is far more common than primary pleural tumors. Malignant mesothelioma is the most important primary malignant pleural tumor and is strongly associated with asbestos exposure.

Solitary fibrous tumor is the most common benign primary pleural neoplasm. Pleural metastases often produce malignant pleural effusion. Patients commonly present with chest pain, dyspnea, cough, and pleural effusion. Imaging studies demonstrate pleural thickening or nodular masses.

Histopathology and immunohistochemistry establish the diagnosis. Prognosis depends on the tumor type and extent of disease.

2. Which etiologic agents are associated with malignant mesothelioma?

Malignant mesothelioma is strongly associated with occupational exposure to asbestos fibers, particularly amphibole asbestos such as crocidolite. The disease typically develops after a long latent period of 20–50 years following exposure.

Workers in shipbuilding, construction, insulation, and asbestos manufacturing are at highest risk. Unlike bronchogenic carcinoma, smoking does not significantly increase the risk of mesothelioma. Chronic asbestos exposure causes repeated mesothelial injury, inflammation, and genetic mutations.

Germline or somatic alterations involving the BAP1 tumor suppressor gene have been identified in many patients. The tumor most commonly involves the pleura but may also affect the peritoneum.

Strict occupational safety measures have reduced its incidence in many countries. Prognosis remains poor despite modern treatment.

3. What are the morphologic characteristics of malignant mesothelioma?

Malignant mesothelioma usually presents as diffuse nodular thickening of the pleura that progressively encases the lung like a rigid shell. The pleural surface becomes gray-white, firm, and irregular. The tumor invades the chest wall, diaphragm, pericardium, and adjacent lung tissue.

Microscopically, three major patterns are recognized: epithelioid, sarcomatoid, and biphasic (mixed). The epithelioid type forms tubules, papillae, or sheets of polygonal cells. The sarcomatoid type consists of spindle-shaped malignant cells resembling fibrosarcoma.

Immunohistochemistry helps distinguish mesothelioma from metastatic adenocarcinoma. Extensive pleural fibrosis and recurrent hemorrhagic effusions are common. Local invasion predominates, although distant metastases may occur in advanced disease.

4. What is the clinical course of disease in patients with malignant mesothelioma?

Malignant mesothelioma has an insidious onset and an aggressive clinical course. Patients usually present with progressive dyspnea, persistent chest pain, dry cough, fatigue, and weight loss. Recurrent pleural effusions are common and often hemorrhagic. As the tumor enlarges, it encases the lung, causing severe restriction of lung expansion and respiratory impairment. Local invasion into the chest wall produces persistent pain.

Diagnosis is established by imaging, thoracoscopy, biopsy, and immunohistochemical studies. Most patients present with advanced disease because early symptoms are nonspecific.

Treatment includes surgery in selected patients, chemotherapy, immunotherapy, and palliative care. Despite advances in management, the overall prognosis remains poor, with a median survival of approximately 12–18 months after diagnosis.      

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DR.C.GANESAN M.D

PROFESSOR OF MEDICINE

 

SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS-SSTRSDO-QAA 023

1. Describe the content of a typical empyema.

 

Empyema is the accumulation of pus within the pleural cavity, usually resulting from bacterial pneumonia, lung abscess, thoracic surgery, or chest trauma. The pleural cavity contains thick yellow-green purulent exudate composed of numerous neutrophils, necrotic cellular debris, fibrin, bacteria, and protein-rich fluid.

The pleural surfaces become inflamed, roughened, and coated with fibrin. As healing occurs, fibroblasts organize the fibrin, leading to pleural adhesions and fibrosis. Untreated empyema may become loculated and difficult to drain. Severe cases may progress to sepsis or bronchopleural fistula.

Patients present with fever, pleuritic chest pain, cough, and dyspnea. Prompt drainage combined with appropriate antibiotics is essential for successful treatment.

2. Describe the main types of pneumothorax.

Pneumothorax is the presence of air within the pleural cavity, resulting in partial or complete collapse of the lung. Spontaneous pneumothorax occurs without trauma and is classified as primary or secondary.

Primary spontaneous pneumothorax commonly results from rupture of subpleural blebs in otherwise healthy young adults. Secondary spontaneous pneumothorax develops in patients with underlying lung diseases such as COPD, tuberculosis, cystic fibrosis, or interstitial lung disease.

Traumatic pneumothorax follows penetrating or blunt chest injury or medical procedures. Tension pneumothorax is a life-threatening emergency in which air enters the pleural cavity but cannot escape, causing progressive mediastinal shift and cardiovascular compromise.

Patients present with sudden chest pain, dyspnea, and reduced breath sounds. Immediate decompression is required in tension pneumothorax.

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 DR.C.GANESAN M.D

PROFESSOR OF MEDICINE

 

SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS-SSTRSDO-QAA 022

List the most common therapy-related pulmonary complications.

Therapy-related pulmonary complications occur following medications, radiation, chemotherapy, oxygen therapy, or bone marrow transplantation. Drug-induced pneumonitis is commonly caused by bleomycin, amiodarone, methotrexate, and nitrofurantoin. Radiation therapy may produce acute radiation pneumonitis followed by pulmonary fibrosis.

Oxygen toxicity causes diffuse alveolar damage after prolonged administration of high oxygen concentrations. Chemotherapy may predispose to opportunistic pulmonary infections due to immunosuppression.

Pulmonary edema may occur after massive blood transfusion or fluid overload. Bronchiolitis obliterans may develop after lung or stem cell transplantation. Pulmonary embolism is another important treatment-related complication.

Early recognition and withdrawal of the offending agent improve outcomes. Careful monitoring minimizes therapy-associated lung injury.

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DR.C.GANESAN M.D

PROFESSOR OF MEDICINE

 

SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS-SSTRSDO-QAA 021 

Which diseases belong to pulmonary hemorrhage syndromes?

Pulmonary hemorrhage syndromes are characterized by bleeding into the alveolar spaces causing hemoptysis and anemia. Goodpasture syndrome is an autoimmune disease caused by antibodies against the glomerular and alveolar basement membranes. Granulomatosis with polyangiitis (Wegener granulomatosis) commonly produces pulmonary hemorrhage associated with systemic vasculitis. 

Microscopic polyangiitis is another important cause of diffuse alveolar hemorrhage. Systemic lupus erythematosus may also produce pulmonary hemorrhage. Idiopathic pulmonary hemosiderosis causes recurrent alveolar bleeding without an identifiable systemic disease. Histologically, alveoli contain numerous hemosiderin-laden macrophages.

Patients present with hemoptysis, dyspnea, anemia, and diffuse pulmonary infiltrates. Early diagnosis and immunosuppressive therapy improve clinical outcomes.

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DR.C.GANESAN M.D

PROFESSOR OF MEDICINE

 

SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS-SSTRSDO-QAA 020

1. Describe the difference between usual interstitial pneumonia (UIP) and desquamative interstitial pneumonia (DIP).

interstitial pneumonia

  

desquamative interstitial pneumonia

Usual interstitial pneumonia (UIP) is the histologic pattern of idiopathic pulmonary fibrosis and is characterized by patchy interstitial fibrosis with marked temporal heterogeneity.

Normal lung alternates with areas of active fibroblast proliferation and dense fibrosis. Honeycomb lung is a prominent feature of advanced UIP. The prognosis is poor because fibrosis progresses relentlessly.

Desquamative interstitial pneumonia (DIP) is strongly associated with cigarette smoking. It is characterized by diffuse accumulation of macrophages within alveolar spaces rather than true desquamation of epithelial cells. Interstitial fibrosis is mild and relatively uniform.

DIP responds well to smoking cessation and corticosteroid therapy. The prognosis of DIP is considerably better than that of UIP.

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2. Define hypersensitivity pneumonitis.

Hypersensitivity pneumonitis, also called extrinsic allergic alveolitis, is an immunologically mediated inflammatory disease caused by repeated inhalation of organic antigens.

Common antigens include moldy hay, bird proteins, fungi, and contaminated humidifiers. Both type III immune complex and type IV delayed hypersensitivity reactions contribute to the disease. Inflammation primarily affects the alveoli and interstitium. Patients present with fever, cough, dyspnea, and malaise several hours after antigen exposure.

Chronic exposure leads to interstitial fibrosis and restrictive lung disease. Histology shows interstitial inflammation with poorly formed non-caseating granulomas. Avoidance of the offending antigen is the cornerstone of treatment. Corticosteroids are useful in severe or persistent cases.

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 DR.C.GANESAN M.D

PROFESSOR OF MEDICINE

 

SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS-SSTRSDO-QAA 019

1. Which organs are most frequently involved in sarcoidosis?

Sarcoidosis is a multisystem granulomatous disease of unknown etiology. The lungs and hilar lymph nodes are the most commonly affected organs. Bilateral hilar lymphadenopathy is a characteristic radiological feature.

The skin is frequently involved, producing erythema nodosum or lupus pernio. Ocular involvement includes uveitis, conjunctivitis, and lacrimal gland enlargement.

Peripheral lymph nodes, liver, and spleen are commonly affected. Cardiac sarcoidosis may cause arrhythmias and heart failure. Neurosarcoidosis involves the cranial nerves, meninges, or brain. Hypercalcemia may occur because activated macrophages produce excess vitamin D.

Although almost any organ may be involved, pulmonary disease predominates.

2. How is the diagnosis of sarcoidosis established?

The diagnosis of sarcoidosis is based on clinical, radiological, and histopathological findings while excluding other granulomatous diseases. Chest radiography and CT scan commonly demonstrate bilateral hilar lymphadenopathy and interstitial lung infiltrates. Tissue biopsy reveals non-caseating epithelioid granulomas without central necrosis. Special stains and cultures exclude tuberculosis and fungal infections.

Bronchoalveolar lavage often shows increased CD4-positive T lymphocytes. Serum angiotensin-converting enzyme (ACE) levels may be elevated but are not specific. Hypercalcemia and hypercalciuria support the diagnosis in some patients.

Pulmonary function tests usually show a restrictive pattern. A combination of compatible clinical features and biopsy-confirmed non-caseating granulomas establishes the diagnosis.

3. Discuss the most frequent clinical symptoms in patients with sarcoidosis.

Many patients with sarcoidosis are asymptomatic and are diagnosed incidentally on chest radiography. Symptomatic patients commonly present with persistent dry cough and progressive exertional dyspnea. Fatigue, fever, weight loss, and malaise are frequent constitutional symptoms.

Chest discomfort may occur because of pulmonary involvement. Skin lesions such as erythema nodosum are common. Ocular manifestations include blurred vision, eye pain, and photophobia due to uveitis.

Peripheral lymphadenopathy may be present. Cardiac involvement may cause palpitations or syncope. Neurological symptoms occur in patients with neurosarcoidosis. Clinical manifestations vary according to the organs involved.

4. What is the clinical course of sarcoidosis?

The clinical course of sarcoidosis is highly variable. Many patients undergo spontaneous remission within two to five years. Others develop chronic persistent disease with progressive pulmonary fibrosis. Pulmonary function gradually declines in patients with extensive lung involvement.

Relapses may occur after apparent recovery. Corticosteroids are the main treatment for symptomatic or progressive disease. Immunosuppressive agents are used in steroid-resistant cases.

Cardiac or neurological sarcoidosis may be life-threatening. Advanced pulmonary fibrosis can lead to pulmonary hypertension and respiratory failure. Overall prognosis is generally favorable, particularly in patients with isolated hilar lymphadenopathy.

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 DR.C.GANESAN M.D

PROFESSOR OF MEDICINE