What is a pleural effusion?
What volume of fluid defines a pleural effusion?
Describe some processes that cause pleural effusion
Accumulation of fluid in the pleural space
Secondary to: increased hydrostatic pressure (CHF, lymphatic blockage), decreased osmotic pressure (nephrotic syndrome), increased vascular permeability (pneumonia)
Describe the clinical manifestations of pleural effusion
dyspnea, pleuritic pain, cough, enlarged hemithorax, dullness on percussion, decreased or absent breath sounds, compression of the lung (atelectasis)
Name (4) systemic conditions that may cause pleural effusion
congestive heart failure
collagen vascular diseases
What is the treatment of choice for empyema (pyothorax)
Organization of the infection and purulent exudate produces adhesions and loculations that limit lung expansion, necessitating surgical removal
Name some underlying conditions leading to hydrothorax
Cardiac failure, pulmonary congestion, edema, cirrhosis, uremia, renal failure
Name some underlying conditions leading to hemothorax
ruptured aortic aneurysm, trauma
Damage to which structure may lead to chylothorax?
What else might cause chylothorax?
lymphatic occlusion secondary to malignancy may also lead to chylothorax
Describe the clinical symptoms of pneumothorax
Chest pain, dyspnea
Absent breath sounds on auscultation
contralateral deviation of the trachea
marked respiratory distress
Describe the common etiologies of spontaneous pneumothorax
secondary to rupture of a pleural bleb or bulla (often in a young patient)
Bronchopleural fistula or bullous emphysema
Describe the presenting symptoms and etiology of tension pneumothorax
What is observed on CXR?
sudden onset of respiratory distress secondary to a chest wall defect (penetrating trauma)
Pneumothorax and collapsed lung with trachea deviated to the contralateral side
What is a pleural fibroma? Describe it.
Rare, solitary fibrous tumor of the lung
well circumscribed, polypoid, pedunculated
cured by simple excision
associated with hypoglycemia and clubbing of the fingers
What cell type proliferates in malignant mesothelioma?
What is the most common underlying etiology?
Neoplastic proliferation of mesothelial cells lining the serosal surfaces
Idiopathic or asbestos exposure (~50% each)
Describe the clinical symptoms of mesothelioma
What is the prognosis?
- insidious, slow-growing neoplasm
- recurrent pleural effusions
- chest pain and dyspnea (advanced)
- pulmonary fibrosis (20%)
Median survival is 18 months
Describe the gross morphological appearance of pleural mesothelioma
Name the two histological subtypes of malignant mesothelioma
Rind of fibrous tissue encasing the entire lung with little-to-no invasion of the parenchyma
Histological: epithelioid type or spindle cell type
What is more common - primary lung malignancy or metastatic tumor?
Name (5) organisms that communly underly granulomatous mediastinitis
Neurogenic tumors are most commonly found in what part of the mediastinum?
- unilocular or multilocular?
- patient age range?
- children aged 5-15 years
- lined with simple cuboidal epithelium and filled with serous fluid
Thymic hyperplasia is commonly associated with what autoimmune disorder?
What is myasthenia gravis?
What are its symptoms?
What mediastinal disorders is it associated with?
Auto-antibodies to the ACh receptors in the neuromuscular junction - due to defective conrontation between ACh-secreting cells with T-lymphocytes in the thymus
Sx: weakness, fatigability, ptosis, diplopia
Associated with: thymic hyperplasia, thymoma, thymic carcinoma
What is a thymoma?
Describe the symptoms
neoplastic proliferation of thymic epithelial cells
usually contains abundant immature T-cells (not part of the tumor)
Frequently associated with myasthenia gravis
slow-growing, rarely metastasizes
Sx: usually asymptomatic, may include cough, dyspnea, chest pain, superior vena cava syndrome, and paraneoplastic syndromes
Describe the cell type found in each of the following histological classifications of thymomas
- Type A
- Type B
- Type AB
- Type A: spindle cells
- Type B: round cells
- Type AB: mixture of both round and spindle cells
Compare the prognosis of encapsulated and non-encapsulated thymomas
encapsulated: cured by complete surgical excision
non-encapsulated: may recur repeatedly and eventually metastasize. Recurrence may lead to thymic carcinoma
Describe the histologic features of thymic carcinoma
No specific or defining features
Closely resembles cell types found in carcinomas of other organs - therefore a diagnosis of exclusion