Pleural Diseases and Disorders Flashcards
- Define parietal pleura, visceral pleura, pleural space, pleural effusion, and pneumothorax.
parietal pleura: membrane that lines chest wall and diaphragm, blood from intercostal arteries and drains into RA
visceral pleura: membranes that lines lung surfaces, blood from bronchial circulation, and venous drain into pulmonary veins
pleural space: potential space with surface tension derived from this thin layer of pleural fluid
pleural effusion: increased fluid in the pleural space
pneumothorax: air in the pleural space
- Describe the mechanisms and pathways by which pleural fluid is formed and absorbed under normal conditions.
pleural space negative pressure -5 at FRC, net inward hydrostatic forces between parietal pleural and pleural space as well as between the visceral pleural space and net outward oncotic forces between the parietal pleura and the pleural space
at the parietal pleura there is ante gradient of 6cm H2O favoring movement from the parietal capillaries to the pleural space, the visceral pleura, the hydrostatic and oncotic pressures balance and no gradient is therefore established
normally, pleural fluid is formed by the parietal pleura
- Describe the mechanisms and pathways by which excessive amounts of pleural fluid and air can accumulate.
CHF increased microvascular pressure and fluid filtration in capillaries of the visceral pleura (L-visceral; R- parietal)
increased capillary permeability, decreased oncotic pressure, lymphatic obstruction, increased peritoneal fluid with fenestrations in the diaphragm or increased negative pleural pressure secondary to collapsed lung
- List common disease states that result in pleural effusions.
CHF parapneumonic effusion malignant pleural effusion pulmonary embolism viral disease cirrhosis with ascites post CABG GI disease TB malignant mesothelioma asbestos exposure
- Identify the distinction between exudative and transudative plural effusions.
transudates: fluid formed by increased hydrostatic pressure or decreased oncotic pressure
exudates: fluid formed by increased permeability of pleural capillaries or in area where fluid originates
- Correlate the pleural fluid findings with the history, physical examination, laboratory findings, and radiologic changes in different diseases and conditions.
PE: side of the effusion over the area of effusion, absent or decreased tactile fremitus; dull or flat percussion note which is most dull over bases; decreased or absent sounds on auscultation
d/dx: elevated hemidiaphragm, pneumonia, pulmonary mass
radiograph: blunted costophrenic angle
effusion is exudate if (any):
ratio of pleural fluid protein level to serum protein level >0,5
ratio of pleural fluid LDH level to serum LDH level >0.6
pleural fluid LDH level ⅔ the upper limit of normal for serum LDH level
- Analyze the changes in appearance, total differential cell count and biochemical values of pleural fluids under different diseases conditions.
Cell count: RBC>100,000, most transudates WBC1000
pleural fluid dx. WBC:
nueutrophil predominance (>50%)- parapneumonic, pancreatitis, pulmonary embolism, subphrenic abscess, early TB
lymphocyte predominance (>50%) malignancy, TB pleuritis, post CABG
eosinophilia (>10%)- air or blood in pleural space, asbestosis related, eosinophilic pneumonia, drug-induced, parasitic, Chrug Strauss syndrome
low pH or glucose are seen in rheumatoid pleurisy, emphysema, TB pleurisy, lupus pleuritis, or esophageal rupture
high triglycerides seen in disruption or obstruction of the lymphatic system (chylothorax)
amylase: acute or chronic pancreatitis and in esophageal perforation or malignancy
pleural fluid cytology: identify pleural malignancies with 3 serial samples improved sensitivity
- Explain how a pleural effusion or pneumothorax can affect respiratory mechanics and gas exchange.
overall pleural effusion fluid will cause a restrictive defect (decreased TLC) with approximately proportional reduction in the different lung sub volumes, aspiration of fluid reduces dyspnea but improve PFTs less than expected
patients with a large effusion usually will have hypoxemia and hypocaptnea (mostly due to atelectatic lung)
- Explain the principles of how to diagnose and treat pleural effusions.
tx. of underlying condition, and removal of accumulated pleural fluid
recurrent: serial drainage with a tunneled pleural catheter or elimination of the pleural space by pleurodesis
- Describe the etiologies of pneumothorax and who is at risk for each type.
primary: cigarette smoking and with being tall and thin (peak age of occurrence in early 20s) related to high mechanical stress in the apex of lung
secondary: in patients with underlying disease where blebs develop and rupture (COPD, CF, pneumonia, sarcoid, TB, LAM and Langerhans cell histiocytosis)
iatrogenic: after transthoracic needle aspiration, subclavian sticks, thracentesis, trans bronchial biopsy, pleural biopsy, positive pressure ventilation, supraclavicular stick or nerve block
traumatic: penetrating chest trauma, fractured ribs, sudden chest compression causes increased alveolar pressure and rupture, with air dissecting towards the pleura and rupturing it
- Explain the pathophysiology of a pneumothorax and derangements seen in lung volumes and blood gases.
entry of air into the pleural space decouples the chest wall from the lung; VC is reduced, PaO2 is reduced and increased A-a gradient
- Define tension pneumothorax and describe its pathophysiology.
if air continues to enter the pleural space, during each inspiration and there is a one way valve limiting excite, the pressure in the pleural space progressively increases until it exceeds atmospheric pressure (can cause a shift in midline structures and reduced right heart filling)
- Describe the therapeutic interventions for a patient with penumothorax.
depends on etiology
supplemental O2 throughout to speed recovery from spontaneous pneumothorax, lower capillary blood N2, establishing a gradient for N2 rich atmospheric air
secondary, large or traumatic causes: draining the pleural air by manual aspiration or using a chest tube
chest tub for tension pneumothorax
recurrent usually undergo pleurodesis to stable or remove blebs
- Describe the clinical findings/symptoms of pneumothorax.
spontaneous: acute chest pain and or dyspnea, usually develops while at rest, chest pain may wane but dyspnea persists, ipsilateral hemithroax moves less on breathing and may appear larger, decreased fremitus, hyper resonant percussion note, and absent or reduced breath sounds
clinical manifestations are often more severe and depend on underlying disease
