Pleural Diseases Flashcards
Pleural Effusion essentials of diagnosis
- May be asymptomatic; chest pain frequently seen in the setting of pleuritis, trauma, or infection; dyspnea is common with large effusions
- Dullness to percussion and decreased breath sounds over the effusion
- Radiographic evidence of pleural effusion
- Diagnostic findings on thoracentesis
Absorption of pleural fluid occurs through
parietal pleural lymphaticcs
A pleural effusion is
an abnormal accumulation of fluid in the pleural space
The five pathophysiologic processes that account for most pleural effusions:
1) transudates
2) exudates
3) empyema
4) hemothorax
5) Parapneumonic pleural effusions
Transudates
Increased production of fluid in the setting of normal capillaries due to increased hydrostatic pressures
Exudates
increased production of fluid due to abnormal capillary permeability
Empyema
Infection in the pleural space
Hemothorax
bleeding into the pleural space
Parapneumonic pleural effusions
exudates that accompany bacterial pneumonias
Diagnostic thoracentesis should be performed when
- there is a new pleural effusion and no clinically apparent cause
- an atypical presentation or failure of an effusion to resolve
*sampling allows visualization of the fluid and chemical and microbiologic analyses to identify underlying dz
Causes of transudates
- Heart failure (>90% of cases)
- Cirrhosis with ascites
- Nephrotic syndrome
- Peritoneal dialysis
- Myxedema
- Atelectasis (acute)
- Constrictive pericarditis
- Superior vena cava obstruction
- Pulmonary embolism
Causes of Exudates
- Pneumonia (parapneumonic effusion)
- Cancer
- Pulmonary embolism
- Bacterial infection
- Tuberculosis
- Connective tissue disease
- Viral infection
- Fungal infection
- Rickettsial infection
- Parasitic infection
- Asbestos
- Meigs syndrome
- Pancreatic disease
- Uremia
- Chronic atelectasis
- Trapped lung
- Chylothorax
- Sarcoidosis
- Drug reaction
- Post-myocardial injury syndrome
Signs and symptoms of pleural effusions
- Dyspnea, cough or respirophasic chest pain
- symptoms more common in patients with existing cardiopulmonary disease
- Small effusion less likely symptomatic than large one
- Large effusion=dullness on percussion and diminished or absent breath sounds over effusion
- massive effusion with increased intrapleural pressure may cause contralateral shift of trachea and bulging of intercostal space
Compressive atelectasis PE
-bronchial breath sounds and egophany just above effusion
Pleural friction rub indicates
infarction or pleurtitis
Grossly purulent fluid signifies
empyema
Empyema vs. chylous effusion
- CLear supernatant above pellet of white cells=empyema
- persistently turbid=chylous effusion–on analysis see high triglyceride (more than 100 mg/dL) often from disruption of the thoracic duct
*so need to centrifuge
Hemorrhagic pleural effusion
- mixture of blood and pleural fluid
- 10,000 red cells/mL create blood tinged pleural fluid; 100,000=grossly bloody
Hemothorax
presence of gross blood in the pleural space usually following chest trauma or instrumentation
-defined as a ratio of pleural fluid hematocrit to peripheral blood hematocrit greater than 0.5
Pleural exudate (vs. transudate)
- effusion that has one or more of these features:
1) ratio of pleural fluid protein to serum protein more than 0.5
2) ratio of pleural fluid LD to serum LD greater than 0.6
3) pleural fluid LD greater than 2/3 the upper limit of normal serum LD
Pleural transudate (vs. exudate)
- occur in setting of normal capillary integrity and don’t show any of the lab features of exudates
- suggests absence of local pleural disease
- Labs: glucose=serum glucose, pH bw 7.4 and 7.55 and less than 1.0 x 10^3 white blood cells/mcL (1.0 x 10^9) with predominance of mononuclear cells
What accounts for 90% of transudates? what are the most common causes of exudates?
- Transudate=Heart failure!!
- Exudate=Bacterial pneumonia and cancer
Useful in assessing parapneumonic effusions
Pleural fluid pH
-pH below 7.3 suggests the need for drainage of pleural space
An elevated amylase level in pleural fluid suggests?
pancreatitis, pancreatic pseudocyst, adenocarcinoma of the lung or pancreas, or esophageal rupture
Suspected tuberculous pleural effusion should be evaluated by
thoracentesis with culture with pleural biopsy since pleural fluid culture positivity for M. tuberculosis is low (less than 23-58% of cases)
- closed pleural biopsy reveals granulomatous inflammation in 60% while culture of 3 pleural biopsy combined with histo exam of pleural biopsy for granulomas yields Dx in 90%
- also helpful is pleural fluid adenosine deaminase and interferon gamma
Over 90% of malignant pleural effusions are exudative or transudative??
Exudative
- Any cancer can case effusions but most common causes are lung cancer and breast cancer
- In 5-10% of malignant pleural effusions, no primary tumor identified
Paramalignant pleural effusion
- effusion in a patient with cancer when repeated attempts to identify tumor cells in the pleura or pleural fluid are non-diagnostic but when there is a presumptive relation to underlying malignancy
- ex: SVC syndrome with elevated systemic venous pressures causing transudative effusion is paramalignant
- if suspect cancer, send to cytology which if negative, repeat thoracentesis
