- SESROSAL MEMBRANES INCLUDE:
- Pleura – visceral and parietal – very small amount of fluid present, minimal amount of protein
- Tunica vaginalis
Pleura – visceral and parietal – very small amount of fluid present, minimal amount of protein; drainage
Drained by lymphatics, so have about 4 ml of fluid in the space, lymphatics allow for drainage in that surface to prevent fluid accumulation
- Pneumothorax is a collection of air in the pleural cavity. Air may arise from outside the chest, from the lung or esophagus: . or collapse of lung..
- Most common cause is some iatrogenic injury
Classification of Pneumothorax
- Traumatic or iatrogenic
- Spontaneous ( without apparent antecedent cause)
- Primary ( no apparent underlying lung pathology)
- Secondary (underlying lung pathology): emphysema, interstitial lung disease, etc.. rupture of the esophagus into pleural space, etc.
- Pneumothorax in which the air leaks into the mediastinal space
- Because of the orientation of the facial planes, the air dissects into the neck, face and subcutaneous tissues of chest
Diseases associated with secondary pneumothorax (not that important to know yet)
- Asthma, COPD, emphysema
- Interstitial lung disease
- Marfan syndrome
- Watch and wait
- Needle aspiration of air
- Chest tube placement – to evacuate the air in the pleural space to allow for re-expansion of the lung
- Often used synonymously with pleuritic pain
- Is the inflammation of the pleura
- Often associated with the accumulation of extra fluid in the space between the two layers of pleura (pleural effusion)
- Pain in the chest made worse with breathing
- Shortness of breath
- “stabbing” sensation, “catching” in the chest with breathing in
Causes of pleurisy
- And many other causes for a pleural effusion
Evaluation of pleuritic chest pain
- Characteristics, onset, etc. :
- Other history: oral contraceptives, recent immobility, or long car or plane travel (PE risk); TB, or asbestor exposure
- Review of systems, find out what symptoms accompany the pain that might suggest a respiratory infection, PE, or malignancy
- Pleural fluid analysis can help determine the cause of the pleurisy
- Get travel history too
- Vital signs
- Dullness to percussion suggests pleural effusion
- Auscultation, a pleural friction rub is the only sigh of pleurisy
- LOOK AT THE PATIENT and excursion..
- Examination frequently normal
- Estimated annual incidence of pleural effusion in the US is estimated to be 1.5 million
- Approx 200,000 are due to malignancy
- Etiology of effusion can be established in maj. Of cases with physical exam, and ..
- Lab evaluation examination of the fluid!!
Common causes of pleural effusions*** know these
- Bacterial pneumonia – with estension into the pleural space
Pleural effusion pathogenesis
- Increased interstitial fluid (inflammation)
- Increased venous pressure (CHF)
- Decrease oncotic pressure (low proteins)
- Decreased pleural pressure (atelectasis of lung)
- Movement of the fluid from peritoneal cavity
- Obstruction of the lymphatic channels
Imaging studies for pleural effusion
- Chest x-ray: PA and lateral views – blunting of costophrenic angles
- Lateral decubitys – identifies free flowing pleural fluid
- CT scan: currently most frequently used; can distinguish empyema from lung abscess; can detect pleural masses; can outline loculated fluid collections
- Ultrasound: useful in guiding placement for a needle in getting fluid out
Findings in pleural effusion: signs and symptoms
- Many patients don’t have any symptoms
- Pleuritic chest pain – inflammation of the parietal pleura
- Other symptoms dry, nonproductive cough and dyspnea
When withdraw fluid – what do you do?
- Examine it!!!
- If clear – good sign
- If hard, and hard to get out – major problem
- If gross blood, NOT GOOD! – probably need a chest tube or thoracic surgery
- Milky, opalescent fluid – chylothorax – blockage of lymphatics..
Should be performed for new and unexplained pleural effusions when sufficient fluid is present
Pleural fluid classification
- Exudate: inflammatory – high in proteins
- Or Transudate: 9/10 times not very inflammatory, not high in proteins
Pleural fluid laboratory examination: Criteria for Exudate vs Transudate
- Ratio of pleural fluid protein to serum protein greater than 0.5
- OR ratio of pleural flid lactate dehydrogenase (LDH) to serum LDH greater than 0.6
- OR pleural fluid LDH greater than two thirds the upper limit or normal for serum LDH (a cutoff value of 200 IU/L was used previously)
- Pleural fluid is an exudate if it meets any of the three criteria
- It is a transudate if it does NOT meet any of these criteria
Basic Lab Tests in pleural effusion
- Fluid protein
- Fluid LDH
- Fluid WBC with diff
- Gram stain
- pH, glucose
- possible Cytology – save some! Amylase – sometimes
- Serum LDH and Serum Protein
- Fluid description***!!!
Exudative Effusion causes – very long list
- Bacteria, viral, Tb, fungus, parasite
- Collagen vascular disease
- Other diseases, trauma, drugs
Transudative pleural effusuions
- Narrows Dx to:
- Hypoalbuminemia – cirrhosis
- Nephrotic syndrome
- Protein losing enteropathy
- All have protein ratio < 0.5, LDH ratio < 0.6
Evaluation of parapneumonic effusion
- An accumulation of a pleural effusion in association with pneumonia.
- Protein ratio >0.5; LDH ration>0.6
- Means EXUDATIVE EFFUSION: .
- To drain the effusion or not depends on: bacteriology and chemistry (pH) of pleural fluid
- If high pH – probably can watch
- If low pH – might really need to drain (pH<7.20); positive chest x-ray or gram stain – low fluid pH probably is complicated and needs aggressive removal
- pH, cell count, gram stain, cultures
- Pleural fluid with lymphocytes greater than 85% of the total nucleated cells, suggests:
- chronic rheumatoid (arthritis) pleuricy,
- (or chylothorax)
- So cell count can be very helpful
- Very infected pleural space
- Positive culture coming out of the pleural space
- A very low pleural glucose concentration (i.e. <30 mg/dL) indicates rheumatoid pleurisy or empyema: .
Pleural Fluid cytology
- Mesothelial cells greater than 5% of total nucleated cells makes a Dx of TB unlikely (metastatic cancer?)
- Suspect palignancy in patients with known cancer or with lymphocytic, exudative effusions, especially when bloody
- Direct tumor involvement of the pleura is diagnosed most easily by performing pleural fluid cytology
Other diagnostic modalities
- Pleural Biopsy: Abrams needle pleural biopsy of the parietal pleura is now used less with abailability of serum markers and thoracoscopy; not used any more
- Thoracoscopy – VATS, can look at pleural surface, and can direct biopsy to the abnormal surface
Pleural effusions in specific diseases
- Rheumatoid effusions have low glucose level (<25 mg/dL)
- Measurement of RF in pleural fluid is not useful, because it can be elevated in other inflammatory states
- Leakage of chyle from a disruption of the thoracic duct leads to a chylothorax.
- Milky pleural effusion, disruption of the lymphatic channels, high triglycerides (>110 mgm/dL): .
Most important thing – need to evacuate it!
Chronic effects of many inflammatory effusions
Can result in fibrosis of pleural surface
Benign pleural reaction in asvestor Induced pleural disease
90-95% of all asbestos used in the US chrysotile.
Four types of benign pleural reactions occur:
- Pleural effusions: .
- Plaques, local areas of fibrosis o fhte parietal pleura: .
- Diffuse pleural fibrosis, extensive visceral pleural fibrosis, with fusion of parietal and visceral pleural surfaces: .
- Rounded atelectasis that occurs when visceral pleural fibrosis extends into the parenchyma and renders a portion of the lung airless .
- Can also get a mesothelioma!
- Rare cancer of the membranes linng the thoracic and abdominal cavities and surrounding organs
- Virtually all cases of mesothelioma are linked to asbestos exposure and is life threatening.
- Symptoms of mesothelioma are shortness of bteath pain in the lower back or side of the chest, coughing, and weight loss
- Mesothelioma is NOT caused by cigarette smoking!
Mesothelioma relation to pleura
Because malignant mesothelioma arises from the mesothelial cells of the serosal membrane, it can be found in any serosal membrane including the pleura, peritoneum, and pericardium: .
Characteristic CT findings of Malignant mesothelioma
- Unilateral pleural effusion
- Thickening of the mediastinal pleura
- Circumferential and nodular pleural thickening of greater than 1cm
- Localized vs. diffuse (invariably malignant!!)…
- To diagnose need to look at histology!! Need biopsy
Drug-induced pleural disease
- Drug-induced pleural disease may present as pleural effusion, fibrosis, toxic or allergic manifestation during the use of a particular class of drugs
- A detailed review of drug intake often reveals the cause for the pleural pathology
- Management: usually, discontinuatin of the drug resolves the pleural process
- In some cases, addition of corticosteroid therapy is helpful
- Transudate vs. exudate
- Description of fluid
- Lab studies for fluid
- Direct biopsy