9/24- Pleural & Mediastinal Disease Flashcards
What are the parietal and visceral pleura?
- Blood supply
Parietal pleura
- Systemic circulation
- Adjacent to chest wall
Visceral pleura
- Bronchial circulation
- Adjacent to lung
How much fluid is normally in the pleural space?
Normal ~15 mL
What causes increased pleural fluid formation? (broad mechanisms and examples)
Increased pleural fluid formation
- Hydrostatic changes: transudative
- CHF (s)
- Atelectasis
- Oncotic changes: transudative (s)
- Altered pleura with increased permeability: exudative (l)
Decreased lymphatic drainage: exudative (l)
Combination of above
(s) = systemic factor; treat systemic condition
(l) = local factor; more serious
What are the symptoms and signs of pleural effusion?
- Shortness of breath
- Sudden onset if cause is air
- More slow/progressive if due to CHF transudate
- Cough
- Less common
- Pleuritic chest pain
- more early; not so much later when pleura is spread wide apart by large effusion
- Decreased breath sounds
- Dullness to percussion
- Decreased tactile fremitus
- Distinguishes this from pneumonia
- Decreased chest wall expansion
- Tracheal shift (massive effusions)
How to distinguish between pleural effusion and pneumonia on physical exam?
Tactile fremitus
- Decreased breath sounds in pleural effusion
What is seen in radiology of pleural effusion?
- Blunting of costophrenic angle on PA CXR (at 100 mL)
- Larger amts: characteristic lower lung field homogeneous density that forms a concave meniscus
- Lateral decubitus film: fluid will “layer” if in significant amount
What is seen here?
Pleural effusion
- Fluid “layers” and somewhat clears lung field
What is seen here?
Large effusion- concave mensicus and shift of mediastinum to the right
When is it safe to do a thoracentesis (how much pleural fluid)?
If you can see ~1 cm of layering
Describe thoracentesis
Removal of pleural fluid transthoracically to diagnosis etiology of effusion and/or treat (remove fluid to reduce symptoms)
- Ultrasound-guided
What is seen here?
Can see diaphragm and overlying fluid (and a little collapsed lung)
What are complications of thoracentesis?
- Pneumothorax (11%, 2% require chest tube; down to 3% know with ultrasound guidance)
- Vasovagal reaction
- Infection (2% of pleural infections)
- Hemothorax
- Splenic/hepatic laceration
- Seeding of tumor (mesothelioma)
- Adverse RX to local anesthesia
- HIV/Hepatitis B (like any needle procedure)
- Re-expansion pulmonary edema
- Depends on rapidity [and a little quantity] of fluid removal due to induced negative P in lung
- Only remove 1-2L at a time, max
- Can measure pleural pressure (nl ~ 5); with pleural effusion P will be 0 -> (+). Keep drawing fluid until too negative (~ - 20)
Should needle be entered right above the lower rib or right below the upper rib?
Just above lower rib
- Vascular bundle located just under ribs, so avoid that
What is seen here?
Patient with large pleural effusion (see meniscus sign on left; right lung)
Same pt following chest tube for fluid removal of his pleural effusion. What is this?
Re-expansion pulmonary edema following rapid removal of pleural effusion fluid
What is the first decision point in evaluation of effusions?
- How is this done/what criteria?
Transudative vs. Exudative effusion
- Based on the results of evaluation of pleural fluid
- Differentiation based on Light’s criteria
What is Light’s criteria?
Exudate has at least 1 criteria, a transudate has none:
- Pleural/serum protein > 0.5
- Pleural/serum LDH > 0.6
- (pleural) LDH > 2/3 upper limit
If you can only do 1 test, want LDH (determines 2 criteria)
What are some causes of transudative effusions?
- Congestive heart failure
- Cirrhosis
- Nephrotic syndrome
- Ascites
- Peritoneal dialysis
- Hypoalbuminemia
What are some causes of exudative effusions?
- Infections (i.e., parapneumonic, TB)
- Malignant disorders(lung CA, mets, mesothelioma)
- Collagen vascular diseases
- Pulmonary embolism
- Gastrointestinal disease
- Pancreatitis and pancreatic pseudocyst (high amylase)
- Esophageal rupture (high amylase)
- Abdominal or retroperitoneal abscess
Are transudative or exudative effusions more common?
Transudative
- Due to commonality of CHF (no.1)
What are the most common causes of effusions (either transudative or exudative)?
- CHF
- Infections (parapneumonic)
- Primary lung malignancy
What causes problems with post coronary artery bypass graft surgery?
If exudative fluid sits there for a long while, visceral pleura thickened and won’t recover even with fluid recovery
- “Trap lung”
- Have to peel visceral pleura off lung
Which type of pleural effusion requires further evaluation?
- Examples of further studies
- When to do a pleural biopsy
Exudative
- Cultures, gram stain if you think infectious
- Cytology if you think cancer
- Consider pleural biopsy for undiagnosed exudates after 2-3 thoracentesis attempts
- No further pleural studies are required in transudative (consider evaluation for underlying processes)
If you get exudate from pleural effusion, what main etiologies are you worried about?
- Neutrophil predominance?
Worried about:
- Cancer
- TB
Neutrophil: bacterial infection
What is a complicated parapneumonic effusion?
- Associations
- Indications
Associated w/ pulmonary infection, do not resolve without intervention
What are signs of complicated parapneumonic effusion (indications for possible chest tube drainage and possible thrombolytic therapy/thoracoscopy)?
- Loculated
- Positive gram stain/culture
- pH under 7.2
- Low glucose: < 60 MG/DL (especially < 40 MG/DL)
- pH between 7.0 and 7.2 and high LDH: > 1000
- Thick Pus
What is seen here?
Complicated parapneumonic effusion:
- Loculated pleural effusion
- Thickened pleura
What are characteristics of a Tubercuous Effusion?
Early-small effusion
- PMN’s
- Culture positivity higher
Later-larger
- 90% lymphocytes
- Positive culture less common PPD negative in 30%
TB markers in fluid:
- Adenosine deaminase
- Interferon gamma, or
- PCR (polymerase chain reaction) for tuberculous DNA Undiagnosed serous, lymphocytic exudate with +PPD requires treatment
What are charcteristics of pleural effusions due to malignancy ?
- What may predict prognosis
- 10% are transudates, not related to pleural involvement
- Effusion may be bloody
- Lymphocyte predominant effusion
- pH under 7.30 (30%) and low glucose predicts a decreased survival time
- Diagnosis made by cytology
What is seen here?
Pneumothorax
What are classifications/causes of pneumothorax?
Spontaneous
- Primary
- Secondary
- Underlying lung dz (e.g. COPD with large bullae)
Traumatic
- Iatrogenic
- Non-iatrogenic
Clinical signs of pneumothorax?
- Dyspnea
- Cough
- Pleuritic chest pain
- Increased pressures on mechanical ventilation
- Decreased chest wall motion
- Hyper-resonance to percussion
- NO breath sounds in that area (really significant)
- Decreased vocal resonance
Describe primary spontaneous pneumothorax
- Cause
- Associations
- Clinical phenotype
- Treatment
- “Idiopathic” pneumothorax
- Usually related to rupture of apical pleural “blebs”
Clinical:
- Usually 20-30 years of age
- Tall, thin
- Mainly smokers
- Males > females (5x)
Presentation:
- Acute onset of severe unilateral chest pain with dyspnea
Treatment:
- Small, non-enlarging pneumothorax: observe
- Large or enlarging: place chest tube
What is the prognosis of primary pneumothorax (PTX)?
- 20-30% recur within 5 years
- Those with 1st PTX are more likely to have subsequent PTX
To prevent recurrence:
- Thoracotomy with over sewing of apical blebs if present and pleural abrasion
- Versus initial attempt at chest tube and chemical pleurodesis (irritate pleura and cause adhesion… to?)
Describe secondary spontaneous pneumothorax
- Associations
- Symptoms/presentation
- Diagnostic method
- Most common with underlying COPD (emphysema)
- Can be difficult to recognize clinically
- Suddenly worsening dyspnea and respiratory status with acute chest pain
- CXR diagnostic
What is a tension pneumothorax?
- Cause
- Signs/symptoms
- Trachea movement?
- Treatment
- Most often occurs during mechanical ventilation or resuscitation
Signs/symptoms:
- Cyanosis and hypotension
- Absence of breath sounds on affected side
- Shift of trachea away from affected side
Treat: large bore catheter to rapidly remove gas followed by chest tube placement
How can the mediastinum be divided?
- Anterior-lying forward and superior to the heart shadow and extending to the anterior vertebrae
- Middle-triangular shaped, extending from the heart shadow to the anterior vertebral border
- Posterior-occupies the space within the margins of the vertebra
What are contents of the anterior mediastinum?
- Thymus gland
- Sub-sternal extensions of thyroid and parathyroid glands
- Aortic arch and major branches
- Innominate veins
- Lymphatic vessels and lymph nodes
What are contents of the posterior mediastinal compartment?
- Esophagus
- Thoracic duct
- Descending aorta
- Lymph nodes
- Azygos and hemiazygos veins
- Vagus nerves and sympathetic chains
What are contents of the middle mediastinal compartment?
- Heart and pericardium
- Trachea and main bronchi
- Hila and LNs
- Phrenic and vagus nerves
Possible masses of mediastinum (for all compartments)? [from picture; skim]
Posterior
- Neurogenic tumors/cysts
- Meningocele
- Lymphoma
- Esophageal disease: neoplasm, diverticula, megesophagus, Bochdalek hernia
- Aneurysm
Anterior:
- Thymomas
- Substernal thyroid
- Parathyroid lesions
- Germinal cell neoplasms
- Lymphomas
Middle
- Bronchogenic cysts
- Pleuropericardial cysts
- Lymphadenopathy: sarcoidosis, malignancy, granulomatous disease
- Aneurysms
- Morgagni hernias
What are symptoms of mediastinal masses?
- Cough: compression of the trachea or bronchi
- Chest pain: traction on tissue, dull, constant, exacerbated when lying down
- Dysphagia (difficulty swallowing), seen with posterior mediastinal masses
Symptoms secondary to nerve compression/invasion
- Hoarseness: recurrent laryngeal nerve
- Horner’s syndrome: (ipsilateral ptosis, miosis, anhydrosis), secondary to stellate ganglion involvement
- Diaphragmatic paralysis: secondary to phrenic nerve involvement
What are symptoms of medisatinal masses?
“Terrible Ts”
- Thymoma
- Teratoma
- Thyroid
- Tumor, especially lymphoma
What is the most common mass in the anterior compartment?
Thymoma
Describe thymoma
- Pt age
- Symptoms
- Pathology
- Poor prognostic signs
- Associations
- 40-60 yrs
- 2/3 are asymptomatic
Pathology: most are benign and if fully encapsulated without evidence of invasion, prognosis is good
Poor prognosis: Invasion and an associated systemic syndrome
Associated syndromes:
- 40-70% of patient have at least laboratory evidence of a “parathymic” syndrome”
- Myasthenia gravis (10-50%) most common
What is seen here?
Thymoma
- No retrosternal air space
What is the most common germ cell tumor?
- Characteristics
- Pt age
- Malignant vs. benign
- Treatment
Teratoma
- Masses are made up of tissue foreign to the area and are predominately of ectodermal derivatives (may contain hair, teeth, etc.)
- Tumor may be cystic or solid
- 80% are benign
- Usually occurs in young adults
- Treatment: surgical resection
What are common masses in the middle compartment?
- Lymphoma (10-20%)
- 1/3 are Hodgkin’s
- Usually in young adults
- 2nd most common mediastinal mass in kids
- Developmental cysts (up to 20%)
- Granulomatous diseases: TB, Sarcoidosis
- Vascular masses (aneurysms)
- Diaphragmatic hernia: herniation of fat or abdominal contents
What is seen here?
Bronchogenic Cyst
What are common masses in the posterior compartment?
- Neurogenic tumors (most common)
- Esophageal lesions: cancer, diverticula, megaesophagus
- Diaphragmatic hernia
- Aneurysms
- Lymphoma
Characteristics neurogenic tumors
- Adult vs. kid
- Symptoms
- Origin
- Most common mass of the posterior mediastinum
- 20% of adult
- 40% of masses in children
Symptoms:
- Usually asymptomatic/benign in adults
- Children 50% are symptomatic and malignant
Derivation:
- Peripheral nerves (ex. neurofibroma)
- Sympathetic ganglia (ganglioneuroma)
- Paraganglionic tissue (pheochromocytoma)
What are some causes of pneumomediastinum?
- Signs/symptoms
- Trauma
- Esophageal perforation
- Infection (gas producing)
- Alveolar Rupture (Valsalva, Labor, Mechanical ventilation)
- Severe substenal chest pain +/- radiation into the neck and arms
- Possible Hamman’s sign (crunching or clicking noise synchronous with heartbeat)-best heard in left lateral decubitus position
Describe acute mediastinitis?
- Causes
- Symptoms
- CXR results
Causes
- Infection within the mediastinum
- Include iatrogenic (perforation of trachea, or esophagus; following sternotomy for cardiac surgery)
- Direct extension
Classic symptoms:
- High fever
- Chest pain
- Hamman’s sign (auscultated mediastinal “crunch” that coincides with cardiac systole)
- Possible evidence of sternal infection
Chest x-ray; mediastinal widening and air fluid levels
Describe chronic/fibrosing mediastinitis
- Causes
Secondary to chronic inflammation and eventual fibrosis:
- Histoplasmosis
- TB
- Fungal disease
- Drugs (methysergide)
- Radiation
