Download DISEASES OF THE DIAPHRAGM, CHEST WALL, PLEURA, AND

DISEASES OF THE DIAPHRAGM, CHEST
WALL, PLEURA, AND MEDIASTINUM
1
Cecil Medicine, 23rd ed. Chapter 100
BOOK REVIEW CONFERENCE
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A. THE DIAPHRAGM
The Diaphragm
3
 m/i respiratory muscle
 separate the thoracic and abd cavities
 2 components (Central noncontractile tendon and Muscle fibers)
 Controlled by phrenic n
 Respiratory function
Diaphragmatic contraction -> abd contents downward, ribs outward -> negative
intrathoracic pressure
 Nonrespiratory function (speech, defecation, and parturition)
-
THE DIAPHRAGM
Dysfunction and Fatigue
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TABLE
 Diaphragmatic
100-1 -- THERAPEUTIC
dysfunction MODALITIES TO IMPROVE DIAPHRAGMATIC FUNCTION
- Lung MECHANICAL
hyperinflation (asthma
REDUCE
LOAD or COPD) -> shorten and flatten the diaphragm -> not
generate the normal expanding action on the thorax -> coupled with ↑airway resistance
Decrease
resistance->
(administer
bronchodilators,
treatdemand
infection,
decrease
and ↓ airway
lung compliance
↑ work of breathing
-> energy
outstript
the inflammation)
supply ->
Reduce
hyperinflation
muscle fatigue, ventilation fail
Decrease ventilatory requirement (administer oxygen, control fever, avoid caloric loads)
IMPROVE
RESPIRATORY
 Diaphragmatic
fatigueMUSCLE CONTRACTILITY AND ENDURANCE
- Rapid and
shallow
breathing, respiratory alternans, and abdominal paradox
Administer
oxygen
therapy
Improve
nutrition and acidosis -> noninvasive or invasive mechanical ventilation
- Hypercapnea
Improve cardiovascular performance
Correct electrolytes (sodium, potassium, calcium, phosphorus)
Administer drugs that improve contractility (β2-agonist, caffeine)
Check for hypothyroidism or drugs that impair contractility (aminoglycosides)
Provide ventilatory muscle training
IMPROVE RESPIRATORY MUSCLE COORDINATION AND ENERGY CONSERVATION
REHABILITATION
RESPIRATORY MUSCLE RESTING
THE DIAPHRAGM
Disorders of Diaphragmatic motion
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 Diaphragmatic paralysis
-
Unilateral paralysis
1. Usually secondary to phrenic n involvement by tumor, neurologic diseases or idiopathic
2. Elevated diaphragmatic leaflet on chest radiograph
->paradoxical diaphragmatic motion with sniffing and coughing on fluoroscope
4. Usually asymptomatic
* Irreversible symptomatic -> surgical plication of the affected hemidiaphragm
-
Bilateral paralysis
1. High cervical trauma, neuropathies, or myopathies
2. Symptomatic early, dyspnea (worsened by the supine position)
3. Inspiratory abdominal paradoxical retraction
-> transdiaphragmatic pressure and/or electromyographic recording
4. Ventilatory failure -> intermittent mechanical ventilation
* Permanent paralysis with intact muscle function -> diaphragmatic pacing
THE DIAPHRAGM
Disorders of Diaphragmatic motion
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 Diaphragmatic hernias
- Congenitally week or incompletely fused area, esophageal hiatus(>70%), or
traumatic rupture of muscle
-
Anterior hernia (foramina of Morgagni, obese, Rt cardiophrenic angle),
Posterior hernia (foramina of Bochdalek, infants, Lt >Rt)
- Severity 1) extension of abdominal contents 2) strangulation
- Chest radiograph -> CT scans, gastrointestinal contrast films, radioisotope scan
of the liver
- Infants, large -> immediate surgical correction
Asymptomatic, adult with previous evidence of a hernia->observation
Surgery for diagnosis or relief strangulation
THE DIAPHRAGM
Disorders of Diaphragmatic motion
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 Hiccup
- Produced by spasm of the diaphragm followed by closure of the glottis during
-
an inspiratory effort
Self-limited, may for days or weeks
Most unknown cause, occasionally sign of disease ( CNS disorder, uremia,
herpes zoster, diaphragmatic irritation), and psychogenic
Subside spontaneously or improve initiating disease
Chronic or debilitating -> local anesthesia or phrenic n crushing
THE DIAPHRAGM
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B. THE CHEST WALL
The Chest Wall
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 Consists of the bony thoracic cage (ribs, sternum, and vertebrae) and the
repiratory muscles
 Thoracic cage (determinant of ventilation and static and dynamic lung volumes)
-> diseases of the bony thoracic cage-> alter the ventilation and ventilationperfusion relationship -> hypoxemia or hypercapnia
TABLE 100-2 -- MOST IMPORTANT RIB CAGE DERANGEMENTS
SPINE
Scoliosis (idiopathic, congenital, paralytic)
Kyphosis
Ankylosing spondylitis
STERNUM, RIBS, OR PLEURA
Pectus excavatum
Thoracoplasty
Fibrothorax
THE CHEST WALL
Derangements of the Chest Wall
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1. Kyphoscoliosis(m/c)
 Scoliosis (lateral angulation of the spine, Rt >Lt, convexity of the curvature)
Kyphosis (less important, anteroposterior angulation of the spine)
 Cobb's angle >70◦(respiratory dysfunction), >120◦ (dyspnea, respiratory failure)
Ribs over the convex side separated and rotated posteriorly & Ribs over the
concave side crowded, displaced anteriorly(decreased thoracic height) >forward bulging of the anterior wall and kyphoscoliotic hump
 Usually idiopathic, begin in child, ventilatory failure in the 4th to 6th decade
 Static lung volume↓, lung compliance↓, hypoxemia, hypercapnia
 Therapeutic approaches
-Surgical correction(cosmetic effects, minimal improvement in puImonary function)
-Oxygen, Intermittent positive pressure ventilation, nighttime ventilatory
assistance, stop smoking, aggressive treatment of bronchospasm and
respiratory infection, weight loss
THE CHEST WALL
Derangements of the Chest Wall
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2. Ankylosing Spondylitis
 fusion of the costotransverse and vertebral joints
 Inspiratory relative fixation of the rib cage
 Ventilatory failure are rare
3. Pectus Excavatum
 Congenital deformity of the lower portion of the sternum -> symmetrical bowing
of the anterior ribs
 Heart, mediastinal structures laterally displaced ->some fail to increase cardiac
output normally during exercise
THE CHEST WALL
Derangements of the Chest Wall
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4. Fibrothorax
 Pleural diseases (hemothorax or asbestosis)
 Treatment is similar to that for kyphoscoliosis, pleurectomy (pleural fibrosis)
5. Flail Chest
 Double fractures of ≥3 adjacent ribs or combined sternal and rib fractures
 Flail segment paradoxically moves inward during inspiration -> inefficient
ventilation -> ↑work of breathing
 m/c accidental chest trauma or after CPR
 supportive care with oxygenation, clear airways, and prevention of infection,
artificial ventilation(ventilatory failure), and chest fixation (large flail chest )
THE CHEST WALL
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C. THE PLERA
Definition
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Parietal Pleura
Visceral Pleura
Cover surfaces
chest wall, diaphragm,
and mediastinum
Lungs, including
interlobar fissures
Blood supply
systemic circulation
pulmonary circulation
Sensory nerves
yes
no
 Consists of a layer of mesothelial cells, smooth semitransparent
 Supported by network of connective and fibroelastic tissue, lymphatics, and vv
 Rich microvilli of mesothelial cells
-> deliver glycoproteins (hyaluronic acid)
-> ↓ friction between the lung and chest wall
THE PLEURA
Physiology
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 5 ~ 10 mL pleural fluid in cavity
facilitates lung expansion and helps maintain lung inflation
 Pleural fluid
-> low
protein concentration(<2
g/dL),
similar pH andOFglucose
value
of blood
TABLE
3 MECHANISMS
THAT LEAD TO
ACCUMULATION
PLEURAL
FLUID
-> form from parietal pleura
↑ hydrostatic
pressure
in theonmicrovascular
(heart
failure)
-> turnover
depends
the Starlingcirculation
forces and
gravity
gradient
*hydrostatic
: parietal pleura
30 (severe
cm H2O,
visceral pleura 10 cm H2O
↓oncotic
pressurepressure
in the microvascular
circulation
hypoalbuminemia)
*oncotic pressure : 25 cm H2O
↓pressure
in the pleural
spaceover
(lungthe
collapse)
-> drainage
to stomas
parietal surface of the low mediastinum, low
chest wall, and diaphragm seem to empty into the subpleural lymphatics
↑permeability of the microvascular circulation (pneumonia)
 Accumulation of pleural fluid
Impaired lymphatic drainage from the pleural space (malignant effusion)
↑hydrostatic force or ↓oncotic pressure ->low-protein transudates
↑outpouring
capillaries
or cells
or (ascites)
blocking of lymphatics -> high-protein
Movement
of fluidby
from
the peritoneal
space
exudates
THE PLEURA
Clinical Manifestations
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 Pain, dyspnea, or cough -> not sensitive and specific
(absent in some large effusions and in critically ill patients)
Pain (unilateral, sharp, worsens with inspiration or cough and radiate to the
shoulder, neck, or abdomen)
Dyspnea (compression of lung tissue and mechanical alterations in the
respiratory muscles as the fluid changes)
 Physical examination
decreased breath sounds
dullness with absent tactile fremitus
THE PLEURA
Diagnosis
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A. Radiologic Examination
 Effusion ->blunting, medial displacement of the sharp costophrenic angle
 Subpulmonic effusion -> elevation of the hemidiaphragm or widening of the
shadow between the gas-containing stomach and the lower left lung margin
 300 mL fluid may fail to be seen on PA chest radiograph
150 mL fluid may be seen on a lateral decubitus view
Supine film may obscure the diagnosis because the fluid layers posteriorly
THE PLEURA
Diagnosis
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A. Radiologic Examination
 pseudotumor
- fluid loculation in an interlobar fissure(m/c minor fissure) -> mass-like
- diagnosis is the presence of pleural fluid elsewhere and a biconvex lenticular
configuration
 Hydropneumothorax(horizontal concave margins)
 Pneumothorax (contrast between the water density of the visceral pleura
centrally and the gas radiolucency without vascular markings laterally,
expiratory film may help outline small pneumothorax)
THE PLEURA
Diagnosis
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A. Radiologic Examination
 US and CT provide better definition of pleural and parenchymal abnormalities
FIGURE 100-1 Ultrasound
image of the left hemithorax
FIGURE 100-2 Computed tomography
of the patient shown in Figure 100-1
THE PLEURA
Diagnosis
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B. Diagnostic procedures
1. Thoracentesis and pleural fluid analysis
2. Percutaneous pleural biopsy
3. Exploration of the pleura
1. Thoracentesis and pleural fluid analysis
 Diagnostic thoracentesis
- diagnostic in approximately 75%, help exclude other important Dx(empyema)
* As a rule, newly discovered effusions should be tapped !!!
- no absolute contraindications
- relative contraindications -> bleeding diathesis, anticoagulation, small
volume, mechanical ventilation, and a low benefit-to-risk ratio
 Therapeutic thoracentesis
- no ≥1000 to 1500 mL at one time because of the re-expansion pulmonary
edema)
THE PLEURA
Diagnosis
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1. Thoracentesis and pleural fluid analysis
 Differentiate “transudate” or “exudate”
- Not absolute, but helpful in suggesting further evaluation and possible Dx
- Exudates defined by least 1
(1)pleural fluid–serum protein ratio >0.5
(2) pleural fluid–serum LDH ratio >0.6
(3) pleural fluid LDH concentration > 200 IU/L
TABLE 100-4 -- CHARACTERISTICS OF PLEURAL FLUID TRANSUDATES
Absolute Value
Pleural Fluid/Serum Value
Protein
<3 g/dL
<0.5
Lactate dehydrogenase
<200IU/L
<0.6
Glucose
>60 mg/dL
1.0
White blood cell count
Cholesterol
<1000/mm3
<45 mg/dL
—
THE PLEURA
Diagnosis
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 Malignancy, empyema (pus), tuberculosis (positive AFB in smears or culture),
fungal infection (positive potassium hydroxide stains or culture), pleuritis of SLE
(LE cells), chylothorax (↑ TG or chylomicrons), urinothorax (pleural fluid–serum
creatinine ratio >1), and esophageal rupture (↑amylase and ↓pH)
 Corrrelation of pleural fluid exudate findings and causative disease
PMNs (bacterial infection), lymphocytes (tuberculosis, lymphoma, leukemia),
eosinophils (non-specific, long-standing fluid or air, previous thoracentesis)
- bloody effusion (trauma, malignancy, pulmonary infarction), white effusion(chyle,
cholesterol, lymphoma), black fluid (aspergillosis), yellow-green (rheumatoid
pleurisy
- putrid odor (anaerobic empyema), ammonia odor(urinothorax)
- ADA (tuberculosis) (see later text)
-
 Complications of thoracentesis (pain, bleeding, pneumothorax, infection, and
spleen or liver puncture
THE PLEURA
Diagnosis
23
TABLE 100-5 -- CORRELATION OF PLEURAL FLUID EXUDATE FINDINGS AND
CAUSATIVE DISEASE
Tests
Diseases
pH <7.2
Empyema, malignancy, esophageal rupture, rheumatoid, lupus, and
tuberculous pleuritis
Infection, rheumatoid pleurisy, tuberculous and lupus effusions,
esophageal rupture
Pancreatic disease, esophageal rupture, malignancy, ruptured ectopic
pregnancy
Collagen vascular disease
Glucose (<60 mg/dL)
Amylase (>200 μg/dL)
RF, ANA, LE cells
Complement (decreased) SLE, rheumatoid arthritis
RBCs (>5000/μL)
Trauma, malignancy, pulmonary embolus
TG>110 mg/dL
Tuberculosis, violation of the thoracic duct
Biopsy (+)
Malignancy
ADA (>40 μg/L)
Tuberculosis
THE PLEURA
Diagnosis
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2. Percutaneous Pleural Biopsy
 undiagnosed exudative effusion (particularly those with lymphocytic
predominance, most frequently malignancy or tuberculosis)
 under local anesthesia with a hook-type needle
 Contraindications (small or loculated pleural effusion, uncooperative, and
anticoagulation or a bleeding diathesis)
 Multiple samples are needed (pleural seeding not be uniform)
 diagnostic 60% for malignancy and 75% for tuberculosis
3. Exploration of the Pleura
 5 to 10% of patients with undiagnosed effusion, the effusion itself disappears
spontaneously or the cause becomes evident and necessary to make a
diagnose
 VATS under local anesthesia, high yield (>85%)
 Open pleural biopsy under general anesthesia, larger specimens and
concomitant lung tissue.
THE PLEURA
Differential Diagnosis
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A. Transudative Effusion
 Biventricular failure with venous hypertension (m/c cause)
 often bilateral, usually Rt>Lt, vascular congestion and cardiomegaly
 Thoracentesis is indicated if febrile, large and unilateral effusions,
pain/unexplained hypoxemia
 liver cirrhosis (5~10% )
- movement of ascitic fluid, Rt>Lt
- radioactive tracer injected in the ascitic fluid appears in the chest
- ascites control, Occasionally chemical pleurodesis for symp, recurrent effusions
 nephrotic syndrome (20%)
- ↓oncotic pressure (hypoalbuminemia) and ↑ hydrostatic forces, peritoneal
dialysis, or atelectasis
- Bilateral
- correct the protein-losing nephropathy
THE PLEURA
Differential Diagnosis
26
B. Exudative Effusions
1. Infections
 Parapneumonic effusion (m/c)
- Uncomplicated & complicated
- Uncomplicated effusions
-> resolve with antibiotics, moderate PMNs, a glucose value similar to that of
blood, pH >7.30, and an LDH <500 U/L
Complicated effusions
-> drainage, large numbers of PMNs(>100,000/mm3), pH < 7.20, glucose <40
g/dL, and LDH >1000 U/L
- Purulent and bacteria -> immediate drainage
- Persistent fever for 48 to 72 hours with complicated effusions
-> drainage is inadequate ?(loculated) -> VATS, intrapleural streptokinase
-> antibiotic is inappropriate?
-> diagnosis is wrong?
THE PLEURA
.
Differential Diagnosis
27
2. Tuberculosis
 Small, moderate effusion on chest radiograph,1/3 parenchymal dis
 Protein(>4g/dl), WBC about 5000 cell/mm3, lymphocyte dominant( PMN
dominant for the first few days), low glucose, pH 7~ 7.3( pH > 7.4 vitually
excluding tuberculosis), ADA( >40ug/L), mycobacterial antigen (rapid
diagnosis)
 Multiple samples from closed pleural biopsy (50~80 % positive), cultures(30~70
% positive)
3. Immunologic causes of pleural effusion
 RA(5%) low glucose(<30ng/dl), low pH, high LDH, low complement, high RA
factor
 SLE(5%) normal pH and glucose, hemolytic complement(C3,C4), LE cells ANA
ratio >1:160
THE PLEURA
Differential Diagnosis
28
4. Malignancy
 Lung ca invasion(m/c), breast ca, ovarian ca, gastric ca
 Abentant RBCs(30,000 to 50,000 /mL), Lymphocyte dominant, occasionally
transudate(5 to 10%), positive cytology(60%), positive biopsy(70%, repeated
thoracentesis)
5. Hemothorax
 Pleural blood (Hct>20%)
 Trauma, hematologic disorders, pulmonary infarction, pleural malignancy
6. Malignant mesothelioma
 80 to 90 % asbestos exposure
 Dispend, cough, Wt loss, pain
 Massive effusion, often bloody, 70% pH <7.3
 Elevated hyaluronic acid, special stain, electron microscopy of biopsy tissue
29
7. Pneumothorax
 (1) perforation of visceral pleura and gas from the lung (2) penetration of the
chest wall, diaphragm, mediastinum, esophagus (3) gas generated
microorganisms in empyema
 Simple spontaneous pneumothorax
healthy, 20 to 40 yrs, spontaneous rupture of subpleural blebs at the apex
Rt>Lt, frequent recurrence, acute pain, dyspnea, cough, decreased breath
sounds, tactile fremitus, ipsilateral hyperresonance
visceral pleural line on chest radiograph
small(<20%), asyptomatic -> observation -> reabsorbed in 7 to 14 days
large(>50%), symptomatic, tension pneumothorax -> chest tube
 Secondary or complicated pneumothorax
Trauma, pulmonary diseases(emphysema ,m/c)
chest tube
30
D. THE MEDIASTINUM
Definition
31
 Mediastinum
- bounded by the thoracic inlet, diaphram,
sternum, vertebral bodies, and pleura
- contain many vital structures
 Anatomic compartments
Anterior
From the sternum to the pericardium, ascending aorta,
and brachiocephalic vessels
contains the thymus, thyroid gl, parathyroid gl, blood vv,
pericardium, and LNs
Middle
Figure 100-4. Anatomic
Compartment of the
Mediastinum
to the posterior pericardium
contains the heart, great vv, trachea, main bronchi, LNs,
phrenic n, and vagus n
Posterior
to the dorsal chest wall
contains the vertebrae, descending aorta, esophagus,
thoracic duct, azygous and hemizygous veins, vagus,
sympathetic chains, and LNs
THE MEDIASTINUM
Clinical Manifestations
32
 Most mediastinal masses are asymptomatic
m/c symptoms are chest pain, cough, hoarseness, and dyspnea
- stridor, dysphagia, and Horner's syndrome infrequently
-
 Syndromes associated with primary mediastinal lesion
Myasthenia gravis in thymoma
- Hypoglycemia in mesothelioma, fibrosarcoma, and teratoma
- Hypercalcemia in parathyroid tumors
- Neurologic symptoms in neurogenic tumors
-
 Physical examination is usually nonspecific
-
superior vena cava obstruction (facial edema, dilated veins, and arm edema)
THE MEDIASTINUM
Diagnosis
33
 Chest CT
-



-
-
initial procedure of choice
Other radiologic evaluation
angiography, esophagography, and MRI
Asymptomatic and benign by CT
careful follow-up
Histologic diagnosis
mediastinoscopy or mediastinotomy for a
nterior and middle compartment lesions
Thoracotomy for middle and posterior co
mpartment lesions or when surgery is th
e treatment of choice for the suspected l
esion
CT-guided needle aspiration has become
the procedure of choice in many centers
Figure 100-5,6,7. PA
and lateral chest
radiograph of patient
with a mass in the
anterior mediastinum.
The mass proved to
be a dermoid cyst in
CT scan.
THE MEDIASTINUM
Diagnosis
34
 Tumors
m/c cause of a mediastinal mass in older pts is a metastatic carcinoma (m/c
bronchogenic carcinoma)
- In young adults, primary mediastinal pathology is more frequent
-
Anterior
Middle
Posterior
Thymoma
Lymphoma
Neurogenic tumors
Lymphoma
Cancer
Enteric cysts
Teratogenic tumors
Cysts
Esophageal lesions
Thyroid aneurysms
Aneurysms
Diaphragmatic hernias
(Bochdalek)
Parathyroid aneurysms
Hernia (Morgagni)
Table 100-6. Most Frequent Causes of Mediastinal Masses
THE MEDIASTINUM
Diagnosis
35
 Tumors
1. Neurogenic tumors
- M/c(20%) posterior mediastinal mass, most benign
- Nonspecific chest pain, nonproductive cough
- Nerve sheath (neurilemoma, neurofibroma) or sympathetic ganglion cells
(ganglioneuroma)
- Pheochromocytomas may occasionally arise in the mediastinum
- Treatment resection
* Neuroblastomas (malignant tumor) require postoperative radiation therapy
2. Thymomas (20%)
- Anterior mediastinum
- 2/3 malignant
- 40% Myasthenia gravis, paraneoplastic syndromes (Cushing's syndrome,
refractory anemia, and hypogammaglobulinemia)
- Treatment regarded as malignant, and surgical resection followed by radiation
therapy
THE MEDIASTINUM
Diagnosis
36
3. Lymphatic tumors (17%)
- Anterior mediastinum
- Hodgkin's lymphoma (most frequent and best prognosis), Non-Hodgkin's
lymphoma, plasmacytomas, and angiomatous lymphoid hamartomas (worse
prognosis)
4. Teratomatous tumors (10%)
- anterior compartment
- 1/3 malignant, more frequent cystic teratomas
- embryologically and histologically linked to the thymus
- Contain squamous cells, hair follicles, sweat gl, cartilage, and calcifications
5. intrathoracic goiter (10%)
- Anterior mediatinum
- usually benign nodular or follicular enlargement of the thyroid gl
- 3/4 stridor, cough, and dyspnea
- occasionally cause superior vena cava syndrome
THE MEDIASTINUM
Diagnosis
37
6. Benign cysts
- Asymptomatic
- Bronchogenic cysts ; middle and posterior compartments (around the
paratrachea or carina), lined with respiratory epithelium and cartilage (not
communicate with the tracheobronchial tree)
- Pericardial cysts ; anterior compartment (cardiophrenic angle), endothelial or
mesothelial lining
- Enteric cysts ; posterior mediastinum, lined by gastric or intestinal epithelium,
may become infected, bleed, or rupture
7. Vascular tumors
- Vascular hamartomas, lymphangiomas, and hemangiomas -> benign
- hemangiopericytomas -> malignant
-
8. Hernias through the diaphragm
- foramen of Morgagni, foramen of Bochdalek, esophageal hiatus(m/c)
THE MEDIASTINUM
Diagnosis
38
 Pneumomediastinum
- Tears in the esophagus or tracheobronchial tree ( -> traumatic) or alveolar
-
rupture ( -> spontaneously or complication of artificial ventilation)
Subcutaneous emphysema or pneumothorax, or both.
Retrosternal pain and dyspnea, classic crepitus of subcutaneous emphysema
(Hamman's sign)
Lateral chest radiograph usually diagnostic
Simple, spontaneous -> generally resolves without treatment
Severe or organ rupture -> surgical drainage and repair
 Superior Vena Cava Syndrome
- Obstruction of blood flow through the superior vena cava
- Causes dilation of the collateral veins of the upper thorax and neck and edema
-
and congestion of the face
Headache, dyspnea, dysphagia, and wheezes
Malignancy m/c cause ( m/c bronchogenic carcinoma, 2nd lymphoma)
invasive procedures are contraindicated
by tumor, Irradiation, chemotherapy, or stent placement should be initiated
before attempts are made to obtain mediastinal tissue
THE MEDIASTINUM