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Pleural cavity Conditions
Ass. Prof. Dr. Hayder Al Saffar
Pleural effusion
There is a potential space between the parietal and visceral pleura that contains
only small amount of pleural fluid at any one time. The amount of pleural fluid is
governed by the factors producing and absorbing it (capillary hydrostatic pressure,
capillary permeability, lymphatic drainage and colloid osmotic pressure)..
Any disturbance of the equilibrium will lead to the development of a pleural
effusion. There are two described types; depending on the protein content of the fluid,
although the distinction is not always clear.
Exudative effusion
Accumulation of protein in the pleural space results if the lymphatic drainage is
deranged. This alters the osmotic pressure within the space and leads to the formation
of an effusion. There is usually an excess of 30g/L of protein.
The underlying pathological mechanisms are:
1. increased capillary permeability — capillary damage or inflammation
2. lymphatic obstruction
3. venous obstruction
The most common pathologies associated with exudative effusions are:
1. malignancy
2. infection
3. connective tissue disease
4. pulmonary infarction
Transudative Effusion
A transudate has less than 30 g/L of protein and is the result of low colloid
osmotic pressure e.g. liver cirrhosis or high hydrostatic pressure e.g. cardiac failure or
a combination of both.
Presentation
The clinical signs depend on the rate of effusion growth. Rapidly developing
effusions may cause severe dyspnoea, whereas slowly developing ones may be very
large but asymptomatic. On clinical examination there are reduced breath sounds on
the affected side with tracheal deviation to the opposite side. The chest is stony dull to
percussion. A pleural effusion may be the initial presentation of a systemic
malignancy in up to 30 per cent of cases.
Investigations
Radiology
A chest radiograph will determine the size of the effusion and may give a clue as
to the etiology (coexistent tuberculosis, hilar shadow, etc.).
Aspiration
thoracocentesis: Fluid is drawn for diagnosis (cytology and biochemistry) and
symptomatic relief. It is important not to remove too much fluid because pulmonary
edema may ensue. Biochemistry will determine whether the fluid is an exudate. If it is
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an exudates, then diagnostic efforts must be directed at finding the cause. Histological
examination of the aspirated fluid may be useful but the absence of malignant cells
does not rule out malignancy. The yield may be increased by pleural biopsy taken at
the same time.
Pleural biopsy/ Thoracoscopy
This is a more invasive technique performed under general anesthesia. The pleura
is opened and the effusion drained by suction. The thoracoscope is introduced and the
parietal pleural and lung are inspected thoroughly. Any suspicious nodules or plaques
may be biopsied and in the case of a recurrent malignant pleural effusion, definitive
pleurodesis may be done.
Treatment
Drainage is the usual treatment for symptomatic cases with the treatment of the
underlying condition, and pleurodesis may be required in recurrent cases.
Recently, VATS drainage, pleural biopsy and talc pleurodesis is an increasingly
performed procedure for managing patients with an undiagnosed or malignant
pleural effusion.
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Pneumothorax
Definition: The presence of air in the pleural cavity .
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Classification of pneumothorax
According to aetiology
1. spontaneous
1.a. primary(idiopathic): occurs without an obvious identifiable cause.
1.b. secondary. Any lung disease that breaches the pleura may cause pneumothorax,
so probably every possible lung disease will, at one time or another, cause a
pneumothorax. The most common causes are obstructive airways disease in any form
and bullous emphysema.
2.Traumatic. See Thoracic trauma section .
3.Iatrogenic. This is commonly seen in general hospital practice as a result of
insertion of central lines for central venous pressure monitoring, intravenous feeding
or cardiac pacing…etc.
According to pathophysiology and clinical presentation
1. closed(simple) pneumothorax
2. open pneumothorax
3. tension pneumothorax
4. haemopneumothorax
According to size
1. small pneumothorax(lung <2cm from the chest wall)
2. large pneumothorax (lung >2 cm from the chest wall)
Definitions related to pneumothorax
Open pneumothorax:
The air enters and exits the pleural cavity from the lung with every respiratory
cycle, the hole through which the air can enter usually present in the chest wall, lung
parenchyma or respiratory bronchiole.
Closed pneumothorax:.
When air accumulates in the pleura under pressure. This depends on the non return
valve-like mechanism, which is inherent in the structure of the lung. This can occur in
any type of pneumothorax.
Tension pneumothorax:
It is the clinical situation in which there is severe deterioration in clinical state with
severe dyspnoea, tachypnoea, tachycardia , sweating and signs of mediastinal shift. It
should be treated urgently on clinical ground.
Haemopneumothorax:
Life threatening condition, air in the pleural cavity is accompanied by extravasated
blood, symptoms are those of pneumothorax with haemorrhagic shock. This should be
differentiated from traumatic haemothorax and the cause of bleeding here is torn of
well vascularized pleural adhesions because of collapsed lung due to pneumothorax.
Diagnosis
The first thing is to suspect a pneumothorax and look for it deliberately in patients
at risk.
On examination the affected side is more resonant and the breath sounds, listened
for laterally in the axilla, are markedly different and reduced on the affected side.
Shifts of the cardiac apex and trachea require severe distortion and are unreliable
signs.
Chest radiography should be diagnostic.
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CT is indicated for certain cases only.
Management
1. Bed rest: should be reserved for small pneumothoraces(better not to be used
at our conditions)
2. Needle aspiration: use special type needle with safety cap as an initial
treatment modality(not routine in our practice, unless as emergency measure
with tension pneumothorax)
3. Chest tube drainage: it is the treatment modality of choice
Chest tube removal criteria:
* Clinical (the patient have no symptoms)
* Radiological (fully expanded lungs)
* Mechanical (no air leak even on coughing)
4. Operative treatment
Surgery for the pneumothorax can be performed by video assisted thoracoscopic
surgery (VATS) or an open procedure (thoracotomy).
The objective (principle) is three fold:
• To deal with any leak from the lung, if leak persists for more than 4-5 days in
idiopathic or 2 weeks in secondary pneumothoraces
• To search for and obliterate any blebs and bullae (bullectomy)
• To make the visceral pleura adherent to the parietal pleura (pleurectomy and
pleurodesis)
1. Bleb resectioncan: be done separately or as an initial part of
pleurectomy
2. Pleurodesis or pleurectomy:
Methods of pleurectomy and pleurodesis
1. Pleurectomy: systematically strip the parietal pleura from the chest wall
2. Pleural abrasion
3. Chemical pleurodesis: usually talk is used and is insufflated into the chest
cavity, either via VATS/surgery or simply via chest tube itself in unfit patients
Indications for pleurectomy and pleurodesis
1. Recurrent or highly possible to recur pneumothorax
2. Specific profession of the patient
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Empyema
Definition
: a suppurative disease of the pleura
Causes of thoracic empyema
a) primary infection of the pleural space can occur, but very rare.
b) secondary infection of the pleural space nearly 100%
contamination from a source contiguous to pleural space 60%
lung
mediastinum(esophagus, nodes)
deep cervical
chest wall and spine
subphrenic, paracolic abscesses
direct inoculation of the pleural space 35-40%
minor diagnostic procedures
post operative infection
penetrating chest injuries
hematogenous seeding in the pleural space <1%
late postpneumonectomy empyema
Symptoms.
The clinical presentation of empyema depends on its stage.
These are symptoms of pus at any site, namely swinging pyrexia with general
malaise. Finger clubbing and weight loss are signs of chronicity. Progressive
dyspnoea occurs as the hemithorax becomes more rigid. There may also be signs and
symptoms of various predisposing conditions (see above). Pus may discharge into the
overlying skin (empyema necessitatis), in rare cases the empyema penetrates through
the visceral pleura and may result in the development of alveolopleural or
bronchopleural fistula that manifested as sudden appearance of purulent sputum.
Since the introduction of antibiotics, chronic empyema is not often seen but it is
still a serious problem when it occurs.
In Iraq, chronic empyema is very common due to the high prevalence of TB.
Pathogenesis
The natural history can be classified into three stages
Early, (exudative) empyema (thin pus, mobile lung and thin pleura). At this stage a
brief period of pleural drainage, with underwater seal and adequate dosage of
appropriate antibiotics, should result in resolution without a residual empyema space,
but inadequate treatment will leads to a chronic empyema .
Established, (fibrinopurulent) empyema: adherent, but still mobile lung caused by
inflamed and thickened pleura with thick pus in the empyema space due to
accumulation of fibrin.
Complete treatment is still possible without surgical intervention.
Chronic, (organized). If progression to chronic fibrothorax has occurred(due to
fibroblast emigration to pleura), aspiration or drainage of pus will not lead to
expansion of the lung because there is considerable fibrosis constricting the lung
parenchyma. The fourth principle of empyema management will not be achieved and
ways to achieve it will depend on fitness of patient to GA.
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Diagnosis
Imaging: CXR, CT scan
Thoracentesis: specially PH, glucose, and culture
Treatment.
The management depends on the stage of the empyema. And the principles of
empyema management are:
1) complete drainage of purulent collection.
2) management of underlying infection.
3) management of associated conditions.
4) obliteration of residual empyema space (if present after complete drainage).
We start treatment with
1. Antibiotics
2. drainage
3. fibrinolytic therapy
4. thoracoscopy
which will be enough in early and established empyemas, but when we have
trapped lung and chronic empyema, drainage will be followed by:
a) in fit patient
1. decortication alone
2. decortication with thoracomyoplasty
A formal thoracotomy (or recently VATS) is performed and the thickened parietal
pleura and the fibrin peel overlying the lung are painstakingly removed, piecemeal if
necessary. This allows the lung to expand. Wide bore drains are inserted and
connected to an underwater drainage system.
Lobectomy: if there is underlying diseased lobe.
Thoracomyoplasty and muscle flap: if residual lung volume is unlikely to expand
after decortication.
b) in unfit patient, open window thoracostomy
rib resection (Eloesser flap) and long term drainage: under local anesthesia
Chylothorax
definition:
the presence of chyle in pleural space.
Pathogenesis of chylothorax
1. Congenital birth trauma
i. Congenital fistula
ii. Malformation of lymphatics
2. Acquired, traumatic postoperative
i. Blunt trauma
ii. Penetrating trauma
3. Acquired, non traumatic neoplastic
i. non neoplastic
ii. SVC obstruction
Symptoms.
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Are those of pleural effusion, underlying disease, and progressive loss of fat, protein,
fluid, and WBC.
Diagnosis
Presence of chylomicrons in pleural fluid
Treatment
A) non operative: by chest drainage, nutritional support, or TPN.
Indications for operative management
1) leak of more than 1L/d for more than one week
2) persistent leak for more than two weeks
3) in children, leak of 100ml/day/year age for two weeks
4) signs of trapped lung syndrome
5) signs of nutritional deficiency
B) Operative: mostly for traumatic cases, and this is done by either direct closure
of the fistula or by subdiaphragmatic duct ligation.