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126 Chapter 3: Respiratory system

Clinical features Pathophysiology
Symptoms include shortness of breath and chest pain. Initially the pleural space is filled with a thin watery fluid
Signsofaneffusion are only present when >500 mL of containing pus cells (purulent effusion). There is then
fluid is present and include reduced chest expansion on laying down of fibrin between the parietal and visceral
the affected side, stony dull percussion note, reduced or pleura, which may become organised to form a thick
absent breath sounds and vocal resonance. fibrous wall around the pus filled cavity.

Investigations
Clinical features
1 Chest X-ray: visible when there is >300 mL, ranges
Patients present with similar features to a pleural effu-
from blunting of the costophrenic angles to dense ho-
sion: dullness to percussion, absence of breath sounds.
mogeneous shadow, usually with a meniscus. Medi-
They often appear generally unwell with tachycardia,
astinal shift occurs with massive effusion.
tachypnoea and pyrexia.
2 Diagnostic pleural aspiration with needle and syringe:
Biochemistry allows the separation into a transu-

date and an exudate on the basis of protein content. Investigations
There is a leucocytosis and X-ray shows a pleural opacity
ApHof less than 7.3 is suggestive of empyema, but
classically posteriorly with a D shaped outline. Needle
may also occur in malignancy, rheumatoid and TB.
aspiration is used to obtain fluid for microscopy, culture
Microbiology if the aspirate is turbid and to search

and sensitivities.
for an infective course.
Blood-staining suggests pulmonary infarction or

malignancy. Management
Cytology to detect neoplastic cells, and distinguish The aim of therapy is to drain the fluid and expand the

acute from chronic inflammation on the basis of lungs whilst treating the infection with appropriate em-
the cellular infiltrate. pirical antibiotics initially. Antibiotics are tailored ac-
3 Pleural biopsy if needed: particularly for suspected cording to microbiology results from the fluid.
mesothelioma and TB. In the early stages needle aspiration may be adequate.
For thicker pus an intercostal drain may have to be

Management inserted.
Is aimed at the underlying cause thus identification is of In some patients, videoscopic assisted thorascopic
primary importance. Large effusions can be treated by surgery (VATS) or open thoracotomy and removal
aspiration or chest drainage, but too rapid drainage can of the walls of the empyema is needed for complete
cause pain and even pulmonary oedema and hypoten- resolution, particularly if the effusion is loculated.
sion. Recurrent malignant effusions can be treated with
chemical or surgical pleuradhesis.
Pneumothorax
Empyema Definition
Defined as air in the pleural space which may be trau-
Definition
matic or spontaneous.
Empyema is pus in the pleural space.
Aetiology
Aetiology
See Table 3.16.
Themostcommoncauseofempyemaispneumoniawith
spread of infection to an associated effusion. A lung ab-
scess can also spread to the pleural space. Exogenous Clinical features
infection may be from a penetrating injury or be iatro- Sudden onset of unilateral pleuritic pain and/or increas-
genic, e.g. following chest drain insertion for an effusion. ing breathlessness is the usual presenting feature. Large
Endogenous infection may be from perforated oesoph- pneumothoraces produce breathlessness, pallor, tachy-
agus or spread from a subphrenic abscess. cardia and even hypotension. About one third recur.