Disease of the Pleura and Pulmonary Cysts

Inflammation of the Pleura is called Pleurisy. In dry Pleurisy, the
pleural surfaces are inflamed without fluid in between them. In many
cases pleurisy is associated with effusion. Both dry pleurisy and
pleural effusion may develop at different stages of the same disease
process.Dry or fibrinous pleurisy: The pleura gets involved from the
disease of the underlying lung. Trauma to the chest may also lead to
Pleurisy. The suggestive symptom is the catching pain felt acutely
over the affected area by inspiratory movements brought about by deep
breathing, coughing or sneezing. Its etiology are as follows:
Pulmonary tuberculosis, Pneumonia, bronchogenic carcinoma, pulmonary
infarction, connective tissue disorders (such as systemic lupus
erythematosus, polyarteritis nodosa, and rheumatoid disease),
rheumatic fever, viral infections (especially Coxsackie [Bornholm
disease), hepatopulmonary amoebiasis, and uraemia.The physical
examination reveals diminution of movement on the affected side and
the presence of pleural friction rub on auscultation. Pleural rub has
a superficial grafting quality. The rub is heard better by gentle
pressure of the chest piece of the stethoscope on the chest wall.
Unlike rales, it is not altered by coughing. With the development of
pleural effusion, the rub may disappear in most cases. Pleural rub has
to be distinguished from crepitations and sounds arising from
movements of the chest wall. Other painful conditions like Pneumonia,
myocardial infarction, and herpes Zoster have to be differentiated
from pleurisy.Pleural effusion: In this condition, fluid accumulates
between the two layers of the pleura. Normally, pleura contains only a
small amount of fluid. The pleural fluid remains in dynamic
equilibrium with blood. Movements of the lung favour the movement of
the fluid in and out of the pleural space. In most of the disease
states, absorption of the fluid is reduced. The fluid may be contained
in the general pleural space or it may be loculated in the interlobar
fissure, infrapulmonary space or may remain adjacent to the
mediastinum. The fluid progressively compresses the subjacent lung
which undergoes collapse.The development of symptoms depends upon the
speed of accumulation of fluid and its quantity. Common symptoms
include dyspnea, pleuritic pain, or symptoms of the underlying
disorder. High fever may occur in acute pyogenic infections.
Tuberculosis may be associated with lower grades of fever. Pleural
fluid is clinically detectable only when it is about 500ml in volume
but radiologically it may be detected even when the volume is only 350
ml. A fully developed moderate or massive effusion reveals fullness of
the intercostal spaces and restriction of respiratory movements of the
same side. Midline structures are shifted to the opposite side.
Percussion elicits stony dullness with the highest level in the axilla
and lower levels in front and back (S-shaped curve of Ellis). This is
the most constant physical sign. The Traube's space, which is the area
overlying the gas bubble or the stomach, is obliterated in left-sided
effusion. Breath sounds, vocal femitus and vocal resonance are
diminished or absent. Aegophony may be present above the level of
effusion. At times bronchial breathing may be heard over a pleural
effusion.Complications include: Respiratory embarrassment, massive
bilateral effusions which may be fatal due to respiratory failure,
secondary infection of the pleural fluid which converts it into
empyema, organization of fibrin from the fluid on the surface of the
collapsed lung (cortication) that prevents re-expansion, and fibrosis
of the pleura and obliteration of the pleural space (fibrothorax)
which develop as a sequel to long standing pleural
effusions.Radiographic appearance: If the fluid volume is small only
the costophrenic angles are obliterated. As the fluid accumulates
further, it throws a triangular lateral opacity obscuring the
hemidiaphragm. Large pleural effusions shift the midline structures to
the opposite side. An interlobar effusion in the oblique fissure
produces an elongated cigar-shaped shadow seen better in the lateral
view. Fluid in the horizontal fissure throws a rounded shadow seen in
the PA-view. The term "vanishing pulmonary tumor" has been used for
inter-lobar effusions since they clear up with treatment.
Character of
the fluid: Pleural fluids may be transudates or exudates. They differ
in physical and biochemical nature. Transudate (Clear, often
bilateral, does not clot on standing, specific gravity less than 1015,
protein content less than 3g/dL, cells less than 100/Cmm). Exudate
(Opalescent or turbid, unilateral, often clots on standing, above
1015, above 3g/dL, cell count is high).Congestive Cardiac failure,
nephrotic syndrome, hypoproteinemia, constrictive pericarditis, and
myxedema may cause transudation into the pleura. Exudates are caused
by tuberculosis, Pneumonias, Pulmonary infarction, bronchogenic
carcinoma, Pleural secondaries, dyscollagenoses and hepatopulmonary
amoebiasis. Rare causes include subphrenic abscess, postmyocardial
infarction syndrome and acute pancreatitis. Tuberculous effusion is
straw-coloured. The fluid is hemorrhagic in malignancy and infarction
and it is chylous (milky) in lymphatic obstruction due to filariasis
and lymphomas. Collection of purulent fluid in the pleura is called
empyema.Microscopy: In acute bacterial infections, neutrophils
predominate, lymphocytes predominate in tuberculosis. Eosinophils may
predominate in dyscollagenoses and pulmonary infarction. Examination
of a wet preparation stained by methylene blue reveals malignant cells
in over 90% of cases of malignant effusions. Identification of the
nature of the malignant cells is done by Papanicolaou's technique. The
nature of chylous fluid is confirmed by demonstrating the presence of
fat. Elevated amylase levels are suggestive of acute pancreatitis (500
units/ml of higher). Values of LDH are raised in exudates.
Gram-staining, Ziehl-Neelsen staining, and culture help in identifying
the causative microbes. When investigations, pleural biopsy may be
attempted. Special (Cope's) needles are available for this purpose.
Though a positive biopsy is diagnostic, a negative biopsy does not
exclude pleural malignancy.Principles of treatment
Pleural effusion
may rarely present as an emergency with respiratory embarrassment. In
such cases, emergency measures are required to give relief-especially
if the effusion is massive or bilateral. The fluid is aspirated by
thoracentesis done in the eighth or ninth intercostal space in the
posterior axillary line after anaesthetising the part. Sufficient
fluid id removed to relieve the distress. Whenever pleural fluid is
aspirated, it is also subjected to diagnostic investigations.Elective
management
Medical therapy is instituted depending on clinical
features and pleural fluid analysis. it is ideal to aspirate the fluid
after instituting specific drug therapy. Aspiration is indicated: to
make the diagnosis; to relieve distress and to remove the exudate so
as to hasten full recovery of the pleura and avoid complications. It
is generally advisable to restrict the volume of fluid removed at one
sitting to 1 Liter or less in order to avoid pulmonary edema.
Aspiration has to be repeated at times. Two or three aspirations will
be adequate in most of the cases of tuberculous effusion. In malignant
pleural fluid tends to re-accumulate even after repeated aspirations.
Drugs used to be instilled intra-pleurally with the hope of raising
the local concentration of the drug. Intra-pleural administration of
drugs my be required only in some rare cases, if proper systemic
therapy is given. Sometimes aspiration of the pleural cavity may give
rise to complications. These include pleural shock, anaphylactic shock
due to anaesthetic, bleeding into the pleural cavity, pulmonary edema,
infection, and accidental introduction of air into the
pleura.PULMONARY CYSTS
Cysts of the Lung may be congenital or
acquired. Congenital cysts are of three varieties:
1.
bronchogenic-these may be solitary or multiple;
2. alveolar cell
types-these also may be solitary or multiple; and
3. mixed types
having elements of both bronchogenic and alveolar cysts.These vary in
size and may be unilateral or bilateral. They may be located anywhere
in the lung. They are filled with fluid at birth, but air enter the
cavity later when bronchial communications develop. The cyst may be
thick- or thin- walled. Cystic disease of the Lung may occur in
association with fibrocystic disease of the pancreas. This is common
in Western countries, but is rare in Asia and Africa.Acquired
Cysts
These may be resent bullous emphysema, subpleural ysts or
parasitic cysts, which include hydratid disease and paragonimiasis.
The severity of symptoms is determined by the extent, size, time of
diagnosis, and presence of complications. When the lung parenchyma is
grossly reduced, respiratory embarrassment and respiratory failure may
develop. Super-added infection is common and this is characterised by
fever, cough, purulent sputum, and even hemoptysis. Though pulmonary
osteoarthropathy may occur, it is a late feature. This is in contrast
to bronchiectasis, in which clubbing is an early feature. Potential
complications are infection, hemoptysis, Pneumothorax, fibrosis, and
Cor Pulmonale.Diagnosis
Cystic disease has to be suspected when a
child presents with recurrent respiratory infections. Presence of
other congenital abnormalities should strengthen this suspicion. X-ray
shows thin-walled cysts, which may be single or multiple.
Tuberculosis, bronchiectasis, and Lung abscess have to be
differentiated. In congenital cystic lung bronchography delineates the
lesions. In the case of single non-communicating cysts, the dye does
not enter the cavity.Treatment
A large single cysts producing
respiratory embarrassment from infancy has to be excised. When the
cysts are multiple, surgery is contraindicated. Medical management is
on the same lines as for bronchiectasis.