- What Is Pleural Effusion ?
• Pleural effusion results from fluid
accumulating in the potential space between
the visceral and parietal pleurae When there
is an imbalance between formation and
absorption in various disease states , in
response to injury , inflammation, or both
locally and systematically .
More Definitions ?
• Parapneumonic Effusion : pleural effusion associated with
bacterial pneumonia, bronchiectasis, or lung abscess .
• Complicated Parapneumonic Effusion : refers to parapneumonic
effusions that require tube thoracostomy for their resolution .
• Loculated Effusion : Fluid anatomically confined and not freely
flowing in the pleural space when there are adhesions between
the visceral and the parietal pleura .
• Sub-Pulmonic Effusion: accumulation of fluid between the lung
& the diaphragm which gives the false impression of an
• Up to 25 ml of pleural fluid is normally present in the pleural
space which is an amount not detectable on conventional
chest radiographs , and is secreted from the parietal pleura
into the pleural space where it is absorbed by the visceral
pleural microcirculation, and lymphatics .
• This small amount of pleural fluid reduces friction between
the pleural layers and allows for smooth lung expansion and
contraction with respiration.
• Under normal circumstances, the direction of pleural fluid
flow is largely governed by the difference in hydrostatic
pressure between the systemic and the pulmonary
• Pleural fluid exists in a dynamic equilibrium in which influx
equals efflux, with approximately 1 L of fluid traversing the
pleural space in 24 hours.
• So pleural effusion develops whenever influx of fluid into
the pleural space exceeds efflux.
• Normal amount 8.4 ml per hemithorax with a WBC count of
1700 per ml 75% of which are neutrophils and 23%
lymphocytes. Protein concentration is low about 15% of
plasma protein concentration. There is no RBCs
• These Are The Most Common :
- Congestive Heart Failure (CHF)
- Bacterial Pneumonia
- Pulmonary Embolism
Other Causes & Associates ?
All kinds of infections of the lung parenchyma or pleura ( B , V , F , P )
Ovarian hyperstimulation syndrome
Collagen vascular diseases ( SLE , RA )
Intra-abdominal processes ( Acute pancreatitis, subphrenic abscess)
Bacterial pneumonia with parapneumonic effusion
Drug-related : Amiodarone, Nitrofurantoin , Dantrolene ,
Methysergide , Bromocriptine , Procarbazine
Lung & breast cancer
Meigs syndrome .
Post abdominal surgery
Endoscopic variceal sclerotherapy
Post liver transplant
Post-coronary artery bypass surgery
Post-cardiac injury syndrome
– Transudate : result from an imbalance between hydrostatic (e.g.,
CHF) and oncotic (e.g., nephrotic syndrome) pressures. This
imbalance results in the production of an ultrafiltrate with low
protein content across the pleural membrane.
– Exudate : result from pleural disease, usually inflammation or
neoplasia, that results in active fluid secretion or leakage with high
– Empyema : Requires the presence of bacteria on Gram’s staining of
the pleural fluid.
– Hemothorax & Chylothorax : From rupture of the thoracic duct are
special instances of pleural effusion
• Some pleural effusions can present as either transudates or exudates
or may have characteristics of both. In the case of pulmonary
embolism, the pathogenesis of pleural effusion is often multifactorial,
reflecting increased pulmonary vascular pressure (a transudative
process) and ischemia and breakdown of the pleural membrane (an
• Massive effusions (>1.5–2 L) are most commonly associated with
malignancy but also can arise in the setting of congestive heart
failure, cirrhosis, and other conditions.
Transudates Vs. Exudates
Light’s criteria for differntiating transudates
Plueral fluid considered an exudate if one or
more of the following is true
1. Plural fluid protein level : serum protein level
2. Pleural fluid Lactate dehyrogenase LDH level :
serum LDH level > 0.6
3. Pleural fluid LDH level > 2/3 * upper limit of
normal for serum LDH level
• History :
Pleuritic chest pain
Hx. of cancer
• Physical :
Dullness to percussion
Decreased breath sounds
Absent tactile fremitus
Other findings: ascites,
JVP, peripheral edema,
friction rub, unilateral leg
• Symptoms associated with pleural effusion are most often due to the
underlying disease process and not the effusion itself.
• Small pleural effusions can be entirely asymptomatic.
• A new pleural effusion may be heralded by localized pain or pain
referred to the shoulder.
• When the volume of pleural fluid reaches 500 mL, dyspnea on exertion
or at rest may occur as a result of compromised pulmonary function.
Egophony and enhanced breath sounds can often be appreciated at
the superior border of the effusion because of underlying atelectatic
• Distended neck veins, an S3 gallop, or peripheral edema suggests
• A right ventricular heave or thrombophlebitis and sinus
tachycardia suggests >>>> PE
• The presence of lymphadenopathy or hepatosplenomegaly
suggests >>>> Cancer
• Ascites may suggests >>>> end stage liver disease
• Signs of consolidation above the level of the fluid in a febrile
patient suggests >>>> Parapneumonic Effusion.
Role Of Chest X-Rays
- Detection and the differential diagnosis are highly dependent upon imaging of
the pleural space.
-Conventional radiographic methods used are frontal, lateral, oblique and
-Blunting of either costophrenic angle is indicative of the accumulation of
between 250 - 500 ml of fluid
-1000 ml of effusion reaches the level of the fourth anterior rib
-Because of gravity, fluid accumulates in subpulmonic location .
Role of CT scan
– Visualization of underlying lung parenchymal processes
that are obscured on chest radiographs by large pleural
– Very Sensitive
– Can distinguish between Lung Abscess & Empyema
– On decubitus radiographs and CT scans, less than 10 mL,
and possibly as little as 2 mL, can be identified
Role of Ultrasonography
– Free vs loculated pleural effusions, and loculated
effusions vs solid masses.
– Thoracentesis of loculated pleural effusions is
facilitated by ultrasound marking or guidance.
– Helpful in Confirming the Presence of a
Small Pleural Effusion.
An unexplained pleural effusion requires further investigation. Unless
required to rule out an immediately life-threatening condition such as
empyema or hemothorax, pleural fluid evaluation may be deferred to an
inpatient or outpatient setting.
No need for thoracentesis for patient with obvious cause may not need
further study (CHF with bilateral effusions) .
Indicated if the effusion is clinically significant with no known cause.
• Also indicated in a patient with CHF if any of the
following are present.
A unilateral effusion, particularly if it is left-sided,
Bilateral effusions, but are of disparate sizes
There is evidence of pleurisy or fever
The cardiac silhouette appears normal on CXR
If no response to diuresis in 48-72 hrs.
The alveolar-arterial oxygen gradient is widened
out of proportion to the clinical setting
- None Absolute.
- Relative include :
• Patient on anticoagulation or with bleeding diathesis
• Very small volume of fluid.
• Patients on mechanical ventilation are at high risk for tension
• Active skin infection at the port of entry.
• Post procedure CXR :
- Indicated only if air is obtained during the procedure or if cough, pain or
• Complications :
- Pain >>> Give Pain Medications NSAIDs Sometimes Opiods
- Bleeding (hematoma, hemothorax, or hemoperitoneum) >>> Fluids
- Pneumothorax >>> Multi-Dependence
- Empyema >>> Sterility
- Soft tissue infection >>> Sterility
- Spleen or liver puncture >>> Ultrasound Guided
- Vasovagal events >>> Multi-Dependence .
- Adverse reactions to lidocaine or topical antiseptic solutions >>> Ask About it
Thoracentesis: Transudate vs. Exudate
1. Gross Appearance
2. Cell Count & Differential
3. Gm Stain, C & S
7. Glucose, Amylase
- Bloody : Cancer, PE, Trauma, Pneumonia.
- Turbid : either due to cells or debris or a high
- Putrid Odor : Anaerobic infection
- Ammonia Odor : Urinothorax
a bloody pleural effusion
occurring in a patient without a history of trauma
or pulmonary infarction
Indicative of Neoplasm
in 90 % of cases!
• A True Hemothorax is when the Pleural Fluid Hct exceeds 50 %
of the Peripheral Blood Hct !
• Beware Of Aortic Aneurisms !!!
• Transudative Effusion :
focus on the systemic cause , rule out a diagnosis of congestive heart failure,
cirrhosis, or pulmonary embolism.
• Exudative Effusion :
dependent on the exact sub-type , send for total and differential cell counts, smears
and cultures for organisms, measurement of glucose and lactate dehydrogenase
levels, cytologic analysis, and testing for a pleural-fluid marker of tuberculosis.
• Consider Chest Thoracostomy
Gross Pus / Empyema
pH < 7.2
Complicated Parapneumonic Processes
Malignant Effusions…but remember the role of pleurodesis!
Other Pleural Fluid Tests
PORCEL et al. AFP 2006; 73: 1212
Other Pleural Fluid Tests
PORCEL et al. AFP 2006; 73: 1212