Pleural Effusion

Pleural effusion, sometimes referred to as “water on the lungs,” is the build-up of excess fluid between the layers of the pleura outside the lungs. The pleura are thin membranes that line the lungs and the inside of the chest cavity and act to lubricate and facilitate breathing.

Differential Diagnosis

Exudative malignancy, infections, connective tissue disease, pulmonary embolism, hemothorax, pancreatitis, chylothorax

Trabsydatuve HF, hypoalbuminemia (GI losing enteropathy, cirrhosis, nephrotic syndrome, malnutrition), SVC obstruction, hepatohydrothorax, urinothorax, atelectasis, trapped lung, peritoneal dialysis, hypothyroidism, pulmonary embolism Note: pulmonary embolism, malignancy, and sar coidosis can present as either exudative or transudative effusions. HF following diuresis may become ‘‘pseudo exudative’’ (check albumin gradient)

Clinical Features

History dyspnea, cough, hemoptysis, chest pain, weight loss, fever, trauma, occupational exposures, past medical history (pneumonia, liver disease, kidney disease, thyroid disease, cancer, HF, thromboembolic disease, connective tissue disease, smoking), medications

Physical vitals, cyanosis, clubbing, tracheal deviation away from side of effusion (if no collapse or trapped lung), peripheral lymphadenopathy, Horner’s syndrome, respiratory examination (decreased breath sounds and tactile fremitus, stony dullness to percussion), cardiac examination, leg swelling (HF or DVT)

Rational Clinical Examination Series Does the patient have Pleural Effusion?

Auscultatory Percussion auscultate with the diaphragm of the stethoscope over the posterior chest wall while gently tapping over the manubrium with the distal phalanx of one finger. Diminished resonance suggests effusion

	Sens	Spc	LR+	LR
Physical
Asymmetric chest expansion	74%	91%	8.1	0.29
Auscultatory percussion	77%	92%	7.7	0.27
Crackles	56%	62%	1.5	0.71
Diminished breath sounds	42 88%	83 90%	4.3  5.2	0.15  0.64
Dullness to conventional percussion	73%	91%	8.7	0.31
Pleural friction rub	5.30%	99%	3.9	0.96
Reduced tactile fremitus	82%	86%	5.7	0.21
Reduced vocal resonance	76%	88%	6.5	0.27
APPROACH ‘‘dullness to percussion and tactile fremitus are the most useful findings for pleural effusion. Dull chest percussion makes the probability of a pleural effusion much more likely but still requires a CXR to confirm the diagnosis. When the pretest probability of pleural effusion is low, the absence of reduced tactile fremitus makes pleural effusion less likely so that a CXR might not be necessary depending on the overall clinical situation’

Investigations

Basic

Labs CBCD, electrolytes, urea, Cr, LDH, total protein, AST, ALT, ALP, bilirubin, INR, PTT, albumin

Imaging CXR (PA, lateral, decubitus), CT chest

Thoracentesis send pleural fluid for cell count and differential, Gram stain, C&S, AFB and fungal cultures, LDH, total protein, pH, and cytology. Under special circumstances, also consider amylase, glucose, cholesterol, adenosine deaminase (for TB), albumin

Special

Biopsy closed pleural biopsy, medical thoracoscopy, bronchoscopy, surgical biopsy (video assisted thoracic surgery)

Diagnostic Issues

Overall Approach generally, if the effusion is >1/4 of hemithorax, enough fluid is present for diagnostic thoracentesis; obtain decubitus film to assess for loculation. In the absence of loculation, and with >10 mm [0.4 in.] layering of fluid on decubitus film, bedside thoracentesis can be attempted; otherwise, request U/S guided thora centesis. If only a small amount of fluid is present (<10 mm [><0.4 in.]) and/or HF suspected, start with diuresis for 2 to 3 days. If no improvement, perform thoracentesis to distinguish between transudative and exudative causes ><10 mm  <0.4 in.]) and/or HF suspected, start with diuresis for 2 3 days. If no improvement, perform thoracentesis to distinguish between transudative and exudative causes

Light's Criteria for Exudative Effusion

Any one of the following criteria would suggest exudative effusion: fluid/serum total protein ratio >0.5, fluid/serum LDH ratio >0.6, fluid LDH >2/3 upper limit of normal serum level

Pleural Fluid Analysis

Pleural Fluid Analysis Fluid Acidosis (pH <7.2) complicated parapneumonic, TB, paragonimiasis, malignancy, rheumatoid arthritis, SLE, hemothorax, esophageal rupture Fluid Glucose (<3.3 mmol/L [< 60 mg/dL]) para pneumonic, TB, paragonimiasis, malignancy, rheu matoid arthritis, Churg Strauss, hemothorax

Fluid Eosinophilia (>10%) paragonimiasis, malignancy, Churg Strauss, asbestos, drug reac tion, pulmonary embolism, hemothorax, pneumothorax, idiopathic (20%)

Cytology for Malignancy the yield for diagnosis with single attempt is 60%, two attempts is 85%, three attempts is 90 95%; obtain as much fluid as possible to increase diagnostic yield

Fluid for AFB obtain as much fluid as possible and ask laboratory to centrifuge collection and to culture sediment to increase diagnostic yield

Management

Symptoms Control O2, diuresis (furosemide), drainage (thoracentesis, pigtail catheter, PleurX catheter, chest tube), pleurodesis (talc slurry or poudrage), surgery (talc slurry, pleuroperitoneal shunt, pleural abrasion, pleurectomy)

Treatment

Diuretics and other heart failure medications are used to treat pleural effusion caused by congestive heart failure or other medical causes. A malignant effusion may also require treatment with chemotherapy, radiation therapy or a medication infusion within the chest.

Specific Entities

Parapneumonic Effusion

Uncomplicated exudative effusion that resolves with resolution of pneumonia. Generally disappears with antibiotics alone

Complicated persistent bacterial invasion and fluid collection. Characterized by pleural fluid acidosis but sterile fluid. Pleural loculation may occur as fibrin gets deposited from inflammation. 

Empyema presence of bacteria in Gram stain or pus in drainage (culture not necessary). pH often < 7.2. For unloculated fluid, chest tube/small bore catheter drainage usually adequate. For loculated effusions, thrombolytics such as streptokinase or TPA could be considered. Thoracoscopy represents an alternative to fibrinolytics. Open decortication is the last resort

Traped Lung stable chronic effusion, especially with history of pneumonia, pneumothorax, thoracic surgery or hemothorax. Diagnosis is established by measuring negative change in intrapleural pressure during thoracentesis. Treat by lung re expansion, sometimes requiring thoracotomy with decortications

Hepatohydrothorax suspect if cirrhosis and portal hypertension, even in the absence of ascites. Pleural effusion results from passage of peritoneal fluid into pleura because of negative intrathoracic pressures and diaphragmatic defects. Do not insert chest tube. Treat with diuresis, salt restriction, and consider liver transplantation/TIPS procedure.