Pleural Effusion, Emergency Medicine

Basics

Description

Normal conditions:
- Pleural space contains 0.1 " 0.2 mL/kg (30 mL in an adult) of clear, low-protein fluid that facilitates movement of the pulmonary parenchyma within the thoracic space.
- Fluid formation and reabsorption are governed by hydrostatic and oncotic forces.
- Normally, the sum of these forces results in movement of fluid into the pleural space from the parietal surface and reabsorption at the visceral surface.
- Lymphatics help remove any excess fluid.
Alteration of any of the above factors results in abnormal fluid accumulation.
Classification:
- Transudative effusion:
  - An ultrafiltrate of serum, containing low protein and cells
  - Results from increase in hydrostatic pressure and/or decrease in oncotic pressure
  - Pleural surface is not involved in the primary pathologic process.
- Exudative effusion:
  - Contains high protein and cells
  - Results from pathologic disease of the pleural surface leading to membrane permeability and/or disruption of lymphatic reabsorption

Etiology

Transudative effusions:
- Congestive heart failure (CHF)
- Peritoneal dialysis
- Cirrhosis with ascites
- Pulmonary embolism
- Acute atelectasis
- Nephrotic syndrome
- Myxedema
- Hypoproteinemia
- Superior vena cava syndrome
- Meigs syndrome:
  - Triad of ascites, benign ovarian tumor, and pleural effusion
Exudative effusions:
- Pulmonary or pleural infection:
  - Bacterial, viral, fungal, tuberculosis (TB), parasitic
- Primary lung cancer
- Mesothelioma
- Metastasis (often from breast cancer, ovarian cancer, or lymphoma)
- Pericarditis
- Pulmonary embolism
Intra-abdominal disorders:
- Pancreatitis, hepatitis, cholecystitis
- Subdiaphragmatic abscess
- Esophageal rupture
- Peritonitis
- Meigs syndrome
Rheumatologic disease:
- Systemic lupus erythematosus
- Rheumatoid arthritis
- Sarcoidosis
Trauma:
- Hemothorax
- Chylothorax
Drugs:
- Drug-induced lupus
- Nitrofurantoin, methysergide, dantrolene, amiodarone, bromocriptine
- Crack cocaine

Diagnosis

Signs and Symptoms

Small effusions are often asymptomatic.
Dyspnea, pleuritic chest pain, and/or cough
Tachypnea, hypoxia, decreased breath sounds, and/or dullness to percussion

History

Underlying primary pathologic process (CHF, pneumonia, pulmonary embolus, pancreatitis) is often the source of complaints.
Dyspnea on exertion or at rest
Cough with large effusion
Pleuritic chest pain with inflammation of pleura
Empyema: Fever, fatigue, weight loss

Physical Exam

Decreased breath sounds
Decreased tactile fremitus
Increased egophony for large effusions
Dullness to chest percussion
Pleural friction rub
Examine for the primary cause of pleural effusion.

Essential Workup

Cardiac monitor and pulse oximetry
CBC, comprehensive metabolic panel, coagulation panel
Chest radiography
Search for underlying cause

Diagnosis Tests & Interpretation

Lab

CBC
Electrolytes, BUN/creatinine, glucose, serum lactate dehydrogenase (LDH), serum protein
Pulse oximetry or arterial blood gas
Coagulation panel
Pleural fluid analysis to determine if transudative or exudative effusion:
- Check pleural protein and LDH levels.
- Light criteria: Fluid is likely exudative if 1 or more of the following criteria are met:
  - Pleural fluid protein/serum protein >0.5
  - Pleural fluid LDH/serum LDH >0.6
  - Pleural fluid LDH >2/3 upper limit of normal serum LDH
If effusion is transudative, no further fluid analysis is usually necessary.
Determining etiology of exudative effusion:
- Initial testing: Cell count with differential, Gram stain and culture, acid fast bacilli stain, pH, glucose, and cytology
- Based on clinical scenario consider: Triglycerides, amylase, albumin, creatinine, adenosine deaminase, and tumor markers.
- RBC and Hct:
  - 5,000 " 100,000/mm3 nonspecific
  - >100,000/mm3 suggestive of malignancy, trauma, or pulmonary embolus
  - Pleural fluid Hct >0.5 serum Hct is by definition a hemothorax.
  - Other causes: Malignancy, TB, aortic rupture
  - Heparinize and chill hemorrhagic samples to be sent for cytology.
- WBC:
  - 1,000 " 10,000/mm3 nonspecific
  - >10,000/mm3 suggestive of parapneumonic effusion, empyema, pancreatitis, rheumatologic, malignancy, or TB
- Glucose:
  - Glucose <60 mg/dL suggestive of complicated parapneumonic effusion/empyema, malignancy, esophageal rupture, or rheumatologic disease
- Triglyceride:
  - Triglycerides >100 mg/dL suggestive of chylothorax, disruption of thoracic duct
- Amylase:
  - Amylase >200 IU/L suggestive of pancreatitis, esophageal rupture, malignancy, TB, or empyema
- pH:
  - Send in a chilled heparinized arterial blood gas syringe.
  - pH < 7 suggests complicated parapneumonic effusion or empyema
- Cytology identifies malignant cells.

Imaging

Chest radiograph:
- Upright chest film:
  - Blunting of the costophrenic angle
  - Requires at least 200 " 250 mL of fluid
  - Presence of subpulmonic effusions may be indicated by loss of supradiaphragmatic vascular markings or an increased space between the gastric bubble and pulmonary parenchyma.
- Lateral decubitus film:
  - Can identify as little as 5 " 10 mL of fluid.
  - Suspect a loculated effusion or alternative diagnosis if effusion fails to layer.
US:
- Has similar sensitivity to lateral decubitus film and can detect as little as 5 " 10 mL of fluid.
- Can differentiate simple effusions from loculated fluid collections.
- Improves patient safety and decreases risk of pneumothorax for thoracentesis
CT chest with IV contrast:
- Most sensitive study for detecting pleural fluid collections and identifying loculated effusions.
- Useful for determination of underlying lung process such as masses and pleural thickening

Consider pulmonary embolism as a cause of unexplained pleural effusion
Obtain lateral decubitus films, or bedside US prior to performing thoracentesis to avoid misdiagnosis and procedural complications.

Diagnostic Procedures/Surgery
Diagnostic/therapeutic ED thoracentesis:

Indication:
- Diagnose new effusion in a toxic patient.
- Relieve symptomatic dyspnea caused by large effusions.
- Diagnostic thoracentesis in a stable patient can be deferred until after the patient has been admitted.
No absolute contraindications.
Relative contraindications:
- Platelets <50,000/mm3
- Prothrombin and partial thromboplastin time >2 normal level
- Serum creatinine >6
Correct coagulopathy if present.
Position patient upright with arms crossed in front to elevate scapula.
Identify superior border of effusion with US, percussion, or egophony.
Mark area 1 interspace below this in the posterior axillary line or the midscapular line.
Prepare area with Betadine, dry, and drape for sterile field.
Anesthetize with 2% lidocaine.
Attach 3-way stopcock between needle and syringe. Enter superior border of rib with needle bevel down, aspirating while advancing.
Use 20G needle for diagnostic aspiration.
Use 16G " 18G needle/catheter (commercial kit) for therapeutic aspiration.
Advance catheter once pleural space entered.
Minimum of 100 cc required for basic studies (protein, LDH, cell count, Gram stain and culture) " more for cytology/additional studies.
Avoid withdrawing >1,500 cc to prevent re-expansion pulmonary edema.
Intraprocedural chest pain may indicate trapped lung or pneumothorax; stop procedure and obtain chest radiograph.
After obtaining fluid, withdraw needle, apply pressure, dress, and obtain post procedural chest radiograph for pneumothorax.
Indications for tube thoracostomy:
- Loculated effusion
- Aspiration of pus
- Complicated parapneumonic effusion with pH < 7, or pleural glucose <60 mg/dL, or positive pleural Gram stain or culture
- Hemothorax

Differential Diagnosis

Intraparenchymal densities:
- Lobar collapse
- Mass, tumor, infiltrative disease
- Pneumonia
Pleural densities:
- Pleural scaring
- Mesothelioma, metastatic disease
Other:
- Herniated abdominal contents
- Paralyzed diaphragm

Treatment

Pre-Hospital

IV access, high-flow oxygen, cardiac monitor, and pulse oximeter.

Initial Stabilization/Therapy

ABCs
High-flow oxygen for shortness of breath
Emergent thoracentesis for significant respiratory compromise.

Ed Treatment/Procedures

Identify and treat underlying pathologic process
Surgical consult for tube thoracostomy if empyema found.
Consult interventional radiology or pulmonology for loculated effusions.

Medication

CHF: Diuresis
Parapneumonic effusion: Antibiotics
Pulmonary embolism: Anticoagulation:
- Bloody effusion is not a contraindication to anticoagulation.
Rheumatologic disease: NSAIDs and steroids
Loculated effusion: Injection of streptokinase or urokinase into pleural space by thoracic surgeon or pulmonologist

Follow-Up

Disposition

Admission Criteria

Respiratory compromise
Unknown cause of the effusion
Primary process requires hospitalization
Presence or suspected parapneumonic effusion or empyema
Observation for 6 hr or admission for potential complications of thoracentesis:
- Pneumothorax
- Re-expansion pulmonary edema
ICU admission for severe hemodynamic and respiratory compromise

Discharge Criteria

Source of the pleural effusion is known.
No evidence of respiratory compromise exists.
Majority of effusions will resolve if the primary process is treated appropriately.
Patient must be reliable and have access to a telephone, a supportive social environment, and adequate follow-up.

Issues for Referral
Arrange appropriate follow-up with oncologist or pulmonologist prior to discharge.

Followup Recommendations

Patients should be instructed to return to the ED for worsening dyspnea, fever/chills, or other symptoms of respiratory distress.

Pearls and Pitfalls

The most common causes of pleural effusion are CHF, pneumonia, and malignancy.
Identify and treat the underlying cause of the pleural effusion.
Bedside US can help characterize the effusion and reduce the risk of pneumothorax with thoracentesis.
Failure to identify fatal causes of pleural effusion such as pulmonary embolism, esophageal rupture, or hemothorax
Failure to drain large effusions that are causing respiratory or circulatory compromise

Additional Reading

Blok B. Thoracentesis. In: Roberts JR, Hedges JR. Clinical Procedures in Emergency Medicine. 5th ed. Philadelphia, PA: Saunders Elsevier; 2009.
Gordon CE, Feller-Kopman D, Balk EM, et al. Pneumothorax following thoracentesis: A systematic review and meta-analysis. Arch Intern Med. 2010;170(4):332 " 339.
Kosowsky JM. Pleural disease. In: Marx JA, ed. Rosens emergency medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, PA: Mosby Elsevier; 2009.
Light RW. Clinical practice. Pleural effusion. N Engl J Med. 2002;346(25):1971 " 1977.

Codes

ICD9

511.1 Pleurisy with effusion, with mention of a bacterial cause other than tuberculosis
511.9 Unspecified pleural effusion
511.89 Other specified forms of effusion, except tuberculous
511.81 Malignant pleural effusion
012.00 Tuberculous pleurisy, unspecified
457.8 Other noninfectious disorders of lymphatic channels
860.2 Traumatic hemothorax without mention of open wound into thorax
862.29 Injury to other specified intrathoracic organs without mention of open wound into cavity

ICD10

J90 Pleural effusion, not elsewhere classified
J91.0 Malignant pleural effusion
J94.0 Chylous effusion
A15.6 Tuberculous pleurisy
S27.1XXA Traumatic hemothorax, initial encounter

SNOMED

60046008 Pleural effusion (disorder)
79231000 Hydrothorax (disorder)
83035003 Chylothorax
83270006 Neoplastic pleural effusion (disorder)
42458003 Traumatic hemothorax (disorder)
446986002 Tuberculous pleural effusion (disorder)

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