Plural effusions Flashcards
What are the most common symptoms of pleural effusion?
Dyspnea, chest pain, cough; often asymptomatic if small.
What are the key physical exam findings of pleural effusion?
Dullness to percussion, decreased tactile fremitus, and decreased breath sounds over the affected area. Large effusions can shift the trachea and cause tracheal deviation.
What are the two main types of pleural effusions?
Pleural effusions occur when there is excess fluid accumulation in the pleural cavity due to increased fluid production or impaired drainage. The two types are Transudative and Exudative.
What are common causes of transudative pleural effusions?
- Heart failure
- Cirrhosis (low albumin)
- Nephrotic syndrome
- Peritoneal dialysis
What is characteristic of pleural effusions secondary to heart failure?
Bilateral, perihilar patchy infiltrates.
What are common causes of exudative pleural effusions?
- Pneumonia
- Malignancy
- Tuberculosis
- Autoimmune disease (e.g., lupus, rheumatoid arthritis)
- Trauma
What is the most common cause of pleural effusion worldwide?
Tuberculosis.
What is the most common cause of malignant pleural effusion?
Lung cancer.
What is a chylothorax?
Pleural effusion due to rupture of the thoracic duct, leading to accumulation of lymphatic fluid rich in triglycerides. Thoracic duct obstruction can cause chylothorax, which often presents with subacute pulmonary symptoms due to pleural effusion. The diagnosis is usually suspected when the pleural fluid triglyceride level is >110 mg/dL.
What is the characteristic finding in chylothorax?
Milky white pleural fluid with high triglycerides (>110 mg/dL).
What is the first-line imaging study for pleural effusion?
Chest X-ray (CXR), which shows blunting of the costophrenic angles.
What imaging modality is more sensitive for detecting small pleural effusions?
CT scan or ultrasound.
What is the role of thoracentesis in pleural effusion evaluation?
Diagnostic and therapeutic procedure used to determine the nature of the effusion unless the cause is clearly heart failure.
What condition is associated with low glucose in pleural effusion?
Rheumatoid arthritis, tuberculosis, empyema, malignancy.
What are Light’s criteria for exudative pleural effusion?
This is a deterministic step in the process to evaluate whether the fluid collected from a thoracentesis is exudative. If any of the three are positive, the fluid is exudative, otherwise, the fluid is a transudate. (1) Pleural protein/serum protein ratio >0.5 mg/dL (basically the fluid from the thoracentesis has at least 50% of the amount of protein seen in the serum, within the pleural cavity), (2) Pleural LDH/serum LDH ratio >0.6 mg/dL (basically the fluid from the thoracentesis has at least 60% of the amount of LDH seen in the serum, within the pleural cavity), finally, (3) Pleural LDH >2/3 of the upper limit of normal serum LDH (the upper limit can be anywhere from 120 to 250 U/L and depends on the facility and is provided in the question).
How are transudative pleural effusions managed?
Treat the underlying condition (e.g., diuretics for heart failure).
What is the general management approach for exudative pleural effusions?
Thoracentesis, chest tube drainage if necessary, and possible surgical intervention if loculated or not draining.
What are the additional pleural fluid tests used for exudative fluids?
- Glucose (low in infection and malignancy)
- pH (7.6 normal, 7.4-7.55 transudative, 7.3-7.45 exudative, <7.2 complicated infection)
- cytology (for malignancy)
- amylase (for esophageal rupture)
What are the three types of exudative fluids?
Exudative fluid can be further classified as parapneumonic effusions, which are uncomplicated, complicated, and empyema.
What characterizes an uncomplicated parapneumonic effusion?
The fluid is shown to be small or moderate and a free flowing sterile exudative with a leukocyte count (WBC) <50,000, pH >7.2 (near-neutral), and negative culture. These can be treated with antibiotics alone.
Why are antibiotics given in uncomplicated parapneumonic effusions?
To prevent progression to complicated effusions or empyema.
What characterizes a complicated parapneumonic effusion?
Bacterial infection, WBC >50,000, pH <7.2, positive culture (~50% cases); requires antibiotics and drainage. Glucose tends to less than 60 mg/dL and LDH is greater than 1000 mg/dL.
What characterizes an empyema?
Frank pus in the pleural space, positive Gram stain and culture; requires antibiotics and urgent drainage.
When should a chest tube be placed for pleural effusion?
If the effusion is large, causing respiratory compromise, or if it is a complicated parapneumonic effusion or empyema. Uncomplicated parapneumonic effusions usually resolve with adequate antibiotic treatment of the pneumonia, and drainage is not required. It is important to distinguish an uncomplicated parapneumonic effusion from a complicated parapneumonic effusion or empyema, both of which represent bacterial infection of the pleural space and usually require drainage in addition to antibiotics. Complicated parapneumonic effusions are generally characterized by pH <7.2, glucose <60 mg/dL, leukocytes >50,000 mm, and markedly elevated lactate dehydrogenase (LDH) (eg, >500 U/L) but falsely negative culture/Gram stain. Empyema represents further progression of infection in the pleural space with frank pus and usually a positive culture/Gram stain. Loculated fluid collections are often present and can complicate drainage.
What is a hemothorax?
Pleural effusion caused by blood accumulation, often due to trauma.
What is the pleural fluid hematocrit cutoff for diagnosing hemothorax?
Pleural fluid hematocrit >50% of serum hematocrit.
