PLEURAL EFFUSION

The pleural space is between two layers of pleura- one that covers the chest wall and the other covers the outer surface of the lung. Normally there is a very thin layer of fluid which acts as a lubricant between the two layers. When there is increased accumulation of fluid- this is known as a pleural effusion. As more fluid accumulates, the lung tissue underneath becomes compressed, and the patient feels increased difficulty in breathing, or shortness of breath. 

Causes
Causes may be: 
1. diseases of the lung and pleura 
a. such as pleurisy- or inflammation of the pleural, 
b. lung infections such as TB
c. lung cancer
d. pulmonary embolism
e. sarcoidosis
f. autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosis (SLE)
2. diseases of other organ systems
a. heart failure
b. liver failure
c. kidney disease
d. esophageal perforation
e. post-op abdominal surgery

Symptoms
Some patients have no symptoms. Others may have fever, chills, or difficulty breathing. The symtoms may depend on the cause of the pleural effusion. 

Diagnosis
Auscultation- friction rub may be present
Chest x-ray- may show areas of inflammation in pneumonia. A left lateral decubitus x-ray, where a patient lies on the left side, may show fluid levels.
Ct scan shows underlying pathology
Thoracocentesis where fluid is removed from the pleural cavity and is examine, may yield the diagnosis.
Pleural biopsy may be done to determine the cause. 

Treatment
Goal is to treat the underlying cause. Bacterial pneumonia is treated with antibiotics. Anti-inflammatory drugs are used to relieve pain. Cough control with suppressant may also help treat pain. Fluid may have to be drained to relieve symptoms.