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Pulmonary and Critical Care Medicine Pleural Effusion Diagnosis Most pleural effusions in the United States are the result of'HF, pneumonia, or malignancy. A thoracentesis is indicated fbr any new unexplained effusion. Observation and therapy without thoracentesis is reasonable in the setting of known UF, small parapneumonic effusions, or following CABG surgery. Testing Point of:care ultrasonography can identify small effusions and determine if they are fiee flowing or loculated and should be used to guide thoracentesis. Pleural fluid is characterized as transudative or exudative. 5?UDY TABLE: Laboratory Tests for ldentifying a Pleural Effusion as an Exudate Test lnterpretation Pleural fluid protein-serum protein ratio >0.5 Pleural fluid LDH >200 U/L(or >2/3 the ULN) Pleural fluid LDH-serum LDH ratio >0.6 An effusion is considered an exudate if any one of the above criteria is met. Criteria are sensitive but not specific. Treatment (diuretics for HF), a dual diagnosis (HF and a concomitant parapneumonic eUusion), or some specific diagnoses (e.g., chylotho rax) can result in discordant exudates (an exudate by either the protein or LDH criterion but a transudate by the other criteria). A common cause of discordant findings is diuretic use. In the setting of ongoing diuresis, if the serun.r to pleural fluid albumin gradient is >1.2 g/dl, the fluid is most likely a transudate. STUDY TABLE: Most Common Causes of Transudative and Exudative Pleural Effusions Transudative Pleural Effusions Exudative Pleural Effusions HF Parapneumonic Cirrhosis Malignancy Pleural fluid cell counts and chemistries can f'urther narrow the differential diagnosis.

STUDY TABLE: Most Common Causes of Transudative and Exudative Pleural Effusions Transudative Pleural Effusions Exudative Pleural Effusions HF Parapneumonic Cirrhosis Malignancy Pleural fluid cell counts and chemistries can f'urther narrow the differential diagnosis. STUDY TABLE: Pleural Fluid Cell Counts and Chemistries If you see this... Think this. Bloody pleural fluid (RBC count 5000-10,000/pL) Malignancy, pulmonary infarction, asbestos related Nucleated cells >50,000/pL Complicated parapneumonic effusions and empyema Lymphocytosis >80% TB, lymphoma, chronic rheumatoid pleuritis, sarcoidosis, malignancy pH <7.2 Complicated parapneumonic effusion Pleural fluid amylase to serum amylase ratio >1 Pancreatic disease, esophageal rupture Glucose <60 mg/dL Complicated parapneumonic effusion or empyema, TB, rheumatoid pleuritis, esophageal rupture Chylothorax (triglycerides >1 10 mg/dL) Disruption of thoracic duct (surgery, trauma), lymphoma, TB 349

Pulmonary and Critical Care Medicine \ Other key points: . Pleural fluid adenosine deaminase is elevated in most TB effusions. o Pleural biopsy is most likely to yield a positive TB culture. . The yield for positive malignant cytologr is maximized after two samples. o Thoracoscopy should be performed for an undiagnosed exudative effusion (two negative cytologz examinations) when malignancy is suspected. Treatment Parapneumonic pleural effusion requires chest tube drainage if Gram stain or culture is positive, when the pH is <7.2, or if it appears loculated on imaging. Anaerobes are cultured in up to 72% of empyemas; empiric antibiotic therapy should include anaerobic coverage. For patients with malignant effusions, indwelling pleural catheters provide symptom reliet and up to 70% of patients achieve spontaneous obliteration of the pleural space (pleurodesis) after 6 weeks. Chemical pleurodesis with talc has a 90% success rate. Pleural Effusion: Chest x-ray showing a right-sided pleural effusion (/eft) that layers out along the right thorax in the right lateral decubitus view (right\. DON'T BE TRICKED . Always obtain thoracentesis for moderate to large effusions associated with pneumonia. o Pleural effusions associated with nephrotic syndrome are common, but pE should be excluded in such patients because PE and renal vein thrombosis often occur in patients with nephrotic syndrome. . Consider pulmonary LAM when chylothorax is diagnosed in a premenopausal woman. TESTYOURSELF A 65 year-old woman has a 2-week history of shortness of breath. A chest x ray shows a large right-sided pleural effusion. Serum LDH is 190 U/L, and total protein is 6.0 g/dl. On thoracentesis, pleural fluid protein is 2.8 g/dl and pleural fluid LDH is 110 U/L. ANSWER: For diagnosis, choose a transudative pleural effusion. 350

Pulmonary and Critical Care Medicine I Pneumothorax i i L Diagnosis ( Symptoms are chest pain and dyspnea. Spontaneous pneumo- thorax is primary when no underlying lung disease is identifia- L i ble. Tall men who smoke are at risk. Subpleural blebs and bullae I L are commonly detected on CT scan and predispose to primary I pneumothorax. I I Secondary pneumothorax is associated with lung disease. I Consider: I I . emphysema as the most common cause of secondary I I pneumothorax o pulmonary LAM in a premenopausal woman presenting with a spontaneous pneumothorax and lung disease . secondary pneumothorax in patients with HIV and P ne u moc y stis jirouecii pneu mon ia . tension pneumothorax with falling BP and oxygen satura large Pneumothorax: Chest x-ray showing left-sided pneumothorax measuring 9 cm at the level of the hilum. tion, tracheal deviation, and absence of breath sounds in one hemithorax Obtain an upright chest x-ray in patients with dyspnea, pleurisy, or both even if the physical examination is normal. The presence of lung sliding with ultrasound imaging indicates no pneumothorax at that specific location, and the presence of a lung point confirms the edge of a pneumothorax.

pneumothorax o pulmonary LAM in a premenopausal woman presenting with a spontaneous pneumothorax and lung disease . secondary pneumothorax in patients with HIV and P ne u moc y stis jirouecii pneu mon ia . tension pneumothorax with falling BP and oxygen satura large Pneumothorax: Chest x-ray showing left-sided pneumothorax measuring 9 cm at the level of the hilum. tion, tracheal deviation, and absence of breath sounds in one hemithorax Obtain an upright chest x-ray in patients with dyspnea, pleurisy, or both even if the physical examination is normal. The presence of lung sliding with ultrasound imaging indicates no pneumothorax at that specific location, and the presence of a lung point confirms the edge of a pneumothorax. Treatment STUDY TAEtEl Management of Pneumothorax Size" and Clinical Symptoms Management <2 cm on chest x-ray, minimal symptoms Needle aspiration or admit to hospital for observation and supplemental oxygen (PSP may be managed as an outPatient if good access to medical care) >2 cm on chest x-ray, breathlessness, and chest pain lnsertion of a small-bore (<14 Fr)thoracostomy tube with connection to a high-volume low-pressure suction system Cardiovascular compromise ( hypotension, increasing Emergent needle decompression followed by thoracostomy tube breathlessness) regardless of size insertion PSP = primary spontaneous pneumothorax. "Measured between lung and chest wall at the level of the hilum. Pleurodesis is performed for a second primary spontaneous pneumothorax and may be performed after a first occurrence in secondary spontaneous pneumothorax.

"Measured between lung and chest wall at the level of the hilum. Pleurodesis is performed for a second primary spontaneous pneumothorax and may be performed after a first occurrence in secondary spontaneous pneumothorax. DON'T BE TRICKED r Do not wait for chest x-ray results before treating suspected tension pneumothorax with needle decompression' 351