What is the most likely diagnosis in a smoker with progressive dyspnea, no infectious symptoms, and a pleural effusion with an exudative appearance, characterized by a pH of 7.13, elevated lactate dehydrogenase (LDH), elevated proteins, and low glucose levels?

Differential Diagnosis

• Single most likely diagnosis
  • 1. Néoplasie: The patient's history of smoking and the presence of a pleural effusion with characteristics of an exudate (high LDH, high protein, low glucose) are highly suggestive of a malignant process, such as lung cancer or metastatic disease to the pleura.
• Other Likely diagnoses
  • 1. Embolie pulmonaire: Although less likely than malignancy, pulmonary embolism can cause a pleural effusion with similar characteristics, especially in the context of a patient with risk factors for thromboembolism.
• Do Not Miss
  • 1. Insuffisance cardiaque: While the patient's presentation and pleural fluid analysis are not typical for heart failure (which usually causes a transudative effusion), heart failure can occasionally present with an exudative effusion, and missing this diagnosis could have significant consequences.
  • 1. Épanchement parapneumonique non-compliqué: Although the patient does not have infectious symptoms, it is crucial not to miss a parapneumonic effusion, as it requires specific management to prevent complications like empyema.
• Rare diagnoses
  • Other rare causes of exudative pleural effusions, such as autoimmune disorders (e.g., rheumatoid arthritis, lupus), could be considered but are less likely given the patient's presentation and the information provided.