Patient presents with complaints consistent with left pleural effusion.  Symptoms include dyspnea, pleuritic chest pain, and cough.  Physical examination reveals decreased breath sounds and dullness to percussion over the left lung base.  The patient reports a history of congestive heart failure, a known risk factor for pleural effusion development.  Differential diagnoses considered include pneumonia, pneumothorax, and malignancy.  Chest X-ray demonstrates blunting of the left costophrenic angle, suggestive of fluid accumulation.  Thoracentesis is planned for diagnostic and therapeutic purposes.  Pleural fluid analysis will be sent for cytology, chemistry, and microbiology to evaluate for infection, malignancy, and transudative versus exudative effusion.  Treatment will be directed at the underlying cause of the effusion and may include diuretics, antibiotics, or other interventions depending on the pleural fluid analysis results.  Patient education provided on the importance of follow-up care and symptom management.  ICD-10 code J90 will be considered, with specific coding determined by the etiology of the effusion.  CPT codes for the thoracentesis and pleural fluid analysis will be documented.  The patient's prognosis depends on the underlying cause of the effusion and response to treatment.