A 28-year-old woman presents with acute onset severe left-sided pleuritic chest pain, dyspnea, and fever (39°C). Chest X-ray shows a left-sided pleural effusion. Pleural fluid analysis reveals: WBC 8,000/μL (90% neutrophils), protein 4.2 g/dL, LDH 450 IU/L, glucose 85 mg/dL, negative bacterial culture, and negative AFB smear. She is hemodynamically stable with SpO₂ 94% on room air. What is the most appropriate immediate next step?

Explanation

## Clinical Context This patient presents with acute pleurisy with an exudative pleural effusion. The pleural fluid analysis has **already been performed** (results are provided in the stem), revealing: neutrophilic predominance (90%), elevated protein (4.2 g/dL) and LDH (450 IU/L), normal glucose (85 mg/dL), negative bacterial culture, and negative AFB smear. She is hemodynamically stable with SpO₂ 94% on room air. ## Pathophysiology of Acute Pleurisy **Key Point:** Acute pleurisy represents acute inflammation of the pleura. The pleural fluid profile here — exudate with neutrophilic predominance, negative cultures, and **normal glucose** — is most consistent with **viral or idiopathic pleurisy**, NOT bacterial empyema (which typically shows low glucose <60 mg/dL, positive cultures, and frank pus). **High-Yield (Light's Criteria):** This is an exudative effusion (protein >3 g/dL, LDH >200 IU/L), but the negative cultures and normal glucose argue strongly against bacterial infection or empyema. ## Why Option C (NSAIDs + Supportive Care) Is Correct Since thoracentesis has already been performed and results are available, the **next step** is management, not further diagnostics. Given: - **Negative bacterial culture and AFB smear** → no indication for empiric antibiotics - **Normal glucose** → rules out empyema and rheumatoid pleurisy - **Hemodynamically stable, SpO₂ 94%** → no indication for chest tube drainage - **Clinical picture consistent with viral/idiopathic pleurisy** The appropriate management is: 1. **High-dose NSAIDs** (e.g., ibuprofen 600–800 mg TID or indomethacin 25–50 mg TID) — first-line for viral/idiopathic pleurisy per Harrison's Principles of Internal Medicine 2. **Supportive care** (analgesics, rest, cough suppression) 3. **Close clinical monitoring** for resolution or development of complications **Clinical Pearl:** Per Harrison's (21st ed.), NSAIDs are the cornerstone of treatment for viral/idiopathic pleurisy. Colchicine may be added for recurrent cases. Antibiotics are NOT indicated in the absence of bacterial infection evidence. ## Why Other Options Are Incorrect - **Option A (Chest tube):** Reserved for empyema (pH <7.2, glucose <60, positive culture/Gram stain, or frank pus). This patient does not meet criteria. - **Option B (Empiric antibiotics):** Not indicated when cultures are negative and clinical picture favors viral etiology with normal glucose. Overuse of antibiotics is inappropriate here. - **Option D (Thoracentesis):** Already performed — this is logically incoherent as a "next step" since the pleural fluid results are already provided in the stem. **High-Yield:** The triad of pleuritic chest pain + exudative neutrophilic effusion + negative cultures + normal glucose = viral/idiopathic pleurisy → treat with NSAIDs and monitor. *Reference: Harrison's Principles of Internal Medicine, 21st ed., Chapter on Diseases of the Pleura; Light RW. Pleural Diseases, 6th ed.*