Ultrasound-guided thoracentesis for diagnosing Nocardia beijingensis-related empyema in a patient with systemic lupus erythematosus: A rare case report

Infections caused by <i>Nocardia</i> species are relatively rare and primarily affect immunocompromised patients. There are few reported cases of <i>Nocardia beijingensis</i> causing empyema in patients with systemic lupus erythematosus (SLE). We present a case of a 49-year-old female patient with SLE on immunosuppressive therapy (corticosteroids and azathioprine), admitted with dyspnea and left-sided pleuritic chest pain. A diagnosis of large parapneumonic left pleural effusion was established based on blood tests, blind thoracentesis findings, and bronchoalveolar lavage results. The patient received empirical intravenous antibiotic therapy with imipenem/cilastatin and vancomycin without isolating the causative organism for 10 days. Three weeks postdischarge, the patient's left pleuritic chest pain worsened, prompting chest computed tomography that revealed multiple loculated pleural-abdominal wall fluid collections. Ultrasound-guided aspiration of these areas yielded pus cultured positive for N<i>. beijingensis</i>. The patient showed improvement following treatment with imipenem/cilastatin and trimethoprim/sulfamethoxazole. This case represents a rare manifestation of N<i>. beijingensis</i> causing pleural and abdominal wall empyema. Ultrasound-guided aspiration, targeting the loculated and encapsulated effusion, played a crucial role in confirming the diagnosis. Empirical treatment with imipenem/cilastatin combined with long-term oral trimethoprim/sulfamethoxazole was found to be effective.