Nocardiosis Presenting as a Solitary Pulmonary Nodule and Pleural Effusion in a Patient with Relapsing Polychondritis

Case Presentation:

An 86‐year‐old man with a history of hypertension and relapsing polychondritis (RPC) on remission with immunosuppressant therapy (MTX and PDN) presented with pleuritic chest pain and shortness of breath 6 months prior to admission. A pleural effusion was diagnosed that resolved with increased prednisone dose. Symptoms recurred 2 weeks prior to admission. Patient denied fever, weight loss, or hemoptysis. Patient is a former 40 packs/year smoker who quit 30 years ago. On examination patient had no lymphadenopathy and had mildly decreased breath sounds on right base. Initial evaluation showed a right pleural effusion and pulmonary nodule. A PET/CT was performed showing a 15‐mm nodule on RUL. A thoracocentesis showed an exudate (protein 3.5/5.7; LDH 160, pH 7.0). An MRI of the brain showed a right frontal 4‐mm lesion. The patient underwent bronchoscopy and video‐assisted thoracoscopy with pleural biopsy and drainage of pleural fluid; cytology and histopathology were negative for malignancy. Culture revealed growth of partially positive acid‐fast thin‐branched filaments, consistent with Nocardia nova complex, sensitive to cotrimoxazole, which was started for treatment. It was considered that most probably the patient's infection was secondary to immunosuppression from long‐term steroid use and that the brain lesion was secondary to Nocardia as well. Patient was discharged and followed up as outpatient by the Infectious disease service. The patient has completed 3 months of therapy without recurrence of symptoms.

Discussion:

Nocardiosis is an infrequent but severe infection caused by weakly gram‐positive and acid‐fast filamentous aerobic soil microorganisms. It most commonly affects immunosuppressed patients. It is an elusive diagnosis that requires culture from tissue or fluid. It is generally susceptible to sulfonamides, and therapy should be prolonged for at least 6 months. Our patient was on prednisone for treatment of relapsing polychondritis, which predisposed him to acquire the infection from Nocardia.

Conclusions:

A high index of suspicion for opportunistic infection such as Nocardia should be acknowledged in immunosuppressed patients presenting with pleural effusion and solitary pulmonary nodule, as this is a treatable condition that dramatically changes the prognosis and treatment of these patients.

Author Disclosure:

M. Auron‐Gomez, none; P. Zimbwa, none; A. Kumar, none; V. Dimov, none.