An 88-year-old man presented with progressively worsening shortness of breath and fever. He has a history of Stage IV squamous cell carcinoma of the lung, status post external beam and stereotactic body radiation therapy. Four months prior to presentation, he was found to have a left-sided malignant pleural effusion. He was readmitted two months later with reaccumulation of pleural fluid and a PleurX catheter was placed.
On presentation, he was febrile with mild hypoxia (90s on 2L). He had dullness to percussion and rales at the left lung base; PleurX catheter was intact without surrounding erythema. He had WBC of 22 with chest x-ray revealing a large consolidation in the left lower lobe with moderate pleural effusion. He was started on broad spectrum antibiotics with vancomycin and piperacillin-tazobactam and subsequently narrowed to ertapenem based on prior culture data.
Computed tomography scan showed numerous foci of gas within the pleural fluid consistent with a gas-producing organism, without finding a visceral source for the possible infection. Plans were made to drain the pleural fluid daily. Pleural fluid analysis showed a pH = 7.2, lactate dehydrogenase 5839 U/L (serum 236), protein 3.1 g/dL (serum 5.0). A gram stain of the fluid revealed many segmented neutrophils and abundant gram-positive rods.
The anaerobic culture ultimately grew Clostridium perfringens, identified by convention biochemicals and by mass spectrometry (MALDI-TOF). He was discharged on day 5, continued on a two-week course of ertapenem and then transitioned to an indefinite course of metronidazole.
Discussion:
We describe a rare case of Clostridium perfringensempyema in a patient with metastatic squamous cell carcinoma of the lung with a favorable outcome after intravenous ertapenem treatment and daily drainage. Aspiration of oropharyngeal contents, invasive procedures to the chest cavity, and bacteremic seeding of the pleural cavity have been proposed modes of clostridial infection. The etiology of the empyema in this patient was likely due to the permanent PleurX given the frequent drainage and long-term placement. There was no indication for PleurX catheter exchange given that the entry site in the chest wall did not show evidence of infection and early initiation of antibiotics and daily drainage markedly improved clinical outcome.
It has been postulated that pulmonary infections due to C. perfringens may be less virulent than infections in other tissues or muscles due to the possibility of toxin inactivation. Specifically, dilution and confinement of the exotoxin in the pleural space has been considered to minimize the systemic absorption of the toxin. There was a high burden of C. perfringensbased on gram stain and pleural fluid culture in this patient; however, he had relatively accelerated recovery with guided antibiotic therapy and drainage.
Conclusions:
It has been hypothesized that underlying pulmonary conditions predispose to Clostridium perfringens empyemas, but this is the first case report to our knowledge in a patient with a known lung malignancy.