Think It Twice Before You Give Piperacillin-Tazobactam

Piperacillin-tazobactam is a Beta-lactam and beta-Lactamase combination antibiotic very commonly used to treat infections, specially in critically ill patients. The most common adverse effects related to its use are mostly gastrointestinal and allergic. Lung infiltration with pulmonary eosinophilia is a very rare event, but when occurs has significant morbidity and mortality. For this reason, physicians should be aware of this possible reaction. This is a case of a 43 year-old woman with medical history of Morbid Obesity who presented to the emergency department complaining of severe stabbing right upper quadrant pain associated with nausea and non-bloody emesis after a heavy meal. Abdominal computed tomography (CT) revealed acute cholecystitis. She was initially treated with piperacillin-tazobactam, intravenous volume expansion and pain medication. The patient underwent cholecystectomy the next day. After surgery, the patient was complained of dyspnea. Arterial blood gases revealed respiratory acidosis and significative hypoxemia. Chest CT revealed bilateral consolidation and ground glass opacities with predominance of upper lobes. Laboratory was unremarkable, without leukocytosis, or eosinophilia, normal procalcitonin, and blood cultures and COVID-19 test were negative. A bronchoscopy was performed to obtain cultures, cell count and cytology analysis. Results showed negative negative microbiology cultures. Cellular differential counts of bronchoalveolar lavage showed a predominance of eosinophils (26% of total cell count. There was no peripheral eosinophilia, and eosinophilia work up, including parasitic infection evaluation was negative. Rheumatologic serologies work-up was also negative. The patient did not received other medications during her short admission, and initial admission X ray was completely normal. Piperacillintazobactam was discontinued and the patient was started in systemic steroids with rapid resolution of hypoxemia after the first 48hrs. Those findings suggested that piperacillin-tazobactam was most likely the cause of Acute Eosinophilic Pneumonia in this patient, after she was started for the treatment for acute cholecystitis. Piperacillin-tazobactam has been rarely associated to acute eosinophilic pneumonia. It may present as an acute hypoxemic respiratory failure as seen in few case reports. Presentation can occur any time during piperacillintazobactam, therapy, usually after days or weeks of therapy. High suspicion of the diagnosis in patients with pneumonia treatment with poor response to antibiotics or multi lobar disease, during therapy with piperacillintazobactam help to identify the diagnosis. Bronchoalveolar lavage with cellular differential > 25% confirm the diagnosis in a patient with no other etiology for pulmonary eosinophilia. Discontinuation of the medication and systemic steroids is the treatment of choice, usually with favorable rapid response.