Abstract
Background
Legionella micdadei is the most common legionella species causing infection after L. pneumophila. It usually causes infection in immunocompromised hosts and leads to nodules with tendency to cavitate. It is difficult to culture which makes diagnosis challenging. We report a case or L. micdadei in an immunocompromised host with cavitary pneumonia.
Methods
Case Report. An 82 year-old female presented with upper abdominal pain for one day duration. She has history of hypertension, coronary artery disease, hyperlipidemia, heart failure, and hypothyroidism. She was diagnosed with hypersensitivity pneumonia 5 months prior, treated with prednisone (40 mg daily). The pain was not associated with nausea, vomiting or diarrhea. She was found with hypoxia despite she denied shortness of breath, cough, hemoptysis or chest pain. There was no fever, chills, headache, myalgia or upper respiratory symptoms. She was afebrile, tachycardic 134/min and hypoxic to 88% on room air. White cell count was 22x10(3) /mcL (90% neutrophils), hemoglobin was 10.4 g/dL, creatinine was 1.23 mg/dL and lactic acid was 3.6 mmol/L. Chest CT scan showed left lower lobe cavitary lesion with surrounding infiltrates (image 1). Quantiferon gold, serum galagtomannan, B-D-glucan, and vasculitis work-up were negative. Bronchoscopy showed a patent airway. Bronchial smears and cultures were negative for bacteria, fungi and mycobacteria. The patient was treated with ceftriaxone and metronidazole with de-escalation to amoxicillin/clavulanate. Bronchial culture was positive for legionella micdadei after discharge, azithromycin was added.
Image 1. Cavitary lesion on thoracic CT
Results
Our patient was considered immunocompromised given steroid use, predisposing her for L. micdadei infection. L. micdadei is considered an opportunistic infection and was reported in hematologic malignancy population. It can cause an invasive lung disease with lung cavities. It needs special media for growth making it difficult to diagnose especially it is not detected by legionella urine antigen.
Conclusion
L. micdadei should be considered in the differential diagnosis for cavitary lung lesions in immunocompromised patients.
Disclosures
All Authors: No reported disclosures
Allergic bronchopulmonary aspergillosis presenting with cavitary lesion and simulating a lung abscess
