The Importance of Clinical Suspicion in the Presence of Reported Lophomonas: A Case Report
Poster #: 071
Session/Time: B
Author:
William Wittler Zak, BS
Mentor:
Catherine Derber, MD, FACP
Research Type: Case Report
Abstract
INTRODUCTION:
Lophomonas blattarum is a protozoan that has been increasingly reported as a possible cause of upper and lower respiratory tract infections in humans. Previously reported cases have involved immunocompromised individuals presenting with non-specific respiratory symptoms such as cough, shortness of breath, and chest pain. There is uncertainty surrounding whether Lophomonas is truly the culprit of such symptoms in patients reported to be infected with Lophomonas. In contrast, Pneumocystis Jirovecii Pneumonia (PJP) is a well-established cause of pneumonia in immunocompromised patients. Both organisms may be detected in a patient through sampling of a bronchoalveolar lavage. Metronidazole has shown effectiveness against Lophomonas, and trimethoprim-sulfamethoxazole (TMP-SMX) is the established first-line treatment for PJP.
CASE INFORMATION:
A 58-year-old man with metastatic pancreatic cancer and stage 3 chronic kidney disease presented to the emergency department for progressive shortness of breath. He had received chemotherapy for pancreatic cancer, which led to chemotherapy-induced nephritis. Consequently, he was prescribed a prolonged course of high-dose prednisone. Shortly after his admission, he developed rapidly worsening respiratory distress of unknown etiology that required intubation. A subsequent chest CT scan revealed diffuse ground-glass and septal thickening in the lungs, with upper lobe predominance, and a new cluster of right upper lobe pulmonary nodules. A Fungitell test returned significantly elevated, and the patient underwent a bronchoalveolar lavage. The initial cytology report was positive for Lophomonas but negative for PJP, bacteria, or malignant cells. However, due to the patient's immunocompromised state and CT findings, clinical suspicion remained high for PJP, and he was started on metronidazole, trimethoprim-sulfamethoxazole, and posaconazole to cover Lophomonas, PJP, and endemic mycoses, respectively. Several days later, a PCR for PJP returned positive despite being negative on initial cytology.
DISCUSSION/CLINICAL FINDINGS:
There is current debate both on whether reports of Lophomonas are true positives and whether a true positive finding would yield clinical relevance. While it has been identified as a presumed respiratory pathogen in samples globally, there is skepticism and limited available literature proving causation of clinical pathology. Therefore, other possible causes of infection should be explored for which there remains a high degree of clinical suspicion, regardless of initial cytology. Given the CT findings and clinical presentation of this patient, prescribing TMP-SMX was the correct clinical decision. Even with the identification of Lophomonas in cytology, clinicians should maintain a high degree of suspicion for alternative causes and seek to identify another primary pathogen.
Lophomonas blattarum is a protozoan that has been increasingly reported as a possible cause of upper and lower respiratory tract infections in humans. Previously reported cases have involved immunocompromised individuals presenting with non-specific respiratory symptoms such as cough, shortness of breath, and chest pain. There is uncertainty surrounding whether Lophomonas is truly the culprit of such symptoms in patients reported to be infected with Lophomonas. In contrast, Pneumocystis Jirovecii Pneumonia (PJP) is a well-established cause of pneumonia in immunocompromised patients. Both organisms may be detected in a patient through sampling of a bronchoalveolar lavage. Metronidazole has shown effectiveness against Lophomonas, and trimethoprim-sulfamethoxazole (TMP-SMX) is the established first-line treatment for PJP.
CASE INFORMATION:
A 58-year-old man with metastatic pancreatic cancer and stage 3 chronic kidney disease presented to the emergency department for progressive shortness of breath. He had received chemotherapy for pancreatic cancer, which led to chemotherapy-induced nephritis. Consequently, he was prescribed a prolonged course of high-dose prednisone. Shortly after his admission, he developed rapidly worsening respiratory distress of unknown etiology that required intubation. A subsequent chest CT scan revealed diffuse ground-glass and septal thickening in the lungs, with upper lobe predominance, and a new cluster of right upper lobe pulmonary nodules. A Fungitell test returned significantly elevated, and the patient underwent a bronchoalveolar lavage. The initial cytology report was positive for Lophomonas but negative for PJP, bacteria, or malignant cells. However, due to the patient's immunocompromised state and CT findings, clinical suspicion remained high for PJP, and he was started on metronidazole, trimethoprim-sulfamethoxazole, and posaconazole to cover Lophomonas, PJP, and endemic mycoses, respectively. Several days later, a PCR for PJP returned positive despite being negative on initial cytology.
DISCUSSION/CLINICAL FINDINGS:
There is current debate both on whether reports of Lophomonas are true positives and whether a true positive finding would yield clinical relevance. While it has been identified as a presumed respiratory pathogen in samples globally, there is skepticism and limited available literature proving causation of clinical pathology. Therefore, other possible causes of infection should be explored for which there remains a high degree of clinical suspicion, regardless of initial cytology. Given the CT findings and clinical presentation of this patient, prescribing TMP-SMX was the correct clinical decision. Even with the identification of Lophomonas in cytology, clinicians should maintain a high degree of suspicion for alternative causes and seek to identify another primary pathogen.