[From ICU to recovery: recurrent pneumonia due to Lophomonas blattarum].

Background: Lophomonas blattarum is a multiflagellate protozoan considered an endocommensal parasite of the cockroach gut. Its identification is clinically relevant in cases of recurrent or refractory pneumonia. The infection manifests with cough, dyspnea, expectoration, bronchiectasis, and pleural effusion; its diagnosis is based on the morphological recognition of the protozoan in respiratory samples, and treatment with metronidazole or tinidazole is usually effective. To describe the manifestations, diagnostic findings, and evolution of a patient with recurrent pneumonia caused by Lophomonas blattarum, the following case is presented. Clinical case: A 73-year-old female patient with type 2 diabetes mellitus, hypertension, hypothyroidism, and depressive disorder, with a history of hospitalization for pneumonia, was admitted with chest pain, progressive dyspnea, hyporexia, edema, and perioral cyanosis. Laboratory studies revealed a ground-glass opacity pattern and bilateral alveolar infiltrates. Given the poor response to treatment, bronchoalveolar lavage was performed, and Lophomonas blattarum was identified by direct microscopy. Treatment with metronidazole was initiated, resulting in clinical improvement and resolution. Conclusions: This case highlights the importance of considering parasitic etiologies in patients with recurrent pneumonia and chronic comorbidities. The timely identification of Lophomonas blattarum by bronchoalveolar lavage allowed for targeted treatment and a favorable clinical outcome.