Lophomonas blattarum - A blunder!

Abstract

Background: Lophomonas blattarum is a parasite colonising gut of cockroaches. There are 136 case reports from immunocompromised patients and children suffering from respiratory tract infections. Here we report a case where broncho alveolar lavage fluid from a child showed structures which convincingly appeared like a flagellate parasite but was later confirmed to be ciliocytophthoria. Case Description: A 5 y old female child hailing from rural southern India came with complaints of cough, cold and abdominal pain since 6 m. In view of increased severity of symptoms, high grade fever and cavitatory lesions in the lung, the child was referred to our centre. We considered the differential diagnoses - Hydatid cyst, Tuberculosis, non infectious causes of lung cyst. Investigations showed Eosinophilia and raised ESR. CT scan of chest showed consolidation with cavities involving apical segment of right lower lobe, anterior segment of left upper lobe suggestive of infective etiology. Broncho alveolar lavage fluid was negative for acid fast bacilli and TB PCR. On wet mount examination, motile structures appearing to have tuft of flagella were seen. Modified Trichrome stain showed numerous inflammatory cells and pyriform shaped structures with tuft of flagella arranged irregularly at one pole. Inner structures were not appreciated very clearly and a presumptive diagnosis of the parasite Lophomonas blattarum was made. The patient was treated with metronidazole 7.5 mg/kg body weight for 10 d awaiting further results. Child improved symptomatically and discharged. Discussion: Since it was difficult to do the molecular tests, we sent the micrscopic photographs and videos to CDC Diagnostic Assistance team to help us solve the case. They confirmed it to be ciliocytophthoria. Bronchial epithelial cells are cylindrical with basal nuclei and a visible terminal bar just beneath the regularly arranged cilia at the other end. This was a learning experience for us to differenciate the cells from the parasite. We now routinely perform special stains on samples found to have motile structures like these. Conclusion: Lophomonas blattarum rarely causes human disease more often misdiagnosed because the movement of the flagellate parasite resembles the motion of detached ciliated bronchoepithelial cells when brochoalveolar lavage fluid is examined under the microscope.