Detached ciliary tufts masquerading as free-living amoebae

Case 1 was an 18-year-old college student who presented with complaints of fever, headache, and vomiting of 2 days duration. On the day of admission, he had altered sensorium in the form of increasing drowsiness. The patient had visited a water park a few days before symptom onset. On examination, signs of meningeal irritation were seen in the form of neck stiffness. Magnetic resonance imaging of the brain showed features suggestive of meningoencephalitis predominantly involving the right basifrontal lobe. Cerebrospinal fluid (CSF) sent for biochemical parameters showed glucose of 1.4 mg/dl and protein of 826.2 mg/dl. Microscopy of the CSF showed neutrophilic pleocytosis with multiple 10–16-μm unicellular, sluggishly motile ciliated structures, which gave an initial impression of the flagellate form of Naegleria fowleri (Figure 1A) . As the patient gave a history of swimming in a water park just before the onset of his symptoms and the brain imaging showed rapidly progressing meningoencephalitis, treatment with amphotericin B and rifampin was started in addition to the empirical antibiotics and steroids. The CSF was cultured for free-living amoebae on non-nutrient agar with overlay of Escherichia coli; CSF microscopy images were sent to the US Centers for Disease Control and Prevention in Atlanta, USA, for a second opinion. The structures were diagnosed as ciliated ependymal cells. Multiplex PCR for CSF pathogens (Xcyton, Bangalore, India) was positive for Streptococcus pneumoniae. Blood cultures grew S. pneumoniae. The patient's condition deteriorated rapidly and he died of cardiac arrest on day 12 of admission. Case 2 was a 73-year-old male with long-standing diabetes and hypertension who presented with facial pain, headache, nasal discharge, and nasal obstruction of 4 months duration. Nasal endoscopy revealed polypoidal changes in the right middle meatus with a thick mucopurulent discharge filling the right maxillary antrum. Magnetic resonance imaging showed features suggestive of mucocele involving the right maxillary, ethmoidal, frontal, and sphenoid sinuses with no intracranial mass. Right unilateral functional endoscopic surgery showed polypoidal changes in the right middle meatus. A right uncinectomy, middle meatal antrostomy, anterior and posterior ethmoidectomy, sphenoidotomy, and frontal recess clearance were done and the defect packed with Merocel. The polypoidal tissue was sent immediately for microbiology and cytological examination (Figure 1B–E), which revealed the motile ciliated forms (Supplementary Material, videos 1–3). Microscopic examination of a wet mount initially showed ciliated cells (Figure 1B and C), which was confirmed on staining (Figure 1D). Stained preparations showed a well-defined nucleus and apical filaments suggestive of ciliated epithelial cells. In the wet preparation, the cells were actively motile (Supplementary Material, videos 1–3) and were mistaken for a parasite. The clinical features and history of the patient did not corroborate a parasitic infection of the sinuses or central nervous system. Ciliated epithelial cells line the respiratory tract, genital tract, Eustachian tube, and ventricles of the brain.1Boggild A.K. Friedmam Y. Sundermann C.A. The parasite that wasn’t: a case of detached ciliary tufts in cerebrospinal fluid.Univ Toronto Med J. 2000; 78: 26-29Google Scholar These cells can detach by constriction and severing of their luminal portions at these sites leaving their nucleus and basal cytoplasm behind. As they retain the mitochondria, these cell fragments remain motile for days.2Kuritzkes D. Rein M. Horowitz S. Droege G. Waldon M.A. Bell D.A. et al.Detached ciliary tufts mistaken for peritoneal parasites: a warning.Rev Infect Dis. 1988; 10: 1044-1047Crossref PubMed Scopus (9) Google Scholar N. fowleri causes primary amoebic meningoencephalitis in individuals who come into contact with fresh water that harbours this free-living amoeba.3Moffitt C. Parasitic infections of the central nervous system.Pediatr Ann. 1994; 23: 424-433Crossref PubMed Scopus (6) Google Scholar The ciliary motion exhibited by detached ciliary tufts (DCTs) can mimic the motility of flagellated amoebae in wet mounts and presents a diagnostic dilemma, as seen in these cases.1Boggild A.K. Friedmam Y. Sundermann C.A. The parasite that wasn’t: a case of detached ciliary tufts in cerebrospinal fluid.Univ Toronto Med J. 2000; 78: 26-29Google Scholar DCTs have been reported in nasal secretions, sputum, peritoneal fluid, and cervicovaginal smears. Knowledge of the occurrence of these structures at various sites will avoid confusion with members of the protozoa, especially when the clinical features strongly indicate a parasitic infection. It is important that suspected cases of primary amoebic meningoencephalitis undergo work-up for molecular confirmation following microscopic diagnosis.4Shakoor S. Beg M. Mahmood S. Bandea R. Sriram R. Noman F. et al.Primary amebic meningoencephalitis caused by Naegleria fowleri, Karachi, Pakistan.Emerg Infect Dis. 2011; 17: 258-261Crossref PubMed Scopus (80) Google Scholar Funding: None. 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