Codetection of pulmonary tuberculosis and toxoplasmosis in a pediatric bronchoalveolar lavage specimen: A cytologist's assistance to clinical management.

Background: Toxoplasmosis causes serious and sometimes life-threatening disease in immunocompromised patients like organ transplant recipients, immunodeficiency disorders or HIV-infected individuals. The co-occurrence of toxoplasmosis in a respiratory sample harboring tuberculosis (TB) may be missed especially in an area endemic for the latter infection.

Case Report: A 10-year-old child presented with complaints of fever with loss of appetite and weight. Based on radiological and clinical features, a presumptive diagnosis of pulmonary TB was made and bronchoalveolar lavage (BAL) performed for cytological and microbiological confirmation. Smears from BAL showed numerous lymphocytes along with few ciliated columnar epithelial cells. Ziehl-Neelsen stain for acid-fast bacilli was positive. The Giemsa-stained cytosmears also showed clusters of crescent-shaped tachyzoites of toxoplasma gondii in a background of lymphocytes. The patient was initiated on anti-tubercular therapy with marked clinical improvement.

Conclusion: A diligent screening of cytosmears for a possible coinfection in a TB-positive sample is essential for the cytopathologists to detect coexisting toxoplasmosis, which is a rare but treatable disease.