Page 332 - Small Animal Internal Medicine, 6th Edition

304 PART II Respiratory System Disorders

particularly if the head and neck are extended more than side. Specimens with overt oral contamination may not
briefly for passage of the endotracheal tube or transtracheal provide accurate information about the airways, particularly
VetBooks.ir catheter. Oral contamination is indicated by the finding of with regard to bacterial infection.
Cytologic results of tracheal wash fluid are most useful
numerous squamous epithelial cells, often coated with bac­
teria, and Simonsiella organisms (Fig. 20.19). Simonsiella
The presence of pathogens such as Toxoplasma gondii, sys­
organisms are large basophilic rods that are frequently found when pathogenic organisms or malignant cells are identified.
stacked uniformly on top of one another along their broad temic fungal organisms, and parasites provides a definitive

FIG 20.17 FIG 20.19
Photomicrograph of Toxoplasma gondii tachyzoites from the Tracheal wash fluid showing evidence of oropharyngeal
lungs of a cat with acute toxoplasmosis. The extracellular contamination. The numerous, uniformly stacked basophilic
tachyzoites are crescent shaped with a centrally placed rods are Simonsiella organisms—normal inhabitants of the
nucleus. They are approximately 6 µm in length. oral cavity. These organisms, as well as many other
(Bronchoalveolar lavage fluid, Wright stain.) bacteria, are adhering to a squamous epithelial cell.
Squamous epithelium is another indication of contamination
from the oral cavity.

FIG 20.18
Tracheal wash fluid from a healthy dog showing ciliated epithelium and few inflammatory
cells.