Tracheal wash from a bull calf
A Brown Swiss bull calf presented to Cornell University Equine Farm Animal Hospital for evaluation of a left humeral fracture. On presentation, the calf was obtunded, recumbent and unable to bear weight. The calf had a body condition score of 2/5 with severe muscle atrophy. Capillary refill time was approximately 2 seconds, but mucous membranes were noted to be pale pink. The heart rate and temperature were within normal limits, while the respiratory rate was 18 breaths per minute with bilateral cranioventral harsh lung sounds, increased respiratory effort and crackles.
Thoracic ultrasonographic and radiographic examination revealed severe bilateral cranioventral lung consolidation, and radiographic examination of the left humerus revealed a complete, comminuted, mid-diaphyseal fracture. Blood was collected for a complete blood count and chemistry panel, and a transtracheal wash was performed and submitted for cytologic examination.
Blood work revealed mild inflammation characterized by a reactive thrombocytosis (907 thou/uL; reference interval [RI]: 252-724 thou/uL) and mild hyperfibrinogenemia (700 mg/dL; RI 100-600 mg/dL, by heat precipitation) with an acute phase response represented by a mild hypoalbuminemia (2.4 g/dL; RI: 3.3-4.3 g/dL) and mild decrease in total iron binding capacity (TIBC, 286 ug/dL; 320-490 ug/dL). A mild hypocalcemia (8.7 mg/dL; RI: 8.9-10.9 mg/dL) was attributed to the hypoalbuminemia (decreased protein-bound fraction).
Images of the transtracheal wash are provided. Evaluate the photomicrographs and answer the following questions:
- Which is/are the predominant cell(s) population in the tracheal wash?
- Based on the images, what are your differential diagnoses?
- What further tests should be performed?
Answers on the next page.