Cytology Evaluation of Equine Lower Airway

What are the normal leukocytes in BAL?

Macrophages 50% decreases with age

Small lymphocytes 30-50% increases with age

<5% neutrophils

Few mast cells and eosinophils

What other cells are in a BAL?

Epithelial and goblet cells

What can contaminate a BAL?

Pollen, plant material, spores, hyphae

Why are neutrophils not always good to show infection in a BAL?

Degenerate very fast so need quick processing

What does Rhodococcus equi look like?

Coccobacilli with thin halo in macrophages

Similar to watermelon seeds

How do you diagnose Rhodococcus equi?

Bacterial culture and PCR for vapA gene

What does squamous cells with numerous bacteria indicate?

Can be upper airway contamination or aspiration pneumonia

Septate fungal hyphae that is not typically found and needs to correlate with C/S

What is the most common septate fungal hyphae?

Aspergillus

Pneumocystis jirovecii

Cannot be cultured need PCR for antigen

What is a cause of noninfectious neutrophilic inflammation?

Equine asthma, has a mild neutrophils, mastocytosis, and eosinophilia

Black arrow

Kurschmann spiral, highly indicative of equine asthma

What can cause eosinophilic inflammation?

Parasite larvae of Dictyocaulus arnfieldi

Allergic bronchitis

Equine asthma

Often clump on the slide

What does EIPH look like?

Numerous RBCs in background

>50% hemosiderophages