The cytopathology of respiratory disease Flashcards
Nasal washes & imprints
- when to use?
- consideration
- chronic discharge
- nasal masses
- foreign bodies
- aggressive sampling often necessary
Tracheal washes (TW)
- what is it, what we see?
- Wash of the large airways
- Normally no leukocytes in the lumen of the trachea or bronchi
- May pick up a few ciliated epithelial cells and goblet cells
Tracheal wash
- how to perform
- Inject saline
- Patient coughs?
- “Wash” large airways
- Re-aspirate sample
- Submit to lab or centrifuge sample gently and prepare slides yourself
Bronchoalveolar lavage (BAL)
- how to perform
- Pass endoscope through naso-pharynx
- Trachea > bronchi > lodge in distal bronchi
- Inject saline > aspirate
- Repeat for different bronchus
- Submit sample to lab or prepare centrifuged smears
BAL
- pros and cons
- Advantages: generally sample small airways +/- alveoli
- Can sample specific sites
<><><><> - Disadvantages: poorly representative of the whole lung
- Need anesthetic in small animals
- Partially occlude airways
Pleural fluid analysis & percutaneous aspirates
- how to perform, what we learn
Submit the whole fluid in an EDTA tube (if bloody) or a red top tube (if clear). The lab determines:
* Cell concentration
* Differential count
* Protein concentration
* Pathologist: Microscopic interpretation
Asthma (non-septic inflammatory airway disease) in horses
- pathogenesis
- Indoor housing
- Recurrent exposure to environmental dust, moulds, bacteria
- Chronicinflammation
- Constricted airways, smooth muscle hyperplasia, chronic inflammation
- Lung remodeling
Inflammatory airway disease (mild asthma) – young horses
- BAL observations
- other signs
- Increased cell concentration in BAL
- Increased macrophages & lymphocytes, mild increase in neutrophils+/- eosinophils +/- mast cells
- Excess mucus
- Cough
- Exercise intolerance
- Do not have respiratory distress at rest
Severe asthma (“recurrent airway obstruction,
heaves”) – chronic disease, older horse
- cells observed
- lesions? signs?
- Predominantly neutrophils
- No bacteria
- Variable increase in mast cells and lymphocytes
- Lung fibrosis, smooth muscle hyperplasia and difficulty breathing at rest
Exercise-induced pulmonary hemorrhage
Pathogenesis
- Hypertension of pulmonary arteries?
- Caudodorsal lobes are affected
- Rupture of lung capillaries
- Contribution of IAD? Poor quality air?
- May be insidious presentation
Bacterial and viral infections of the equine respiratory tract
- agents
- observations for bacterial vs viral infections
> diagnostic tests
- Bacteria: Rhodococcus equi, Streptococcus zooepidemicus, S. equi
- Equine herpes virus, rhinovirus, influenza virus
- Bacterial infections: suppurative +/- macrophage inflammation, organisms present > need to culture
- Viral infections: no specific cytological changes, fever, cough > serology, PCR
Non-septic inflammatory airway disease in the dog and cat
Pathogenesis:
- Chronic exposure to environmental allergens with predilection for inducing IL-5 production > eosinophil proliferation
- Chronic irritation from pollutants, smoke, viral
infections > IL-8 production, suppurative inflammation, interstitial fibrosis
Dogs – allergic resp disease
- cells we observe, test to use
- other observations
- Typically eosinophils are increased, but may not be the predominant inflammatory cell population in BAL
- Small airway disease – BAL!
- Excess mucus
- Often have blood eosinophilia
Cats - asthma
- history
- cells
- other observations, blood, disease
- Cats with asthma may have only a brief history of illness
- Eosinophils typically predominate
- Blood eosinophilia variable
- Bronchial asthma, acute bronchitis, chronic bronchitis – pathogenesis?
Parasitic airway disease - common agents
- Eucoleus (Capillaria) aerophilus (dogs, cats)
- Oslerus (Filaroidus) osleri (dogs)
- Crenosoma vulpis (dogs)
- Paragonimus kellicotti (carnivores)
- Aelurostrongylus abstrusus (cats)
- Dictyocaulus viviparous (cattle, llamas, alpacas)
- D. filaria (small ruminants, llamas, alpacas)
- D. arnfieldi (horses, donkeys)
