Tracheobronchial Disease Flashcards by jared Jensen

What structures are typically affected with tracheobronchial disease

Nasopharynx
Trachea
Bronchi
Bronchioles

these are the conducting airways- not for gas exchange but important to warm, humidify, and filter the air

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What are the purposes of the conducting airways like the nasopharynx, trachea, bronchi, bronchioles

these are the conducting airways- not for gas exchange but important to warm, humidify, and filter the air

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What are the 3 main cell types in the trachea

1) Pseudostratified Ciliated- move mucus to mouth so we can swallow it
2) Goblet cells
3) Basal cells - stem cells- regenerate epithelial lining

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What are the defenses that the conducting airway system has

1) Epithelial barrier: physical barrier
2) Mucus- to trap in particles
3) Mucociliary elevator- moves mucus outwards to then be swallowed
4) Oxidant defenses
5) IgA antibodies
6) Lysozymes, defensins, mucins, NO (not pathogen specific)

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In the conducting airways, what are typical responses to insults

1) Epithelial cell desquamation- stripped away
2) Goblet cell hyperplasia
3) Increased mucus production
4) inflammation and bronchoconstriction

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Why do patients need to cough

epithelial cell desquamation, losing the ciliated epithelium

goblet cell hyperplasia with increased mucus production
bronchoconstriction

need to cough to force mucus out

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What are the consequences of insult to the conducting airways

ex: virus leaves no defense system (ie mucociliary system)

susceptible to secondary infection: opportunistic bacteria in the lower airways

parenchymal infection occurs (pneumonia)

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What are the clinical signs of tracheobronchial disease

-hacking cough
-stridor
-wheezes
-inspiratory, expiratory effort
-airway obstruction
-dyspnea

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What are the two big causes of a cough

1) Cardiac
2) Respiratory- conducting or respiratory zones

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What evidence might tell you that a cough is from cardiac disease

Murmur
Arrhythmia
Abnormal Pulse Quality
Abnormal perfusion
Parameters
Collapse

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Respiratory disease can be from disease in what zones

Conducting zone
-Nasopharynx
-Trachea
-Bronchi
-Bronchioles
-Smooth Muscle

Respiratory Zones
-Respiratory Bronchioles
-Alveolar ducts, sacs
-alveoli
-interstitium

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What are the clinical signs of disease in the respiratory zone
-Respiratory Bronchioles
-Alveolar ducts, sacs
-alveoli
-interstitium

-Cough
-Dull Moist crackles
-Dyspnea
-Restrictive pattern
-Systemic illness
-Fever *
-Hypoxemia

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What are the clinical signs of disease in the conducting zone
-Nasopharynx
-Trachea
-Bronchi
-Bronchioles
-Smooth Muscle

-Stertor or Stridor
-Dry, elicited, honking
-Wheezes
-Clear BV sounds
-Obstructive pattern
-Normoxemia

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How do the sounds differ between conducting zone disease vs respiratory

Conducting: stertor or stridor, dry, elicited, honking, wheezes
Clear BV sounds

Respiratory: cough, moist, crackles, dull

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What are typical etiologies of conducting zone disease

Vascular (bleeding, clotting, BP) : hemorrhage

Infectious: viral, bacterial, fungal, parasitic, protozoal

Toxin/Trauma: inhaled toxin, crushing

Anatomic: inhaled FB, tracheal stenosis

Metabolic: ?

Inflammatory: allergic airway disease, GE reflux

Neoplasic: airway mass

Degenerative: tracheobronchial malacia

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What are viral causes in a dog with a conducting zone cough

1) Distemper (CZ +RZ)
2) Influenza (CZ + RZ)
3) CIRDC (CZ+/- RZ)
-canine adenovirus type 2
-canine parainfluenza virus
-canine respiratory coronavirus
-Canine influenza (H3N2, H3N8)
-Canine herpes virus
-Canine distemper virus

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What are bacterial causes of a dog with conducting zone cough

1) Mycoplasma
2) Hematogenois pneumonia (RZ)
3) Secondary bacterial infection after viral illness (RZ)

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What are fungal causes in a dog with a conducting zone cough

Blastomycosis (RZ)
Coccidiomycosis (RZ)

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What are fungal causes in a dog with a conducting zone cough

aberrant larval migration (RZ)

lung worms

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What are the 6 agents in the CIRDC

1) canine adenovirus type 2
2) canine parainfluenza virus
3) canine respiratory coronavirus
4) Canine influenza (H3N2, H3N8)
5) Canine herpes virus
6) Canine distemper virus

leads to a secondary infection

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Today, what are the two most common CIRDC causes

Canine influenza and herpes virus today

use to be: adenovirus type 2 and parainfluenza

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What is the pathophysiology of CIRDC

1) Adherence to respiratory epithelium and cilia
2) Infection of epithelial cells, necrosis and loss
3) Destruction and loss of cilia
4) Increase mucus production
5) Stimulate immune cell influx

without these defense systems, secondary bacterial infection occurs to come in and impact the mycoplasma

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What are common secondary bacteria that occur after primary CIRDC infection

Mycoplasma cynos

Bordatella bronchispetica

Strep. equi subs zoo epi.

other secondary opportinistics

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How are contagious viral pathogens typically spread

Aerosol spread

What is the incubation of viral respiratory pathogens

Typically 2-10 days

What factors increase risk for respiratory pathogens

1) Crowding 2) Poor ventilation, sanitation 3) Frequent intro of new animals 4) Stressed animals 5) Lack of vaccination

What are the CIRDC clinical signs

Asymptomatic Acute Dry, hacking cough sneeze serous nasal discharge serous ocular discharge (transition zone)

What factors contribute to the severity of CIRDC

-Secondary infection -pathogen -age (young) -co-infection -vax status

What are the clinical signs of CIRDC with secondary infection

systemically ill febrile moist, productive cough respiratory distress hypoxemia

What are diagnostics you can do for CIRDC

-thorough history -physical exam +/- CBC, chemistry, UA +/- thoracic radiographs others: infection respiratory panels, airway sampling, CT

What might prompt you to do further investigation of CIRDC

-severe or rapidly progressive clinical signs -suspected secondary pneumonia -symptoms persist longer than 7 to 10 days -shelter outbreaks -pattern of endemic respiratory disease -necropsy

What is a canine respiratory screen

culture, molecular diagnostics assays that take 1-2 weeks for results samples: nasal swab, TTW, necropsy tissues screens for multiple respiratory pathogens not reasonable for critically ill patients due to the long amount of time it takes for the results

What are some limitations of canine respiratory screen

-pathogen may not be present at the sampling site -commensal overgrowth -oathgen may be diffucult to cultivate -antimicrobials may hinder -acute illness may precede antibody production -vaccination -previous exposure doesnt prove disease -only detects pathogens on panel -MLV may cause positives -viral shedding may end before sample collection

How might you achieve airway sampling

1) Transoral wash 2) Transtracheal wash 3) BAL

Do animals need to have anesthesia for transoral wash

Yes

Do animals need to have anesthesia for transtracheal wash

No - can be awake

What is a downside to transoral wash

1) It is non-specific really need diffuse lung disease because you dont know where the saline reaches 2) Under anesthesia- cannot cough

Why are transtracheal washes better than transoral

You also have the downside of it being non-specific (you dont know where youre sampling from), however, the animal is awake and can cough

What is the pros and cons of BAL

can visualize the disease via scope and the sampling is specific cons: need anesthesia, dangerous when extubate, and expensive

What is the normal composition of airway cytology

1) Alveolar macrophages (90%) 2) Small lymphocytes 5-14% 3) Eosinophils 5% (cats 25%) 4) Neutrophils <5-10% 5) Mast cells <2% *numbers change based on what disease process is going on

In addition to your inflammatory cells, what else should you look for on airway cytology

Ciliated epithelium Goblet cells tells you that it came from the airway

What are the different types of results you can get for airway cytology

1) Non-septic suppurative 2) Septic suppurative 3) Eosinophilic 4) Neoplastic 5) Hemorrhagic

What is the process of the cough reflex

1) Stimuli on the larynx, trachea, bronchi 2) Vagal nerves (afferent limb) reaches the cough centre in the medulla oblongata 3) Efferent motor nerves reach the laryngeal and respiratory muscles 4) Cough

How long should you isolate CIRDC dogs

2 weeks after the cough stops

What are examples of cough suppressants

1) Hydrocodone 2) Butorphanol 3) Codeine 4) Dextromethorphan

What are the downsides of using cough suppressants

you dont want him not coughing because then hes at a higher risk of pneumonia however they are important so the dog sleeps good idea for overnight

opioid agoinst that suppresses cough reflex in the medullary cough center has drying effect to respiratory mucosa best for oral cough suppression

Hydrocodone

What should you be aware of when using hydrocodone for cough suppression

1) Combo drugs in the store- dont want tylenol or others 2) controlled drug

you should limit use of hydrocodone for cough suppression to

overnight use it has drying effect to respiratory mucosa

What is the downside to using butorphanol for cough suppression

poor oral bioavailability doses need to be really high good for injection in hospital

a kappa agonist, mu antagonist that has poor oral bioavailability so its use for cough suppression should be limited to hospital injection

Butorphanol

an NMDA-receptor agonist that reduces cough receptor sensitivity poor oral bioavailability, short half life

dextromethorphan

For conducting airway disease, when do you consider antibiotics

1) Evidence of bacterial infections -Fever -Mucopurulent discharge -Wet cough -Lethargy -Inappetance -Pneumonia on radiographs 2) Young patients or immunosuppressed patients

What are good empiric antibiotic options for dogs with conducting airway disease

1) Doxycycline - suspected primary infection with B. bronchiseptica or M. cynos no evidence of secondary pneumonia 7-10 day course 2) Clavamox- treatment of secondary bacterial pneumonia

Clavamox is ineffective against what respiratory pathogens

Mycoplasma Bordatella resistance

Clavamox is used for treatment of

secondary bacterial pneumonia Ineffective against mycoplasma, and has bordatella resistance

Doxycycline is for suspected primary infection with

B. bronchiseptica or M .cynos and no evidence of secondary pneumonia do 7-10 day course

What is the risk of Doxycycline in young animals ***

Dental enamel hypoplasia, discoloration