Tracheal & Bronchial Disorders Flashcards
What is the most common sign of tracheobronchial disease? What else is seen?
cough (possibly productive)
- retch/gag
- increased respiratory effort/dyspnea
- wheezing
- inspiratory sounds
- tachypnea
- cyanosis
What 2 conditions should be considered if there is a patient with chronic cough?
- structural disease of the airways, causing weakening of the cartilaginous support
- chronic inflammation of airways, resulting in mucus accumulation and secondary bacterial infection
How do the 3 regions of the lower respiratory system indicate tracheobronchial disease?
- LARYNX = hoarse bark, gagging, inspiratory effort
- TRACHEA = cough and respiratory distress
- BRONCHI = cough and respiratory distress
What is the general rule out list for patients with a cough?
- Cardiovascular - DOGS with enlarged LA
- Allergic - asthma, eosinophilic bronchopneumopathy
- Trauma - FB, collapsing trachea
- Neoplasia
- Inflammatory/Infectious - pharyngitis, bronchitis, pulmonary fibrosis, kennel cough, pneumonia, abscess
- Parasites - lung worms, heart worm, migrating GI parasites
What conditions must be considered in a clinical patient with cough?
cardiogenic disorders
- physical exam (murmur), chest radiographs
What are 4 causes of cough when heart disease is present? What are some signs seen on a radiograph?
- heart failure leading to pulmonary edema
- left atrial enlargement causes pressure on the airways
- heartworm disease
- heart base tumor
- pulmonary edema
- enlarged LA
- air in stomach from swallowing air
What are some non-cardiogenic causes of cough in clinical patients?
- tracheal collapse
- hypoplastic trachea
- infectious tracheobronchitis
- perihilar lymphadenopathy
- lower airways and pulmonary parenchyma pneumonia
- cancer
- environmental contaminants
What are the 2 major factors that contribute to canine infectious respiratory disease (kennel cough)?
- HOST FACTORS - stress, immune status, previous exposure
- ENVIRONMENT - overcrowding, poor ventilation
In what dogs is kennel cough most common? What plays a huge role in its spread?
PUPPIES from breeders, pet stores, and boarding facilities
fomites —> very contagious and spreads quickly at dog shows, kennels, shelters, clinics, and pet stores
What are the uncomplicated and complicated versions of kennel cough?
UNCOMPLICATED = not “sick”, only involving the upper airways eliciting a dry cough on tracheal palpation, serous oculonasal discharge, gagging, retching (can evolve!)
COMPLICATED = “sick”, involving both upper and lower airways with a moist cough and more mucopurulent oculonasal discharge (can develop bronchopneumonia)
In what 3 situations is diagnostic testing recommended in patients with kennel cough?
- patients do not respond to supportive care
- signs/evidence of systemic disease
- outbreak
usually a presumptive diagnosis is enough and clinically healthy dogs can harbor CIRD pathogens
What are the 2 most common viral causes of kennel cough? What other viruses can contribute?
- canine parainfluenza virus (CPIV)
- canine respiratory coronavirus (CRCoV) - no vaccine
- canine adenovirus 2
- canine herpesvirus 1
- canine distemper virus (more serious)
- canine influenza virus
What is the most common bacteria that causes kennel cough? How does it cause disease? What are some other bacteria that can contribute?
Bordetella bronchiseptica - attaches to cilia of bronchial epithelium and interferes with motility, leading to mucus accumulation and inflammation
- Mycoplasma cynos
- Streptococcus equi subsp. zooepidemicus
- secondary invaders
In what way is Mycoplasma cynos unique? How does it contribute to kennel cough?
lacks a cell wall and is the smallest living organism capable of independent existence —> penicillins, like Clavamox, will NOT work
significantly associated with increased severity of respiratory disease, but its role is not well understood
What 5 diagnostics should be evaluated in the complicated form of kennel cough?
- hemogram: leukocytosis with left shift
- thoracic rads: bronchopneumonia signs
- tracheal wash cytology and culture
- PCR panels (most causes of kennel cough are part of the normal flora…)
- fecal float or Baermann for lungworms
What are the 3 major treatments for the uncomplicated form of kennel cough? What is important to note?
- restrict exercise
- isolate
- Doxyxyxline if Bordetella is suspected
usually resolves within 2 weeks, but the cough can linger
What 3 systemic antibiotics are recommended for complicated kennel cough? What is not recommended?
- Doxyxycline
- Azithromycin
- Enrofloxacin
Penicillin —> poor levels in respiratory secretions
What 4 cough suppressants are recommended for complicated kennel cough? When is their use contraindicated?
- Butorphanol
- Hydrocodone
- Codeine derivatives
- Dextromethorphan
if bacterial pneumonia is present
What is the best way to diagnose kennel cough?
respiratory PCR done simultaneously with a culture —-> gives an idea of what components are involved and culture backs up diagnosis for bacterial components
What are the 2 options for vaccines against kennel cough? How else can infection be prevented?
- parenteral CAV2 and CPIV vaccine - blocked by maternal antibodies —> repeated every 3-4 weeks until 16 weeks
- intranasal CPIV and Bordetella vaccine - not blocked by maternal antibodies and protects within 4-14 days (recommended for high-risk dogs) —> infer superficial antibodies and help prevent disease
- sanitation with Clorox diluted 1:32
- proper ventilation in kennels
- quarantine
What is the most significant canine influenza virus strain in the US? What are the most significant clinical signs? How is it spread? Diagnosed?
H3N2 (also H3N8)
coughing and fever that can progress to worsening disease
direct contact with respiratory secretions/fomites
PCR samples within 72 hrs, acute and convalescent titers, viral isolation
In what dogs is an influenza vaccine most important? How does the vaccine help?
dogs that attend canine day care centers, travel to dog shows, go to kennels, or go to dog parks
decreases the severity of clinical disease and viral shedding, but does not prevent infection (herd immunity!!)
Why must respiratory PCRs be used carefully for diagnosing kennel cough?
NOT PERFECT —> positive results do not imply causation —> modified live vaccine will show positive, some microorganisms are part of the normal flora, co-infection is common
How can we tell if antibiotics are necessary for treating kennel cough?
a transtracheal wash is performed and the fluid is cultured and sent out for PCR
What tracheal worm is commonly found in younger dogs in kennels? How do they affect the trachea?
Oserlus osleri
larvae are ingested, molt in the small bowel, migrate to lungs, bronchi, and trachea forming cream colored nodules
In what 4 ways can Oserlus osleri infections be diagnosed? What are the most common signs?
- tracheal mass on x-ray shows nodules on the carina
- mass see with bronchoscopy and sampled
- fecal or Baermann (can be negative due to intermittent shedding)
- cytology of tracheal wash reveals ova or larvae
coughing, wheezing, dyspnea
How is a Oserlus osleri infection treated?
Ivermectin or Fenbendazole
(preventatives important!)
In what dogs is tracheomalacia (collapsing trachea) most common? What are the most common clinical findings?
toy or small breeds (often obese)
- history of dry or worsening cough (goose honking)
- cough worsens with excitement, exercise, eating, or heat
- cough elicited by tracheal palpation
- retching of clear secretions
- episodes of cyanosis or collapse
- mitral valve disease can exacerbate signs
What is tracheomalacia (collapsing trachea)? What is the most common cause?
narrowing of the tracheal lumen, resulting from weakening of the cartilaginous rings, redundancy of the dorsal tracheal membrane, or both
reduction in chondrocytes, glycosaminoglycans, and chondroitin sulfate in the tracheal rings
What dog breeds are most commonly affected by primary tracheomalacia? What causes primary tracheomalacia?
Pomeranians, mini and toy Poodles, Yorkies, Chihuahuas, Pugs
chronic inflammation, trauma, external pressure
What are the most common triggers of tracheomalacia (collapsing trachea)?
- obesity
- cardiomegaly
- inhalation of irritants and allergens
- periodontal disease
- respiratory infections
- endotracheal intubation
Where is tracheomalacia most often more pronounced? Why is it considered dynamic?
cervicothoracic junction
- CERVICAL trachea collapses during INSPIRATION
- THORACIC trachea collapses during EXPIRATION
What 3 conditions are commonly concurrent in patients with tracheomalacia?
- bronchomalacia
- airway infection - inflammation of airway mucosa and impaired function of the mucociliary apparatus
- hepatomegaly and abnormal liver function tests - hypoxia causes liver disease
What is the gold standard for diagnosing tracheomalacia? What other 2 diagnostics can be done?
bronchoscopy —> assesses dynamic change, can look for concurrent disease
- thoracic/cervical x-rays - during inspiration and expiration
- fluoroscopy
What sedation and cough suppressants are recommended for emergency tracheomalacia treatment? Why are corticosteroids used? What else needs to be done?
Acepromazine, Butorphanol, Hydromorphone, Diazepam, Gabapentin
injectible Butorphanol, oral Hydrocodone
single dose is used to decrease inflammation
get into an oxygen-rich environment - O2 cage, nasal catheterization, intubation
What is recommended for chronic management of Grade I or II tracheomalacia? What is important to note?
- weight loss
- thoracic harness
- avoid excitement and sedate if necessary
- avoid smoke, dust, pollen, carpet cleaners, and airway irritats
- avoid heat and humidity
this is likely a progressive disease that can worsen over time and affect lower airways and bronchi
What 4 cough suppressants are recommended for chronic management of tracheomalacia? What 2 corticosteroid?
- Butorphanol
- Hydrocodone
- Cerenia
- Lomotil (diphenoxylate)
Prednisone and Fluticasone —> taper over 2-4 weeks
Why are bronchodilators indicated for tracheomalacia? What are 3 examples?
help reduce clinical signs in patients with intrathoracic tracheal collapse by dilating small airways and reducing the pressure gradient
- extended release Theophylline
- Terbutaline
- Albuterol
When is surgical intervention recommended for tracheomalacia?
30% will not respond to medical management and still experience cyanosis, dyspnea, or syncope; or those with higher grades
- endoluminal stents are recommended, but a last-ditch effort