Lecture 26 11/18/24 Flashcards
What are the general characteristics of coughing?
-cough reflex triggered by stimulating cough receptors in the larynx, trachea, and/or bronchi
-draw air into the lungs to augment force of expulsion
-acute cough is less than 3 weeks duration
-want to rule out cardiac disease in every coughing animal
What are the characteristics of canine infectious respiratory disease complex (CIRDC)?
-any contagious, acute-onset resp. infection in dogs
-typically involves upper resp. tract
-acute and highly contagious
-etiology can be bacterial and/or viral
-synergistic infections possible
What are the viral etiologies of CIRD?
-canine parainfluenza virus
-canine adenovirus 2
-canine herpesvirus 1
-canine distemper virus
-canine respiratory coronavirus
-canine influenza virus
-canine pneumovirus
What are the bacterial etiologies of CIRD?
-Bordetella bronchiseptica
-Mycoplasma cynos
-Streptococcus equi subsp. zooepidemicus
What are the characteristics of Bordetella bronchiseptica?
-normal resp. tract inhabitant
-gram neg. aerobic bacillus
-commonly a secondary pathogen
-can cause severe primary infections
-high morbidity, low mortality
-often seen with CPIV
What is the pathogenesis of Bordetella bronchiseptica?
-incubation period of 2-10 days
-can be shed for months
-clinical signs vary from mild upper resp signs to severe bronchopneumonia
-transmission via inhalation/airborne route
-highly contagious
-causes dry paroxysmal cough and nasal discharge
How does Bordetella bronchiseptica cause damage to the lungs?
-bacteria attach to and colonize resp. epithelium
-attachment initiates ciliostasis
-bacteria express exo/endotoxins to promote cellular injury and bacterial survival
-adherence occurs via adhesins
What are the characteristics of Bordetella in cats?
-can be a primary pathogen
-risk factors include overcrowding, stress, and age
-clinical signs include sneezing and nasal discharge
-clinical signs may progress to dyspnea, cyanosis, and death, especially in kittens
What are the characteristics of Mycoplasma?
-many species are commensal
-lack a cell wall
-fastidious
-colonizes ciliated and non-ciliated epithelium
-can persist in the lungs up to 3 weeks after infection
-transmitted via aerosol
What are the characteristics of Streptococcus equi subsp. zooepidemicus?
-beta-hemolytic Lancefield C Strep. species
-contact with horses identified in some cases of the bacteria in dogs
-causes acute severe bronchopneumonia
-clinical signs begin mild but progress rapidly over 24-48 hours
-severe fibrinosuppurative, necrotizing, hemorrhagic bronchopneumonia
What are the characteristics of canine parainfluenza?
-enveloped RNA virus
-most common viral isolate of CIRD
-pure viral infection causes mild signs
-most common sign is a high pitched honking cough from vocal fold swelling
-does not survive well in environment
What are the characteristics of canine adenovirus 2?
-nonenveloped dsDNA virus
-frequently isolated in upper resp. disease
-mild signs
-typically seen with other infectious agents
-very contagious
-survives in environment for months
What are the characteristics of canine coronavirus?
-enveloped RNA virus
-no evidence that it is a primary CIRD pathogen
-resp virus is different than the enteric virus
-species specific
-signs typically mild
-strains can mutate
What are the characteristics of canine influenza H3N8?
-community acquired virus found in many states
-typical signs of upper resp disease, including cough and nasal discharge
-up to 20% of cases are asymptomatic
What is the pathogenesis of canine influenza H3N8?
-incubation of 2 to 4 days
-virus sheds for 7 to 10 days
How is canine influenza H3N8 diagnosed?
-paired serology
-virus detection by PCR
What is the importance of canine influenza H3N2?
mutated avian influenza virus that has now adapted to the dog
What are the characteristics of canine influenza treatment and prevention?
-supportive care
-isolation; virus can persist in environment
-vaccine available
-oseltamivir/tamiflu not studied and not recommended
What are the characteristics of canine distemper virus?
-enveloped single strand neg. sense RNA virus
-infection rate is much higher than disease rate
-approximately 25-75% of susceptible dogs are subclinically infected and clear the virus
What is the pathogenesis of canine distemper?
-spread by aerosol when there is contact between animals
-excreted up to 60 to 90 days post infection
-resp. tract is not the primary target
-vaccination against distemper is associated with significantly lower risk of CIRDC and severe resp. signs
What are the characteristics of canine distemper presentation?
-varies with strain virulence, age of host, immunocompetence, and body systems affected
-many cases are subclinical
-often confused with kennel cough and parvovirus
What are the clinical signs of distemper?
-fever
-depression
-anorexia
-conjunctivitis
-cough
-vomiting
-diarrhea
-dehydration
-sudden death
-chewing gum seizures
-myoclonus
How is canine distemper diagnosed?
-clinical signs
-ophthalmologic exam
-CBC
-biochem
-possibly radiology
-IgG and IgM serology
-PCR on urine (can be positive with vaccination)
What is the therapy for distemper?
-isolation
-supportive care
-treatment of secondary infections
-nutritional support
-anticonvulsants if seizures occur
What are the characteristics of the canine distemper vaccine?
-maternal immunity can interfere with response to vaccine
-MLV and recombinant vaccines available
-attenuated live vx can cause encephalitis in immunocompromised puppies less than 6 weeks of age
-distemper involvement in CIRDC is rare due to vaccination
What are characteristics of an uncomplicated case of CIRDC?
-mild, self-limiting disease
-all ages susceptible
-incubation period of 3 to 10 days
-dry, harsh, non-productive cough
-duration of 7 to 10 days
-no other clinical findings
What are the characteristics of a complicated case of CIRDC?
-seen in young puppies and immunocompromised dogs
-productive cough
-fever, depression, and naso-ocular discharge common
-thoracic rads will show signs of infection
-lasts 1 to 3 weeks
-potentially fatal
How is CIRD diagnosed?
-history of exposure
-blood work and radiographs (may be normal)
-TTW/ETW for culture and sensitivity
-PCR panels
What is the therapy for CIRD?
-treatment of specific infections
-antibiotics only when needed
-humidify air
-potential for cough suppressants and bronchodilators
-rest
-harnesses instead of collars
-isolation of animals for at least 2 weeks
How is CIRD prevented?
-avoid contaminated areas
-decrease stress and overcrowding
-vaccinate for resp diseases
Which parasites can cause coughing?
-Filaroides osleri
-Crenosoma vulpi
-Capillaria aerophilia
What are the potential upper resp. causes of cough?
-parasites
-foreign body
-chemical or mechanical irritant
What are the characteristics of chronic bronchitis in dogs?
-incurable with an insidious onset
-chronic and persistent cough
-no identifiable or persistent primary cause
-syndrome, not necessarily final diagnosis
What is seen on physical exam in dogs with chronic bronchitis?
-normal body condition
-wheezes
-crackles
-increased airway sounds
-persistent cough, often with terminal retch
What are the potential etiologies of chronic bronchitis?
-defect in mucociliary function
-airway parasites
-infections
-inhaled irritants
-allergy
-aerodigestive disorders
What are the differential diagnoses for chronic bronchitis?
-left atrial enlargement/heart disease
-heartworm disease
-collapsing trachea
-neoplasia
-fungus
How is the underlying cause of chronic bronchitis diagnosed?
-exclusion of all potential primary/secondary causes
-baseline blood work; look for eosinophilia
-fecal for lungworms
-heartworm testing
-arterial blood gas and pulse ox
-6 minute walk test
What are the findings on radiology in dogs with bronchitis?
-prominent bronchial structures/”donuts”
-interstitial infiltrate
-bronchiectasis
-overall not super specific
How is chronic bronchitis diagnosed?
-radiology
-TTW/ETW
-bronchoscopy (collapse of airways = worse prognosis
What are the treatment goals for chronic bronchitis?
-reduce inflammation
-limit cough
-improve exercise stamina
-slow progression of disease and reduce airway remodeling
What are the prevention steps for chronic bronchitis?
-reduce environmental contamination
-prevent exposure to potential underlying pathogens
-reduce obesity
-use harnesses instead of collars
-prevent excessive barking
How is chronic bronchitis treated?
-corticosteroids/inhaled glucocorticoids
-bronchodilators
-potentially antitussives
-antibiotics if concurrent infection is present
When should cough suppressants be considered?
when a cough is non-productive, exhausting, painful, or causing potential for lung damage
When are cough suppressants contraindicated?
productive coughs that are used to remove possible infectious fluids and secretions from the lungs
What are the characteristics of hydrocodone/hycodan?
-hydrocodone combined with atropine
-atropine exerts significant side effects
-atropine limits dosing but discourages abuse
-suspected action based on binding to mu opioid receptor
What are the characteristics of maropitant/cerenia?
-NK1 receptor antagonist
-inhibits substance P, a potent NK1 receptor agonist
-prevents bronchoconstriction, chemotaxis, and neutrophil adhesion caused by substance P
What are the characteristics of neuromodulators?
-includes drugs such as gabapentin and amitriptyline
-used for chronic, idiopathic coughs
-can help with sensory neuropathy and laryngeal irritability
What are the characteristics of mucokinetic drugs?
-help eliminate resp. secretions by changing viscosity
-include acetylcysteine and guaifenesin
What are the characteristics of antihistamines?
-may be useful if cough is suspected to have allergic component
-direct effects occur by blocking H1 receptors in central and peripheral nervous systems
-indirect effects include reduced mucous secretion and sedation
What are the characteristics of coughing cats?
-not as common as dogs
-typically not treated specifically for coughing
-cough often caused by chronic lower airway inflammatory disease
