Lecture 26 11/18/24

Question 1

What are the general characteristics of coughing?

Answer 1

-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

Question 2

What are the characteristics of canine infectious respiratory disease complex (CIRDC)?

Answer 2

-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

Question 3

What are the viral etiologies of CIRD?

Answer 3

-canine parainfluenza virus
-canine adenovirus 2
-canine herpesvirus 1
-canine distemper virus
-canine respiratory coronavirus
-canine influenza virus
-canine pneumovirus

Question 4

What are the bacterial etiologies of CIRD?

Answer 4

-Bordetella bronchiseptica
-Mycoplasma cynos
-Streptococcus equi subsp. zooepidemicus

Question 5

What are the characteristics of Bordetella bronchiseptica?

Answer 5

-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

Question 6

What is the pathogenesis of Bordetella bronchiseptica?

Answer 6

-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

Question 7

How does Bordetella bronchiseptica cause damage to the lungs?

Answer 7

-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

Question 8

What are the characteristics of Bordetella in cats?

Answer 8

-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

Question 9

What are the characteristics of Mycoplasma?

Answer 9

-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

Question 10

What are the characteristics of Streptococcus equi subsp. zooepidemicus?

Answer 10

-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

Question 11

What are the characteristics of canine parainfluenza?

Answer 11

-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

Question 12

What are the characteristics of canine adenovirus 2?

Answer 12

-nonenveloped dsDNA virus
-frequently isolated in upper resp. disease
-mild signs
-typically seen with other infectious agents
-very contagious
-survives in environment for months

Question 13

What are the characteristics of canine coronavirus?

Answer 13

-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

Question 14

What are the characteristics of canine influenza H3N8?

Answer 14

-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

Question 15

What is the pathogenesis of canine influenza H3N8?

Answer 15

-incubation of 2 to 4 days
-virus sheds for 7 to 10 days

Question 16

How is canine influenza H3N8 diagnosed?

Answer 16

-paired serology
-virus detection by PCR

Question 17

What is the importance of canine influenza H3N2?

Answer 17

mutated avian influenza virus that has now adapted to the dog

Question 18

What are the characteristics of canine influenza treatment and prevention?

Answer 18

-supportive care
-isolation; virus can persist in environment
-vaccine available
-oseltamivir/tamiflu not studied and not recommended

Question 19

What are the characteristics of canine distemper virus?

Answer 19

-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

Question 20

What is the pathogenesis of canine distemper?

Answer 20

-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

Question 21

What are the characteristics of canine distemper presentation?

Answer 21

-varies with strain virulence, age of host, immunocompetence, and body systems affected
-many cases are subclinical
-often confused with kennel cough and parvovirus

Question 22

What are the clinical signs of distemper?

Answer 22

-fever
-depression
-anorexia
-conjunctivitis
-cough
-vomiting
-diarrhea
-dehydration
-sudden death
-chewing gum seizures
-myoclonus

Question 23

How is canine distemper diagnosed?

Answer 23

-clinical signs
-ophthalmologic exam
-CBC
-biochem
-possibly radiology
-IgG and IgM serology
-PCR on urine (can be positive with vaccination)

Question 24

What is the therapy for distemper?

Answer 24

-isolation
-supportive care
-treatment of secondary infections
-nutritional support
-anticonvulsants if seizures occur

Question 25

What are the characteristics of the canine distemper vaccine?

Answer 25

-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

Question 26

What are characteristics of an uncomplicated case of CIRDC?

Answer 26

-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

Question 27

What are the characteristics of a complicated case of CIRDC?

Answer 27

-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

Question 28

How is CIRD diagnosed?

Answer 28

-history of exposure -blood work and radiographs (may be normal) -TTW/ETW for culture and sensitivity -PCR panels

Question 29

What is the therapy for CIRD?

Answer 29

-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

Question 30

How is CIRD prevented?

Answer 30

-avoid contaminated areas -decrease stress and overcrowding -vaccinate for resp diseases

Question 31

Which parasites can cause coughing?

Answer 31

-Filaroides osleri -Crenosoma vulpi -Capillaria aerophilia

Question 32

What are the potential upper resp. causes of cough?

Answer 32

-parasites -foreign body -chemical or mechanical irritant

Question 33

What are the characteristics of chronic bronchitis in dogs?

Answer 33

-incurable with an insidious onset -chronic and persistent cough -no identifiable or persistent primary cause -syndrome, not necessarily final diagnosis

Question 34

What is seen on physical exam in dogs with chronic bronchitis?

Answer 34

-normal body condition -wheezes -crackles -increased airway sounds -persistent cough, often with terminal retch

Question 35

What are the potential etiologies of chronic bronchitis?

Answer 35

-defect in mucociliary function -airway parasites -infections -inhaled irritants -allergy -aerodigestive disorders

Question 36

What are the differential diagnoses for chronic bronchitis?

Answer 36

-left atrial enlargement/heart disease -heartworm disease -collapsing trachea -neoplasia -fungus

Question 37

How is the underlying cause of chronic bronchitis diagnosed?

Answer 37

-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

Question 38

What are the findings on radiology in dogs with bronchitis?

Answer 38

-prominent bronchial structures/"donuts" -interstitial infiltrate -bronchiectasis -overall not super specific

Question 39

How is chronic bronchitis diagnosed?

Answer 39

-radiology -TTW/ETW -bronchoscopy (collapse of airways = worse prognosis

Question 40

What are the treatment goals for chronic bronchitis?

Answer 40

-reduce inflammation -limit cough -improve exercise stamina -slow progression of disease and reduce airway remodeling

Question 41

What are the prevention steps for chronic bronchitis?

Answer 41

-reduce environmental contamination -prevent exposure to potential underlying pathogens -reduce obesity -use harnesses instead of collars -prevent excessive barking

Question 42

How is chronic bronchitis treated?

Answer 42

-corticosteroids/inhaled glucocorticoids -bronchodilators -potentially antitussives -antibiotics if concurrent infection is present

Question 43

When should cough suppressants be considered?

Answer 43

when a cough is non-productive, exhausting, painful, or causing potential for lung damage

Question 44

When are cough suppressants contraindicated?

Answer 44

productive coughs that are used to remove possible infectious fluids and secretions from the lungs

Question 45

What are the characteristics of hydrocodone/hycodan?

Answer 45

-hydrocodone combined with atropine -atropine exerts significant side effects -atropine limits dosing but discourages abuse -suspected action based on binding to mu opioid receptor

Question 46

What are the characteristics of maropitant/cerenia?

Answer 46

-NK1 receptor antagonist -inhibits substance P, a potent NK1 receptor agonist -prevents bronchoconstriction, chemotaxis, and neutrophil adhesion caused by substance P

Question 47

What are the characteristics of neuromodulators?

Answer 47

-includes drugs such as gabapentin and amitriptyline -used for chronic, idiopathic coughs -can help with sensory neuropathy and laryngeal irritability

Question 48

What are the characteristics of mucokinetic drugs?

Answer 48

-help eliminate resp. secretions by changing viscosity -include acetylcysteine and guaifenesin

Question 49

What are the characteristics of antihistamines?

Answer 49

-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

Question 50

What are the characteristics of coughing cats?

Answer 50

-not as common as dogs -typically not treated specifically for coughing -cough often caused by chronic lower airway inflammatory disease