L05: Respiratory System (Brown) Flashcards
Tracheobronchial region defense mechs.
- mucociliary apparatus moves cranially
- cough reflux
- MALT (cellular and humoral responses)
Pulmonary region defense mechs.
- mucous
- pulmonary alveolar macs
- other lymphocytes from blood
Microbial flora of URT (nasal cavity, pharynx) in BOTH dogs and cats
Staph (coag-positive more severe) Strep Corynebacterium E. Coli Pasteurella multocida Pseudomonas aeruginosa Klebsiella Bordetella bronchiseptica Mycoplasma
Microbial flora in URT more common in CATS
Micrococcus
Microbial flora in URT more common in DOGS
Bacillus Neisseria Enterobacter Moraxella Proteus Alcaligenes Clostridium
CS of URTD
Sneezing, stertor, stridor, nasal d/c, voice change, facial deformity, epistaxis
Coughing, gagging, choking, open-mouth breathing, inspiratory dyspnea, halitosis
Bacterial rhinitis usually 2ary to:
- nasal trauma
- FB
- reflux
- oronasal fistula
- neoplasia
- dental dz
- viral, fungal, parasitic infection
- bacterial bronchopneumonia
*abx may only clear 2ary bacterial infection
Possible causes of SEROUS nasal d/c
Nasal mites
Allergy
Early viral infection
Stress
Possible causes of MUCOID or MUCOPURULENT nasal d/c
Systemic dz Oronasal/periodontal dz Nasal neoplasia Inflammatory nasal disease (reactive or primary) Fungal rhinitis FB 2ary bacterial infection
Possible causes of epistaxis
Systemic dz Trauma Nasal neoplasia Fungal rhinitis Inflammatory nasal dz
Viral agents assoc. with feline URTD
Calicivirus
Feline rhinotracheitis (feline herpesvirus 1)
Chlamydophyla felis
FELV/FIV associated disease
Non-viral agents assoc. with feline URTD
Mycoplasma
Reovirus
Fungal rhinitis (cryptococcus neoformans)
Bacterial rhinitis
Tables slide 5-6
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Chars. Of cryptococcus neoformans in cats
- most common fungal infection in cats**
- comes from pigeon droppings (ubiquitous saprophyte)
- can disseminate to eyes, CNS, skin on head
- tx: long-term antifungals (fluconazole, itraconazole, ketoconazole)
Feline chronic rhinitis/sinusitis cause
- accounts for ~35% of feline rhinitis (uncommon in dog)
- viral RT infections + impaired immune response causes mucosal and turbinate damage
- recurring 2ary bacterial infections established (can be commensals; bordetella and mycoplasma suspected but unknown)
Feline chronic rhinitis/sinusitis prognosis and tx
Prognosis: guarded, cure unlikely
Tx: supportive:
- mucolytics, decongestants
- antivirals have little efficacy
- long-term (2-4 mo.) of abx
- short-term abx select for Pseudomonas spp.**
- severe cases may require perforation or excision of turbinate
Common abx used for management of CRS**
Clavamox Azithromycin Chloramphenicol Clindamycin Doxycycline Marbofloxacin Metronidazole Pradofloxacin
all except Metronidazole will not be effective against or will result in resistant Pseudomonas
*Chloramphenicol, Clindamycin, and Doxy can cause esophagitis and/or immunomodulatory effects
Microbial flora of LRT
Most common:
- Pasteurella multocida
- Moraxella
- Klebsiella
- Enterobacter
- Corynebacterium
Generally result from aspiration from URT
CS of LRTD
Cough, gagging, panting, tachypnea, exercise intolerance, open-mouth breathing
Expiratory dyspnea
CS of Pleural disease
INSPIRATORY dyspnea usually w/o stridor
Cough, gag, pant, tachypnea, ex. Intolerance, open-mouth breathing
LRT =
Intrathoracic trachea, bronchial tree, pulmonary parenchyma
Canine Infectious Resp. Disease (CIRD) aka Kennel Cough causative components
Viral:
- K9 adenovirus, K9 parainfluenza most common
- also: coronavirus, influenza, herpesvirus
2ary bacterial:
- Bordetella bronchiseptica
- Strep canis
- Mycoplasma cynos
- Strep equi zooepidemicus (
2 forms of CIRD
Uncomplicated and complicated (pneumonia)
Dx of complicated CIRD
- TTW w/ culture/cytology
- CBC/Chem (inflammatory leukogram)
- rads (intersitial, segmental atelectasis)
- acute/convalescent serology for viral agents
Transmission, incubation, and clinical course of CIRD
Trans: direct contact, indirect contact (fomites), aerosols
Incub: 3-10d
Clinical course: 6-10 days (uncomplicated)
With CIRD, if exudate transitions from mucoid to mucopuruent, which agent most suspected as cause?
Bordetella
Natural upper resp. Tract defense mechanisms
- resident microbes
- vibrissae (hair)
- nasal chonchae (inc. turbulence)
- mucous lining
- cilia
- pharyngeal lymphoid tissue (MALT)
- sneeze reflex
Prevention of CIRD
- parenteral and intranasal vax avail.
- takes at least 5d to be effective
- IN evokes local mucosal immunity and has no interaction w/ maternal Ab
- provides 3-10 mo. Of immunity against Bordetella, and 3 yrs. against viruses
- IN vax can have side effects 2-5d post-vax
Bordetella bronchiseptica zoonotic?
Yes - to immunosuppressed, children
Prevalence of Bordetella bronchiseptica in cats
- 30-80% in multicat households
- unknown significance
- upper and lower RD reported
- vax NOT recommended in cats unless high density or known outbreak
Diagnostics for Bordetella bronchiseptica
- CBC, Chem, U/A
- Rads
- TTW, BAL +/- lung aspirates
- culture if pulmonary abscesses
- fungal culture if rads supportive
- can do virus isolation, PCR, serology if viral etiology suspected
Most common cause of bacterial pneumonia in young dogs
Viral infection followed by secondary bacterial infection, often with opportunistic normal airway flora (hematogenous spread less common)
Most common cause of bacterial pneumonia in older dogs
Aspiration pneumonia/FB
Tx of bacterial pneumonia
- ID underlying cause
- abx
- control of airway secretion
HOST factors that predispose to bacterial pneumonia
- age
- metabolic dz
- poor nutrition
- neuromuscular dz
- anatomic abnormalities
- anesthesia/surgery
Environmental factors that predispose to bacterial pneumonia
- high animal density
- unsanitary conditions
- poor ventilation
- presence of young/unvaccinated
- stress
- presence of animals with URTD
- **concurrent viral infection
Most common pathogens assoc. with bacterial pneumonia
Gram +: staph, strep, enterococcus
Gram -: E. Coli, pseudomonas, Bordetella, Pasteurella, Klebsiella, Actinobacillus
Anaerobic: bacteroides, clostridium, fusobacterium
Tx of mild pneumonia
TMS or clavamox
Tx of moderate pneumonia
Clavamox + enrofloxacin
Or Amikacin
Tx of severe pneumonia
Clavamox + enrofloxacin or
Timentin-clavulanic acid or meropenem or imipenem
Viral pneumonia usually causes URTD or LRTD?
URTD, char. By uncomplicated pneumonitis
-pneumonia rare (exceptions: CDV, influenza viruses)
Bacterial-viral synergism
Virus decreases pulmonary antibacterial defenses:
- loss of ciliated epithelial cells –> dec. clearance
- cellular desquamation, protein leakage –> media for bacterial growth
- dec. surfactant production
- dec. macrophage chemotaxis
*leads to chronic interstitial pneumonia –> pulmonary fibrosis –> asthma/COPD
Systemic mycoses that can cause fungal pneumonia
Histoplasma capsulatum
Blastomyces dermatitidis
Coccidiodes immitis
Cryptococcus neoformans
+/- Aspergillis, Sporotrichosis, Candida
Lower resp. Pathogens of cats
Pasteurella E. Coli Staph Strep Pseudomonas B. Bronchiseptica \+/- Mycoplasma
Agents responsible for serofibrinous pleural effusions
- Infectious canine hepatitis virus
- Lepto
- distemper
- other canine and feline viral URD
- tuberculosis
Agents responsible for granulomatous/pyogranulomatous pleural effusions
FIP
Fungal
Causes of bacterial or fungal pleural effusions
- penetrating thoracic wounds
- extension from pneumonia
- migrating FB
- esophageal perforations
- extensions from cervical lumbar or mediastinal infections
- hematogenous
Pathogens most assoc. with pyothorax in dogs
Anaerobic bacteria: fusobacterium, nocardia asteroides, actinomyces
Pathogens most assoc. with pyothorax in cats
Pasteurella multocida and anaerobes
Fungal causes of pyothorax (rare)
Blastomyces
Candida
Aspergillus
Cryptococcus
Tx for pyothorax
- drain and lavage
- supportive care (fluids, abx)
- FB removal if applicable
