Upper Airway Pathology Flashcards
respiratory epithelium
pseudostratified, ciliated columnar epithelium
contains ciliated and goblet cells
function of goblet cells
produce mucus lining to protect the epithelium
mucous lining
bi-layered mucus
outer layer: site of commensal bacteria
inner layer: moveable gel produced by goblet cells to keep bacteria away from epithelium (rapidly turned over)
epistaxis
nose bleed; can be unilateral or bilateral
is epistaxis specific for a particular disease
no - nonspecific
common causes of epistaxis in dogs
- rhinitis (usually fungal - aspergillus)
- neoplasia
common causes of epistaxis in horses
- ethmoidal progressive hematoma
- guttural pouch mycosis
mycotic rhinitis
fungal infection leading to rhinitis; fungi proliferate to form mats on the surface of the tissue
most common cause of mycotic rhinitis in dogs and horses
aspergillus fumigatus
most common cause of mycotic rhinitis in cats
cryptococcus neoformans
causes “roman nose”
guttural pouch mycosis
inhaled fungi accumulate in the guttural pouch and forms large fungal mats
most commonly aspergillus
what is a risk of guttural pouch mycosis
internal carotid runs through the guttural pouch –> aspergillus invades internal carotid and can cause death by either exsanguination or embolization of fungi to the brain
rhinitis and most common causes in young vs older animals
inflammation of the nose
young: viral
old: fungal or neoplastic
why does rhinitis predispose animals to secondary infection
inflammation –> destruction of mucous lining and epithelium –> loss of protective layers –> increased susceptibility to secondary infection
bacterial overgrowth can lead to aspiration pneumonia, toxemia, or sepsis
equine rhinitis causes
equine herpesvirus 1 & 4
streptococcus equi
EHV characteristics
herpesvirus; has a long latency in CN V ganglia - can get chronic disease even after recovery
EHV 1 vs EHV 4 infection
EHV 1: systemic - causes viremia leading to rapid deterioration
EHV 4: local - causes self-limiting rhinitis
both can lead to encephalomyelitis and abortion
strangles
infection with streptococcus equi bacteria
suppurative rhinitis and lymphanditis
can strept equi be commensal
NO - if present, always causes disease
bastard strangles
systemic spread of strept equi that begins with rhinitis but becomes septic
causes systemic abscesses
bovine respiratory disease complex (BRDC)
any combination of viral, bacterial, and mycoplasma pathogens that produce respiratory disease
often combined with stress/shipping events
includes IBR and shipping fever
infectious bovine rhinotracheitis (IBR)
primary upper airway disease caused by BoHV-1
severe rhinitis w/ crusting discharge (“rednose”) caused from necrosis of the respiratory epithelium along the nasal cavity, larynx, and trachea
BoHV-1 characteristics
herpesvirus - establishes latency in CN V ganglia
can get chronic disease after initial recovery, especially if stress induced
can shed in environment
what can IBR predispose the cow to
secondary pneumonia
trachea necrosis –> decreased ability to clear pathogens –> predisposition for pneumonia
pus from fibrinonecrotic trachea can move to the lungs and cause secondary pneumonia
shipping fever
secondary upper airway disease caused by IBR (as part of the BRDC)
BoHV-1 clears the epithelium –> allows bacteria to start growing –> enters the lungs –> pneumonia
what is the most common and severe pathogen in BRDC
mannheimia haemolytica
produces leukotoxins (bacterial endotoxins) that attract neutrophils and lyse them to release their enzymes –> liquefactive necrosis of the tissue
what other viruses are often involved in BRDC
BPIV-3 (parainfluenza; paramyxovirus)
BRSV (respiratory syncytial; paramyxovirus) - “enzootic pneumonia”
BCoV (coronavirus)
atrophic rhinitis
turbinate destruction that occurs in pigs from co-infection by:
- bordetella bronchiseptica
- pasteurella multocida type D
causes PERMANENT loss of turbinates - pig will be predisposed to secondary infection for the rest of its life
