Upper Airway Pathology

Question 1

respiratory epithelium

Answer 1

pseudostratified, ciliated columnar epithelium

contains ciliated and goblet cells

Question 2

function of goblet cells

Answer 2

produce mucus lining to protect the epithelium

Question 3

mucous lining

Answer 3

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)

Question 4

epistaxis

Answer 4

nose bleed; can be unilateral or bilateral

Question 5

is epistaxis specific for a particular disease

Answer 5

no - nonspecific

Question 6

common causes of epistaxis in dogs

Answer 6

• rhinitis (usually fungal - aspergillus)
• neoplasia

Question 7

common causes of epistaxis in horses

Answer 7

• ethmoidal progressive hematoma
• guttural pouch mycosis

Question 8

mycotic rhinitis

Answer 8

fungal infection leading to rhinitis; fungi proliferate to form mats on the surface of the tissue

Question 9

most common cause of mycotic rhinitis in dogs and horses

Answer 9

aspergillus fumigatus

Question 10

most common cause of mycotic rhinitis in cats

Answer 10

cryptococcus neoformans

causes “roman nose”

Question 11

guttural pouch mycosis

Answer 11

inhaled fungi accumulate in the guttural pouch and forms large fungal mats

most commonly aspergillus

Question 12

what is a risk of guttural pouch mycosis

Answer 12

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

Question 13

rhinitis and most common causes in young vs older animals

Answer 13

inflammation of the nose

young: viral
old: fungal or neoplastic

Question 14

why does rhinitis predispose animals to secondary infection

Answer 14

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

Question 15

equine rhinitis causes

Answer 15

equine herpesvirus 1 & 4
streptococcus equi

Question 16

EHV characteristics

Answer 16

herpesvirus; has a long latency in CN V ganglia - can get chronic disease even after recovery

Question 17

EHV 1 vs EHV 4 infection

Answer 17

EHV 1: systemic - causes viremia leading to rapid deterioration

EHV 4: local - causes self-limiting rhinitis

both can lead to encephalomyelitis and abortion

Question 18

strangles

Answer 18

infection with streptococcus equi bacteria

suppurative rhinitis and lymphanditis

Question 19

can strept equi be commensal

Answer 19

NO - if present, always causes disease

Question 20

bastard strangles

Answer 20

systemic spread of strept equi that begins with rhinitis but becomes septic

causes systemic abscesses

Question 21

bovine respiratory disease complex (BRDC)

Answer 21

any combination of viral, bacterial, and mycoplasma pathogens that produce respiratory disease

often combined with stress/shipping events

includes IBR and shipping fever

Question 22

infectious bovine rhinotracheitis (IBR)

Answer 22

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

Question 23

BoHV-1 characteristics

Answer 23

herpesvirus - establishes latency in CN V ganglia

can get chronic disease after initial recovery, especially if stress induced

can shed in environment

Question 24

what can IBR predispose the cow to

Answer 24

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

Question 25

shipping fever

Answer 25

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

Question 26

what is the most common and severe pathogen in BRDC

Answer 26

mannheimia haemolytica

produces leukotoxins (bacterial endotoxins) that attract neutrophils and lyse them to release their enzymes –> liquefactive necrosis of the tissue

Question 27

what other viruses are often involved in BRDC

Answer 27

BPIV-3 (parainfluenza; paramyxovirus)
BRSV (respiratory syncytial; paramyxovirus) - “enzootic pneumonia”
BCoV (coronavirus)

Question 28

atrophic rhinitis

Answer 28

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