Lecture 17 - Diseases of the airways 1 Flashcards
what is the most common route by which injurious agents enter the respiratory tact?
- inhalation: aerogenous route
- via blood; systemic
what are the various defences of the upper respiratory tract?
- sneezing reflex
- coughing reflex
- warming and humidification of inspired air by nasal mucosa = prevent desiccation
- mechanical filtration
- nasal hairs: trap large particles
- mucociliary clearance
- chemical defence: lactoferrin, lysozyme, b defensins
normal microflora
what is primary ciliary dyskenisa?
structural or functional abnormalities to the cilia
what are the clinical signs that are suggestive of disease of the nasal cavity or nasopharynx?
nasal discharge = most common sign sneezing snorting reverse sneezing gagging open mouthed breathing decreased exercise intolerance face rubbing facial deformity/ boney remodelling
what are the congenital malformations that involve the nasal cavity in the domestic cavity
- severe craniofacial deformities
- facial clefts
- cystic nasal conchae
- choanal actresis
- brachycephalic airway syndrom
what three conditions commonly predispose an animal to severe cranoifacial deformities? what are they?
- holoprencephaly –> forebrain deformities typically including ageneisis, or severe hypoplasis of olfactory bulbs and tracts = abnormal differentiation of the forebrain into cerebral hemispheres, olfactory system, optical vessels, thalamus and hypothalamus
- chrondrodysplasia –> inherited, impaired longitudinal growth of cartilage –> dispropriate dwarfism
- wry nose
what are two common facial clefts seen?
- chelisoschisis - cleft lip
- palatoschsis - cleft palate
what are the consequences of palatoschisis?
animal can’t suck, if they can may risk aspiration pneumonia
what is cystic nasal conchae, in what animals does it normally develop in?
commonly seen in cattle
uni or bi lateral smooth surfaced bony projecting nodules in ventral nasal meatus
what is choanal actresis? what usually causes choanal actresis?
uni or bilateral failure of formation of a communicating channel between the nasal cavity and nasopharynx
usually due to persistence of choanal membrane
what are the various possible components of brachycephalic airway syndrome? which animals are affected by this syndrome?
BAS refers to multiple congenital abnormalities found in brachephalic dog breeds
may include:
- stenotic external nares - lack rigidity = collapse on insp
- elongated soft palate - SP too long for epiglottis = obst.
- everted laryngeal saccule - sit behind epiglottis, become oedematous = obstruction
- laryngeal collapse- larynx fatigued due to chronic obst.
- tracheal hypoplasia = airflow
BRACHYCEPHALIC DOG BREEDS AFFECTED = bulldogs, boxers, boston terriers, pugs and pekingese
what is epistaxis?
haemorrhage from the nose
what are potential causes of epistaxis
trauma, foreign bodies, tumour, severe rhinos, intense sneezing episodes, bleeding disorders.
infrequently may be caused by - systemic hypertension, right sided congestive heart failure or intra nasal vascular aneurysm
what is a progressive ethmoid haemoatoma in horse?
unilateral space occupying mass of organising haemorrhage and reparative granulation tissue in the submucosa of ethmoid tubrinates
what breeds do ethmoid haemoatoma commonly affect?
TB’s and arabian breeds
what is rhinitis?
inflammation of the nasal cavity
what are potential causes of rhinitis in domestic animals?
- viruses e.g. canine distemper
- bacteria
- fungi
- parasites
- foreign body - stick, splinter, grass seed
- allergen
acute rhinitis is characterised by ___ and ____ and exudation into the nasal cavities
mucosal oedema
hyperaemia
most forms of rhinitis are self limiting and follow a chronological sequence of what kinds of inflammation
- serous
- catahharal
- purulent
- fibrinous
describe the exudate commonly seen in serous rhinitis and what cell type predominates? describe the gross appearance of the sub mucosa.
- acute - clear, watery nasal discharge
- contains few leukocytes
- submucosa is oedematous and hyperaemia
= MILDEST FORM eg/ early stage of viral infection, exposure to cold air or mild nasal irritant
describe the exudate commonly seen in catharral rhinitis and what cell type predominates? when does catharral rhinitis usually appear?
- hrs - days
- nasal exudate typically mucoid due to increased production by mucosal goblet cells and submucosal glands
- additional recruitment of neutrophils and sloughing epithelial cells
describe the exudate commonly seen in purulent (suppurative) rhinitis and what cell type predominates? does pus indicate bacterial infection?
- exudate thickens = large numbers of neutrophils, accompanying EROSION AND ULCERATION of nasal mucosa.
- pus does not indicate bacteria infection –> suggest there is enough need for neutrophils
describe the exudate commonly seen in fibrinous rhinitis, what does this indicate?
indicative of severe nasal mucosal injury
w/ marked increase in vascular permeability
= leakage of fibrin and neutrophils
what are some causes of fibrinous rhinitis in domestic animals?
- fungal rhinitis
- infectious bovine rinhotracheatitis
- fusobacterium necrophrum
- allergic rhinitis: hay fever
what are some gross and histological nasal lesions that can develop if rhinitis becomes chronic?
- progressive fibrosis of the nasal submocas
- atrophy of the submucosal seromuccoid glands
- hyperplasia
- squamous metaplasia of the mucosal epithelium
- formation of proliferative soft tissue mass in the submucosa
- destruction and atrophy of nasal turbinate bones
- deviation of the nasal septum and eventually gross craniofacial deformity
what is lymphocytic-plasmacytic rhinitis? in which species is it common? how is it characterised histologically?
- common form of rhinitis in dogs and cats
- associated with persistent catarrhal - mucoplurant discharge
- histological characterised by submucosal infiltrates of lymphocytes and plasma cells
what are possible causes of chronic granulomatous to pyogranulomatous rhinitis in domestic animals
how is it characterised histologically?
- chronic allergic rhinitis, chronic fungal infections, foreign bodies, chronic infections
- characterised by accumulation of submucosal macrophages and smaller number of lymphocytes, plasma cells, neutrophils, or eosinophils
what is allergic rhinitis? in which species is it recognised in?
type I hypersensitivy to allergens –> exudation of eosinophils and mucus
recognised in dogs and cats
what are polyps and where can polyps develop as a consequence of chronic inflammation of the upper respiratory tract?
what species are polyps especially common in
polyps are masses of well vascularised reparative CT that arise as a consequence of chronic inflammation
- arise within nasal cavity, nasopharynx, auditory tubes
- cats <3 yr old and horses
what is sinusitis?
inflammation of paranasal sinus
what is a common cause of sinusitis
it is a common extension of rhinitis
which paranasal sinus are often affected in sinusitis?
frontal
maxilalry
in which species is sinusitis most often diagnosed and why?
horses - limited drainage of sinuses
suppurative guttural ouch infection is most often caused by
streptococcus equi
- strangles infection with guttural pouch involvement a sequel to abseccsation of the retropharyngeal lymph nodes
fungal infections of the guttural pouch is most often caused by
aspergillus fumigatus
- most often seen in stabled horses probs because they whale spores from mouldy hay
what are common names for suppurative and fungal guttural pouch infections
suppurative - gut pouch empyema
fungal - gut pouch mycosis
what are some potential consequences of guttural pouch empyema/mycosis
- compression or inflame and necrosis of cranial nerves VII, IX, X, XI, XII and/or symp trunk
- rupture and severe epistaxis of the internal carotid artery
- damage to vagus nerve –> laryngeal hemiplasia
define guttural pouch tympany
accumulation of air in guttural ouch
what species if guttural pouch tympany most often seen in
foals up to 1 yr old, most often fillies
due to abnormal valvular function at the nasopharyngeal orifice of the auditory tube
