Approach to Horses with Facial Swelling & Nasal Discharge Flashcards
What are the nasal conchae
thin, scrolled shaped bony structures
what is the function of nasal conchae
increases surface area of the nasal cavity
provides rapid warmings and humidification of air as it passes into lungs
what are the nasal conchae divided into
dorsal
middle
ventral
common meatuses
what do the dorsal and ventral conchae enclose
a recess and a bulla
what are the structures of the nasal conchae
caudal to the dorsal and ventral conchae are the dorsal conchal sinus and ventral conchal sinus
what can cause infections of the bullae
cause chronic unilateral nasal discharge with and without concurrent paranasal sinusitis
how many paranasal sinuses are there
7
what are the paranasal sinuses
- dorsal (endoturbinate I) conchal sinus
- middle (endoturbinate II; ethmoid) conchal sinus
- ventral conchal sinus
- sphenopalatine sinus
- frontal sinus
- rostral maxillary sinus
- caudal maxillary sinus
name the paranasal sinuses
- rostral maxillary sinus (RMS)
- caudal maxillary sinus (CMS)
- ventral conchal sinus (VCS)
- sphenopalatine sinus (SPS)
- frontal sinus (FS)
- ethmoid (E)
name the paranasal sinus anatomy
- frontomaxillary opening
- dorsal conchal sinus (DCS)
- infraorbital canal
- septum between RMS and CMS
- caudal bulla of VCS
name the paranasal sinus anatomy
- rostral maxillary sinus
- caudal maxillary sinus
- sphenopalatine sinus
- frontal sinus
- dorsal conchal sinus
how do the sinuses relate to dentition
tooth roots of the caudal four maxillary cheek teeth are closely associated with maxillary sinuses
triadan 08 and 09: associated with rostral maxillary sinus
triadan 10 and 11: associated with caudal maxillary sinus
triadan 07 may be associated with rostral sinus
how do the sinuses related to dentition in young horses
alveoli of large cheek teeth reserve crowns occupy much of these maxillary sinuses
with age, alveoli remodel and retract, resulting in increased sinus cavity volume
which cheeck teeth can result in secondary sinusitis
periapical infection of the caudal maxillary cheek teeth
how do the paranasal sinuses communicate
directly: maxillary sinuses communicate with the middle nasal meatus through nasomaxillary aperture
indirectly: dorsal, middle, and ventral conchal sinuses, the frontal sinus and the sphenopalatine sinus communicate indirectly with the middle nasal meatus through the caudal maxillary sinus
what are the most common clinical signs of paranasal sinus disease
persistent, purulent unilateral nasal discharge
what are the less common clinical signs of paranasal sinus disease (8)
- facial swelling
- focal or diffuse and progressive or static as well a reduced airflow through a nostril(s)
- external draining tracts
- halitosis (malodorous breath)
- epiphora (excessive tearing from eyes)
- respiratory stertor (abnormal respiratory noise)
- enlarged submandibular lymph nodes
- head tilting
what does the clnical exam of a horse with unilateral, malodorous purulent nasal discharge
make sure to thoroughly palpate the patient’s face/skull
facial symmetry
any abnormalities including lumps or depressions, submandibular lymph node swelling or evidence of external draining tracts
what abnormalities can be seen on upper airway endoscopy
exudate coming from nasomaxillary aperture, ethmoid hematomas and/or distortion of the nasal septum or conchae
why is a dental exam important
dnetal disease is the most common cause of paranasal sinusitis in horses
what should an oral exam entail
use a dental mirror and evaluate the dental arcades thoroughly
assess one Triadan row at a time, looking at the occlusal surface and interdental space of every cheek tooth
what are the radiographic views used to assess the sinuses
- latero-lateral
- dorsoventral
- dorso30lateral-ventrolateral oblique views for maxillary arcades
what view is this
latero-lateral
what view is this
oblique views
dorso30lateral-ventrolateral oblique
what view is this
dorsal-ventral
how are radiographs labelled
the image should always be labelled as the side adjacent to plate
what are the landmarks for radiographic positioning
- lateral canthus
- midline of face
- facial crest
what does the latero-lateral view assess
paranasal sinuses
how is a latero-lateral view taken
centre the x-ray beam just dorsal to the facial crest and collimate to dorsal midline and the lateral canthus of the eye
what abnormalities can be seen on latero-lateral view
fluid lines
intra-sinus soft tissue opacities
fractures
what view is this and what are the structures
normal latero-lateral
blue: frontal sinus
green: dorsal conchal sinus
red: rostral maxillary sinus
purple: caudal maxillary sinus
yellow: sphenopalatine sinus
what view is this and structures
normal latero-lateral view
blue: dorsal conchae
green: ventral conchae
what is shown here
what are fluid lines
represent a collection of fluid (most likely purulent exudate in cases of sinusitis) within the paranasal sinuses
what is shown here and what view is this
latero-lateral
soft tissue opacity in the dorsal conchal sinus
what is shown here and what view
latero-lateral view
horse with chronic bilateral purulent nasal discharge
fracture of the maxillar
what are the dorso30lateral-ventrolateral oblique views used to assess
apices of the maxillary cheek theeth to help rule out dental disease as a cause of paranasal sinus disease
how is a dorso30lateral-ventrolateral view taken
beam should be centred 1cm dorsal to the rostral aspect of the facial crest and aimed roughly 30 degrees ventrally
the window for collimation is the same as a latero-lateral view
what are radiographic anatomy of significance with regards to teeth on oblique views (3)
- enamel
- periodontal ligament
- lamina dura: radiographic representation of cortical alveolar bone, which lines the alveolus in permanent teeth
what are radiographic abnormalities that can be seen on oblique views (5)
- periapical sclerosis and halo formation
- periodontal ligament widening
- loss of the lamina dura
- clubbing of tooth apices
- hypercemetosis
what are the structures shown here
what abnormality is shown here
periapical infection
what is shown here and what is the abnormality
periapical infection
what abnormality is shown
what abnormality is shown here
periapical clubbing
periapical infection
what is shown here
hypercementosis
periapical infection
what does the dorso-ventral view used to assess
nasal caivty and axial compartments of the paranasal sinuses
how is the dorsal-ventral view taken
x-ray plate is placed under the mandible and the beam is centred between facial crests
what abnormalities can be identified on dorso-ventral views
ventral conchal sinusitis and space occupying lesions
what are the normal structures of the dorso-ventral views
caudal maxillary sinus
rostral maxillary sinus
ventral conchal sinus
what is shown here
ventral conchal sinusitis
what are the disadvantages of radiographs
2D image of a complex 3D structure
identifying diseases can be difficult esp those that are subtle
whehn is CT indicated (3)
- when radiographic findings are equivocal or normal in the face of disease
- when medical and/or surgical treatment is unsuccessful
- evidence of multifocal or extensive disease or the extent of the disease is unknown
what are the two types of sinus surgeries
- sinus trephination: making a small hole into the sinus
- sinusotomy: making a large window into the sinus
where is sinus trephination done
into the frontal sinus
what does sinus trephination allow and when is it useful
evaluation of all paranasal sinuses compared to protals made into the maxillary sinuses
useful in young horses whose cheek teeth occupy much of the maxillary sinuses
what are the landmarks for sinus trephination into the frontal sinus
usually made 0.5cm cadual to an imaginary line drawn between the left and right medial canthi and halfway between midline and the ipsilateral medial canthus
what is sinuscopy
direct endoscopy of the paranasal sinuses following trephination
all sinuses can be evaluated if using a frontal trephination portal once the maxillary septal bulla is broken down surgically
what is the maxillary septal bulla
anatomical division between rostral paranasal sinuses (rostral maxillary and ventral conchal sinuses) and caudal paranasal sinuses (dorsal conchal sinus and caudal maxillary sinus)
what is sinusotomy
makes a large window into the paranasal sinuses for direct visualization via a three sided flap
when is sinusotomy indicated
if removal of a large mass or a significant amount of inspissated material is required
what are the causes of primary sinusitis
bacteria sinusitis
fungal sinusitis
what are secondary sinusitis
dental disease
paranasal sinus cysts
ethmoidal hematomas
trauma
neoplasia
what does primary sinusitis most commonly occur after
a transient upper resp viral infection
how does purulent exudate accumulate witihn the paranasal sinuses during primary sinusitis
increased mucous production, mucosal inflammation, impaired drainage from nasomaxillary aperture and impaired mucociliary clearance
this is due to a upper resp viral infection
what is the most common bacterial isolate in primary sinusitis
Streptococcus zooepidemicus
how is acute primary sinusitis treated
most spont resolve
but may also require 2 week course of antimicrobials (Strep. zooepidemicus is responsive to penicillin or trimethoprim/sulfamethoxazole) and anti-inflammatories (NSAIDs such as phenylbutazone)
plus feeding from the floor to facilitate drainage from the sinuses
how are chronic cases of primary sinusitis treated
it’s important to rule out secondary sinusitis as a cause (dental disease) if the c/s have been present for more than 2 months
where there is gross thickening of sinus mucosa (impedes drainage) a foley catheter may be placed to drain + irrigate to remove any purulent exudate present
how is sinus irrigation done
best performed through a trephination site made into the frontal sinus
foley catheter and irrigated using warm plain isotonic saline or isotonic saline with 0.01% povidine iodine
should drain freely through the nose after it comes through the nasomaxillary aperture
what is primary fungal sinusitis
fungal infection of paranasal sinuses
what can primary fungal sinustis cause as a clinical sign
head shaking where fungal plaques have been identified on the infraorbital canal within the paranasal sinuses
how is primary fungal sinusitis treated
surgical debridement via trephination or a bone flap followed by topical antifungal therapy
what is the most common cause of secondary sinusitis
dental disease most often due to apical infection of the caudal 07s to 11s of the maxillary arcades
how is secondary sinusitis treated due to dental disease
removal of affected tooth/teeth, followed by sinus irrigation through a foley catheter placed via a trephine opening into the frontal sinus
- perioperative antimicrobials (penicillin +/- metronidazole) and anti-inflammatories (NSAIDs such as phenylbutazone)
what is a paranasal sinus cyst
expansive, fluid filled, space occupying mass which usually originates in the maxillary sinus but can extend into all paranasal sinuses
can impair normal drainage from nasomaxillary aperture
what are the common clinical signs of paranasal sinus cysts (5)
- mucopurulent nasal discharge
- progressive distortion of the frontal, maxillary and/or conchal bones
- reduced nasal airflow
- epiphora (excessive tearing from eye)
- exophthalmos (bulging of eye)
what are the diagnostic findings in paranasal sinus cyst
distortion of nasal conchae may be observed on upper airway endoscopy
rounded, soft tissue opacity lesions may be identified within the frontal or maxillary sinuses on radiography
what is shown here
space occupying mass of soft tissue opacity
how are paranasal sinsu cysts treated
surgical removal either through bone flap or trephine followed by lavage of the sinus
distortion of nasal cavities and septum remodel rapidly after surgery and facial distortion eventually resolves
do paranasal sinus cysts recurr normally
no its rare
what are progressive ethmoid hematomas
slow-expanding, non-neoplastic masses that originates in or around the ethmoid larnyrinth or occasionally the paranasal sinuses
what are the casues of progressive ethmoid hematomas
unknown but theorized that hemorrhage occurs into the submucosa of an endoturbinate, causing mucosa to stretch and thicken, forming the capsule of a hematoma
over time they enlarge by repeated hemorrhage into the submucosa
are progressive ethmoid hematomas usually unilateral or bilateral
unilateral
what are common clinical signs of progressive ethmoid hematomas
- intermittent unilateral serosanguinous nasal discharge
- respiratory stritor
- halitosis
what are less comon clinical signs of progressive ethmoid hematomas
- head shaking
- dyspnea
- facial deformaties
- presence of a mass at the level of the nares
how are ethmoid hematomas diagnosed
history + clinical exam + upper airway endoscopy + radiography
a tan/brown/red mass may be visualized coming from the ethmiod labyrinth or nasomaxillary aperture
how are progressive ethmoid hematomas treated
surgical removal or ablation
surgical removal typically for large masses
smaller can be ablated through transendoscopic injection of 4% formaldehyde
is it common for progressive ethmoid hematomas to recurr
yes after surgical removal approx 43% will recurr
what is the most common neoplasia involving the paranasal sinuses
squamous cell carcinoma
what are the clinical signs of neoplasia in the paranasal sinuses
unilateral nasal discharge
respiratory stritor
facial swelling
epiphora
halitosis
what will be seen on oral exam with paranasal neoplasia
loose maxillary cheek teeth or abnormal tissue along the hard palate
how is paranasal neoplasia treated
pallitive through surgical removal of as much mass as possible –> successful removal of the entire mass is usually not possible due to invasivness
what is the prognosis of paranasal neoplasia
long term prognosis is poor
