32a: Equine Sinus and Nasal Disease

How do all the sinuses drain into the nasal cavity

Through the nasomaxillary opening

Which sinus connects directly to the nasal cavity

Maxillary sinus

Sinus that lives under the forehead of horses

Frontal sinus

Sinus that communicates extensively with the frontal sinus

Dorsal conchal sinus (→ conchofrontal sinus)

Compartments of the maxillary sinus

Rostral and caudal

How does the maxillary sinus connect to the conchofrontal sinus

The caudal maxillary sinus is connected via the frontomaxillary opening to the conchofrontal sinus

Where does the rostral maxillary sinus drain into the nasal cavity

The nasomaxillary opening drains into the middle meatus

How does the rostral maxillary sinus connect to the ventral conchal sinus

Through the conchomaxillary opening

Maxillary tooth roots that are present in the rostral maxillary sinus

8’s and 9’s

Maxillary tooth roots that are present in the caudal maxillary sinus

10’s and 11’s

T/F: sinus disease typically has unilateral nasal discharge

True, the maxillary sinus empties into the nasal cavity rostral to the back of the nasal septum

When does sinus disease cause bilateral nasal discharge

If there is bilateral sinus disease or if it erodes through the nasal septum

History questions to ask when evaluating for sinus disease

• What treatments have been give already

• Any difficulty breathing

• Any changes in eating

CS of sinus disease

• Nasal discharge

• Facial swelling and deformity

• Decreased airflow from the nasal passage

Less common CS of sinus disease

• External draining tracts

• SQ emphysema (trauma)

• Malodorous breath (dental)

• Ocular discharge

• Stertor

Parts of your physical exam that help evaluate the sinuses

Sinus percussion and oral exam

Normal v diseased sinus percussion

Normal sinus should be hollow, will not be if there is fluid or tissue

Diagnostics for sinus disease

• Endoscopy

• Rads

• Sinocentesis

• Sinoscopy

• CT

• MRI

Function of endoscopy for evaluating the sinuses

Evaluates airway patency and potentially the source of any drainage

Rad findings associated with sinus disease

• Opacities

• Fluid lines

• Dental abnormalities

• Bony pathology

Function for sinocentesis

Find sinusitis or cysts

Gold standard for diagnosing sinus disease

CT

Function of sinoscopy for sinus disease

Diagnosis and treatment

Surgical approaches to the sinus

• Maxillary sinus flap

• Frontonasal sinus flap

• Trephination

Margins for maxillary sinus flap

Box between rostral facial crest and medial canthus and between infraorbital canal and facial crest

Margins for frontonasal sinus flap

Box between supraorbital foramen and rostral extent of the lateral margin and between dorsal midline and 2/3 the way to the medial canthus

Surgical approach to the sinus that gives you access to all the sinuses (technically)

Frontonasal sinus flap

Primary sinusitis

Some respiratory/nasal disease causes obstruction of nasomaxillary drainage, resulting in mucus accumulation

Primary pathogen for primary sinusitis

Streptococcus of some sort from the URT

T/F: true primary sinusitis is rare

True

Treatment for acute primary sinusitis

Antimicrobials (ex: penicillin)

Treatment for chronic primary sinusitis

• Repeat sinus lavage

• Surgical debridement if inspissated

Most common type of sinusitis

Dental sinusitis

Causes of dental sinusitis

• Apical infection of caudal maxillary teeth

• Dental fractures

• Severe diastema

• Supernumerary cheek teeth

Diagnostics for dental sinusitis

• Oral exam

• Endoscopy

• Rads

• CT

Radiographic findings consistent with an apical infection of the maxillary cheek teeth

Clubbed, blunted root with surrounding lucency

CS of dental sinusitis

• Purulent, smelly nasal discharge

• Malodorous breath

• Weight loss, dropping feed

Treatment for dental sinusitis

Remove the tooth

Methods for tooth removal in a horse

• Oral extraction

• Minimally invasive buccotomy

• Lateral buccotomy

• Repulsion (please no)

What should you do after you remove a tooth

Pack the socket with dental impression material