Diseases of the Equine Nasal Passages and Paranasal Sinuses

Lecture 33

What is the medical term for a nosebleed?

epistaxis

List causes of unilateral epistaxis.

dry mucous mmebranes (cold weather)

exertion

ethmoid hematoma

nasal polyps

guttural pouch mycosis

neoplasia

List causes of bilateral epistaxis.

EIPH (racehorses, barrel horses)

head trauma

clotting disorders

severe pleuropneumonia

What is the first major site of upper airway resistance?

external nares (nostrils)

What is the etiology of atheroma or epidermal inclusion cyst of the external nares?

cyst in the false nostril - cause unknown

How can we diagnose atheroma or epidermal inclusion cyst of the external nares?

mass (3-5cm) spherical nodule

FNA and cytology if indicated

How can we treat atheroma or epidermal inclusion cyst of the external nares?

surgical removal

What prognosis is associated with atheroma or epidermal inclusion cysts of the external nares?

excellent with no recurrence reported

What can lead to problems of the nasal passages?

trauma, inflammation, infection, neoplasia, congenital issues such as wry nose

How can we diagnose problems of the nasal septum?

clinical signs —> respiratory noise, decreased airflow, nasal discharge, facial deformity

radiography —> DV view reveals thickening, malformation, and septal deviation

endoscopy NOT helpful

CT

How can we treat problems of the nasal septum?

resection of the septum —> need to leave the rostral section to prevent collapse

What are nasal polyps?

pedunculated growths from the mucosa of the nasal cavity, septum, etc

What clinical signs can be associated with nasal polyps?

inspiratory dyspnea, nasal discharge, odor

How can we treat nasal polyps?

surgical excision

What is the etiology of progressive ethmoid hematoms in the nasal passages?

slowly expanding, non neoplastic mass that originates from submucosa of ethmoid labyrinth or paranasal sinuses

usually unilateral and can expand down the nasal passages and/or into the sinuses

What clinical signs can be associated with progressive ethmoid hematomas?

unilateral epistaxis with serosanguinous discharge

respiratory noise

dyspnea

head shaking

halitosis

facial deformity

How can we diagnose progressive ethmoid hematoma?

endoscopy reveals greenish-yellow to purplish-red mass, smooth surface, may have fungal plauqes, biopsy

radiographs

How can we treat progressive ethmoid hematoma?

surgical excision for mass removal and destruction of origin

transendoscopic using laser and intra-lesional formalin injection with 4% formaldehyde every 3-4 weeks

All paranasal sinuses eventually drain through what?

nasomaxillary opening

What tooth roots reside in the paranasal sinus?

maxillary PM4, M1, M2, M3

What is the most common clinical sign of sinusitis?

unilateral nasal discharge

Primary sinusitis is often caused by what?

upper respiratory infection especially strep sp

Secondary sinusitis is often caused by what?

tooth root abscess, trauma (facial fracture), neoplasia

What clinical signs can be associated with sinusitis?

nasal discharge (odor, purulent, unilateral)

± epiphora, conjunctivitis

± enlarged submandibular lymph nodes

± respiratory noise

± facial deformity (rare with sinusitis, more common with paranasal sinus cysts)

Unilateral nasal discharge usually comes from where?

sinuses, nasal cavity

Bilateral nasal discharge usually comes from where?

guttural pouches, nasopharynx, lungs, both paranasal sinuses

How can we diagnose sinusitis?

radiographs reveal opacity in the sinus and fluid lines

endoscopy shows pus at the nasomaxillary opening blocking view into the sinus

How can we diagnose sinusitis that has been refractory to treatment?

sinocentesis with cytology and culture followed by lavage

sinoscopy to visualize the sinus

CT for complicated cases

How can you perform a lavage for primary sinusitis?

copious lavage with 5-10 L of sterile warm saline with systemic antibiotics based on C/S

Why might treatment for sinusitis fail?

inspissated pus in ventral conchal sinus

failure to treat primary problem

fungal infection

neoplasia

What is the etiology of sinus cysts?

fluid filled structure lined by epithelium - unknown etiology but congenital possible

What clinical signs can be associated with sinus cysts?

facial deformation

unilateral mucoserous nasal discharge with no odor

reduced airflow on affected side

How can we diagnose sinus cysts?

radiographs show space occupying without bone destruction

CT/MRI

How can we treat sinus cysts?

remove them - make sure you also remove cyst lining so it does not recur

What is the most common sinus neoplasia?

squamous cell carcinoma

What clinical signs can be associated with sinus neoplasia?

nasal discharge, facial deformity, loos teeth, epiphora

How can we diagnose sinus neoplasia?

aspirate fluid for cytology

biopsy

How can we treat sinus neoplasia?

surgical margins difficult/impossible to get so we typically euthanize affected animals

What are the different bone flap approaches used for surgery of the sinuses?

frontonasal

maxillary

What type of bone flap approach is this?

frontonasal

What type of bone flap approach is this?

maxillary

What tools are used to create a bone flap?

mallet and osteotome

oscillating saw

What complications can occur with sinus surgery?

hemorrhage especially with ethmoid hematomas

recurrence

failure to resolve clinical signs

What are important considerations for surgery of the sinuses?

make a large opening into nasal cavity to facilitate drainage

post op lavage may be needed so plan to place a foley catheter just in case

pack the sinus post op to control hemorrhage then remove 48-72 hours after surgery