Equine diseases of the head & neck 2

What are the important components of the anatomy of the nares/nostrils?

• Alar folds

• Supported by alar cartilages —> keep nostrils open

  • need to be as wide as poss during exercise

• Facial nerve

• Nasal diverticulum (false nostril)

List some examples of nasal disorders

• Trauma —> lacerations

• Facial nerve paresis / paralysis

• Nasal atheroma

• Alar fold collapse

What can cause facial nerve paresis?

• GA / recumbency where pressure over facial nerve

• Iatrogenic e.g. surgery of face

• Most often temporary paresis, will resolve with time

What are the clinical signs of facial nerve paresis / paralysis?

• Facial swelling

• Asymmetry

• Reduced airflow

• Nasal stertor

• +/- facial distortion

• Poor performance

  

How is facial nerve/paresis diagnosed?

• Observation

• Palpation

How do you deal with lacerations of the nares?

• Precise anatomical repair important

• Minimal debridement —> good blood supply, preserve the tissues

• 2/3 layer closure

• Monitory for rubbing of suture

What are the problems with chronic scarring following lacerations of the nares?

• Performance limiting (reduced nasal flow)

• Cosmesis may be important (show horses)

What is an epidermal inclusion cysts /nasal atheroma?

Cyst within nasal diverticulum (false nostril)

What are the clinical signs of nasal atheroma?

Non-painful swelling at nasoincisive notch

What is the diagnosis, tx & prognosis of nasal atheroma?

Dx —> History, visual appearance, histopathology.

Tx —> surgical removal (usually under LA + standing sedation)

Prognosis —> excellent with surgical removal; likely to recur with simple drainage.

What is alar fold collapse?

Flaccid or redundant alar folds

• Respiratory tract noise at exercise

• Exercise intolerance in performance horses

• Pathogenesis = Unknown

How is alar fold collapse diagnosed and treated?

Dx —> fluttering sound at exercise (ddx laryngeal/ soft palate disorders) temporary sutures

Tx —> can resect folds

What separates the nasal passages?

Nasal septum & vomer bone

Describe the anatomy of the dorsal and ventral conchae

• Thin scrolls of cartilage and bone

• Divide nasal passage into 3 meati:

  • Dorsal

  • Middle

  • Ventral

• Form conchal sinuses caudally

What are the key anatomical features of the nasal passages?

• Sinuse drainage angle

  • Where paranasal sinuses drains into nasal passages

  • Usually 2-3mm —> can't directly access paranasal sinuses in normal horse using nasal endoscope

• Ethmoidal turbinates

What are the congenital disorders of the nasal passages?

• Wry nose (nasal septal deviation)

• Choanal atresia (rare)

  • Membrane that should not be present is → severe airway blockage

What are the acquired disorders of the nasal passages?

• Trauma (iatrogenic common)

• Progressive ethmoid haematoma (PEH)

• Fungal rhinitis

• Foreign bodies (rare)

What are the clinical signs of diseases of the nasal passages?

• Nasal Discharge

• Abnormal resp noise (altered flow of air?)

• Dyspnoea

• Malodorous smell —> e.g. fungal infection

• Facial / nasal Distortion

• Head Shaking

• Snorting / rubbing nose

What can cause nasal trauma in a horse?

• Epistaxis (nose bleed)

• Kick/ blunt trauma

• Iatrogenic

  • Trauma during nasogastric intubation / endoscopy common

How do you avoid iatrogenic trauma of the nose?

• Ensure tube placement in VENTRAL meatus not middle meatus (more likely to traumatise ethmoturbinates)

• Use smooth tube

• Lubricant on end of tube

• Do not force tube when meet resistance

• Haemorrhage will stop in 5-10 mins if ethmoturbinates traumatised

What are progressive ethmoid haematomas?

• Encapsulate non-neoplastic mass

• Unknown aetiology

• Locally invasive (does not metastasise)

• Grows into nasal passages / paranasal sinuses

What are the clinical signs of progressive ethmoid haematomas (PEH)?

• Epistaxis (nasal passages / sinuses)

  • Usually intermittent

  • Often slightly brown/red colour

• +/- Facial swelling (sinuses)

How do you diagnose PEH?

• Nasal PEH:

  • Endoscopy —> characteristic yellow/green lesion on ethmoid

  • +/- computed tomography

• Sinus PEH:

  • Radiography

  • Sinoscopy

  • CT

    • Assess cribiform plate

    • Possible intracranial extension (formalin contraindicated for tx —> find out whether extends into sinuses / brain before using)

• Check both sides —> often bilateral

How do you treat PEH?

• In nasal passages

  • Intra lesional formalin —> CT first

  • +/- Laser excision/ ablation if small

• PEH within the sinuses

  • Sinus flap surgery

    • Treat sinusitis

    • Remove lesions +/- laser

(recurrence common)

What are the types of fungal rhinitis?

• Primary (Uncommon in UK)

• Secondary

  • Fungal disease 2° to bacterial sinusitis common

What are the clinical signs of fungal rhinitis?

• Unilateral purulent/haemorrhagic nasal discharge

• +/-Malodorous smell

• Occasionally nasal stertor

How do you diagnose and treat fungal rhinitis?

D —> endoscopy and fungal culture

Tx —> removal of fungal plaques and necrotic bone, topical antifungal treatment (Eniloconazole lavage)

How many paranasal sinuses are there and how many groups?

• 7 pairs of paranasal sinuses

• 2 functional groups

  • No communication between groups

  • Sinuses within each group share drainage into the nasal passages

What are the groups and names of the paranasal sinuses?

Rostral group (2 sinuses)

• Rostral maxillary (RMS)

• Ventral conchal (VCS)

Caudal group (5 sinuses)

• Caudal maxillary (CMS)

• Frontal (FS)

• Dorsal conchal (DCS)

• Sphenopalatine (SP)

• Ethmoid sinus (ES)

What are the key anatomical points regarding the paranasal sinuses?

• Proximity to other structures

  • May cause disease in these e.g. intrasinus PEH can extend into brain

  • Disease may extend from these structures

    • Periapical regions of teeth → 2° sinusitis

• Rostral & caudal groups separated by oblique bony septum

  • Important when performing flushing of sinus compartments

What is being indicated in these images?

Conchal bullae —> air filled but can become infected

then form dorsal & ventral conchae

List the diseases of the paranasal sinuses

• PRIMARY SINUSITIS

• SECONDARY SINUSITIS

  • PAI / fungal

• SINUS CYSTS

• SINUS PEH

• NEOPLASIA

• TRAUMA

What is the most common presentation of paranasal sinus disease?

• NASAL DISCHARGE

• FACIAL SWELLING

What are the clinical signs of paranasal disease?

• Predom unilateral nasal discharrge (may be bilateral if bilateral sinus dx)

  • nature of discharge —> serous / purulent / mucopurulent / haemorrhagic

• Facial swelling

• Facial deformitiy

• Decreased nasal airflow

How is disease of the sinus diagnosed?

What causes primary sinusitis?

• Prev. URT infection

• Streptococcus spp most commonly

What causes secondary sinusitis?

1. Dental disease (60% of 2°)

2. Sinus cyst

3. PEH

4. Neoplasia

5. Fungal sinusitis (rare)

MUST treat sinusitis & primary cause of sinusitis

How is sinusitis diagnosed?

• Endoscopy —> visualise purulent material coming from sinus drainage angle

  

• Rads:

  • fluid line on lateral view,

    

  • radiodensity in sinuses on DV views

  • poor sensitivity for identifying cause of 2° sinusitis

• CT —> gold standard, teeth = greater sensitivity, useful for pre op planning

How is 1° sinusitis treated?

• Antimicrobials

  • Culture & sensitivity to rule out strep equi

• One course only

  • e.g. trimethoprim sulphonamides for 7-14d

  • Poor response indicated further infection

  • Do not try diff antibiotics —> resistance

• NSAIDs e.g. phenylbutazone

• Feed from ground (encourage drainage)

• Dust free management —> reduce URT inflam

• Turn out as much as possible —> drainage & reduce inflam

• Surgical draiange if does not respond (most mild, acute cases respond)

What is the most freq cause of 2°sinusistis?

Dental dx

Why does dental disease cause secondary sinusitis?

• Close proximity of alveolar bone to maxillary sinuses

  • Upper 08/09s —> Rostral Maxillary Sinus (RMS)

  • Upper 10/11s —> Caudal Maxillary Sinus (CMS)

How is 2° sinusitis diagnosed and treated

D:

• Rads insensitive

• CT gold standard

Tx:

• Removal of infected tooth

• Management of sinusitis

In what animals are paranasal sinus cysts seen?

• Young horses most common but can see in all ages

  • Aetiology unknown —> filled with yellow, viscous fluid

What do paranasal sinus cysts cause?

• Erosions & distortion & they expand

  • Nasal passage deformity

  • Facial swellings

What are the clinical signs of paranasal sinus cysts?

• Facial swelling

• Reduced nasal airflow (can be subtle to detect)

• Nasal discharge

• Nasal stertor

How are paranasal sinus cysts diagnosed and treated?

D:

• Rads

• Sinoscopy

• CT

Tx —> surgical removal via trephine portals / sinus flap

What signs are associated with sinus neoplasia?

• Facial swelling

• +/-nasal discharge, head shaking

  • May not be detected until extensive growth has already occurred

What are the common types of sinus neoplasia?

• SCC

• Adenocarcinoma

• Fibro-osseous tumors

• Myxoma (benign tumour of heart)

How is sinus neoplasia diagnosed and treated?

D:

• Rads / Sinoscopy

• CT

Tx:

• Usually too extensive to treat

• Debulking and radiotherapy uncommonly performed (costs/ facilities)

What is sinus trauma caused by?

Direct trauma e.g. running into tree

How is sinus trauma diagnosed and treated?

D:

• Clinical signs

• Radiography

• +/- US and CT

Tx:

• Removal/ stabilisation of bone fragments

• Flushing of sinuses to remove blood / purulent material

What are the trephine sites for sinoscopy?

• Frontal sinus (blue)

• Caudal maxillary (orange)

• Rostral maxillary (red)

  

enables access into sinuses for diagnosis (sinoscopy) & tx e.g. flushing

What are sinus flaps?

• Used to increase access into sinuses for removal of masses/other treatment

• Often performed under standing sedation (avoid GA —> costs/risk, less haemorrhage)

• Rectangular, bony flap created

What are the possible sites for sinus surgery?

• Maxillary sinus flap

• Frontonasal flap

dependent on location of lesion

What are the potential complications of sinus surgery?

• Haemorrhage

• Infection of the trephine portal / sinus flap

• Bone sequestrum formation

• Poor cosmesis (white hair)

• Recurrence of sinusitis

What is empyaema conchal bullae?

• Chronic infection of dorsal or ventral conchal bulla

  • Relatively newly recognised

  • Surgical techniques for draiange

What is suturitis?

• Perisotitis of the suture line in skull

  • frontonasal suture most common —> can occur after sinus surgery

• Bilateral, firm, swelling in nasofrontal region

  • May be painful at first

  • Settle & become non-painful

• Usually regresses with time but some can be permanent

What is dentigerous cysts?

• Congenital condition —> failure of closure of 1st branchia cleft

• Swelling on head —> usually @ base of ear, firm ± discharging sinus tract but can occur elsewhere (rare)

How are dentigerous cysts diagnosed?

Clinical signs, rads, CT

How are dentigerous cysts managed?

• Can be left untreated

• Usually removal requested cosmetically —> risk of infection developing / problems selling horse

Describe surgical excision of dentigerous cysts

• Performed under GA

• Advanced & specialist

• Prognosis good —> no cyst remnants should be left in situ