Lecture 10: Brachycephalic Syndrome (Exam 2) Flashcards
Describe brachycephalic breeds
- Have compressed face w/ poorly dev nares & a distorted nasopharynx
- Head shape is the result of an inherited dev defect in the bones of the base of the skull
- Head bones grow to a norm width but have been reduced in length
- Soft tissues of the head are not proportionately reduced & often appear redundant
List breeds that are typically affected
- English bulldogs
- French bulldogs
- Pug
- Boston terrier
- Shar pei
- Cavalier king charles spaniel
- Lhasa apso
- Shih tzu
- Boxer
- Pekingese
Define brachycephalic syndrome
The combo of the surgically addressable conditions causing upper airway obstruction in brachycephalic breeds
What are the major components of brachycephalic airway syndrome (BAS)
- Stenotic nare
- Elongated soft palate
- Everted laryngeal saccules
What are a associated conditions w/ BAS
- Laryngeal collapse
- Hypoplastic trachea
- Nasopharyngeal turbinates
- Tracheal collapse
- Tonsil eversion
What are some other abnorms that may cause or contribute to upper respiratory obstruction in brachy breeds
- Tracheal collapse
- Obesity
- Laryngeal paralysis
- Masses obstructing the glottis, larynx, or trachea
- Traumatic disruption of the airway
What are stenotic nares
- Congenital malformations of the nasal cartilages that result in medial collapse &/or partial occlusion of the external nares
- Airflow into the nasal cavity is restricted & greater inspiratory effort is necessary (causes mild to severe dyspnea)
How can stenotic nares cause the airway to narrow more
As more & more neg pressure is exerted to breathe, intratracheal & intrapharyngeal pressure become high enough to cause surrounding tissue to collapse
How are stenotic nares corrected
- Removal of the alar folds
- Recession wedge
What is the most common component of BAS
Elongated soft palate
Why is an elongated soft palate a problem
- Soft palate is pulled caudally during inspiration & obstructs the glottis (increases inspiratory effort & causes more turbulent airflow)
- Laryngeal mucosa becomes inflamed & edematous (narrows the airway even more)
What is considered the first stage of laryngeal collapse & is reported in over half of dogs w/ BAS
Everted laryngeal saccules
What do everted laryngeal saccules partially or completely obscure
The vocal folds
What is hypoplastic trachea
- Congenital tracheal stenosis that affects the entire length of the trachea
- Associated w/ cont. respiratory distress, coughing, & recurrent tracheitis
- Can be tolerated in the absence of concurrent respiratory/ CV dx
How can hypoplastic trachea be Dxed
Radiographically by determining the tracheal to thoracic inlet diameter ratios
What is the typical hx of a dog w/ BAS
- Noisy breathing
- Varying levels of respiratory distress
- Frequent retching or gagging
- Trouble swallowing b/c of thick saliva or occlusion of the airway
- Concurrent GI signs
- Exercise intolerance
- Cyanosis
- Restless sleeping
- Collapse
What can make clinical sx of BAS worse
- Excitement
- Stress
- Increased heat & humidity
What causes stertor & stridor
Complete or partial obstruction in the airway
Describe stertor
- Low pitched sound
- Results from flaccid tissue vibrating through the respiratory cycle
- Sounds like a snore
Describe stridor
- High pitched sound
- Results from rigid tissue vibrations
- Typically assoc w/ laryngeal/tracheal dx
T/F: Some, all, or none of the BAS clinical sx maybe present upon PE
True
What are some sx that can be seen on the PE of a dog w/ BAS
- Pharyngeal & laryngeal auscultation = stretor & inspiratory stridor
- Inspiratory effort sx
- Mucous membrane sx (norm color, pale, or cyanotic)
- Restless & anxious (esp when restrained)
- Hyperthermia b/c of ineffective cooling
- GI tract distension
List the sx of increased inspiratory effort
- Retraction of lip commissures
- Open mouth breathing
- Constant panting
- Forelimb abduction
- Exaggerated use of abdominal muscles
- Paradoxical movement of the thorax & abdomen
- Recruitment of acc. respiratory muscle
- Inward collapse of the ICS & thoracic inlet
- Orthopneic posture
What is orthopneic posture
Extended head & neck w/ reluctance to lie down
How are stenotic nares IDed on a PE
- Nares are pulled medially or may remain relatively stationary on inspiration (can be mild, mod, or severely deviated medially during inspiration)
- Airflow through the nares can be assessed by holding a glass slide or cotton near them
What diagnostic imaging should be done
- Thoracic radiographs
- Lateral cervical radiographs
- Advanced imaging maybe needed for severe cases
What are the thoracic radiographs going to detect
- Underlying cardiopulmonary abnorms
- Cardiomegaly, pulmonary edema, & pneumonia
What is evaled on the lateral cervical radiographs
- Nasopharynx
- Soft palate
- Larynx
- Entire length of the trachea
- Nasopharyngeal, laryngeal, & tracheal masses
Describe a pharyngoscopy/laryngoscopy
- General ax req
- Done w/ a rigid laryngoscope
- Eval the soft palate
- Do a functional assessment of the larynx
What can be noted when evaluating the soft palate in dogs w/ BAS
- Overlay the epiglottis
- Is thickened & has a roughened inflamed tip
- Inflamed & edematous arytenoids
- Inflamed & everted tonsils
- everted laryngeal saccules
What emergency medical management is needed for BAS
- Airway
- Oxygen
- +/- Sedation
- Glucocorticoids
- Cooling
What is some long term medical management of BAS
- Weight reduction
- Exercise restriction & elim of precipitating causes
- Glucocorticoids
- Supplemental O2 & cooling for mod to severe resp distress
What animals are Ax & post op risks
Animals w/ upper respiratory obstructions
What procedures are need for sx treatment
- Stenotic nares resection
- Resection of elongated soft palate
- Resection of everted laryngeal saccules
When should stenotic nares resection be performed
- When the animals is old enough to be safely anesthetized
- When the animals nasal tissues have matured enough to hold sutures (as early as 3 to 4 M)
When is a resection of an elongated best performed
When the animal is young ( 4 to 24 M) & before laryngeal cartilages deform & collapes
When is an everted laryngeal saccules excision performed
@ the same time as the soft palate correction (some surgeons choose to leave them in young dogs w/ mild to mod clinical sx)
Describe px positioning for BAS sx
- Sternal recumbency w/ mouth fully open
- Maxilla suspended
- Mandible secure ventrally w/ tape
- Chin not allowed to rest on the table or pads
- Sponges placed around the endotracheal tube & the glottis
- Oral cavity gently lavaged w/ dilute antiseptic
- Mucosal surfaces should not be scrubbed
What are the steps to correct stenotic nares
- Grasp the margin of the nares & make a v shaped incision around the forceps approx 1 to 3 mm deep into the alar fold
- Remove the vertical wedge of tissue
- Control the hemorrhage w/ digital pressure & by reapposing the cut edges
- Place 3 to 4 simple interrupted sutures w/ absorbable material
How are sutures placed when correcting stenotic nares
From medial to lateral when closing
What can happen if using electrosurgery for a staphylectomy
- May increase post op swelling
- May ignite oxygen if proper precautions are not take
Describe hemorrhage seen in a staphylectomy
- Mild to mod
- Controlled w/ gentle pressure
How far/much should the caudal margin of the soft palate be shortened
- Contact the tip of the epiglottis
- Contacts the roof of the nasopharynx when pushed dorsally
What can happen if there is resection of too much soft palate
- Nasal regurgitation
- Rhinitis
- Sinusitis
Describe the steps of a staphylectomy
- Visually mark the site of proposed resection
- Grasp the midline tip of the soft palate w/ thumb forceps or place a stay suture
- Place additional stay sutures @ the proposed site of resection on the right & left borders of the palate
- Transect across 1/3 to half the width of the soft palate
- Begin a simp cont suture pattern @ the border of the palate & appose the oropharyngeal & nasopharyngeal mucosa
What are complications that are possible when resecting everted laryngeal saccules
- Laryngeal swelling
- Laryngeal webbing
- Regrowth
When it is recommended for saccules be removed
Only when believed to contribute significantly to airway obstruction
Describe post op care & assessment
- Px req constant monitoring
- Before extubation, induction drugs, laryngoscope, endotracheal tube, & O2 need to be immediately ava
- Hospital observation is rec for 24 to 72 H
- With hold food for 12 to 24 H
Why is food with held
May traumatize swollen tissues, causing swelling, airway obstruction, aspiration, or all of the above
What is the prognosis after surgical correction
- Most will be improved but not norm
- Good to excellent long term outcome for majority of dogs
- 5% experience major complications
Describe the prognosis after surgical correction for english bulldogs
Have been found to have a worse response to sx when compared w/ all other breeds combined & are more likely to dev aspiration pneumonia post op
What is laryngeal collapse
Form of upper airway obstruction caused by loss of cartilage rigidity that allows medial deviation of the laryngeal cartilages (arytenoid collapse)
Describe stage 1 of laryngeal collapse
Commonly referred to as laryngeal saccule eversion
Describe stage 2 of laryngeal collapse
- Advanced stage
- Medial deviation of the cuneiform cartilage & aryepiglottic fold = aryepiglottic collapse
Describe stage 3 of laryngeal collapse
- Advanced stages
- Medial deviation of the corniculate process of the arytenoid cartilages = corniculate collapse
What are some ways to manage laryngeal collapse
- Weight loss
- Avoid overheating
- Sedation & steroids
- Permanent tracheostomy
