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Brachycephalic Airway Syndrome 129

Clinical Presentation • Secondary airway changes can develop due • Older animals (>7 years) that have previously
DISEASE FORMS/SUBTYPES to increased airway resistance. compensated throughout life should receive
VetBooks.ir mild exercise intolerance may be present from saccule eversion; grade II, cuneiform ○ Advanced nasal imaging (CT) may identify Diseases and Disorders
advanced imaging.
○ Laryngeal collapse (grade I, laryngeal
• Subclinical: mildly stertorous breathing or
early in life. Patients continue to have physi-
process collapse; grade III, corniculate
caudal aberrant turbinates or intranasal
process collapse)
epidermoid cysts.
ologic changes that can cause progression
to clinical disease later in life. ○ Pharyngeal collapse ○ Fluoroscopy may be necessary to diagnose
• Clinical: patients have active clinical signs ○ Tracheal collapse pharyngeal collapse.
that adversely affect quality of life. ○ Everted tonsils ○ Retroflex pharyngostomy to identify
+/− treat caudal aberrant nasal turbinates
HISTORY, CHIEF COMPLAINT DIAGNOSIS
• Stertor (heavy snoring) is the most common TREATMENT
complaint, with stridor (high pitched) less Diagnostic Overview
common. Initial diagnostics for BAS should identify Treatment Overview
• Exercise intolerance, cyanosis, or collapse concurrent disease processes that can complicate Treatment consists of addressing surgically
• Insomnia surgical correction. Thoracic radiographs can correctable abnormalities that can functionally
• Owners may notice inability to get comfort- identify pulmonary disease that may hinder open the upper airway. Ideally, this should occur
able after exercise. ability to compensate under general anesthesia as young as possible, before development of
• Occasional regurgitation may be present sec- and are necessary to identify hypoplastic trachea. secondary affects that occur due to chronic
ondary to hiatal hernia or gastric ulcerations. Acute onset of clinical signs in a middle-aged negative pressure in the upper airway.
○ Acute onset of severe dyspnea may occur to older individual should raise concern
secondary to aspiration pneumonia. about other conditions exacerbating clinical Acute General Treatment
○ Must rule out noncardiogenic edema signs. • If dyspnea is severe on presentation or during
secondary to obstructive episode hospitalization
Differential Diagnosis ○ Minimize patient anxiety with sedatives
PHYSICAL EXAM FINDINGS • Upper airway mass (neoplasia/polyp, granu- (e.g., butorphanol 0.3 mg/kg, aceproma-
• Flat face with stenotic nares (common but loma, abscess, epidermoid cyst, pharyngeal zine 0.01-0.2 mg/kg).
not uniformly present) sialocele) ○ Administer glucocorticoids to reduce
• Stertor or sometimes stridor; increased • Laryngeal collapse airway inflammation and swelling (dexa-
inspiratory sounds • Pharyngeal collapse methasone SP 0.1-0.5 mg/kg).
• Increased bronchovesicular sounds if concur- • Cervical or laryngeal trauma ○ Supplement oxygen with placement in
rent pneumonia or noncardiogenic edema • Laryngeal paralysis oxygen cage/tent (p. 1146)
(± crackles), or bronchitis (± wheeze) • Laryngeal neoplasia ○ Orotracheal intubation or tracheostomy
• If in respiratory distress: cyanosis, labored • Rhinitis (p. 1166) if necessary
breathing, collapse, hyperthermia • Once stabilized, relieve upper airway obstruc-
• ± “Puffing out” of thoracic inlet during Initial Database tion by surgical correction.
respiration (due to lung lobe herniation) • Complete blood count may identify mild • Stenotic nares
• Examination of the soft palate and laryngeal polycythemia. Chemistry panel may show ○ Lateral or vertical alarplasty
ventricles should take place after heavy mild increase in TCO 2 or mild decrease in ○ Trader’s technique
−
sedation (p. 1125). HCO 3 . • Elongated soft palate
• Thoracic radiographs usually identify ○ Shorten excessive palatal tissue
Etiology and Pathophysiology hypoplastic trachea but should be performed ○ Landmarks are caudal pole of the laryngeal
• Selective breeding has led to rostrocaudal to evaluate pulmonary disease. tonsils and tip of the epiglottis in an
shortening of the skull and nasal passages ○ Ratio of trachea diameter to thoracic upright position when the tongue is in
in these breeds. inlet < 0.15 consistent with hypoplastic its normal position.
• Redundant pharyngeal soft tissues contribute trachea ○ Sharp excision of soft palate requires
to increased airway resistance and various ○ Bulldogs typically have a smaller ratio of suturing of palatal mucosa. Extra care
degrees of obstruction of the nasal passages < 0.12. should be made to appose the cut edges
and pharynx during inspiration. of the nasoesophageal and oropharyngeal
• To achieve appropriate oxygenation, increased Advanced or Confirmatory Testing palatal mucosa.
force is necessary to pull air in. The excessive • Sedated upper airway examination using a ○ CO 2 laser and cautery excision can cause
negative pressure causes inflammation, rapid-acting induction agent (e.g., alfaxalone granulation tissue when not sutured (not
edema, and weakening of the components 1-3 mg/kg slowly IV to effect or propofol recommended).
of the upper airway (larynx, pharyngeal wall, 1-6 mg/kg IV to effect) • Tonsillar eversion
soft palate). ○ Confirmation of elongated soft palate and ○ Excise tonsils if obstructing airway
• This also contributes to an increase in eversion of laryngeal ventricles • Everted laryngeal saccules
intraabdominal pressure, leading to possible ○ Palate should not extend past the caudal ○ Excision should be performed very care-
herniation (lung lobe herniation, hiatal pole of the tonsil and should barely make fully so as to not cause too much trauma
hernia, urethral prolapse). contact with an upright epiglottis. (Keep ventrally with scissors or scalpel blade.
• Primary anatomic components of BAS (any/ head and tongue in a natural position to CO 2 laser should be used only with
all may be present) best evaluate.) guarded endotracheal tube.
○ Stenotic nares ○ Also evaluate for everted tonsils, redundant ○ If not everted and just effacing tissue, may
○ Elongated soft palate (caudal to tip of or hyperplastic pharyngeal soft tissues, decide not to treat
epiglottis) advanced stages of laryngeal collapse • Laryngeal collapse
○ Hypoplastic trachea (tracheal diameter/ ○ Clinician should be prepared to intubate/ ○ Only surgically correct if impairing
thoracic inlet ratio < 0.15) (p. 521) ventilate if necessary ventilation
○ Caudal aberrant nasal turbinates (nasal • Arterial blood gas analysis often identifies ○ Partial arytenoidectomy may also be useful
turbinates obstructing nasopharynx) hypercapnia and hypoxemia (p. 1315). ○ Permanent tracheostomy

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