9 – Examination of Respiratory Tract

Question 1

Distant exam

Answer 1

• Posture
• Breathing rate and pattern (8-12)
• Nostril flare (horse)
• Nasal discharge
  o Unilateral vs. bilateral
  o Characteristics: colour, consistency, blood

Question 2

Physical exam continued

Answer 2

• Airflow at nostrils
• Sinus percussion
• Submandibular lymph nodes
• Spontaneous or inducible cough?
• Tracheal and lung auscultation
• Rectal temperature

Question 3

Hyperpnea

Answer 3

• Increase in RR AND depth of respiration

Question 4

What are some manifestations of dyspnea?

Answer 4

• Tachypnea
• Extended head and neck
• Mouth breathing (not horses)
• Nostril flaring (no cattle)
• Increased effort
• Abdominal effort
• Abducted elbows
• Stridor
• Anxious expression
• Cyanosis with severe distress
• Anorexia

Question 5

Tachypnea can be physiologic (exercise, heat), but pathologic at REST

Answer 5

• Need for additional O2
• Compensation for metabolic acidosis
• Heat stroke
• CNS disease
• Weakness of respiratory muscles/motor nerves

Question 6

When might the need for additional O2 occur?

Answer 6

• Decreased O2 in environment: high altitude, fire or toxic fumes
• Disorders disrupting O2 transfer: respiratory tract disease, CV disease
• Decreased O2 carrying capacity of blood: anemia, abnormal hemoglobin

Question 7

Excessive environmental heat

Answer 7

• Dissipate heat through respiratory system: panting
• Labored breathing in very hot environment
• Thermoregulation: DOGS and cats

Question 8

What are some abnormal tracheal and lung sounds?

Answer 8

• Increased intensity/harshness (compared to trachea)
• Crackles: fluid build up
• Wheezes: narrowed
• Absence of sounds

Question 9

Dyspnea: intrathoracic airway obstruction

Answer 9

• Lower airway
• Dynamic airway collapse during expiration
• Expiratory distress

Question 10

Dyspnea: intrathoracic airway obstruction

Answer 10

• Upper airway
• Dynamic airway collapse during inspiration (Ex. laryngeal hemiplegia)
• Inspiratory distress

Question 11

Dyspnea: fixed airway obstruction

Answer 11

• Intraluminal mass
• Bronchoconstriction
• Inspiratory and expiratory distress
  o Severity depends on anatomic site

Question 12

Dyspnea: restrictive disease

Answer 12

• Pleural effusion
• Inhibition of lung expansion
• Inspiratory distress

Question 13

What is the purpose of rebreathing examination?

Answer 13

• Rebreathe expired air
• Deeper breaths
• Clinical findings to observe
  o RR
  o Respiratory pattern and effort
  o Coughing
  o Lung sounds
  o Recovery

Question 14

Minimum database

Answer 14

• (arterial) blood gas
  o O2 saturation
  o Acid-base disorders
• CBC
  o Systemic inflammation/infection
  o Acute vs. chronic inflammation

Question 15

Diagnostic tests

Answer 15

• Diagnostic imaging
  o Radiography (head/sinuses/teeth, guttural pouches, lungs)
  o CT (head ONLY in horses)
  o Ultrasound (lungs)
• Airway endoscopy
• Airway sampling
  o Naso-pharyngeal and guttural pouch swab/wash: PCR
  o Tracheal wash (need to be sterile): cytology, bacterial C&S testing
  o BAL: cytology, bacterial C&S testing

Question 16

Endoscopy

Answer 16

• *do NOT want to bump ethmoids (horses)
  o Go along VENTRAL MEATUS (guttural pouches, larynx, pharynx)
• Lower airway: trachea and lungs
• *image is a mirror (‘opposite’)

Question 17

BAL cytology interpretation

Answer 17

• *interpret findings together with clinical sings
• Mild to moderate equine asthma: different phenotypes
  o Eosinophilic inflammation (<5 years old)
  o Mast cell inflammation (usually younger)
  o Neutrophilic inflammation (>7 years old)

Question 18

Sinusitis

Answer 18

• Primary
  o Viral or bacterial
• Secondary
  o Dental disease
  o Cysts
  o Neoplasia
  o Foreign body
  o Trauma

Question 19

Diagnosis: for sinusitis

Answer 19

• History
  o Upper respiratory tract infections
  o Trouble eating, weight loss (dental disease)
  o Unilateral nasal discharge (can be bilateral)
• PE
  o Nasal discharge
  o Sinus percussion
  o Submandibular lymph nodes
• Radiography (or CT)
  o Fluid line: shouldn’t be filled with fluid (accumulates ventral, might change depending on head position)

Question 20

Guttural pouch diseases

Answer 20

• Empyema
• Mycosis

Question 21

Guttural pouch: anatomy

Answer 21

• Diverticula of eustachian tubes
• Connect pharynx to middle ear
• Separated into medial and lateral compartment: stylohyoid bone (ends in temporohyoid joint)
  o Fascial (VII) and vestibulocochlear (VIII) nerves located close to the joint
• Medial compartment is larger
• Openings located in dorsolateral aspect of pharynx

Question 22

Guttural pouch: neurology, medial compartment

Answer 22

• Internal carotid artery
• Cranial cervical ganglion
• *CN IX, X, XI, XII
• *sympathetic nerves
• Retropharyngeal lymph nodes
• *recurrent laryngeal nerve
• External carotid artery

Question 23

Guttural pouch: lateral compartment

Answer 23

• Maxillary artery
• Caudal auricular artery
• Superficial temporal artery

Question 24

The clinical signs of a guttural pouch disease may be variable

Answer 24

• Damage to CN IX or X: nasopharyngeal dysfunction, dysphagia (can’t swallow)
• Damage to recurrent laryngeal nerve: unilateral laryngeal hemiplegia
• Involvement of sympathetic nerve fibers: Horner’s syndrome
  *extension of infection to adjacent structures is rare, but can occur

Question 25

What are the 3 DDx for a horse bleeding from nose?

Answer 25

• Exercise induced pulmonary hemorrhage
• Guttural pouch erosion
• Guttural pouch hematoma