General Evaluation of the Equine Lower Respiratory Tract Flashcards
How should the normal equine lung look? What lobes are found on each side?
lack deep interlobar fissures and distinct lung lobes
- LEFT = cranial, caudal
- RIGHT = cranial, intermediate, caudal
Where does the trachea bifurcate in horses? Which bronchus is more susceptible to disease?
5-6 intercostal space
right bronchus is more straight = right pulmonary disease more common
How does the respiratory epithelium differ down the airway?
becomes thinner and less ciliated
What are the 2 vascular supplies of the lung? What happens at each?
- PULMONARY - low pressure, low resistance; gas and nutrient exchange
- BRONCHIAL - nutrient supply to lymphatics, vascular and airway components
What are important aspects to an equine history to diagnose respiratory disease?
- age and breed (signalment)
- environment (housing, feeding)
- job (race vs. pasture)
- recent events
- endemic disease
- trauma
- vaccination history
- chief complaint
- prior medical problems
What are important aspects to inspection of a patient for diagnosing respiratory disease?
- demeanor
- posture
- mental status
- movement
- deformation
- nasal discharge
- cough
- respiratory effort (dyspnea)
- respiratory effort
(nostrils should be flat at rest, if they’re consistently abducted, there is an increased respiratory effort)
What landmarks should be palpated and percussed for diagnosing respiratory disease?
- nostrils (air flow, odor)
- area over sinus (should be hollow)
- lymph nodes
- larynx/pharynx
- trachea
- jugular
- neck
- chest
In what conditions should auscultation be done? What piece of equipment is commonly used?
quiet conditions (hard in the field and in barns)
rebreathing bags —> cover nostrils to obstruct breathing and listen to the first few breaths for accurate and quality sounds
What do wheezes and crackles upon auscultation indicate?
WHEEZE = inspiratory, bronchoconstriction
CRACKLES = moist, fluid
What is important to note about normal equine respiration?
there is a small abdominal component during expiration (active phase)
- however, a continuously pumping chest shows increased effort
What is dyspnea? Tachypnea? Hyperpnea? Apnea? Hyper/hypoventilation?
DYSPNEA = difficulty breathing
TACHYPNEA = rapid, shallow breathing
HYPERPNEA = increased frequency and depth of breathing
APNEA = no discernable breathing
HYPER/HYPOVENTILATION = alveolar ventilation (PaCO2)
What are the 2 major indications for respiratory endoscopy? How do horses typically react?
- visualization of internal anatomical strucures (see discharge or inflammation)
- determine additional exams
tend to be insensitive to scopes in trachea —> hyperresponsiveness is typically pathological
What does mucus in the trachea typically indicate?
non-specific sign of inflammation
What does blood in the trachea typically indicate?
sign of recent hemorrhage, especially when properly times after exercise (30-120 mins post, exercise-induced pulmonary hemorrhage)
How should the bronchial septum look in a healthy horse? What 3 things can change its appearance?
should be very thin
- age
- inflammation
- edema
What are 4 reasons that pulmonary radiographs are especially difficult in horses?
- only laterals are possible in adults
- four films are required to cover lung fields
- equipment is especially expensive
- chest movement restricts techniques
What are 3 indications for pulmonary radiographs?
- infectious/non-infectious lower respiratory disease
- pneumothorax
- diaphragmatic hernias
How are ultrasounds used for respiratory disease diagnosis in equine medicine?
can only observe surface of parenchyma, but are able to see fluid accumulation
- pleural effusion!
