Cough/ Nasal discharge Flashcards
What is the physiology of cough?
Cough reflex removes secretions from the tracheobronchial tree promise to the level of the segmental bronchi
Mucociliary escalator => Continuous waves of ciliary motion that start at the level of the bronchioles
What is the neural pathway initiating cough?
Involuntary reflex - involve sensory receptor through tracheobronchial tree —> predominantly vagal nerve
Voluntary
T/F: irritants can trigger both bronchoconstriction and cough and bronchoconstriction is a constant component of cough
True
Both work through separate reflexes though
What can stimulate a cough?
Bronchoconstriction
Excessive mucous production
Deposition of inhaled particles
Release of inflammatory mediator (infectious disease)
Exposure to hot or cold air
Intramural or extramural pressure (tumor, fibrosis, pleural effusion)
Sloughing of airway epithelium (eg smoke inhalation)
Enhanced epithelial permeability
The mucociliary mechanism is made up of a pseudostratified columnar epithelium, how long does this take to regenerate when damaged? How does this relate to resolution of clinical signs?
7weeks
If clinical signs do not resolve right away it could be because of the time it takes to regenerate
ESP with viral conditions —> kills epithelium
What cells secrete surfactant like substances that aids in maintaining patency of airway?
Clara cells
Metabolize airbone toxins
What do premature foals lack that can cause them to suffer from pleuropneumonia ?
Clara cells
Lack of surfactant keeps the airway open
Decreased mucociliary clearance can be caused by?
Decreased cell number Mucous plug Dehydration Irritant gases Dust Cold weather Anesthetic
What will you do as part of your PE on a coughing animal?
Auscultation HR
Increase HR, RR, RE and fever
Nasal discharge
- mucopurulent
- anaerobic bacteria: associated with foul smell
Palpate the thoracic wall
- pleura friction rubs
- fractured ribs
Rebreathing exam
- inhalation of expired CO2
- Eupnea and hyperpnea
When listening to lung sounds, increased lung sounds with crackles and wheezes indicate?
Pneumonia
On auscultation of the lungs, a ventral dull sounds may indicate??
Pleuropneumonia
What is the DDX for cough with fever?
Infectious
Secondary to non-infectious condition
What is the DDX for coughing with no fever?
RAO Larynx or pharyngeal abnormality Parasitic EIPH Foreign body Neoplasia Trauma
What is the peracute clinical manifestation of pleuropneumonia?
Fever Depression Anorexia Pleuodynia : smiler signs to colic (abducted elbow, laminitic, weight losss) Cough may not be present Lung sounds may be normla
Hyperpnea Weight loss (catabolic, decreased appetite)
What are the viral respiratory diseases that can cause a pneumonia?
Equine influenza Equine herpes 1 and 4 Equine viralarteritits Equine adenovirus Equine rhinovirus Hendra virus
A young horse with high fever, cough, and lameness. You ruled out laminitis with hoof testers..
What is your DDX
Both
Equine influenza and equine herpes virus cause respiratory problems and a polysynovitis
EHV can also have conjunctivitis, lymphadenopathy, edema, and vasculitis
What systems do EHV1 and EHV4 affect?
EHV1: respiratory and neurologic
EHV4: respiratory and reproductive
What virus causes respiratory disease, abortions and foal pneumonia but most infections are Subclinical
Equine viral arteritis
Who is most likely to be infected with equine adenovirus
Immunopcompromised foals (SCID)
It is late winter-early spring, and a young horse presents with nasal discharge, laryngitis, and mild bronchitis..
What would be you top ddx?
Equine rhinovirus
What viral disease causes febrile illness, facial swelling, head pressing, and recumbency and can also be zoonotic
Hendra virus
What are the aerobic bacteria that can cause a pneumonia?
Strep zooepidemicus Staph aureus Actinobacillus equuli Pasturella E. Coli Klebsiella pneumoniae Pseudomonas Rhodococcus equi
What are the anaerobic bacteria that can cause pneumonia ?
Bacteroides fragilis
-common in horses with physiologic stress, including transportation, exercise, and viral infection
Parasitic infection of horses lungs?
Dictylocaulus arnfildi (lung worm )
Parascaric equorum (roundworm) — migrate through lung during PPP
In what environment are you more likely to see a primary fungal pneumonia?
Dry and dusty
Stress is a major contributor for bacterial pneumonia/pleuropneumonia.. what are some stressors in a horse?
Transportation — head elevated can compromise mucociliary clearance/ dehydration can decrease secretions
Exercise —increase in peripheral neutrophil function and oxidative burst of alveolar macrophages
Anesthesia — cuff pressure to high (tracheal necrosis, dorsal recumbency cause atelectasis , anesthetics cause depression of resp defense mechanisms