The Respiratory Tract Flashcards
What are the nostrils made of
Cartilaginous rings, expanded by small muscles
What is cavallo by Pisanello
Surgically slit nostrils
What is the role of the ethmoid turbinate
Prevent dust and particles from entering the horse’s airways
At the end of nasal passage
The pair of blind sacs that arise from the tubes of the middle ear with large vessels running through it are…
Guttural pouches
What are the hypotheses on guttural pouch function?
- May influence internal carotid artery BP
- Cerebral blood cooling mechanism operating at times of physical stress/exercise (cool air and exposed artery = cool blood)
*** identify everything on pic on slide 23
DO it
How many pairs of sinuses does a horse have
Six
Why are the frontal and maxillary sinuses commonly associated with disease?
Young horses have long tooth roots which reach the maxillary sinus cavity (which open into the frontal sinuses)
If tooth is diseased, so is sinus
What is the role of the pharynx
Crossroads between the larynx and the esophagus
How does the pharynx change when the horse is eating vs breathing
Swallowing = soft palate elevates and prevents air from being drawn in through nose. Larynx (usually open) closes and forms seal over trachea, preventing food from entering/directing it towards esophagus
Breathing = soft palate lies over oral cavity (mouth). Larynx is open, sealing of the esophagus which prevents air from entering stomach
*** slide 31
Can horses breathe through their mouthes
Difficult due to epiglottis
The cartilages that help control airflow by pulling open when air is taken in are…
Arytenoid cartilages
Which one, inhaling or exhaling, is an active process?
Inhaling
Which muscle contracts to create negative pressure and draw air in
Diaphragm
What cartilage is pulled open to allow air to pass intro trachea, bronchi and bronchioles and down to the alveoli
Arytenoid cartilage
How would you go about physically examining the horse respiratory tract
Rhythm, rate, auscultation (character: clear?, wheeze?)
Bag the horse = deep breathing
Nasal discharge
Technique used to diagnose respiratory disorders…
Endoscopy (tube w camera)
Three methods used to take samples from the trachea or lower airway:
Transtracheal aspiration
Endoscopic collection of tracheal fluid
Bronchoalveolar lavage
Bacterial infection of guttural pouch is called…
Guttural pouch empyema
Fungal infection of the guttural pouch is called…
Guttural pouch mycosis
How are guttural pouch infections diagnosed
One-sided nasal discharge
Radiographs of skull
Endoscopic exam of the guttural pouch
How do you treat GP empyema?
Flush with saline + antimicrobials, administer systemic antimicrobials
Surgery
How do you treat GP mycosis
Difficult
Surgery attempting to tie off carotid artery
Complication/prognosis of GP mycosis?
Plaques of fungal growth may erode carotid artery = fatal hemorrhage
Often untreatable and fatal
Prognosis/complications of GP empyema
Difficult, can be successful
Long term infection = chondroids (pus)
Nerve paralysis leading to obstruction of airflow when horse takes a breath…
Laryngeal Hemiplegia (Roaring)
What does laryngeal hemiplegia mean
Larynx
Hemi = half
Plegia = partial paralysis
How is roaring diagnosed
Clinical signs, endoscopy of upper airway
What side does roaring affect, what happens
Left side (always), vocal cord collapses into airway
Name of the surgery that can help roaring
Tieback (holds cartilage open)
How do you treat roaring
Not always necessary
Surgery (tieback + ventriculectomy)
Complications of laryngeal hemiplegia?
May increase risk of exercise induced pulmonary hemorrhage
Condition where soft palate interferes with function of the epiglottis
Dorsal displacement of the soft palate (DDSP)
What happens during DDSP
Soft palate displaced over top of epiglottis, affecting its function
how is DDSP diagnosed
Endoscopic exam
Does DDSP occur intermittently
Yes, but if it occurs during high intensity exercise it leads to exercise intolerance
How is DDSP treated
Tongue tying tightens soft palate
Anti-inflammatories
Surgery
Is DDSP serious
Not a problem is high intensity exercise not required
Complications of DDSP?
Pneumonia
Most common lung disease of horses…
Chronic Obstructive Pulmonary Disease (COPD) / heaves
What happens during COPD
Airways inflame, leading to thicker walls, spasms of muscles, mucous discharge
Difficulty expiring = effort needed
Underlying causes of COPD?
Allergies, exposure to dust, molds, viral respiratory infection
Stabled horses
Clinical signs of COPD?
Mild exercise = laboured breathing
Chronic cough
Nasal discharge
Seasonal
Heave line
How is COPD diagnosed
Clinical signs
Wheezing on auscultation
Endoscopy + sample collection
Allergy testing
How is COPD treated
Manage environment
Bronchodilators
Open up airways, break up mucus, reduce inglammation
How serious is COPD? Complications?
Debilitating
More susceptible to infections (pneumonia)
Horses bleeding from lungs following hard exercise are referred to as bleeders and suffer from…
Exercise Induced Pulmonary Hemorrhage (EIPH)
How is EIPH diagnosed
Endoscopy (blood in airways)
How is EPIH treated
Diuretic reduces bleeding, but has performance-enhancing effects
Reduce feed/water on competition day
How serious is EIPH? Complications?
Decline in performance, manageable
Scar tissue builds up every time it occurs
More susceptible to infections / airway irritation = pneumonia
Bacterial infection of upper respiratory tract spread from horse to horse directly or by fomites
Strangles, horse distemper (viral disease - fever, coughing)
What is catarrh
Mucous
What happens during strangles
Lymph nodes become so large/inflammed = pressure leads to trouble breathing
What is a fomite
Object capable of carrying infectious organism (brushes, clothing, trailers)
What agent causes Strangles
Streptococcus equi
Clinical signs or strangles?
Fever
Serious nasal discharge -> mucopurulent discharge
Cough
Enlarged lymph nodes
How do we diagnose strangles
Fever
Abscessed lymph nodes
Culture abscess material / pharyngeal wash
How do we treat strangles
Controversial
Antimicrobials if febrile
Encourage drainage of lymph nodes (hot packs, poultices, lance/flush w antimicrobials (penicillin))
If horse is bright no antimicrobials
How serious is strangles
Usually resolves
Outbreaks can occur
Can survive in environment for months
Horse is infected for 6 weeks
How do you prove your horse is non infectious
3 pharyngeal washes cultured/PCR’d
What are the three major complications of strangles
Metastatic (change in position/form) abscesses
‘bastard strangles’
Purpura hemorrhagica (rash of purple spots)
Carrier state
What is the issue with bastard strangles?
Any lymph node could be abscessed and may rupture
What is the issue with purpura hemorrhagica
Severe autoimmune rxn leading to leaky blood vessels
Clinical signs of purpura hemorrhagica caused by strangles
Edema, swelling of legs/skin/internal organs
Petechial or ecchymotic hemorrhages on mucous membranes
Difference between petechial and ecchymotic hemorrhages
Petechiae = red/purple dots (leaking capillaries) small
Ecchymosis = occur deep within dermal layer, large
What is the issue with strangles chronic carriers?
Guttural pouch infection
Repeated outbreaks
Viral respiratory disease that commonly infects young horses and is zoonotic
Influenza
Can people get equine influenza?
No? Some people have antibodies for it but no cases of illness
How is influenza spread, what is the incubation period
Aerosol
1-3 days
What are the clinical signs of equine influenza
Fever
severe, deep, repetitive cough
How do we diagnose influenza
Fever/cough
Blood work
Nasal swab
Flu antibody levels at time of illness and three weeks later
How do we treat influenza
Management (rest, avoid stress, NSAIDS)
Is influenza serious
Most serious respiratory issue
Rapid spread
Susceptible to compliations (secondary infections, COPD)
Respiratory disease caused by herpes virus
Rhino(nose)pneumonitis(lungs)
What does rhinopneumonitis affect
Respiratory, reproductive, neurological
Two serotypes of rhinopneumonitis
EHV-1 (respi,repro,neuro)
EHV-4 (respiratory, lymph nodes)
Rhinopneumonitis is common in what age group
4-8 months
Clinical signs of rhinopneumonitis
Fever, nasal discharge, cough
How do we diagnose rhinopneumonitis
Clinical signs
Antibodies
How is rhinopneumonitis treated
Management (rest, avoid stress, NSAIDS)
How serious is rhinopneumonitis? Complications?
Mild and self limiting
Can cause abortion, secondary bacterial infections
