Respiratory Disease & Treatment Flashcards
When considering a horse may have a respiratory illness what are some relevant questions to ask the owner?
• How long have the symptoms been present?
• Are the symptoms getting worse?
• Has the horse been exposed to another, diseased horse?
• Has the horse been vaccinated? What vaccines has it had?
• Where is the horse housed? What conditions is it housed in?
• Is there a seasonal component to the symptoms?
What would a physical exam of a horse, searching for signs of respiratory illness, involve?
• Assessing breath rate / rhythm
• Ausculation, listening for wheezing, crackles, or clear breath sounds
• Bagging the horse to encourage taking deep breaths
• Looking for nasal discharge
• Palpating the lymph nodes
• Endoscopy (especially to examine the larynx) or Remote Dynamic Endoscopy
• Treadmill testing
•Taking samples of fluid from the trachea or lower airway
• Radiographs
• Ultrasound
What are the three most common methods of collecting fluid samples from a horses trachea or lower airways?
• Transtracheal Aspiration
• Endoscopic Collection
• Bronchoalveolar Lavage
What are the two possible types of gutteral pouch infections?
• Bacterial: Gutteral Pouch Empymia
• Fungal: Gutteral Pouch Mycosis
How is Gutteral Pouch Empymia/Mycosis diagnosed?
•Looking for one-sided nasal discharge
•Radiographs of the skull
•Endoscopic examination of the gutteral pouch
How is Gutteral Pouch Empymia treated?
•Flushing with saline & antimicrobials
•Systemic antimicrobials
•Surgery
How is Gutteral Pouch Mycosis treated? Why is it difficult to treat?
•Surgery to tie off the carotid artery
•Plaques may form and erode the carotid artery, leading to a fatal hemorrhage
How serious is Gutteral Pouch Empymia? What complications can occur?
•Difficult and expensive to treat, but can be successfully resolved
•Long term infection can lead to chondroids, thickened or congealed (inspissated) pus
How serious is Gutteral Pouch Mycosis? What complications can occur?
•Very serious, often untreatable and potentially fatal
•Fatal hemorrhaging of the carotid artery
What is Laryngeal Hemiplagia (Roaring)? Is there a known cause?
•Paralysis of the Recurrent Laryngeal Nerve leading to the obstruction of airflow by the Arytenoid Cartilages (usually on the left side).
•The cause is unknown, but larger horses seem to be at risk
How is Laryngeal Hemiplagia diagnosed?
•Listening for “roaring”, the sound of laboured breathing due to the obstruction of the horse’s airway
•Endoscopy
How is Laryngeal Hemiplagia treated?
○Surgery
*Placing large sutures to hold the paralyzed arytenoid cartilage back
*Possibly accompanied by ventriculostomy to scar down
*Arytenoidectomy if it is severe
How serious is Laryngeal Hemiplagia? What complications can occur?
•Mild, sometimes treatment is unnecessary
•May increase risk of Exercise-Induced Pulmonary Hemorrhage
What is Dorsal Displacement of the Soft Palate (DDSP)? What may happen if this occurs during high intensity exercise?
•A condition where the soft palate is displaced dorsally over the top of the epiglottis, interfering with it’s function
•Horse will exhibit exercise intolerance and abnormal breathing sounds
How is Dorsal Displacement of the Soft Palate (DDSP) diagnosed?
•Endoscopy
•Excercise to confirm because intermittent DDSP is normal
How is Dorsal Displacement of the Soft Palate (DDSP) treated?
Treatments:
•Tongue tying
•Anti-inflammatories
○Surgery
•Sternothyrohyodeus Myectomy (controls larynx movement)
•Staphylectomy (removing the soft palate)
•Injecting the epiglottis with Teflon
How serious is Dorsal Displacement of the Soft Palate? What complications can occur?
*DDSP may occur intermittently; this is normal. It becomes a problem if it occurs during high-intensity exercise.
*Pneumonia
What is Chronic Obstructive Pulmonary Disease (COPD)? What else is this disease called? How common is it?
○Inflammation of the airways resulting in:
•Thickened airway walls
•Bronchospasms
•Discharge of mucous and inflammatory cells
•Increased difficulty exhaling
○Also called Heaves or Reactive Airway Disease
○This is the most common airway disease among horses
What causes Chronic Obstructive Pulmonary Disease (COPD?)
*Allergies
*Exposure to dust, mould, or other airway irritants causing chronic inflammation. More likely if a horse lives in a stable.
*Viral respiratory illness when young
How is Chronic Obstructive Pulmonary Disease (COPD) diagnosed?
○Clinical Signs
*Mild exercise intolerance
* Laboured breathing
*Chronic cough
*Persistent nasal discharge
*Heave line
*Seasonal allergies: Dust sensitivity (summer). Mould sensitivity (winter)
○Wheezing on auscultation
○Endoscopy with sample collection
○Bronchoalveolar Lavage
○Allergy testing
How is CHronic Obstructive Pulmonary Disease (COPD) treated?
*Environmental management, reduction of exposure to respiratory irritants
*Bronchodilators (clenbuterol)
*Corticosteroids (isoflupredone)
*Expectorants
*Inhaler medications (bronchodilators/corticosteroids)
*Allergy shots (antihistamines)
How serious is Chronic Obstructive Pulmonary Disease (COPD)? What complications can occur?
*Debilitating disease
*Increased risk of infection, pneumonia, and pleuropneumonia
*Allergies
What is Exercise-Induced Pulmonary Hemorrhage (EIPH)? What are the affected horses sometimes called?
*When a horse bleeds from its lungs following hard exercise
*Affects race horses and jumpers, sometimes called bleeders
What causes Exercise-Induced Pulmonary Hemorrhage (EIPH)?
*Exact cause is unknown
*May be caused by increased capillary pressure in the lungs due to the increased demand on the heart during exercise
How is Exercise-Induced Pulmonary Hemorrhage (EIPH) diagnosed?
*Endoscopy: blood will be visible in the airway for several hours following exercise
How is Exercise-Induced Pulmonary Hemorrhage (EIPH) treated?
*Diuretics (furosemide): not completely effective (~50%) and controversial because of its performance-enhancing effects
*Reduce feed and water on race day
How serious is Exercise-Induced Pulmonary Hemorrhage (EIPH)? What complications can occur?
*May cause a decline in performance
*Manageable but not curable
*Increased risk of infection and airway irritation (higher susceptibility to pneumonia/pleuropneumonia)
What is Strangles?
*Equine Distemper
*A bacterial infection of the upper respiratory tract caused by streptococcus equi
*Highly contagious through direct contact or fomites
What is “Distemper”? What is Catarrh?
*A viral disease causing fever, coughing and catarrh
*Mucous
What is a fomite?
A non-living object capable of carrying an infectious organism
How is Strangles diagnosed?
○Clinical Signs
*Fever (39.4 ̊C-41.1 ̊C)
*Serous nasal discharge, then mucopurulent nasal discharge
*Cough
*Enlarged lymph nodes (may abscess and drain)
*Occasionally depression & anorexia
○Culture of abscess material
○Pharyngeal wash
How is Strangles treated?
In the case of an outbreak:
*Monitor temperatures
If the horse is febrile:
*Antimicrobials (penicillin)
*Lancing and flushing with antiseptic solution infused with antimicrobials (if fever persists after draining)
If the horse is NOT febrile:
*Encourage drainage with hot backs and poultices
*Lancing then flushing with antiseptic solution
*Antimicrobials not used as long as the horse is bright and eating/drinking
How serious is Strangles? What happens if there is an Outbreak? What are the three major complications?
How Serious?:
*Strangles will usually resolve without complications, but it is highly contagious and difficult to contain
Outbreaks:
*Bacteria can live on surfaces for months
*Horses must be isolated
*Isolation protocols, disinfectants, and antiseptics must be used
*Horses are infectious for six weeks following recovery. To prove a horse is recovered, three pharyngeal washes must be performed (culture & PCR)
Complications:
*Metastatic abscesses (bastard strangles)
*Purpura hemorrhagica
*Carrier state
What are Metastatic Abscesses (Bastard Strangles)? Why are they a concern?
*Abscesses that change in size or form
*Any abscessed lymph node could rupture internally
What is Purpura Hemorrhagica? Why is it a concern?
*A rash of purple spots caused by internal bleeding
*It is a severe autoimmune reaction that leads to antibody-antigen complexes depositing in the basement membrane of blood vessels
*Leads to leaky blood vessels
What are the clinical signs of Purpra Hemorrhagica?
*Edema
*Swelling of the legs, skin, and internal organs
*Large areas of sloughed skin
*Organ Failure
*Death
*Petechial or ecchymotic hemorrhages on mucous membranes
What is a chronic carrier? What makes them a concern?
*A horse that is a perpetual host of streptococcus equi
*Risk of guttural pouch infection
*May cause outbreaks
*Pharyngeal washes must be screened (time-consuming and expensive)
What is influenza?
*A zoonotic viral respiratory infection commonly affecting young horses
*Incubation period of 1-3 days
*Spread via aerosol
*Risk of severe outbreaks
How is Influenza diagnosed?
○Clinical Signs
*Fever
*Severe, deep, repetitive cough (caused by damage to the respiratory tract)
○Blood work
○Nasal swab (isolation of the virus is difficult)
○Antibody levels at the time of illness and three weeks later
How is influenza treated?
*The horse is likely already recovering once it is diagnosed
*Rest in a well-ventilated area (one week of rest for every day or fever)
*NSAIDs
*Managing any secondary bacterial infections
How serious is Influenza? What complications can occur?
*It is the most serious respiratory issue
*May require up to three months of rest
*Spreads rapidly
*Risk of secondary bacterial infections *Predisposes young horses to Chronic Obstructive Pulmonary Disease (COPD)
What is Rhinopneumonitis? What are the two serotypes?
*A respiratory disease caused by a herpes virus. Passed in nasal discharges for 3 weeks following infection, and has a 2-10 day incubation period. Symptoms are not as severe as influenza.
Serotypes:
*EHV-1: affects the vascular endothelium (especially the nasal mucosa, lungs, placenta, adrenal, thyroid, and CNS)
*EHV-4: primarily affects the respiratory tract and lymph nodes
*most commonly affects horses between four and eight months old
How is Rhinopneumonitis diagnosed? Why might there not be an attempt made to diagnose it?
In most cases no attempt will be made to diagnose because the disease is mild and most horses recover with no complications
○Clinical Signs
*Fever
*Nasal discharge
*Cough
○Virus isolation
○Antibodies
How is Rhinopneumonitis treated?
*Rest in a well ventilated area
*NSAIDs
How serious is Rhinopneumonitis? What complications could occur?
*Generally mild and self-limiting
*Vaccination can help prevent it
*Abortion in pregnant mares
*Secondary bacterial infections
