Equine Respiratory Flashcards
1
Q
How is strangles spread?
A
- Spread by contact with nasal secretions (direct contact, snorting, coughing) or discharges, such as from draining abscesses.
- Spread indirectly through contaminated hands, clothing, equipment, water or feed sources.
2
Q
Where does strangles colonise?
A
Colonises nasopharyngeal mucosa and purulent nasal discharge.
3
Q
What is the pathophysiology of strangles?
A
- Infection spread via lymphatics to lymph nodes, causing LNs to enlarge
- Abscesses within LNs can rupture and drain to the surface as purulent discharge
4
Q
What can occur in sequalae to strangles?
A
- Can cause guttural pouch empyema
- Spread of bacteria to other sites – organs/LNs
- Purpura haemorrhagica – immune complex deposition causing vasculitis causing oedema and haemorrhages
5
Q
Why may there be haemorrhage from the guttural pouch?
A
Vascular structures adjacent to the guttural pouch. Infection may cause loss of integrity of blood vessel walls causing haemorrhage.
6
Q
What is the pathogenesis of progressive ethmoid haematoma in horses?
A
- Proliferative but non-neoplastic
- Presents as an enlarging haemorrhagic nasal mass that can cause obstruction of the nasal passages
- May cause local distortion and destruction of the soft tissues and bone, ulceration of the mucosa encapsulating the mass may result in mild haemorrhage and epistaxis
7
Q
What is the pathophysiology of paranasal sinus cysts in horses?
A
Fluid filled cyst with a thin wall of bone lined by respiratory epithelium. Causes airway obstruction, facial distortion and compression of surrounding soft tissues and bone.
8
Q
What are the clinical signs of paranasal sinus cysts in horses?
A
Facial swelling
Epiphora
9
Q
How is equine asthma managed?
A
- Management changes are most important to reduce exposure to organic dusts and mould
- Bronchodilators
- Corticosteroids - side effects laminitis
- Mucolytics – bromhexine
10
Q
What are the respiratory techniques in order to assess the equine upper respiratory tract?
A
Endoscopy
Endoscopy during exercise
Nasopharyngeal swabs/guttural pouch lavage
Radiography
Computed Tomography
Ultrasonography
11
Q
Where should endoscope and stomach tube be passed in horses?
A
Via the ventral meatus – largest opening, least likely to cause nosebleed
12
Q
How are the nasal passages of a horse endoscoped?
A
- Steer tip slightly down/use your thumb to push the endoscope medially and ventrally as you pass it
- If pass up middle meatus, may hit ethmoid turbinates and give horse a nosebleed
13
Q
How is the nasopharynx of a horse endoscoped?
A
- The dorsal pharyngeal recess can be seen
- The guttural pouch ostia are visible dorsolaterally on the pharyngeal walls
14
Q
How is the guttural pouch of a horse endoscoped?
A
- Entrance to the guttural pouch from slit like ostia in nasopharynx
- Pass guidewire down biopsy channel of endoscope
- Pass this through guttural pouch ostia
- Rotate the endoscope, then pass endoscope into the guttural pouch
15
Q
When is guttural pouch lavage indicated?
A
If empyema or to detect strep equi equi/strangles
16
Q
How is a nasopharyngeal swab done in a horse?
A
- Pass long nasopharyngeal swabs via the ventral meatus into the nasopharynx and stimulate the horse to swallow
- This encourages the release of any discharge from the guttural pouches
17
Q
What comprises the nasopharynx?
A
Dorsal pharyngeal wall, lateral pharyngeal walls and the soft palate ventrally. The soft palate in the floor of nasopharynx
18
Q
Describe the equine soft palate.
A
- The equine soft palate is longer than in other species – extending up to the larynx
- The soft palate sits underneath the epiglottis
19
Q
Why is the horse an obligate nasal breather?
A
Larynx positioned through the ostium intrapharyngium like button through a button hole
20
Q
What is the advantage of endoscopy of a horse during exercise?
A
More accurate than endoscopy at rest
21
Q
What are equine laryngeal ultrasounds useful for?
A
To assess laryngeal cartilages and the echogenicity of muscle
22
Q
Why is sinus trephination done in equine?
A
- For sinoscopy which allows direct visualisation of the sinus structures/pathology
- For placement of a foley catheter in order to lavage the sinuses if sinusitis is present
23
Q
What does lateral view of an equine head radiograph allow?
A
Permits evaluation of the air filled paranasal sinuses and the nasal passages. Dental arcades are superimposed on this view
24
Q
What does dorsoventral view of an equine head radiograph allow?
A
The view permits comparison of one side of the head with the other
25
What does oblique view of an equine head radiograph allow?
Evaluation of teeth roots since they are projected free of other bony or dental structures
26
What are the techniques used to assess the equine lower respiratory tract?
Endoscopy
Tracheal wash/bronchoalveolar lavage
Radiography
Ultrasound
Lung biopsy/thoracocentesis
27
How are the equine lower airways endoscoped?
- Passing endoscope/tube into tracheal tract – extend hands
- Passing the endoscope/tube into the oesophagus – flex the head and pass on when the horse swallows
28
Why is tracheal endoscopy done in horses?
Primarily to look for mucus and blood
29
What is BAL used to sample?
- Bronchoalveolar lavage (BAL) at the level of the lungs
- Samples a specific peripheral lung segment only
30
What is BAL correlated with?
Tracheal washes and BAL not always well correlated
BAL correlates better with pulmonary histopathology
31
What must be ensured when doing an equine tracheal wash?
Don’t let the horse put its head down
32
When is BAL not performed?
While horse acutely dyspnoeic
33
Why is thoracocentesis done?
- To obtain a sample for cytology
- To drain pleural fluid and improve ventilation
34
When are lung biopsies done?
- If indicated by thoracic ultrasound/radiographs
- Complications
- A final effort to obtain a diagnosis/prognosis
35
What is the clinical presentations of nasal, sinus and guttural pouch disorders in horses?
- Nasal discharge
- Head swelling/abnormality
- Reduced airflow
- Abnormal respiratory noise
- Dysphagia
36
What are the types of nasal discharge in horses?
Serous
Mucoid
Purulent
Haemorrhagic
Feed contaminated
37
Where does nasal discharge originate in horses?
If bilateral, it most likely originates caudal to the nasal septum. The origin of the discharge can be from anywhere in the respiratory tract.
38
List the disorders of the equine nasal passages.
Ethmoid haematoma
Primary sinusitis
Secondary sinusitis
Sinus cysts
Sinonasal neoplasia
Head trauma
Guttural pouch empyema (chondroids)
Guttural pouch mycosis
Guttural pouch tympany
39
What is ethmoid haematoma in horses?
- Unknown aetiology
- Any age
- Benign polypoid soft tissue mass that grows from ethmoids
40
What are the clinical signs of ethmoid haematoma in horses?
- Unilateral epistaxis that is intermittent and low volume
- Can be fresh tickle or blood or dirty/old blood
41
What is the treatment for ethmoid haematoma?
Resection or repeated injection with formalin
42
Describe the structure of the paranasal sinuses of a horse.
- Between dorsal conchal sinus and frontal sinus
- Between ventral conchal sinus and rostral maxillary sinus
- Between caudal maxillary sinus and spheopalatine sinus
- Between frontal sinus and caudal maxillary sinus
43
What lies in the rostral maxillary sinus of a horse?
The reverse crowns of the maxillary 3rd and 4th teeth triadan 08/09
44
What lies in the caudal maxillary sinus of a horse?
The reserve crowns of the maxillary 5th and 6th teeth triadan 10/11
45
How does the size of the maxillary sinus of a horse change?
The size of the maxillary sinuses increases with age as the cheek teeth shorten due to wear
46
What is a common feature of primary and secondary sinusitis in horses?
Accumulation of exudate within sinus and ipsilateral nasal discharge
47
Distinguish primary and secondary sinusitis in horses.
Primary - following URT infections
Secondary - dental infections, intrasinus benign and malignant growths and head trauma
48
What is the clinical signs of sinusitis in horses?
Purulent nasal discharge
Smell of discharge/malodorous – dental or fungal
Ipsilateral submandibular lymphadenopathy
49
How does primary sinusitis arise in horses?
From obstruction of mucociliary clearance and inoculation with bacteria
50
What happens in acute primary sinusitis in horses?
Follows an upper respiratory tract infection, self-limiting or responds to antimicrobials
51
What happens in chronic primary sinusitis in horses?
Thickening of sinus mucosa from inflammation, leads to obstruction of mucus drainage, inspissation occurs
52
How is primary sinusitis treated in horses?
- Short course of antimicrobials
- Feed from the ground to facilitate drainage
- 2 courses of antibiotics of <2 weeks
- More than 2 weeks, reassessing why such cases are non-responsive
53
What is the pathophysiology leading to chronic/permanent primary sinusitis in horses?
- Arise if inflammation remains in 1 or more compartments
- Due to restricted drainage caused by mucosal deciliation and/or mucosal thickening of the ostium and in the longer term
- Due to inspissation of pus
54
What happen in dental secondary sinusitis in horses?
Arises from inoculation of maxillary sinuses with bacteria from dental pulpitis affecting caudal maxillary teeth – usually 08s-11s
55
What is the clinical signs of dental secondary sinusitis in horses?
Bacteria are often anaerobic resulting in malodourous discharge
56
How is dental secondary sinusitis treated in horses?
- Dental extraction
- Irrigation of exudates from contaminated compartments
- Sealing of oral cavity from alveolus while mucosa granulates
57
How is chronic sinusitis in horses treated?
- Warm isotonic saline best
- Anti-inflammatories as causes irritation
- Careful diagnostic imaging to reveal inspissated material
- Mechanical debridement essential followed by lots of lavage
58
What are sinus cysts in horses?
- Expansile, produce mucus and distort surrounding bone
- Usually unilateral
59
What are the clinical signs of sinus cysts in horses?
Head swelling
Nasal occlusion
60
How are equine sinus cysts treated?
Surgical exposure via a nasofrontal flap or trephine and resection of cyst lining
Aims are to remove physical lesions, remove solid exudates and restore nasomaxillary drainage
61
How are sinonasal neoplasias in horses presented?
- Older horses
- Present as chronic sinusitis
- Associated with facial swellings
62
What can happen to the equine sinuses in head traumas?
- Bleeding from the conchal venous plexus
- Associated with head fracture – palpation and ultrasound better than radiographs
- Can develop secondary sinusitis from presence of blood in sinuses
63
What is guttural pouch empyema?
- Retropharyngeal lymph node abscesses burst dorsally and purulent exudate sits in guttural pouch
- Strep equi equi or strep zooepidemicus
64
What is the result of chronic exudate in guttural pouch empyema?
- Results in solid chondroid formation
- The inspissated exudates act as a reservoir for infection of other horses with strep equi
65
What are the clinical signs of guttural pouch empyema?
Purulent nasal discharge and pyrexia
66
How is guttural pouch empyema treated?
Lavage and drainage
67
What is the presentation of guttural pouch mycosis?
- Epistaxis – fatal if untreated, fungal plaque on internal carotid artery, external maxillary or external carotid
- Dysphagia and so cough due to food aspiration
- Fungal plaque on nerves
- Vascular occlusion on the cardiac and cerebral side of the lesion
68
How is guttural pouch mycosis treated?
Topical treatment with antifungal agent
69
What is the prognosis of guttural pouch mycosis?
Good if no pharyngeal dysphagia, no bilateral laryngeal paralysis, limited haemorrhage.
Guarded if severe haemorrhage or severe neurological dysfunction
70
What are the breed predispositions to guttural pouch tympany?
Arab foals
71
What is guttural pouch tympany?
- Congenital dysfunction of ostia
- Unilateral more common
- Pharyngeal swelling
- Dysphagia
72
How is guttural pouch tympany treated?
Indwelling foley catheter or laser fenestration to allow air to escape
73
What are the clinical signs of infectious respiratory diseases in horses?
Nasal discharge
Cough
Pyrexia
Lymphadenopathy
Tachypnoea
Inappetence
Depression
74
What are the clinical signs of infectious respiratory diseases in athletic horses?
Fatigue
Exercise intolerance
Poor performance
Prolonged recovery
75
What are the aspects of infectious respiratory diseases that differentiate them from non-infectious diseases?
- Pyrexia
- High white blood cells/fibrinogen
- Lymphadenopathy
- Multiple horses affected
76
Does a fever indicate infectious equine respiratory disease?
Fever presenting alone should be considered as possible infectious respiratory disease. Absence of fever in the presence of respiratory clinical signs does not definitively rule out infectious respiratory disease.
77
When it is essential to identify the pathogen involved in equine infectious disease?
In outbreaks of respiratory disease or cases where respiratory disease is associated with abortion
78
What are the diagnostic tests to investigate infectious equine respiratory disease?
- Paired samples - taken 10 – 21days apart, to confirm a rising antibody titre
- Nasal swab
- Nasopharyngeal swab
- Guttural pouch lavage
79
How is the causal viral agent of infectious equine respiratory disease identified?
- Virus isolation
- Immunoassay (ELISA, IF) detects viral protein
- PCR detects viral nucleic acid
- Detection of antibodies
80
How is the causal bacterial agent of infectious equine respiratory disease identified?
- Bacterial culture - enables antibiotic sensitivity
- PCR testing available for Strep. equi and Strep. zoooepidemicus
- ELISA
81
What is the incubation period of equine influenza virus?
1-3 days
82
How is equine influenza virus spread?
Inhalation – influenza spreads effectively as an aerosol over distances of 50 yards
83
Where is equine influenza virus located in the body and this effect?
Virus replicates in URT and LRT – damages respiratory epithelium
84
What are the clinical signs of equine influenza virus?
Pyrexia
Dry cough
Nasal discharge
Submandibular lymphadenopathy
Inappetence
Depression
85
Describe the severity of clinical signs of equine influenza virus.
- Clinical signs usually subside within a few days – unless secondary bacterial infection
- Clinical signs more severe in unvaccinated horses
86
How is equine influenza virus diagnosed?
- Clinical signs
- Virus detection (PCR on nasopharyngeal swab)
- Serology
87
Distinguish the best times to take a nasopharyngeal swab for PCR and for serology.
Best time to swab is during active clinical signs.
With serology, antibody count won’t rise until after clinical signs so must wait for 2nd sample
88
How is equine influenza virus treated?
- Rest
- Clean air
- NSAIDs
- 1 week rest for every 1-day of pyrexia – allow respiratory epithelium to heal
- Antibiotics only required if secondary bacterial infection
89
How is equine influenza virus prevented?
Biosecurity and vaccination
90
What is the epidemiology of equine influenza virus in uncomplicated infection?
Most horses stop shedding virus within about 10 days after initial uncomplicated infection
91
What is the signalment of equine herpesvirus?
Especially young horses
Milder respiratory symptoms in older horses
92
Which strains are responsible for equine herpes virus?
EHV 1 and EHV 4 most common
- EHV 4 – respiratory disease
- EHV 1 – more commonly associated with neurologic disease and abortion, less commonly with respiratory disease
93
What is the epidemiology of equine herpesvirus?
- Infection by inhalation
- Incubation period variable
- Immunity short lived
- Lifelong carrier state is possible
- EHV-4 restricted to URT
- EHV-1 access to other body systems
94
How is equine herpesvirus persistent in the population?
Carriers – periodic reactivation and shedding of virus due to stress
95
What are the clinical signs of equine herpes virus 1 and 4?
Mild pyrexia
Occasional cough
Nasal discharge
May have submandibular lymphadenopathy
Depression
Inappetence
96
Where else can equine herpes virus 1 infect?
Foetus = abortion
Brain and spinal cord = paralysis
97
How is equine herpes virus diagnosed?
- Clinical signs
- Haematology - lymphopenia/neutropenia
- Virus isolation – nasal or nasopharyngeal swab or heparinised blood
- Serology
- Virus detection (PCR) on nasal swab or aborted foetus material and from fatal neurological cases
98
How is equine herpes virus treated?
- No specific treatment
- Rest
- NSAIDS
- Antibiotics if secondary bacterial infection
- Palatable feed
99
How is equine herpes virus prevented?
- Control difficult due to carriers
- Isolate incoming horses to a yard for 21 days
- Vaccination - to reduce shedding
100
How is equine herpes virus vaccinated against?
2 vaccinations 1 month apart. Regular booster every 6 months. In-foal mares should be vaccinated at 5,7 and 9 months of pregnancy.
101
What is the signalment of strangles?
Any age but younger horses often have more severe clinical signs
102
What is the incubation period of strangles?
7-14 days
103
How is strangles spread?
Nasal or oral infection. Organism multiplies in URT lymph nodes. Haematogenous or lymphatic spread can lead to infection in remote lymph nodes and other tissues. Persistence in guttural pouches of organisms.
104
What are the clinical signs of strangles?
Depression
Inappetance
Pyrexia
Purulent nasal discharge
Lymphadenopathy with/without abscessation
Painful swallowing with head outstretched
Cough
Severe lymphadenopathy >dyspnoea or dysphagia
105
What are the 2 possible complications of strangles?
Guttural pouch empyema
Guttural pouch chondroids
106
What are the possible rare complications of strangles?
- Bastard strangles – associated with lymphatic or haematogenous spread
- Immune mediated myopathies – rhabdomyolysis/atrophy
- Purpura haemorrhagica – immune mediated vasculitis
107
How is acute infection of strangles diagnosed?
- Haematology - leucocytosis, neutrophilia, hyperfibrinogenaemia)
- Culture/PCR from abscess swab
- PCR far more sensitive
- ELISA
108
How are carriers diagnosed and acutely?
- Perform approximately 4 weeks after end of clinical signs
- 3 sequential nasopharyngeal swabs 5-7 days apart - culture and PCR)
- Guttural pouch lavage (culture and PCR)
- Presence of antibodies on ELISA blood test
109
How is strangles treated?
- Isolate
- Strict hygiene
- Enhance maturation of abscesses by applying hot packs. When ruptured flush regularly
- NSAIDs
- Soft palatable food
- Convalesce 4-6 weeks
110
When are antibiotics used to treat strangles?
Antibiotics can prolong the disease
- Critical cases with life-threatening airway obstruction
- Cases of purpura haemorrhagica
- Treatment of internal/disseminated abscesses in cases of bastard strangles
- Adjunctive treatment for guttural pouch empyema
- Treatment of chronic carriers
111
How is guttural pouch empyema caused by strangled treated/
- Cornerstones to therapy are lavage and drainage twice daily for 7-10 days
- Chondroids can be removed using a transendoscopic basket
112
What is the effect of strangles vaccines?
Immunity fairly short lived, but shown to reduce clinical signs and abscesses
113
What are some possible practices for preventing infectious respiratory disease?
- Quarantine period for any new horses
- Test for carrier status
- Monitor for evidence of disease
- Hygiene practices
- Optimise nutrition, provide access to clean fresh water, clean dust free stable environment, minimise stress
- Vaccination program
114
What are the objectives in controlling an outbreak of infectious equine respiratory disease?
- Prevent spread of infection to new premises
- Prevent infection of new arrivals to infected premises
- Control of the outbreak within the infected premises
- Ensure all horses are free of infection at the end of an outbreak
115
What are the actions to control an outbreak of infectious equine respiratory disease?
- Isolation
- Hygiene
- Keep youngstock away from broodmares
- Movement of horses on and off premises stopped
- Fly control
116
What is tracheal endoscopy, tracheal wash and bronchoalevolar lavage used to assess in horses?
- Mucus
- Blood
- Sensitivity of trachea – how much they cough during a procedure
- Structural abnormalities
- Foreign body
- Thickening of the carina
- Blunting of the carina – oedema and remodelling
- Mucus accumulation occurs with an imbalance of secretion and clearance
117
What is the severity of equine respiratory disease based on?
Based on the proportions of inflammatory cells on cytology of TW and BAL samples
118
How are tracheal wash and bronchoalveolar lavage interpreted?
- Neutrophilia is most common inflammatory response in horses, irrespective of whether cause is infectious or non-infectious.
- Neutrophils <20% TW, <5-10% BAL
119
What should be taken into consideration when interpreting tracheal wash cytology?
- Normal bacterial flora of conducting airways vs true infection
- Impaired mucociliary clearance
- Contamination during procedure
120
Define equine asthma.
A lower respiratory tract disease resulting from airway inflammation and in more severe cases small airway obstruction caused by an immune-mediated hypersensitivity to inhaled particles.
121
What is the pathogenesis of equine asthma?
Airway inflammation
Airways obstruction due to:
- Bronchospasm
- Accumulation of mucus
- Changes in airway wall caused by oedema, inflammation and remodelling
122
What is the signalment of mild to moderate equine asthma?
Any age horse, high prevalence over 70%
123
What is the signalment of severe equine asthma?
Middle aged and older horses. Average onset age is 9 years old. Prevalence is 10-15%
124
What are the clinical signs of mild to moderate equine asthma?
Poor performance
Prolonged recovery from exercise
Cough
Nasal discharge
No increased respiratory effort
Not systemically ill
125
What are the clinical signs of severe equine asthma?
Coughing
Tachypnoea/dyspnoea
Exercise intolerance
Nasal discharge
Nostril flaring
Heave line
126
What are the acute signs of severe equine asthma?
- Respiratory distress at rest
- Marked dyspnoea
- Dilated nostrils
- Paroxysmal coughing
127
What are the chronic signs of severe equine asthma?
Coughing
Exercise intolerance
Increase in respiratory rate
Nasal discharge
128
How does endoscopy diagnose equine asthma?
Increased mucus within the trachea – severe asthma may have pooling
129
How does tracheal wash and bronchoalveolar lavage diagnose equine asthma?
Reveal neutrophilic inflammation. Degree of neutrophilic inflammation increases with severity of disease. Less commonly, may see mixed inflammatory response, eosinophilic inflammation or increased mast cells
130
How can severe asthma be diagnosed?
Response to bronchodilator - IV buscapan, clenbuterol or atropine
131
How is mild to moderate asthma treated?
Aim to decrease environment dust and control airway:
- Environmental management
- Corticosteroids
132
What are the advantages of treating equine asthma with inhalation and nebuliser therapy?
- High local concentration in airways
- Rapid onset of action
- Reduced total dosage
- Decreased risk of side effects
- Reduced detection time in competition horses
133
What are the disadvantages of treating equine asthma with inhalation and nebuliser therapy?
- Poor access to restricted airways
- Lack of patient compliance
134
How is acute exacerbation of severe equine asthma treated?
- Remove from stable
- Administer bronchodilator for immediate relief of airway obstruction - IV buscopan/clenbuterol/atropine
- Corticosteroid to reduce inflammation – IV dexamethasone
135
What is the most common use of buscapan?
Spasmolytic - colic treatment
136
How is chronic presentation of severe equine asthma treated?
- Environmental management
- Corticosteroids – reduce inflammation. Prevent tolerance to β2
- Bronchodilators, antibiotics, mucolytics used widely in treatment of lower airway disease
- Bronchodilators - relieve airway obstruction. Tolerance develops rapidly when used orally alone so adjunct corticosteroids
- Mucus affecting medications. Excessive mucus production will resolve with improvements in airway inflammation
137
What are the environmental management strategies of equine asthma?
- Turn out where possible
- Low-dust bedding. Turn banks everyday
- Optimising ventilation
- Remove horse from stable when mucking out/sweeping
- Thorough clean – remove all dust and cobwebs. Power-hose floor to decrease ammonia
- Soak hay
138
What is summer pasture associated obstructive pulmonary disease?
- Trigger is a pasture environment
- Aetiology likely due to hypersensitivity to environmental allergens (pollens, moulds)
- Seasonal
139
How is summer pasture association obstructive pulmonary disease treated?
As for asthma except that horse should be removed from the pasture
140
What is the pathogenesis of exercise induced pulmonary haemorrhage?
- Haemorrhage originates from the caudo-dorsal lung lobes
- Stress failure of pulmonary capillaries due to high pulmonary intracapillary pressure
- Negative inspiratory pressures within airways leads to rupture of the capillary wall
141
What are the contributing factors of exercise induced pulmonary haemorrhage?
- Possible association between lower airway inflammation and EIPH
- Upper airway obstruction to exacerbate EIPH
- Atrial fibrillation
142
What are the clinical signs of exercise induced pulmonary haemorrhage?
- Epistaxis
- Reduced exercise tolerance – probably related to the volume of haemorrhage
- Prolonged recovery post exercise
143
How is exercise induced pulmonary haemorrhage diagnosed?
- Endoscopy
- In less obvious cases RBCs haemosiderin-laden macrophages in TW and BAL
- Thoracic radiography (opacity in caudodorsal lung fields
144
How is exercise induced pulmonary haemorrhage treated?
- Eliminate any potential underlying cause
- Reduce severity of EIPH
145
What are the predisposing events for bacterial pneumonia in adult horses?
- Inhalation of feed material e.g. choke/dysphagia
- Airway foreign body
- General anaesthesia
- Stress/long distance travel (shipping fever)
- Post viral infection
- Penetrating trauma
146
What is the biggest risk factor that contributes to pleuropneumonia as a result of long distance transport?
Horse needs head down to for mucociliary clearance so in transport, head usually tied up and can’t clear mucus.
147
What are the clinical signs of bacterial pneumonia in adult horses?
Fever
Depression
Lethargy
Cough
Nasal discharge
Pleuropneumonia - infection has spread to pleural cavity = pleural effusion
Pleural pain
Endotoxaemia
Rapid shallow respiration
Lack of breath sounds ventrally
Abnormal sounds dorsally if pleural effusion
148
How is bacterial pneumonia diagnosed in horses?
- High WBC and fibrinogen
- Bacterial culture of pleural fluid and TW or BAL samples
- Thoracic ultrasound
- Thoracic radiography
- Thoracocentesis
149
How is bacterial pneumonia in horses treated?
- Broad spectrum antibiotics
- Supportive care – NSAIDs, fluid therapy, nutritional support
- Thoracocentesis and drainage
150
What happens if a horse is 1 day late for vaccination?
The whole course must be started again
151
How come we were allowed to extend vaccination when there was a vaccine shortage but now need to vaccinate every 6 months?
For every month that goes by past 6 months, the vaccine’s efficacy is reduced. Had no choice, running out of vaccines
152
What are the new vaccine regulations in January 2024?
Vaccinations that are up-to-date from January 1st 2024 and correct will not be affected, so won’t need to restart any courses.
153
What are the most common adverse reactions of equine vaccines?
Stiffness
Localised swelling
Lethargy
Pyrexia
154
How must adverse reactions to vaccination be monitored?
- Most reactions are self-limiting. Can consider NSAIDs if stiffness or pyrexia continue
- Monitor localised swelling for pain and abscess formation.
- If horse repeatedly has vaccine reaction, can try administering a different product, in case it is reaction to the carrier
155
Describe the left systolic murmurs.
Between lub and dub, LV contracting, so murmur here would be mitral regurgitation and blood goes inappropriately from LV to LA. Could also be ejection murmur, normal ejection of blood from the LA to the aorta.
156
Describe the right systolic murmurs.
Tricuspid regurgitation for blood flows inappropriately from RV to RA. Could also be VSD where blood goes from LV to RV.
157
Describe the diastolic murmurs.
Aortic regurgitation, where blood flows inappropriately from the aorta to the left ventricle, looks like a decrescendo murmur graphically. Could also be a physiological murmur which occurs in early filling and sounds like a 2 fold squeak.
158
Describe the arrythmias in horses.
Sinus arrhythmia (causing sinus tachycardia), AF, VF, AVB, idioventricular rhythm, sinus bradyarrhythmia, atrial flutter, APC (premature complex), VPC. VPC causing ventricular tachycardia or ventricular fibrillation cause death in the horse so is important to do exercising ECG.
159
How is severe aortic regurgitation in the horse characterised?
By haemodynamically arterial pulse, as you get a strong pulse initially when blood flows LV to aorta but then drops off again because there is severe regurgitation.
160
Describe cough receptors in horses.
In the horse the upper airway cough receptors are less active than in other species
161
What stimulates receptors to induce coughing?
- Bronchoconstriction
- Excessive mucus production
- Deposition of inhaled particles
- Release of inflammatory mediators
- Infectious diseases
- Intramural/extramural pressure on airways (tumour/abscess)
- Cold air
162
Describe the diagnosis of a horse with slight white bilateral nasal discharge that is most obvious after exercise, who seems well in himself with an occasional cough.
Fairly typical of mild to moderate asthma. Often cough more evident than nasal discharge in asthma. During exercise hyperpnoea tracheal mucus becomes apparent at nostrils as discharge, therefore nasal discharge exacerbated by exercise common. Common in asthma for horse to be well in self.
163
Describe the diagnosis of a horse with watery bilateral nasal discharge for a few days and now is yellowish in colour, is not eating and seems quiet.
Fairly typical of respiratory infection. Often viral infection will start as bilateral serous nasal discharge. With secondary bacterial infection then get mucoid or mucopurulent discharge. Not eating and seems quiet are typical of infection
164
Describe the diagnosis of a horse with a trickle of blood at one nostril a few days ago, who now has a stream of bright red blood coming from one nostril.
Fairly typical of GPM. Common to have smaller bleed before larger bleed. Also consider head trauma/rectus capitis rupture. If massive GPM bleed will often be bilateral epistaxis.
165
Describe the diagnosis of a horse with unilateral small amounts of bloody discharge that is rust coloured mixed with some mucus.
Fairly typical of ethmoid haematoma. With EH, blood can be fresh (red) or old (rust/brown). Typically low volume.
166
Describe the diagnosis of 2 pony yearlings just purchased from local sales, both of who have bilateral purulent discharge that is off colour.
Fairly typical of Strangles (Strep.equi) as young horses, recently brought into yard.
167
Describe the diagnosis of a horse with cream like nasal discharge from one nostril.
Unilateral therefore probably sinusitis or GPE. Consider endoscoping to see if discharge from guttural pouch ostia or sinus drainage angle.
168
Describe the diagnosis of a horse with foamy nasal discharge that is a green-brown colour with food.
Most likely choke/oesophageal obstruction. Sometimes profuse white frothy discharge - saliva - depends on how much food eaten.
169
Describe the diagnosis of a racehorse with a trickle of blood at both nostrils after racing.
Most likely EIPH, endoscope trachea to confirm pulmonary haemorrhage.
170
Describe the diagnosis of a horse that came back from jumping in Ireland last week with snotty discharge both nostrils, seems unwell, is coughing and breathing laboured.
Concerned about pleuropneumonia/shipping fever. Might just be respiratory infection
171
Describe the diagnosis of a young horse with cream coloured foul smelling discharge from 1 nostril.
Unilateral discharge so nasal passages, sinus, possibly GP. Foul smelling indicates mycotic or anaerobic. Dental sinusitis would be most common. GPM less likely to result in foul smelling discharge than dental/mycotic sinusitis.
172
Why is routine endoscopy carried out in racehorses?
- Usually post training
- Usually un-sedated
- Check upper airway and laryngeal function
- Check trachea for mucus and blood
- Often done in run up to race
- Often done post-race if poor performance
173
When is tracheal wash done in racehorse practice?
Often done in run up to race and post-race if poor performance
174
What are wind ops in racehorse practice?
Fairly routine use. Need to be declared to BHA
175
Name 3 wind ops in racehorse practice and describe their premises.
Soft palate cautery – stiffen soft palate
Hobday – to remove ventricle/vocal cord
Laryngeal tie forward – dorsal and rostral positioning of larynx. Recreate action of TH muscle
