Respiratory Flashcards
(250 cards)
1
Q
What are some factors that the presentation of equine respiratory disease is dependent on?
A
Location, duration, severity, specific pathology, type and level of athlete
2
Q
T/F: Equine are obligate nasal breathers
A
True
3
Q
T/F: The presence of CxS at rest is a sign of a more severe involvement of disease
A
True
4
Q
What % of sport horses that have poor performance were tied with respiratory disease?
A
70%
5
Q
What anatomical structures of the respiratory system have small airways?
A
Small bronchi and bronchioles
6
Q
What is the pulmonary arterial pressure of a horse at rest?
A
25-30 mmHg
7
Q
What can the pulmonary arterial pressure get to at exercise?
A
125 mmHg
8
Q
The pulmonary system has _____ pressure, ____ volume; the bronchial system has _____ pressure, ____ volume.
A
low, high; high, low
9
Q
What is the pressure of air in the lungs at rest? exercise?
A
100 mmHg, 220 mmHg
10
Q
Why does Pa02 decrease in the face of intense exercise?
A
The increased blood flow from the work results in decreased exchange time
11
Q
How high can the negative intrathoracic pressure get with exercise?
A
-30 to -45 cm H2O
12
Q
What % total airway resistance does the upper airway account for during exercise and why?
A
80% from dynamic collapse as the airway pressure becomes more negative
13
Q
What is the normal respiratory rate at rest?
A
8-12 bpm
14
Q
If you see abdominal press, and expiratory difficulty, is this a lower or upper airway dysfunction?
A
Lower airway
15
Q
If you see the head and neck extended and an inspiratory noise, is this a lower or upper airway obstruction?
A
Upper airway obstruction
16
Q
What are some noises that you would hear from an upper respiratory issue?
A
Stridor, Roar, Snore
17
Q
How can you test for exudate in the trachea?
A
You can shake the trachea and hear a rattling noise
18
Q
What are the two abnormal lung sounds heard from auscultation?
A
Crackles and wheezes
19
Q
What would a dullness in the percussion of the thorax potentially indicate?
A
Fluid accumulation, increased tissue density
20
Q
What method is the most relevant in diagnosing upper airway diseases and involvement?
A
Endoscopy
21
Q
What method can be used to analyze both upper and lower airway dysfunction?
A
Radiographs
22
Q
What are somethings ultrasound can pick up on the thoracic cavity?
A
Masses, trauma, foreign bodies, pleural effusion, fibrosis, fluids, inflammation, pus, lung shape
23
Q
Where do you inject your tube for a transtracheal wash?
A
The bifurcation of sternothyrohyoideus muscle
24
Q
What is TTW limited to?
A
Can only see cell types but can be cultured
25
T/F: TTW is non-sterile while BAL is sterile
False
26
When would BAL be indicated to use?
Diffuse pulmonary disease
27
T/F: Lower airway disease leads to bilateral nasal discharge
True
28
Upper airway disease is almost always dealing with ________ as lower airway disease almost always deals with ________.
Inspiration; expiration
29
What are some examples of non-infectious upper airway disease?
Allergic rhinitis, DDSP, LLH
30
What are some examples of infectious upper airway disease?
Infectious sinusitis, strangles, viral respiratory disease
31
What are some examples of non-infectious lower airway disease?
Recurrent airway obstruction, smoke inhalation
32
What are some examples of infectious lower airway disease?
Pleuropneumonia, foal pneumonia
33
What are the most common causes of epistaxis in horses?
Upper: Trauma, guttural pouch mycosis, progressive ethmoid hematoma
Lower: EIPH, pulmonary abscess rupture
34
T/F: Guttural pouch mycosis is primarily seen in older quarterhorse females
False. No age, breed, or gender predilections
35
T/F: Guttural pouch mycosis formed a delayed chronic epixtaxis
False. Spontaneous, though several initial bouts of minor hemorrhage
36
How does guttural pouch mycosis lead to epixtaxis?
The fungal invasion of the pouch leads to the erosion of the artery walls in that chamber
37
What artery is most common affected by guttural pouch mycosis?
Internal carotid artery, thought to be from high oxygen tension
38
What is the most common CxS with guttural pouch mycosis? Second most common?
First - Unilateral Epistaxis
| Second - Dysphagia
39
What will you see with guttural pouch mycosis with endoscopy?
Plaque of necrotic tissue. Brown, yellow, white, black color with visualization of blood
40
What are the ways to treat guttural pouch mycosis?
Medical - Topical antifungals
Surgical - Ligation of affected blood vessel, balloon catheter, transarterial coil
41
What complication may occur with external carotid occlusion?
Blindness
42
What is the chance of fatal hemorrhage occurring with guttural pouch mycosis?
50%
43
What types of horses do you normally see with progressive ethmoid hematoma?
Older (>4 years), thoroughbred and Arabians
44
What % of ethmoid hematoma cases are bilateral?
15-20%. Most are unilateral
45
T/F: Ethmoid hematoma cases usually require emergency attention because the can be fatal
False. Mild, spontaneous, intermittent
46
T/F: Progressive ethmoid hematoma typically has less blood than a guttural pouch mycosis case
True
47
How can you diagnose ethmoid hematoma?
Endoscopy to visualize mass directly.
48
What are skull radiographs used for with ethmoid hematoma?
To check the extent of the mass and its involvement
49
Why would you biopsy an ethmoid hematoma? What ddx would there be?
To differentiate from other masses. Nasal polyps, neoplasia, fungal, etc
50
What is the preferred treatment for ethmoid hematoma?
Surgical ablation of the mass - YAG procedure
51
How would you medically treat ethmoid hematoma?
Intralesional formalin to cause necrosis from protein hydrolysis.
52
What are the chances of recurrence after surgery?
40% after a few months or years
53
T/F: Exercise induced pulmonary hemorrhage is associated more with the breed of the exercise rather than the intensity and duration.
False. INTENSITY MATTERS
54
What are some risk factors for EIPH?
High intensity exercise, previous EIPH episodes, older age, amount of mucus and material in tracheobronchial area
55
What is the most popular theory on the pathogenesis behind EIPH?
Capillary rupture theory. Stress on pulmonary capillaries from high cardiac outputs exceeding the tensile strength of the vessels, rupturing them and causing hemorrhage
56
What is the pressure on the pulmonary capillaries on a horse during intense exercise?
Up to 110 mmHg (that's high)
57
What pressure can the left atrium get to with intense exercise?
70 mmHg (that's high)
58
What is the biggest clinical sign you will see for EIPH?
Poor performance - quitting
59
What % of EIPH cases exhibit epistaxis?
1-10% (low)
60
What is the best way to diagnose EIPH?
Endoscopy.
61
Define the grading system of EIPH with epistaxis.
Grade 0 - No blood detected anywhere
Grade 1 - Couple flecks of blood, <1/4 of trachea circumference
Grade 2 - One-three streams of blood, 1/3-1/2 trachea circumference
Grade 3 - Multiple streams, 1/3 trachea circumference
Grade 4 - Lots of blood. 90% of trachea surface. Pooling of blood
62
What kinds of cells will you see in the respiratory secretions in a horse with EIPH?
Hemosiderophages
63
What is the grading system for alveolar macrophage hemosiderin?
```
0 - No blue coloration
1 - faint blue stain
2 - Dense blue in small portion of cytoplasm
3 - deep blue in most of cytoplasm
4 - Dark blue throughout all cytoplasm
```
64
What is the most characteristic feature with thoracic radiographs in a horse with EIPH?
Increased interstitial patterns in caudo-dorsal lung fields
65
T/F: Radiographs on EIPH cases are often disappointing
True
66
How do you treat EIPH and how does it work?
Furosemide. Reduces blood volume -> reduction in weight and work and pressure.
67
What does furosemide do with regards to epistaxis related EIPH?
Most report that it does nothing, but maybe reduces severity.
68
What are the increased chances of a horse winning a race when given furosemide?
140%
69
What physical object can you place on a horse to potentially prevent EIPH?
Nasal strips
70
By how much do nasal strips chance the pulmonary arterial pressure? Furosemide?
Nasal strips - 0
| Furosemide - 7 mmHg
71
What are some causes of stridor that are not related to distress?
Dorsal displacement of the soft palate, Epiglottic entrapment, Laryngeal hemiplegia
72
Which type, intermittent or persistent, is most represented in horses with DDSP?
Intermittent
73
When do you see IDDSP?
When the horse exercises
74
What is usually the origin of persistent DDSP?
Neurogenic
75
T/F: IDDSP causes are usually multifactorial and varied
True
76
What are some of the causes of DDSP?
Thyroid muscle dysfunction, inflammation, retraction of tongue or larynx, hypoplastic epiglottis, respiratory disease
77
What are the CxS of DDSP?
Quitting at the last half of the race, breathing noises when running
78
T/F: DDSP can be difficult to notice, especially when the horse is at rest
True
79
How can you diagnose DDSP?
Endoscopy
80
What will you with endoscopy on a horse with DDSP?
Ventral placement of the epiglottis relative to the soft palate during exercise
81
How can you treat DDSP medically?
Treat any underlying causes
Tongue tie (retracts tongue to prevent retraction of larynx)
Throat support device (TSD) - holds the larynx in place so it does not displace
82
How can you treat DDSP surgically?
Laryngeal tie-forward
Sternothyrohyoid myectomy (strap muscle resection)
Staphylectomy - resection of part of soft palate
Combinations of these occur too
83
What CxS does epiglottic entrapment cause?
Exercise intolerance, respiratory noise, coughing
84
What happens with epiglottic entrapment?
The epiglottis is enveloped by the aryepiglottic and subepiglottic tissues
85
What % of EE case are associated with hypoplastic epiglottises?
30%
86
T/F: Epiglottic entrapment often concurrently occurs with DDSP
True
87
T/F: Much like DDSP, epiglottic entrapment is usually intermittent.
False. Persistent
88
What do you see on endoscopy on horses with EE?
Loss of scalloped edge of epiglottis
89
Can you typically diagnose EE with endoscopy at rest?
Yes
90
What is currently the preferred method of treatment for EE?
Transendoscopic laser correction
91
What is happening with the larynx in a horse with laryngeal hemiplegia?
The horse cannot fully dilate the larynx on the affected side, producing an obstruction of airflow and a noise
92
Idiopathic laryngeal hemiplegia is also associated with damage to _______________________.
left recurrent laryngeal nerve
93
What are some causes of LH?
Perivascular jugular injections
Guttural pouch inflammation
94
What is the most common complaint with LH?
Exercise intolerance
95
T/F: LH delivers an abnormal expiratory noise.
False. Inspiratory
96
What are the grades of LH via endoscopy?
Grade I & II - full abduction of arytenoid cartilages during exercise and rest
Grade III - 77% have significant dysfunction during exercise
Grade IV - paralysis evident during rest
97
What is the 'slap' test?
Slap the saddle area of the horse to cause an adduction flicker on the other side. Both arytenoids should reponse symmetrically
98
What treatments can be done for LH?
Laryngoplasty for grade III and IV, ventriculectomy, laryngeal re-innervation, arytenoidectomy
99
What are etiologies for stridor associated with respiratory distress?
Upper airway obstruction (strangles, LH, lymphosarcoma, GP tympany, hyperkalemic periodic paralysis)
Tracheal collapse
Pulmonary Disease (RAO, viral pneumonia, interstitial pneumonia, diaphragmatic hernia, pneumothorax)
100
What is the main agent associated with guttural pouch empyema?
Steptococcus equi var zooepidemicus
101
What do you see when you lower the head of a horse with guttural pouch empyema?
The nasal discharge worsens
102
What CxS are seen with guttural pouch empyema?
Lymphadenitis, parotid swelling, dysphagia, chondroids
103
How can you diagnose guttural pouch empyema?
X-rays, endoscopy, percutaneous centesis
104
How do you treat GPE?
Flush the pouch - sedate, lower head, tube with catheter, flush with LRS
105
T/F: Parenteral antibiotics are not preferred to treat GPE
True. Give oral TMS
106
When is surgery indicated for GPE?
If flush doesn't work and if chondroids are present
107
What agent causes strangles?
Streptococcus equi var equi
108
T/F: Strangles is highly contagious
True
109
What age of horses are most susceptible to strangles?
Young horses
110
What CxS are seen with strangles?
Fever, yellow green purulent nasal discharge, cough, swelling of submandibular lymph nodes
111
What is the general crystallization of lymph node drainage called?
Bastard strangles
112
What is the first symptom that emerges with strangles?
Fever for first 3 days.
113
At what stage of the disease does strangles become the most contagious?
When the lymph nodes are ruptured and drained into the environment.
114
What other problems can strep equi cause?
Retropharyngeal lymph node edema and compression -> respiratory distress, GP empyema, laryngeal hemiplegia
115
What organisms are associated with guttural pouch empyema?
Streptococcus equi var zooepidemicus
Streptococcus equi var equi
116
What are the CxS seen with guttural pouch empyema?
Intermittent nasal discharge that is worsened when the head is lowered
Dysphagia
Chondroids
117
How do you diagnose guttural pouch empyema?
Endoscopy
118
How to treat guttural pouch empyema?
Sedation, repeated flushing, penicillin, TMS oral
119
What are retention catheters used for in regards to guttural pouch empyema?
Repeated daily treatments
120
T/F: Purpura hemorrhagica is a form of septic vasculitis that occurs in young horses, typically secondary to strangles.
False. Form of ASEPTIC vasculitis in OLDER horses
121
What are the common CxS with purpura hemorrhagica?
Demarcated areas of edema (limbs, abdomen, head)
122
T/F: PH has a low mortality.
True
123
How do you treat PH?
Penicillin, NSAIDS, hydrotherapy, DMSO, steroids (all for inflammation treatment)
124
What are the three most common causes of pneumonia?
Secondary bacterial infection (form viral), primary bacterial infection, aspiration pneumonia
125
What is the most common form of pleural effusion seen in the horse
Parapneumonic pleural effusion
126
What agent is the most common cause of pneumonia in the horse?
Bacteria
127
What are the risk factors associated with pleuropneumonia in the horse?
Long distance travel from transport, environmental stress, disease, exercise
128
What will you see on a BAL of a horse that has traveled over 1200 miles?
Decreased numbers of macrophages, neutrophils, and lymphocytes
129
What are the CxS seen with pleuropneumonia?
Fever, weight loss, pectoral edema
130
What will you hear on thoracic auscultation on a horse with pneumonia?
absent lung sounds on the ventral part of the body and louder cardiac auscultation
131
How can you determine the level of fluid in the lungs in a horse?
Thoracic percussion
132
What will you see on the CBC of a horse with pleuropneumonia in the early stages? Late stages?
Early: normal fibrinogen, looks like acute endotoxemia
Late: elevated fibrinogen, neutrophilia
133
What will you see on ultrasound of a horse with pleuropneumonia?
Fluid, fibrin, abscesses
134
What are the factors that contribute to the prognosis for pneumonia?
Amount of systemic fibrinogen (>1000 is poor)
Type of organism (E.coli is bad)
About of fibrin in the pleural space
Odor & Gas = anaerobes (bad)
135
How do you treat pneumonia?
Systemic antimicrobial therapy - metronidazole
Drain the thorax (large chest tube)
anti-inflammatories (Banamine, DMSO)
136
T/F: Strangles is highly contagious, especially in older horses
False, younger horses
137
What is the causative agent responsible for strangles?
Strep equi var equi
138
What lymph node is abscessed with strangles?
Submandibular lymph node
139
How long is the development phase of strangles?
0-7 days
140
When is the maturation and rupture of lymph nodes in strangles?
7-14 days (1 week after development)
141
What is are the CxS for strangles?
Fever*, nasal discharge, swelling and draining of lymph nodes, brain abscesses can happen too
142
What lymph node can strangles spread to, which can cause a severe complication?
Retropharyngeal
143
What is happens with bastard strangles?
The infection spreads systemically and forms abscesses to lymph nodes throughout the body - lung, mesentery, liver, spleen, kidney, brain
144
T/F: Strangles is extremely important to treat
False. If the animal is not depressed and eats okay, let the disease run its course
145
How can you treat strangles?
Hot pack for abscesses, ISOLATION, penicillin*, symptomatic treatment
146
How can you prevent strangles?
Quarantine new horses, test new horses, isolate, and vaccine
147
What is the new vaccine that should be used for strangles prevention called?
Intranasal - Pinnacle vaccine
148
T/F: Horses older than 6 months do not get disease from R. equi
True
149
How does R. equi evade the immune system?
they prevent macrophages from fusing their phagosomes and lysosomes
150
What are the CxS seen with R. equi?
Fever, dyspnea, depression,
POLYSYNOVITIS - immunemediated
Osteomyelitis and septic physitis
Mesenteric lymph node enlargement
151
What are the 4 patterns of radiography in a horse with R. equi?
Abscess pattern
Miliary pattern
Broncho-pneumonia pattern
Interstitial pattern
152
What will you see on CBC with R. Equi?
Marked inflammatory response (neutrophils and fibrinogen)
153
What are other methods, besides radiographs and CBC, to diagnose R. equi?
ELISA for antibodies, AGID, ultrasound
154
T/F: R. equi is difficult to treat
True
155
What meds do you for R. equi?
Erythromycin estolate, rifampin, anti-inflammatories, antiulcers, hyper immune serum (prevention)
156
What are some tests to run to monitor the progression of disease and treatment?
WBC count, fibrinogen levels, temperature, ultrasound
157
What is the % survival for horses with R. equi?
70-80%
158
T/F: Cough is a respiratory defense mechanism
True
159
Besides the cough reflex, what other mechanism protects the horse from respiratory infection?
Mucociliary escalator - pushes things up and out of the lungs/respiratory tract
160
What nerve is associated with the cough reflex?
Vagal nerve (also glossopharyngeal, and trigeminal)
161
What are some things that stimulate a cough?
Bronchoconstriction, inhaled particles, inflammatory mediators, hot/cold air, mural pressure, edema
162
What type of epithelium are responsible for mucociliary clearance?
Pseudostratified ciliated columnar epithelium
163
How long do the airway epithelium take to heal?
7 weeks!
164
What do clara cells do?
Produce surfactant to maintain patency of the airway, and metabolize airborne toxins
165
What do you want to rule out first when you see a horse coughing?
Cardiovascular disease
166
What are forms of auscultation to test for coughing?
Rebreathing (bag), and checking lung sounds
167
What will you hear in a horse with pneumonia? Pleuropneumonia? Pleural effusion?
Pneumonia: increased lung sounds, crackles and wheezes
Pleuropneumonia: ventral dull sound
Pleural effusion: loud heart sounds from improved sound conduction
168
What would palpation of the thoracic wall help find during physical examination?
Friction rubs of the pleura, and rib fractures
169
What is a DDx for coughing if the horse is also febrile?
Infection
170
What are some DDx for coughing without fever?
RAO, laryngeal issue, parasites, EIPH, foreign body, cancer, trauma
171
T/F: Equine influenza is an uncommon form of respiratory disease
False
172
What age of horses are usually affected by equine influenza?
Younger (~3 years old)
173
What happens to the horses respiratory tract when infected by influenza?
Their ciliated epithelium is destroyed -> cough
174
Which subtypes of equine herpes leads to coughing?
EHV 1 and EHV 4
175
Which form of EHV also has reproductive symptoms? Neurologic?
Repro + resp = EHV 4
| Neuro + resp = EHV 1
176
How long is the virus incubate for with EHV?
3 days
177
What other symptoms will you with with EHV?
Conjunctivitis, lymphadenopathy, edema, vasculitis, polysenovitis
178
T/F: EHV2 - 5 are clinically important
False. Low pathogenicity
179
What will you see with equine viral arteritis?
Respiratory disease, abortions, foal pneumonia
180
Which viral disease has long lasting immunity after infection or vaccine administration?
Equine viral arteritis
181
What type of horses get equine adenovirus?
SCID foals
182
What CxS are presented with Hendra virus?
Fever, facial swelling, head pressing, recumbent
183
T/F: Aerobic bacteria infections are commonly seen in horses undergoing physiologic stress from exercise, transportation, and anesthesia.
False. Anaerobic
184
What is the lungworm associated with the horse?
Dictyocaulus arnfieldi
185
What roundworm can affect the horse respiratory system?
Parascaris equorum
186
What is the most common fungal organism that is secondary to bacterial infection?
Aspergillus
187
What % of carboxyhemoglobin is detectable to diagnose disease?
>10%
188
How does anesthesia lead to respiratory distress and infection?
Excessive cuff pressure -> tracheal necrosis
Anesthetic drugs -> depression of defense mechanisms
189
What are some symptoms seen with trauma to the thoracic region?
Fractured ribs, hemothorax, pneumothorax
190
Where do you perform an abdominal tap in a horse?
Caudal to the 6th rib
191
T/F: Thoracic cancer is common in horses
False. Low incidence
192
What virus is associated with equine multinodular pulmonary fibrosis?
EHV-5
193
What do you see with equine multinodular pulmonary fibrosis?
Diffuse bronchointerstitial pattern with multiple coalescing circular nodules in the lung field
194
What do you see on PE and lab tests with EMPF?
Poor hair coat, increase RR, abnormal lung sounds, dry cough, increased WBC, fibrinogen, anemia
195
What do you see on U/S with EMPF?
Multiple circular hypoechoic masses
196
How might you treat EMPF?
Corticosteroids, NSAIDs, antibiotics, antivirals, bronchodilators, O2, immune modulators
197
How can a horse get foal pneumonia when <1 month old?
In-utero, meconium, iatrogenic, viruses (EHV, adeno)
198
How does a foal 1-6 months old get foal pneumonia?
S. zooepidemicus, R. equi
199
What will you see in the blood work with acute foal pneumonia? Chronic?
Acute: Hyperfibrinogenemia and neutropenia
Chronic: neutrophilia, anemia of chronic disease
200
What benefits do radiographs have over other endoscopy when dealing with pneumonia?
Evaluates deeper parenchyma, amount of consolidation, and progression
201
How do you determine the appropriate treatment in a case of foal pneumonia?
TTW with cytology of sample
202
What will you see on the arterial blood gas with foal pneumonia?
Hypoxemia, hypercapnia, respiratory acidosis
203
How do you treat pneumonia?
Hydrate for acute infection, antimicrobials (broad spectrum first, then based on culture), NSAIDs, bronchodilators, palatable feed, rest
204
What other method of anti-microbial administration is 12 times higher in concentration and much less toxic than IV admin?
Aerosolized anti-microbial therapy
205
What are some complications with foal pneumonia?
May not respond to treatment, and might develop into pleuropneumonia
206
How do you diagnose and treat pleuropneumonia?
Diagnose - thoracocentesis, C/S, cytology, ultrasound
Treat - rest, antimicrobials, NSAIDs, thoracic lavage
207
When is a thoracotomy indicated?
If the patient does not respond to meds
208
What is the prognosis for pleuropneumonia?
Fair - strep
Poor - mixed bacterial infection, anaerobes
Guarded - gram (-)
209
What are some differences between Inflammatory airway disease and recurrent airway obstruction?
IAD - occasional cough, poor performance, no increase in resp effort
RAO - frequent cough, exercise intolerance, increase respiratory effort
210
What ages are affected by IAD? RAO?
IAD - any age
RAO - older >7
211
How long does IAD last in the system? RAO?
IAD - spontaneous improvement, minor treatment
RAO - lasts for weeks, strict control and treatment. cannot be cured
212
Which disease, RAO or IAD, is seasonal?
RAO
213
What are three similar traits between RAO and IAD?
Airway hyper-responsiveness, airway obstruction, airway remodeling
214
What was the old name for RAO/heaves?
Chronic obstructive pulmonary disease (COPD)
215
What does the ACVIM consensus call RAO and IAD? (hint: humans often have this)
Equine asthma
216
Which case, RAO or IAD, is considered more mild?
IAD
217
What types of horses most noticeably have IAD?
Athletic race horses
218
What are some causes of IAD?
Exact cause unknown
Allergens, particles in the environment, infectious agents
219
What kind of cells will you see on a BAL in case of IAD?
Mast cells increased
220
T/F: You see increased levels of IgE with IAD
False.
221
How do you diagnose IAD?
BAL, pulmonary function test
222
What are the main cells you will in the BAL of an IAD case?
Neutophils (>10%)
Mast cells (>5%)
Eosinphils (>5%)
223
What do pulmonary function tests determine?
Pressure, volume, and flow of the lungs
224
What instruments are used with a PF test?
Oscillometry, plethysmography
225
What molecule is used with Pulmonary Function Test?
Histamine for bronchoprovocation
226
How do you treat IAD?
Reduce dust in the air, change bedding, change feed, anti-inflammatories
227
What is the main source of inflammation for recurrent airway obstruction?
The environment
228
What four characteristics get determine a ddx for RAO?
1. ) excessive mucus production
2. ) neutrophil accumulation
3. ) bronchial hyperreactivity
4. ) reversible bronchoconstriction
229
A case of RAO comes into your clinic. What would you expect to be the history of the horse?
Comes from a wet and cool climate, change in environment 1-3 months prior that had poor ventilation, dust exposure, pollen and mold
230
T/F: RAO cases always have nasal discharge
False
231
What is the respiratory rate on horses with RAO?
>40 breaths/min
232
What is the main CxS seen with RAO?
Heaves* - abnormal breathing effort
233
What PE methods would you want to pursue when suspecting RAO?
Thoracic percussion
Auscultation - crackles, wheezes
Rebreathing bag
234
How does the inflammation in RAO lead to the delayed clearance of the mucus in the respiratory system?
The epithelial cells are destroyed in the process which are responsible for mucus clearance
235
Name five processes of pathology that occur with RAO
1. ) Inflammation
2. ) Bronchoconstriction
3. ) Mucus accumulation
4. ) Airway thickening
5. ) Impaired gas exchange
236
Name some inflammatory mediators and explain how they lead to bronchoconstriction.
Histamine and serotonin: release of Ach which acts on muscarinic receptors of smooth muscles -> constriction
237
What does a narrow airway from RAO lead to?
Deficient gas exchange -> arterial hypoxia -> increased respiratory effort
238
What will you see under the microscope with RAO?
Goblet cell hyperplasia, epithelial damage, smooth muscle hypertrophy and hyperplasia, scarring
239
What cells will you see on a BAL of RAO?
Neutrophilia (>25%)
| no change in mast cells or eosinophils
240
What will endoscopy show you with RAO?
Edematous distal airways, inflammation and airway collapse
241
T/F: Imaging is considered a good monitoring aid for RAO
True
242
What is the Hay challenge test?
A tool for RAO diagnosis where you expose the horse to moldy hay and see their response
243
What is the most important treatment for RAO?
Environmental management
244
What are the three main classes of bronchodilators?
Anticholinergics, B2-agonists, Phosphodiesterase inhibitors
245
Name an anticholinergic drug, how it works, and some side effects
Atropine (2 hrs) - blocks acetylcholine -> less smooth muscle contraction
S/E: ileus
246
Name a B2-agonist and explain how it works. Any side effects?
Clenbuterol - increases intracellular cAMP levels
S/E (high doses): anxiety, tachycardia
247
Name a phosphodiesterase inhibitor and its effects. Any side effects?
Aminophylline - inhibits breakdown of cAMP
S/E: none!
248
T/F: Prednisone is indicated to treat RAO
False. Use Dex and PredniSOLONE
249
T/F: Give the glucocorticoid meds before the bronchodilator when treating RAO
False. Give the bronchodilator first, then the steroids
250
What are some good inhaled corticosteroids used to treat RAO?
Fluticasone, beclomethasone
