IAD Flashcards
(105 cards)
1
Q
What symptoms do horses with Heaves (Recurrent Airway Obstruction - RAO) and Summer Pasture-Associated RAO exhibit?
A
They exhibit marked lower airway inflammation and obstruction, frequent coughing, increased respiratory effort at rest, and exercise intolerance.
2
Q
How can clinical signs and airway obstruction in horses with RAO be reversed?
A
By using corticosteroids, bronchodilators, or making environmental changes.
3
Q
At what age does Recurrent Airway Obstruction (RAO) principally affect horses?
A
It principally affects horses over 7 years of age.
4
Q
List the clinical signs of RAO.
A
Severe airway inflammation, frequent coughing, increased respiratory effort even at rest, and exercise intolerance.
5
Q
What are the treatment options for RAO?
A
Administration of corticosteroids and bronchodilators, and environmental management to reduce allergens.
6
Q
Which age group of horses is commonly affected by Inflammatory Airway Disease (IAD)?
A
Horses of all ages, but it is commonly reported in young horses.
7
Q
What are the clinical signs of IAD?
A
Subtle signs including poor performance and occasional coughing, with normal breathing at rest.
8
Q
Describe the nature of inflammation in IAD.
A
Mild inflammation with limited pulmonary dysfunction, requiring sensitive diagnostic methods for detection.
9
Q
What diagnostic method reveals excess tracheobronchial mucus in both RAO and IAD?
A
Airway endoscopy.
10
Q
What does BALF cytology show in both RAO and IAD?
A
Mild increases in neutrophils, eosinophils, and/or metachromatic cells.
11
Q
How can pulmonary dysfunction be confirmed in both RAO and IAD?
A
By evidence of lower airway obstruction, airway hyperresponsiveness, or impaired blood gas exchange.
12
Q
What systemic signs of infection exclude a diagnosis of RAO or IAD?
A
Anorexia, lethargy, fever, and hematologic abnormalities.
13
Q
What respiratory effort at rest excludes a diagnosis of IAD?
A
Increased respiratory effort at rest.
14
Q
What term is used to describe horses with airway disease ranging from mild (IAD) to severe (RAO)?
A
Equine asthma syndrome.
15
Q
Name two similarities between equine asthma syndrome and human asthma.
A
Chronic airway inflammation and respiratory symptoms such as coughing, difficulty breathing, and expiratory airflow limitation.
16
Q
Does IAD necessarily progress to RAO over time?
A
No, IAD does not necessarily progress to RAO over time.
17
Q
Which age group is more commonly reported to be affected by IAD?
A
Young horses.
18
Q
What clinical signs are associated with IAD?
A
Poor performance and chronic (>3 weeks) occasional coughing.
19
Q
What should be ruled out if poor performance is the only complaint in IAD suspected horses?
A
Non-respiratory causes must be ruled out.
20
Q
What diagnostic methods confirm IAD?
A
- Airway endoscopy revealing excess tracheobronchial mucus (score ≥2/5 for racehorses and ≥3/5 for sports/pleasure horses).
- Bronchoalveolar lavage fluid (BALF) cytology showing mild increases in neutrophils, eosinophils, and/or metachromatic cells.
- Documenting pulmonary dysfunction through lower airway obstruction, airway hyperresponsiveness, or impaired blood gas exchange.
21
Q
What are the exclusion criteria for diagnosing IAD?
A
Evidence of systemic signs of infection such as anorexia, lethargy, fever, hematologic abnormalities, and increased respiratory effort at rest.
22
Q
What are the general clinical signs of IAD in horses?
A
The signs are generally nonspecific and subtle.
23
Q
How is decreased performance in horses with IAD characterized?
A
It is associated with excess tracheal mucus but not with tracheal wash neutrophilia, BALF neutrophilia in racehorses, delayed recovery of respiratory rate after exercise, exaggerated respiratory effort during work, and is limited by impaired pulmonary gas exchange.
24
Q
What are the specific signs of decreased performance in IAD-affected horses during intense exercise?
A
Intensely exercising horses with IAD exhibit worsening of exercise-induced hypoxaemia, and lower speeds of exercise are obtained with a blood lactate concentration of 4mmol/l.
25
Describe the nature of the cough in horses with IAD.
It is a chronic, intermittent cough lasting more than 3 weeks, associated with increased neutrophil proportions in BALF, and can occur both at rest or during exercise. Occasional coughing can indicate an increased risk of developing RAO, and the absence of a cough does not rule out IAD.
26
How effective are questionnaires in identifying cases of severe airway inflammation like RAO compared to IAD?
Questionnaires are effective in identifying cases of severe airway inflammation like RAO, but their usefulness for distinguishing IAD-affected horses from controls based on owner-reported clinical history seems limited.
27
What does thoracic auscultation typically reveal in IAD-affected horses?
Thoracic auscultation usually does not reveal abnormalities, but some IAD-affected horses can exhibit increased breath sounds or subtle wheezes, particularly during rebreathing manoeuvres.
28
What is the significance of serous to mucopurulent nasal discharge in Thoroughbred racehorses in training?
It is commonly observed, with some indication of an association between increased nasal discharge and increased tracheal mucus in older racehorses. Nasal discharge can also indicate an increased risk of later developing RAO.
29
What does airway endoscopy reveal in horses with IAD?
It reveals excess tracheobronchial mucus.
30
What scoring system is used for airway endoscopy in racehorses and sports/pleasure horses?
A score of ≥2/5 for racehorses and ≥3/5 for sports/pleasure horses.
31
What does bronchoalveolar lavage fluid (BALF) cytology show in horses with IAD?
It shows mild increases in neutrophils, eosinophils, and/or metachromatic cells.
32
What is chronic cough associated with in BALF cytology?
Increased neutrophils in BALF.
33
How is impaired blood gas exchange assessed in horses with IAD?
Through blood gas analysis during and after exercise.
34
What does thoracic auscultation typically reveal in IAD-affected horses, and what can be observed in some cases?
Thoracic auscultation typically does not reveal abnormalities, but some IAD-affected horses may exhibit increased breath sounds or subtle wheezes, especially during rebreathing manoeuvres.
35
How is IAD pathogenesis defined?
It remains incompletely defined with multiple etiological agents potentially involved.
36
WWhat environmental factor is linked to IAD development in horses?
High levels of aerosolized particles and gases in stables.
37
What are the components of the respirable fraction contributing to IAD?
Organic particles (fungi, moulds, endotoxin, beta-D-glucan, microorganisms, mite debris, vegetative material), inorganic particles (ultrafine particles <100 nm, inorganic dusts), and noxious gases.
38
How do aerosolized allergens and endotoxins contribute to IAD?
They induce inflammation in the respiratory tract, with high eosinophil and mast cell counts in BALF, along with Th-2 cytokines (IL-4 and IL-5) indicating aeroallergens' role.
39
What effect does dust exposure have on older horses?
Exposure to high levels of organic dust and endotoxin results in mild to moderate BALF neutrophilia.
40
How do environmental factors like cold, dry environments affect IAD?
They might contribute to BALF neutrophilia, but their role is likely limited.
41
What does dysregulation in inflammatory cell homeostasis lead to?
It leads to clinical signs of variable severity in IAD.
42
What are the specific inflammatory cells in BALF indicating different types of IAD?
Metachromatic cells (associated with airway hyperreactivity and subclinical pulmonary obstruction) and neutrophilic IAD (linked with cough and tracheal mucus presence).
43
How does BALF eosinophilia vary with age in horses?
It is more common in young horses (<5 years old) and less frequent in older horses.
44
How does BALF neutrophilia vary with age in horses?
It is more frequent in older horses (>7 years old) indicating a shift in the inflammatory response with age.
45
What markers are associated with innate immune activation in IAD?
Increased gene expression for TNF-α, IL-1β, and IFN-γ, along with protein concentrations linked to abnormal BALF cytology.
46
What does Th-1 polarization drive in IAD?
It drives luminal neutrophilia.
47
What is associated with increased BALF neutrophil percentage in the adaptive immune response?
mRNA expression of IL-17 and IL-23 (Th1).
48
What cytokines are linked with mastocytic IAD form indicating Th-2 type polarization?
Increases in IL-4 and IL-5.
49
What genetic factors are related to IAD in horses?
Differences in gene regulation related to proinflammatory, stress-mediated responses, and oxidative balance metabolism.
50
How does omega-3 polyunsaturated fatty acid supplementation affect IAD?
It improves clinical signs and BALF neutrophilia, although oxidative stress marker (8-isoprostane) remains unchanged.
51
What bacterial species are associated with increased risk of IAD in racehorses?
Streptococcus zooepidemicus and Actinobacillus/Pasteurella species.
52
What is the role of viral infections like equine influenza in IAD?
It commonly causes transient lower airway inflammation, but the role of viral infection in IAD is controversial and lacks conclusive evidence.
53
What is the diagnosis of IAD (mild to moderate equine asthma) based on?
1. The presence of clinical signs of lower airway disease (poor performance, cough).
2. Documentation of lower airway inflammation based on excess mucus on endoscopy, BALF cytology, or abnormal lung function.
3. Exclusion of severe equine asthma (RAO/heaves) and other respiratory diseases.
54
What are the clinical signs of poor performance in horses with IAD?
Inability to maintain expected levels of athletic performance, which can manifest as slower racing times, decreased stamina, or reluctance to perform in non-racing horses.
55
Describe the nature of chronic coughing in horses with IAD.
Persistent cough that lasts for more than 3 weeks; it's important to rule out other causes of poor performance such as upper airway obstruction or musculoskeletal disease.
56
What is the mucus scoring system used in endoscopy for horses with IAD?
Grade 0: No visible mucus.
Grade 1: Single to multiple small blobs of mucus.
Grade 2: Larger but non-confluent blobs.
Grade 3: Confluent or stream forming mucus.
Grade 4: Pool forming mucus.
Grade 5: Profuse amounts of mucus.
57
What are the findings during endoscopy in healthy horses vs. horses with IAD?
Healthy horses typically have no visible mucus (Grade 0) or few isolated specks (Grade 1), while horses with IAD may exhibit mucus accumulation ranging from small amounts at the thoracic inlet (Grade 2) to continuous streams along the trachea (Grades 3-5).
58
How is Bronchoalveolar Lavage Fluid (BALF) cytology used to confirm IAD diagnosis?
Recommended based on clinical signs and endoscopy.
250-500 mL of 0.9% saline is infused via endoscope or BAL tube.
Abnormal BALF cytology includes mild to moderate increases in neutrophils, eosinophils, and/or mast cells.
59
What are the BALF reference values for healthy controls?
Total nucleated cell count ≤530 cells/µL
Neutrophils ≤5%
Eosinophils ≤1%
Metachromatic cells (mast cells) ≤2%.
60
What cytological values indicate IAD and RAO?
IAD:
10% neutrophils
5% mast cells
5% eosinophils
RAO:
25% neutrophils
Decreased lymphocyte and alveolar macrophage counts
61
What hematological findings are typically observed in pleasure horses with IAD?
Hematology is usually unremarkable in pleasure horses with IAD.
62
How might performance indicators reflect IAD in horses?
IAD sufferers show impaired physiological responses to exercise, such as lower speed at a blood lactate of 4mmol/l or a heart rate of 160/200 bpm.
63
What blood biomarkers are associated with IAD in racehorses?
Serum surfactant protein D (SP-D) concentrations are higher in racehorses with IAD but do not correlate with BALF cytology.
64
How does IAD negatively impact lung function in horses?
IAD negatively affects lung function both at rest and during exercise, impairing gas exchange and affecting performance.
65
What methods are used to detect changes in lung mechanics in horses with IAD?
Rebreathing Method: Detects changes consistent with airway obstruction.
Post-Exercise Airflow Measurement: Reveals obstruction immediately after strenuous exercise.
66
What sensitive lung function tests can detect airway obstruction in horses with IAD?
Forced Expiration and Impulse Oscillometry, although they have limited accessibility and are available only in specialized research laboratories.
67
How is airway hyperresponsiveness tested in horses with IAD?
Through field testing, showing a satisfactory reproducibility. Horses with IAD display bronchoconstriction and cough, likely due to the airway's response to inhaled irritants.
68
How can RAO be differentiated from IAD?
Laboured breathing at rest differentiates RAO from IAD. RAO-affected horses show increased respiratory efforts and lung dysfunction at rest, while IAD horses do not.
69
What are the clinical features of viral infections that differentiate them from IAD?
Systemic clinical signs such as fever, lethargy, cough, and nasal discharge. Diagnosis is made via PCR, immunofluorescence, virus isolation, and a rise in serum antibody titer.
70
How is bacterial bronchitis and bronchopneumonia distinguished from IAD?
hrough blood work, radiographic, and ultrasonographic chest evaluation, showing severe infection signs like fever, depression, decreased appetite, weight loss, leucocytosis with neutrophilia, and increased immunoglobulins.
71
How is lungworm infection (parasitic pneumonitis) identified and differentiated from IAD?
By the presence of larvae in tracheal wash fluid, history of contact with donkeys, and resolution with parasiticidal drugs. It shows eosinophilic inflammation in BALF, more so than eosinophilic IAD.
72
How is Exercise-Induced Pulmonary Hemorrhage (EIPH) diagnosed and differentiated from IAD?
By detecting blood during tracheoscopy, hemosiderin-laden macrophages in BALF, and poor correlation with tracheal mucus score and BALF neutrophil counts.
73
What methods help diagnose neoplasia, differentiating it from IAD?
Bronchoscopy, thoracic radiography, ultrasonography, and cytologic and histologic findings from biopsies.
74
How are upper airway diseases distinguished from IAD?
Through upper airway endoscopic, radiographic, and ultrasonographic studies. These diseases show exercise intolerance, occasional coughing, abnormal breathing sounds (stridor, stertor), absence of mucopurulent secretions, and lower airway inflammation.
75
What is the management of horses with IAD based on?
Clinical experience and studies from RAO (Recurrent Airway Obstruction) horses, focusing on reducing lung inflammation and improving environmental quality to alleviate symptoms.
76
Why are glucocorticoids often used empirically to treat IAD?
Due to their analogy with RAO, where neutrophils accumulate in high numbers in lower airways.
77
What must be ruled out before using immunosuppressive treatments for IAD?
Active infectious processes.
78
What evidence suggests the efficacy of dexamethasone and fluticasone in treating IAD?
Non-peer-reviewed evidence suggests they can decrease airway hypersensitivity and reactivity, although BAL cytology often remains unaffected if air quality remains unchanged.
79
What are the differences between inhaled and systemic corticosteroids in terms of benefits and risks?
Systemic Corticosteroids: Rapid and effective improvement in clinical signs and lung function, but potential for increased adverse effects.
Inhaled Corticosteroids: Lower risk of adverse effects, but considerations include fluticasone propionate metabolite detected in blood and urine, and adrenal suppression observed with beclomethasone dipropionate.
80
What is sodium cromoglycate used for in horses with IAD?
Mast cell stabiliser: To treat airway inflammation, improving clinical signs and reducing bronchial hyperresponsiveness in young racing horses with high BALF mast cell counts.
81
How is interferon alpha administered and what is its effectiveness in treating IAD?
Administration: Oral low-dose (50–150 U every 24 hours for 5 days).
Effectiveness: Reduces neutrophilic airway inflammation and relapse likelihood, higher doses (450 U) are less effective, and mast cell and eosinophil counts are unaffected.
82
How does supplementation with Docosahexaenoic Acid (DHA) affect IAD?
DHA (1.5 g/day for 2 months) alongside a low-dust diet rapidly improves clinical signs of IAD and RAO, showing more rapid improvement than a low-dust diet alone.
83
What are CpG Oligonucleotides and their relevance to IAD?
Inhaled nanoparticles that induce a Th2/Th1 shift, decreasing neutrophil percentages and improving lung function and clinical signs in RAO horses. Relevance to IAD is unknown.
84
What is the potential benefit of a modified soluble curcumin derivative in treating IAD?
Inhalation decreases BAL fluid cellularity and myeloperoxidase activity by targeting neutrophil apoptosis, potentially useful for IAD with neutrophilia.
85
Why is the use of bronchodilators in IAD considered empirical?
The degree of bronchoconstriction is too low to induce clinical signs at rest and has not been well documented at rest or during exercise.
86
What common medications are used as bronchodilators for IAD?
Clenbuterol, Aminophylline, Pentoxifylline, Theophylline.
87
What considerations should be taken when using bronchodilators in IAD?
Use with environmental dust reduction measures to prevent increased exposure of the lower airways to dust, best combined with corticosteroids, and prolonged use of beta-2 agonists can lead to tachyphylaxis
88
What common agents are used as mucolytic and mucokinetic agents for IAD?
Acetylcysteine, Bromhexine, Ammonium Chloride, Potassium Iodide infusions.
89
: What is the efficacy of mucolytic and mucokinetic agents in treating IAD?
There is little evidence supporting their efficacy in IAD or RAO, with a lack of published randomized-controlled trials.
90
List the dosages and frequency of administration for dexamethasone and prednisolone in treating IAD.
Dexamethasone: 0.04 mg/kg IV or IM once per day, 0.05 mg/kg PO once per day.
Prednisolone: 1.1–2.2 mg/kg PO once per day.
91
List the dosages and frequency of administration for bronchodilators like aminophylline and clenbuterol in treating IAD.
Aminophylline: 5–13 mg/kg IV every 12 hours, 6–12 mg/kg PO every 12 hours.
Clenbuterol: 0.8–3.2 µg/kg PO every 12 hours.
92
List the dosages and frequency of administration for beclomethasone and fluticasone in aerosol treatment for IAD.
Beclomethasone: 1–8 µg/kg every 12 hours.
Fluticasone: 1–6 µg/kg every 12 hours.
93
What bronchodilators are used in aerosol treatment for IAD and their dosages?
Albuterol: 1–2 µg/kg every 1–3 hours.
Ipratropium bromide: 0.2–0.4 µg/kg every 8–12 hours, 2–3 µg/kg 0.02% solution every 8–12 hours via ultrasonic nebulizer.
94
What cromone is used in aerosol treatment for IAD and its dosage?
Cromolyn sodium, 200 mg 0.02% solution every 12 hours via jet nebulizer, 80 mg 0.02% solution every 24 hours via ultrasonic nebulizer.
95
How can using low-dust feedstuff and bedding reduce airborne particle concentrations?
Using low-dust feed and bedding can significantly reduce airborne particle concentrations by cutting respirable dust levels and reducing mould concentrations.
96
What are some effective bedding alternatives to straw?
Switching to low-dust materials like cardboard, wood shavings, and complete pelleted diets or haylage reduces dust and aeroallergen exposure.
97
How does feeding dry hay impact lung inflammation risk?
Feeding dry hay significantly increases the risk of lung inflammation.
98
How can replacing dry hay with soaked hay or haylage reduce respirable dust exposure?
Immersing hay in water reduces exposure to respirable dust by approximately 60%, and feeding hay on the ground rather than from hay nets significantly lowers respirable dust exposure in the breathing zone.
99
What measures can improve ventilation in barns to decrease airborne particles and other irritants?
Enhancing barn ventilation, using mechanical ventilation, opening barn doors, and designing more open stables improve ventilation and reduce dust exposure.
100
Why is controlling environmental dust crucial for preventing IAD?
Controlling environmental dust limits dust generation from feed and bedding, and ensures proper ventilation, which is essential for preventing IAD.
101
How does the feeding method affect dust levels in the breathing zone?
Feeding hay from a hay net results in greater than 4-fold increased exposure to respirable dust in the breathing zone compared to feeding the same hay on the ground.
102
What impact do different feed and bedding materials have on airway inflammation?
Different feed and bedding materials may have variable concentrations of endotoxin, which can directly contribute to airway inflammation.
103
How can barn design and ventilation practices reduce dust exposure?
More open stable designs and increased ventilation, regardless of the season, reduce dust exposure. Good ventilation practices are essential, particularly during feeding and cleaning when dust levels peak.
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