Week 9- Equine Lower Respiratory Tract Disorders Flashcards

1
Q

What are the three main signs of an airway disease in horses?

A
  1. Cough
  2. Nasal Discharge
  3. Abnormal breathing patterns/ Sounds
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2
Q

What is a normal breathing pattern in horses?

A
  • 8-16 bpm
  • minimal chest or abdominal wall movement
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3
Q

What is an abnormal breathing pattern in horses

A
  • Increased rate/ depth
  • any changed breathing pattern should be noted
  • any abnormal sounds associated with breathing
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4
Q

What is expiratory dyspnoea?

A

exaggeration of the biphasic expiratory phase with
increased incorporation of the abdominal muscles →
producing an obvious biphasic or double expiratory
lift: ‘heave

typical of small airway obstruction

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5
Q

What is inspiratory dyspnoea?

A

associated with a stertorous or stridorous noise
during inspiration
Indicative of upper airway obstruction
Occasionally, inspiratory dyspnoea may occur with
severe restrictive lung diseases (e.g. pneumonia,
interstitial disease, pneumothorax, rib fracture)

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6
Q

What is combined inspiratory and expiratory dyspnoea?

A

Suggestive of severe upper or lower airway
obstruction, diffuse pulmonary disease or pleural
disease

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7
Q

What may cause a ‘crackling’ sound?

A

‘popping’ open of airways that were
closed during expiration;
= ‘bubbling and crackling’ sounds caused
by air bubbling through excessive mucus
in the airway

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8
Q

What may cause a ‘wheezing’ sound?

A

musical notes produced by air flowing
through narrowed airways

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9
Q

What does pleural friction sound like?

A

‘crunching/creaking’ sounds due to the
rubbing together of inflamed pleural
surfaces

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10
Q

What is mild and severe asthma in horses also known as?

A
  • Mild = inflammatory airway disease
  • Severe= recurrent airway obstruction
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11
Q

What does mild Equine Asthma look like clinically?

A
  • Common in young performance horses
  • Intermittent coughing (38% of cases)
  • Nasal discharge
  • Lung auscultation- usually normal sounds
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12
Q

What causes mild equine asthma?

A
  • Poor ventilation
  • Dusty hay/ bedding
  • Infectious agents
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13
Q

What does severe equine asthma look like clinically?

A

Common in mature horses and ponies
→ (usually > 7 years old)
* Subacute-chronic presentation
* Abdominal effort/nostril flaring
* Coughing
* “Wheezes and crackles

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14
Q

What causes severe equine asthma?

A
  • Poor ventilation:
    → Dusty hay/straw bedding (moulds)
    → NH3, H2S,….
  • Seasonal environmental allergens
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15
Q

What is the pathophysiology of severe equine asthma?

A
  • Airway hyperesponsiveness
  • Inflammation
    1. Increased mucus prodcution
    2. Bronchospasm
    3. Airway remodelling
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16
Q

How would you treat severe equine asthma medically?

A
  • Glucocorticoids
  • B2 adrenergic agonists
  • Muscarinic antagonists
  • Furosemide
17
Q

How would you treat severe equine asthma environmentally?

A
  • Manage from the pasture
  • minimise dust levels in the stable
  • avoid overhead lofts
  • feed complete diets
  • consider using a dust extractor
18
Q

What does RDC stand for?

A

respirable dust
concentration
= defined as the portion that is
of a sufficiently small
aerodynamic size (usually with
a diameter of <5 μm) to allow
penetration of the peripheral
(= smaller) airways

19
Q

What may cause an infectious airway disease?

A
  • Viral: EHV, EIV, ERV, (EVA)
  • Bacterial: Streptococci,
    Actinobacillus,
    Rhodococcus etc.
  • Parasitic: Dictyocaulus
20
Q

What are the two most common types of equine herpes virus?

A
  • EHV-1
  • EHV-4
21
Q

When is Equine Influenza Virus most common?

A

Most common in horses commingled under stressful conditions
* Viral spread: through aerosolization of viral particles + fomites
* short incubation period (1 to 3 days)
* high fever, depression, paroxysmal and persistent coughing, nasal discharge (serous →
mucopurulent), submandibular lymphadenopathy, myositis, anorexia
* Horses with influenza = at risk of secondary bacterial infection that may progress to
bronchopneumonia and/or pleuropneumonia

22
Q

How might you treat bacterial pneumonia?

A

Broad-spectrum antibiotic + general
supportive care
→ When disease is severe or chronic or involves marked
immunosuppression: guarded prognosis!

23
Q

What is rhodococcus equi?

A

Gram-positive, intracellular bacteria → causes chronic suppurative
bronchopneumonia with abscessation
* Foals: 1–5 months of age

24
Q

What are the clinical signs of rhodococcus equi?

A

mild and nonspecific early in the course of disease
* become more pronounced as pneumonia progresses
* cough, fever, lethargy, and increased respiratory effort – respiratory
distress.

25
Q

How would you diagnose rhodococcus equi?

A

culture of R. equi and identification via PCR (from transtracheal wash
sample).
→ radiology and ultrasonography

26
Q

What are the clinical signs of interstitial pneumonia?

A

May present with chronic but progressive dyspnoea/tachypnoea, weight loss, fever
(persistent or recurrent). Auscultation – harsh lung sounds with variable wheezing and crackling

27
Q

How might you diagnose interstitial pneumonia?

A
  1. History and clinical signs. Lack of response to standard therapy for lower airway diseases.
  2. Leukocytosis and hyperfibrinogenaemia.
  3. Thoracic radiography – interstitial infiltrate
  4. Endoscopy (Bronchoalveolar lavage = BAL)
28
Q

How might you treat interstitial pneumonia?

A

Treatment: There is no treatment.
→ Long-term antiinflammatory drugs or corticosteroids may be beneficial in chronic interstitial
inflammatory diseases.
→ Acyclovir or valacyclovir may be helpful in early cases of EHV-5 infection (equine
multinodular pulmonary fibrosis

29
Q

What is equine multinodular pulmonary fibrosis?

A

Uncommon/rare
* Weight loss, fever, respiratory distress
* Can affect any age
* Diagnosed by radiography/ultrasound/ biopsy
* Commonly associated with EHV-5 infection (relevance?)
* Might respond to glucocorticoids (or vanciclovir?) if treated
early

30
Q

What is the most common thoracic neoplasia tumour?

A

Granular cell tumour (myoblastoma)
→ By far the commonest primary tumour in horses.
→ Average age 13 y, but can be quite young (eg, 6 yo).
→ May cause chronic coughing, tachypnoea and weight
loss.
→ Endoscopy/radiography: masses grow into bronchi and
bronchioles.
→ Locally invasive but do not metastasise.
→ A benign and slow-growing tumour but may:
o cause persistent coughing
o block bronchus and cause focal pneumonia

31
Q

What is a mediatsinal tumour?

A
  • Most common in mature to elderly horses
  • Weigt loss, lethargy, anorexia
  • non-septic pleural effusion on the ultrasonography
32
Q

What is EIPH?

A

Bleeding from the caudodorsal lung lobes during
exercise

33
Q

What causes congestive heart failure?

A

Mitral insufficiency → pulmonary hypertension → oedema
* Rare in horses
* Likely to have tachycardia and severe left sided systolic murmur
* Might respond to digoxin/furosemide in short-term?
* Try benazepril