EIPH Flashcards
What is EIPH?
Exercise induced pulmonary haemhorrhage
What are the clinical signs of EIPH? (5)
- None!
- Most don’t bleed significantly to the point where they get epistaxis usually! EPIH is the most common cause of epistaxis, but not every horse will bleed enough with EIPH will have epistaxis
- poor performance
- sudden onset exercise limitation
- swallowing after exercise
- Epistaxis
How do we diagnose EIPH? (2)
Endoscope
Cytology
What is the clinical significance of EIPH?
- a large proportion of horses are positive following racing in endoscopic surveys
- there is no relationship between the presence or absence of EIPH and finishing place
- When they bleed a lot, can result in poor performance, but not every horse with small amount of EIPH will result in poor performance
What is the pathogenesis of EIPH? (2 theories)
- UNKNOWN – controversial
- haemorrhage is from pulmonary rather than bronchial vessels
- typically located in the caudodorsal lung lobes
- Capillary stress failure theory
- High pressures in pulmonary vasculature due to CO and capillaries rupture
- Mechanical theory
- As horse gallops, pressure from GI onto diaphragm and caudal lung lobes, result in mechanical failure
- Haemorrhage is always from pulmonary vessels and caudal dorsal vessels where pressures are highest
What is the CAPILLARY STRESS FAILURE THEORY?
- Pressures generated within the pulmonary capillaries during exercise exceed their stress failure point
- Pulmonary capillaries are an inevitable anatomical weak point due to normal equine cardiopulmonary physiology:
- THIN WALLED
- normal Thoroughbreds become hypoxic and hypercapnic during exercise, at peak gallop. That may be an important contribution as to why you get vasoconstriction
- Hypoxia induced vasoconstriction, don’t perfuse the part that doesn’t have enough oxygen! Therefore by doing this, increase pressure in lungs
Why does EIPH affect the CdD lobes?(3)
- Higher blood flow
- lower intrinsic vascular resistance – but if this is exacerbated by vasoconstriction, may have important part
- Displacement of the diaphragm causes transient falls in alveolar pressure
- Lower alveolar pressure leads to greater transmural pressure
- Wall stress: Transmural pressure x radius/ wall thickness
What predisposes a horse to EIPH? (5)
Age
Type of horse
- LOWER AIRWAY DISEASE
- E.g. IAD or RAO – important risk factor
- Need to identify the risk factors and take them away
- UPPER AIRWAY DISEASE
- CARDIAC DISEASE
- Increases pulmonary artery pressure
- Atrial fibrillation
- Mitral valve disease
- Only clinical sign for a cardiac abnormality might be bleeding at exercise
How can we diagnose EIPH? (5)
- Clinical evidence of EIPH
- only present in more severe cases
- Bilateral epistaxis, but only present in most severe cases
- Endoscopy
- Can be scoped as screening process
- Bronchoalveolar lavage
- RBCs, haemosiderophages
- Radiography
- Not something used regularly
- Scintigraphy
- currently experimental
- Not something used regularly
What can be seen here?
EIPH
RBCs, haemoglobin within foamy macrophages – haemosiderinphages
What can be seen here?
EIPH
Lots of blood and coating walls of trachea
What is this?
Mild case of EIPH
How can we manage EIPH? (3)
- Difficult to manage
- Identify and address any predisposing diseases
- Break haemorrhage-inflammation cycle
- Modify training programme to reduce episodes
- Dust-free environment
- Furosemide
- Not allowed in horse races in UK, shown to protect from developing of EPISTAXIS, not EIPH- so less likely to bleed from their nose if they have this
- Probably works by reduced circulation volume – may reduce circulation BP and it is also it is a weak vasodilatory effect
- ?antibiotics
- Horses that have had a severe bleed will need treatment, blood is also culture media for bacteria also – so antibiotics to prevent pneumonia after severe bleed
What drugs can we use for EIPH and what 2 effects does it have?
What is the problem in the UK?
- Diuretic effect
- Reduce circulating volume
- Reduce weight
- Vasodilator effect
- In USA, but not UK, horses can race on furosemide
What is a nasal strip? What do they do?
Where can and can’t we use them?
•Hold nostrils open and widely used in eventing world, not allowed in racing in the UK at this point – can train with them though
What is the prognosis for EIPH?
- GOOD TO FAIR
- if associated with respiratory infection or other predisposing cause can be identified and treated
- or having minimal impact on performance
- POOR
- for idiopathic bleeders with performance limitations
What is the impact of EIPH on UK racing? (3)
- No restrictions on ‘bleeders’
- Furosemide is not allowed for racing
- Nothing to make them rest them
What is the effect of EIPH on the ROW horse racing? (2)
- 3 Strikes and out
- If epistaxis, not acceptable – they are removed from racing
- Furosemide allowed
What diseases are foals susceptible to? (3)
- Infectious causes (bacterial)
- Congenital abnormality
- Sepsis, trauma, other
What diseases are weanlings susceptible to?
•Infectious causes (bacterial) & contagious
What disease are youn adults susceptibe to?
- Inflammatory airway disease
- Infectious causes (bacterial and viral and mycoplasma)
What disease are old horses susceptible to?
•Recurrent airway obstruction
IS URT more or less common than LRT?
What type of horse is it more common in?
- Less common than lower airway disease
- Mainly young horses (yearlings and two-year-olds)
What viral (3) and bacterial (1) disease is tehre of the URT?
- VIRUSES
- Equine influenza
- Equine Herpes Virus 1&4
- Equine Viral Arteritis** Notifiable Disease
- BACTERIA
- Streptococcus equi equi
What are the risk factors for foal resp disease? (10)
What is respiratory distress syndrome and what is it associated with (2)?
- Atelectasis (failure of lungs to expand) due to
- inadequate surfactant function
- structurally immature lung and muscles of respiration
- associated with prematurity and dysmaturity
- Maturity of lungs requires formation of surfactant to break down lung surface tenion so airways can be patent
What is this?
BACTERIAL & ASPIRATION PNEUMONIA
Focal, bronchialveolar
ventral and hilar area
What is this?
ATLECTASIS
Alveolar
Premature foal
No visible lung tissue, can only see cartilage enclosed main stem bronchioles
What is this?
VIRAL PNEUMONIA
Diffuse, Interstitial
What signs should we be looking out for in foal MM?
- Also looking for signs of sepsis: congestion/injection, petechiae
- Results in congestive MM
- Inappropriate MM vasodilation in a face of an animal that is hypovolaemic
Right pic - pinna of ears with petechial haemorrhage
What is the problem with Parascaris Equorum?
- Not a major pathogen
- Can cause transient nasal discharge as migrating through lungs
