In the mucous membranes of the respiratory tract antibodies are bound to mast cells. When an allergen interacts with an IgE molecule the associated mast cell releases histamine and other inflammatory mediators. , hyperemia and hypertrophy of the bronchial wall as well as causing the increased permeability of the pulmonary blood vessels. Chemotaxic inflammatory mediators trigger an influx of neutrophils and eosinophils to the airways, further increasing the inflammatory response and promoting the over-production of mucus. Histamine causes Allergies tend to occur , depending on the specific hypersensitivity. Individual horses tend to exhibit allergies at the same time every year or when in a specific location. Signs & symptoms include bronchiospasm, coughing, nasal or lacrimal discharge, poor performance, exercise intolerance and COPD.
Diagnosis is through S&S, blood analysis, nasal swab & TA.
Treatment antihistamines &
corticosteroids.
Exercise Induced Pulmonary Haemorrhage (EIPH)
Exercise Induced Pulmonary Haemorrhage (EIPH) is commonly called epistaxis, and horses suffering from EIPH are called “ ”. Epistaxis describes bleeding from the nostrils, or blood being present in the nostrils, but it is not synonymous with EIPH as epistaxis can be caused by pathologies other than EIPH.
Exercise induced pulmonary haemorrhage is caused by:
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These three situations often occur together, making the exact cause of EIPH difficult to isolate. Chronic inflammation of the small airways causes of these airways. Fibrosis reduces the elasticity of the airway causing adjacent segments of the airway to have different elastic and tensile properties. During strenuous exercise the force and turbulence of ventilation increases, as does the pulmonary blood pressure. Turbulent airflow causes the airway walls to . Areas of fibrosis are more resistant to stretch, causing the airway to tear as the fibrotic and non-fibrotic portions stretch at different rates. Tears in the walls of the bronchioles allow blood to enter the lumen of the airway. Haemorrhage is exacerbated by the high pulmonary blood pressure causing larger volume of blood to flow into the airways. If the volume of blood is sufficient it will be pushed rostrally and may be visible in the . Blood in the airways reduced the lumen of the airways and reduces the lungs’ ability to perform
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