PG . 34
AQHA HORSE HEALTH
Keep a description and take some photos of any discharge especially if it changes .
Important information can be gleaned from a description and a history of the :
• whether one or both nostrils are involved
• the nature of the discharge ( clear , pus , blood , food )
• whether other horses are affected
• the volume at different times of day and in relation to exercise ( the purulent nasal discharge associated with chronic sinusitis and inflammatory lesions of the lower airway may be more profuse after exercise )
• whether the horse also has concurrent eye secretions conjunctivitis , a cough or any swollen areas on the head and face .
Horses that are well and healthy may produce a small amount of clear , watery nasal discharge after exercise - that little trickle at the end of the ride or after a long trip in the trailer that goes away without a second thought ( Figure 1 ).
A mucoid or mucus discharge indicates proteins is present and this is a sign of inflammation . Inflammation occurs early in viral infections that could be anywhere in the respiratory tract - from the nasal cavity to the far reaches of the bronchial tree . Herpes viruses are the most common cause of a sero-mucoid nasal discharge in all horses . During the EI outbreak we saw horses with classic , mild to severe symptoms and while herpes is much milder it must be assumed that every horse has and is exposed – and herpes is for life ! Once infected , the virus remains with the horse for life , and if stressed or suffering a respiratory infection , horses may show symptoms of herpes again – or they may remain symptom-free but shed the virus exposing other horses . Foals and aged horses are the most likely to have symptoms which can range from a slight snotty nose to a flu-like illness with fever and cough .
A mucopurulent discharge indicates that white blood cells are present . White blood cells are the bodies ‘ police force ’ to fight bacterial infections - but they can also be present in viral or fungal infections . Viscous , purulent discharges often have a strong unpleasant smell and contain high numbers of white blood cells . The discharge could be opaque , white , yellow or green and occur with a range of bacterial , viral and fungal infections – but rarely with allergies ( dust , mycotoxins , indoor airquality , surface moisture on arenas , pollen , ammonia , car exhaust gas ). A horrid-smelling discharge is usually the result of sinusitis ; dental disease ; fungal infections in the nasal cavity or guttural pouch ; tumours , or gangrenous pneumonia . A yellow-ish , bilateral discharge is typical of strangles .
Veterinary monitoring is helpful as at least 10 % of horses infected with strangles will end up with chronic infections in the guttural pouches . A ‘ carrier state ’ can also develop in horses that carry the bacteria in the guttural pouch for months after they have recovered and although they appear clinically well and healthy with no signs of infection , they shed bacteria in nasal discharges and are a source of infection for other susceptible horses .
Discharges containing food material and saliva are usually bilateral and mostly a sign of swallowing problems ( choke , botulism , tumours , foreign bodies , guttural pouch enlargement ) which may be located in the throat ( pharynx ) or oesophagus . Food-containing discharges may also occur in colics with gastric reflux .
A bloody discharge is a sign of serious pathology . Blood can originate from anywhere within the respiratory tract and careful examination is needed to determine the source of the bleeding .
Causes include :
• exercise induced pulmonary haemorrhage ( EIPH ) that is a bilateral discharge appearing within a few hours of strenuous work . Although not an emergency , EIPH can occur when tiny blood vessels in the lungs rupture due to large pressure changes and is exacerbated by any concurrent inflammatory airway disease . There are several veterinary treatments that can help reduce the incidence and effects of EIPH , but very often once a horse has ‘ bled ’ it is more likely to bleed again . EIPH is a common cause of poor performance .
• guttural pouch fungal infection : if a nasal discharge containing blood appears unrelated to exercise and is associated with a muco-purulent nasal discharge it may be caused by guttural pouch mycosis .
• upper respiratory tract issues : blood in a unilateral discharge more often occurs with upper respiratory tract lesions such as the progressive ethmoid haematoma ( PEH ) tumour ; traumatic sinus haemorrhage after a fall or a kick to the head ; the presence of cysts , polyps and masses in the nasal cavity and fungal infections of the sinuses . These can all grow quite large before they are detected . Sometimes the discharge may also be purulent , copious and bad-smelling . Tumours in the sinuses can produce intermittent , low-grade , unilateral bleeding that may contain pus .
Blood appearing as frank haemorrhage from the nose can be deadly if it is due to a fungal infection in the back of the horse ’ s nasal cavity ( guttural pouch mycosis ). The fungal infection damages a major blood vessel in the area and causes it to rupture and the bleeding is usually from both nostrils . Emergency surgery can be life-saving .
Horses can also develop a tumour called a ‘ progressive haematoma of the ethmoid plate ’ which can be a source of nasal blood . Although they usually cause a low-grade , unilateral bloody discharge , they can also rupture and cause frank haemorrhage .
If your horse has even a small amount of blood in a nasal discharge , discuss promptly with your veterinarian as an endoscopic exam can determine its source .
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