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Location: East Midlands, UK
Joined: Mar 2006
Posts: 8,775
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Hope this helps:
Technically a stroke will not occur in the dog due to a complex system of filtration at the base of the brain which will filter out any blood clots that originate in the heart. We do see however something we call acute vestibular disturbances which can look similar and have similar effects in dogs as a mild stroke would in people. These are classified in many ways but the majority are called idiopathic (no cause on pathology).
A vestibular disturbance can be central in the brain or peripheral in the middle or inner ear. The main symptoms of a vestibular attack will be nystagmus (flickering of the eyes), unco-ordination, weakness on one side, head tilt to the opposite side and in the first stages you often see vomiting, circling, paddling, rolling over and often loss of bowel and urinary continence.
The cause of peripheral vestibular disease is usually an ear infection or trauma to the ear. This can include using ear cleaners etc. in the ear when the ear drum is not intact. Cancer of the middle ear can also cause this but very rarely. Treatment is either treating the infection or removing the source of inflammation be it stopping the drops or removing a grass seed etc.
Central vestibular disease is more common and is more likely to mimic a stroke. Central disease can be caused by a brain tumour, infection in the brain (not common), trauma, haemorrhage, systemic disease with kidney/liver failure, diabetes and anoxia (lack of oxygen) to the brain. This latest one is probably the most common and can be related to heart, breathing and circulatory problems. The lack of oxygen leads to swelling locally which can lead to permanent damage occurring. Vivitonin which I have discussed previously works by increasing the oxygen availability in the brain without increasing the overall amount of blood going through the brain by allowing the blood to penetrate deeper. Oxygen is the most potent anti-inflammatory that is know to reduce swelling on the brain hence the reason this drug is used. Other treatments involve trying to stabilise the nerve tissue and reduce inflammation. Steroids where used in high doses in the past to achieve this effect.
Vestibular disease is always sudden on onset. If symptoms come on slowly over time then I would also suspect a brain tumour to be the cause and dogs that have one episode are high risk for repeat episodes so should have preventative measures taken to reduce the risk.