A stroke describes a loss of functional brain cells as the result of insufficient circulation after a blocked vessel or a ruptured artery inside the brain, and subsequent bleeding.
The animal suffers sudden symptoms such as dizziness, collapsing, disorientation or seizures. Blindness can also occur. Sympoms may regress partially or fully. A common complication is paralysis ( i.e. of facial muscles or limbs).
Strokes in dogs result almost exclusively from advanced age.
In cases where symptoms are severe the animal will have to be hospitalized. An intravenous catheter has to be introduced in order to administer drugs, which can help to dissolve the thrombus (coagulated blood) inside the brain. A prognosis for full recovery is often difficult to state. However, usually, the older the animal the higher the risk of permanent damage.
The symptoms mentioned above should always be considered a clinical emergency. Take your animal to a veterinary practice or clinic immediately.