Strokes are less common in guinea pigs than heart attacks and it is very easy to distinguish the two. The symptoms are total collapse with the head and sometimes the body contorted from waist up at forty five degrees. There is nystagmus of the eyes, that is, they slowly slip towards one corner of the eye then rapidly jerk back to the central postion, repeatedly. At the slightest touch the animal will freak out and the heart beat is very rapid.
These symptoms are, of course the very opposite to those of a heart attack victim and consequently the treatment is different.
Put the animal in a box with lots of hay and leave it in the dark for about two to three hours and leave it to stabilise in peace and quite. If it has a repeat stroke, the chances are that it will die. However, in more cases than not, providing the animal gets the chance to stabilise in it's own time, the prognosis is fairly good.
As it is so important to leave the animal in peace, you must monitor it very quietly, so put it in a place where it can be observed without out having to move the box it is in. Once the animal will allow you to touch it and handle it without traumatising it, in my experience this usually takes two to three hours, you must think about rehydrating it, subcutaneously at the dose rate of twenty to thirty ml per session.
If the owner cannot do this it has to be taken to a veterinary surgeon, or preferably one should be called out, for the less the animal is disturbed, the better.
In the cases I have dealt with, after two rehydrations which were about six hours apart, I managed to get the animals to take fluid orally. Never attempt to rehydrate orally until you are certain that the animal can swallow with ease.
The nystagmus sometimes clears by the time the animal is ready for the first rehydration, but more often than not it continues at a gradually reduced rate and for a day or so is replaced by the hunted look that heart attack victims suffer from.
It can take for up to two weeks for the head and body to level up but most animals who suffer strokes are left with a slight tilt to the head, which is more noticeable when they are picked up. Sometimes it is necessary to give the same kind of water therapy as for the heart attack cases, see Swimming therapy
The good news is that stoke victims usually make a complete recovery. There is less incidence of second strokes as there is of repeats of heart attacks.