QUESTION

My cat has had two previous instances of a sudden paralysis of a paw, front right and back right but both of these recovered quickly after injections and rest. This time it has happened again to the back right leg but seemed to be much more serious, he went into shock so we rushed him to the vets, where he got another injection and a repeat two days later. This time though, the leg has recovered (he was dragging the whole leg) but the paw is still limp and he is knuckling whenever he walks.The vet has just given him two further injections and said we'll give him another month. Is there anything we can do to encourage the nerves to recover? I've read about methylcobalamin (B12) as something that could help. Is it worth trying? Or would a splint help him to stop knuckling? He doesn't seem ill at all, it will be so difficult to have to think about putting him to sleep just because of his paw.
Alison

ANSWER

Dear Alison
To get these sort of paralysing events in the legs I would think you are almost cartainly dealing with thromboembolisms where a blood clot forming in the heart then goes through the blood stream and affects the circulation in the leg causing immobility. When these are very small they block the blood vessel a long way down where there is actually more than one blood supply coming in to most tissue hence a rapid recovery.

When it blocks in the femoral artery then it will cut off circulation to the whole leg initially and is a very painful episode thus putting the cat into a state of shock. In a 16 year old cat there is usually an underlying cause and things that are worth looking into including hyperthyroidism (overactive thyroid), hypertrophic cardiomyopathy (thickened walls of heart) and valvular endocarditis (inflammed or infected heart valves).

If I am correct then the treatment is looking at treating the underlying cause to reduce the possibility of clots forming and using something to thin the blood. the best thing to thin the blood is using asprin which is used at 30-60mg per cat two - three times a week. Asprin is poisonous to cats if used at higher doses and should not be used unless there has been a problem clearly identified but in these occaisions can save lives.

The blood clot will form either due the heart valves being damaged allowing the clot to form or blood flow through the heart being disturbed allowing a clot to form in the heart. These are detectable on ultrasound examination of the heart. Most cats with these problems will have an audible heart murmer but not all so a normal sounding heart does not rule out the conditions.

I think you need to try to find a diagnosis as to why these episodes are occuring rather than looking into vitamin B12, which I would be sceptical about doing much good in speeding recovery. Physiotherapy is a far more important thing than splinting as you need to get the muscles and associated ligaments used to moving again.

Paul Wilson