Can an episode of Feline Hyperesthesia Syndrome be triggered by injections (sub-cutaneous fluids in

Hello,

My cat has advanced stage kidney failure and receives daily sub-cutaneous injections, a shot of Ranital for acid reflux and a phosphorous blocker in powder form with food. She has been diagnosed about 4 months ago after crashing and stabilized after IV treatment. Today, about 5-10 minutes after I have given her her morning shots, she started displaying the following symptoms: dashing around the flat, jumping on/off furniture, general agitation, diluted pupils, rolling/rippling skin, twitching, shaking off her paws and kicking erratically, vicious grooming, biting her paws, etc. This lasted approx. 10 minutes after which she calmed down and went to sleep. It was pretty scary. She did run around and can be very vocal sometimes but I attributed it to a normal form of cat play, and today's behaviour was totally new to me.

After googling these symptoms, I'm suspecting it might be a case of Feline Hyperesthesia syndrome. Now, I will consult the vet just in case, to rule out any other causes but since it may very likely be FHS it makes me wonder: can an episode be triggered by stress/pain? My cat dislikes her shots (tries to hide if she sees the syringe) and I assume it's stressful to her and a little bit painful - anyway as much as an injection would be to anybody.

Thanks!

CB

Subqs are given under the skin so are not "injections" per se. They are not being given into the muscle or anything like that, and while they are not necessarily comfortable all the time, they don't, as a rule, cause pain. It's possible the "bubble" is pressing on a nerve - now THAT could be painful.

What meds are you giving your cat? Are you giving mirtazepine by any chance, and if so, how much?

I disagree that subcutaneous injections don't cause pain. If you've ever had medication you've had to inject into your belly you'd know (but less pain than injecting in a muscle, for sure). Supposedly the scruff of a cat's neck doesn't have as many nerves, but it does still have nerves. My cat can tell the instant the needle's in, even before I start pushing the plunger and even when I use a teeny tiny insulin needle. Different spots on the scruff are definitely more sensitive than others (which for me makes it hard to follow the advice of use a different spot each time).

But depending on where the big fluid bubble ends up, I can conceive of that irritating a nerve, probably more than the initial injection itself.

While lI don't think it's actually FHS, I do agree that with that particular jab, you may have hit either a nerve or something unusual or that the pressure from the "water balloon" is hitting a nerve somehow.  Probably wouldn't happen again in a million tries.  I know with our girl, we once hit a capillary or something in her scruff, because when we pulled the needle out when we were finished, there was a tiny bit of blood, which we never see.  And she flinched that time when the needle went in.  Now,  what are the chances of doing that ?