5 month old kitten has tremors and trouble walking

Hello. I really need help, because we can't figure out what's wrong with our five month old tabby kitten Zika that we rescued around August. Around a week and a half ago, some of our other kittens ate asparagus fern and got sick, however they all got better except for Zika. Zika didn't have common symptoms for a poisoning, instead he had a high fever and became lethargic. After a few days, all of our cats were healthy, but Zika started losing balance, he had trouble coordinating and started walking wobbly, he refused to eat anything, lost a lot of weight and started having tremors and shaking violently. He also became itchy, whenever I touch him, he twitches and starts scratching or grooming. We took him to the vet and they gave him vitamins and infusion, which helped him, however temporarily as the next day, he started having tremors and a high fever (40°C) again. The vet can't get a diagnosis, they suggested cerebellar hypoplasia, but he only recently started having symptoms. Please help.

Hello - so we have tremours, itching, a temperature of 40 and a suggestion of cerebellar hypoplasia, although as you suggest it would be an unusual age to start with such a thing out of the blue.  Without knowing anything more, from all of these many miles away, I would wonder whether the kitten is fitting, which can be hard-going on any brain but particularly a tiny one.  Fitting does create a high temperature, so it's hard to tell whether the neurological signs came after the fever or caused it.  Low blood sugar, brain lesions, drugs/ toxins and infectious diseases (viruses etc) are amongst the differentials based only on what I have heard.   Unfortunately, speculate is all I can do from here and it sounds as though, in real terms, you need to decide to trust your vet or get a second opinion.  Good questions for your vet include, 'why do you think this?'  'What other differentials have you ruled out?'  'What stops it from being this?'  'What is the prognosis from here' and, if not satisfied, 'please could we arrange a second opinion / referral?'  Good vets mind the latter much less than you'd expect;  if we are right, it increases your confidence in us.  If we are wrong, we learn something and help the animal.  I don't know much about what is going on and hope that your kitten is being looked after in the immediate term.  I hope that something here might prove helpful to your situation.