Hello from Prague, Czech Republic. We have been fighting with exactly the same symptoms of my cat (7 months old male) for past two weeks. The cat can't walk, he is pulling his rear legs. No fever, he eats the cat litter sand, hiding away and he is very drowsy. We tried everything, antibiotics (quite a few of them), corticoids, steroids with no results whatsoever. He is not getting better or worse. The vet did the ELISA FIP test which turned positive. I do not trust this test. We have one more cat that had similar problems the vet did the same FIP test and recommended euthanasia. We did not do it, the cat healed and haven't had any problems since then (>2.5 years). Recently we have found that cat had ascarides worms (to our surprise as we use the Stronghold regularly and he does not have access outside of our apartment). I had quite an argument with the vet as he was diagnosing the FIP from the test only (the cat has no other usual FIP symptoms like vomiting, diarrhea, fever etc.). The vet also said that this might be a blod block or neurological issue combined with the worms (ascarides). I'll keep you updated regarding our progress.