Why Is My Kitten Lethargic and Weak in the Limbs?

A lethargic kitten with weak limbs is worrying and can have many causes. Medical ones include a cat cold, infectious diseases such as cat flu, feline distemper, or feline coronavirus, and calcium or trace-element deficiencies that weaken growing bones. Non-medical causes range from a normal post-vaccine reaction to simple hunger. Because a single symptom isn't enough to diagnose, and kittens can decline fast, a vet check is the safest move.