What would make a cat lose wait and nails to fall out?

my friends cat lost 5 pounds in a year and now its nails are falling out and he is loosing his appitite.and he gets his shots on time every year.What would make a cat lose wait and nails to fall out?
Check kidney function, complete blood count. My 10 y.o. lost 4 of 16 lbs., we found out he had a nonremovable mass on one kidney, other was shriveled up, but after some i.v. fluids, he is FINE, gained all the weight back, and it's been 3 years. Get kitty checked out. There's definitely an imbalance somewhere and it doesn't have to do with shots. My cats have never gotten shots and they're fine and live a long time.What would make a cat lose wait and nails to fall out?
Yearly vaccinations only provide protection from certain contagious diseases.





Weight loss and loss of apetite are clear signs of health problems. That cat needs an exam and treatment now.





It could be as simple as worms, or more complicated, like hyperthryroidism. That would explain the nail shedding. They do shed a layer on occasion, but cats with hyperthyroidism shed them often. Not the whole nail, just an outside layer.





Your friend should take the cat to the vet for a fecal (stool) test, and blood chemistry panel with a T4 (thyroid) test.
5 pounds is a LOT of weight to lose for a cat. And his claws are falling out?! It's normal for a cat to shed the outer sheath of their claws every now and then, but anything more than that is bad news. That is extremely serious. VET, NOW. There are any number of things your cat can get which can not be prevented by vaccines, and it's the pet owner's responsibility to take the animal to get medical care when it shows signs of illness. And claws ';falling out'; is a really big deal. Please, please tell your friend to take this cat to a vet IMMEDIATELY.
I don't know, but I wouldn't have let it go that far....would have gotten it right to a vet....which I advise you to do ASAP.