[header] How to diagnose and treat the cause of deformed cat nails [title] Look for thicker nails. [step] The nails of cats should be thin and sharp, not thick. If your cat's nails become thicker and harder, this may be a symptom of an underlying health problem. 
[substeps] Older cats can develop thicker nails as they age. Thickening of the nails sometimes occurs with an increase thirst.