Urination

• The most common symptom of kidney problems is that your cat will urinate frequently with little urine output.
  
  

Lethargy

• Because your cat is in pain, it will sleep longer, be listless and not engage in normal activities.
  
  

Vomiting

• Cats with kidney disease may be prone to vomiting, especially in advanced stages of the disease.
  
  

Thirst

• Because your kitty is peeing constantly, it may be thirsty and drink more water than usual.
  
  

Pupil Size

• Dilated pupils are an immediate sign that your cat's blood pressure is elevated. This is due to renal failure and is extremely serious.