Lethargy in cats can actually be very difficult to diagnose as cats typically are not highly active animals

Determining the severity of the lethargy and its duration becomes important when distinguishing between an acute (short term) or chronic (long term) aetiology.

As a stand alone sign, it is not an emergency however if combined with other clinical signs it may be. Cats will require a full diagnostic workup including a physical examination, urinalysis, and diagnostic imaging.

Possible Causes

It can be normal following exercising or as a result of aging.

More serious conditions associated with lethargy include:

  • Heat stress • Infection • Parasites • Poisoning • Hormonal disorders • Nutritional disorders
  • Liver or kidney disease • Heart disease • Respiratory disease • Urinary tract infections
  • Gastrointestinal disorders • Inflammatory diseases • Immune-mediated diseases • Cancer

Lethargy is commonly seen along with nearly all symptoms of illness or injury. Lethargy as a solitary symptom in a cat is unlikely to be significant.