Excessive vomiting, diarrhea, drinking, and urinating are also commonly seen signs. The cat may seem hyperactive and nervous, and in many cats this is displayed as increased vocalization. You may suddenly feel as if your cat is screaming at you more often than usual, especially in the night and early morning hours. The coat can look unkempt if the cat is undergrooming, but excessive grooming is also possible with resultant hair loss. Lesions on the skin can cause shedding of the fur and your cats claws may seem to grow faster and longer than normal.
Heat intolerance is common since the cat's own internal thermostat has been revved up.
You may notice them always looking for the coolest place in the house or yard to rest. The cat may have difficulty breathing and an inability to tolerate exercise or stress. Until the cat is stabilized, usually on antithyroid medication, anesthetic administration is very risky, again further reason to notice the waring signs and most common symptoms early on. Because this condition can affect every organ and system in the feline body, early detection is critical. Several effective courses of treatment exist today.