Question: Dog has started exhibiting voracious appetite, but went from 6 lbs to 5 lbs and feels like he has no muscle mass. He acts like he is starving constantly but eats well. He has a history of bladder stones and has been eating Hills U/D exclusively for 2 years. No increase in water consumption or urination noted. He is bright and alert, has good haircoat and is not lethargic. CBC/Chem were normal, T4 came back low so vet ran thyroid screen and said it was low. Started on 0.1 mg Soloxine BID yesterday. Previous meds taken (not taking now) Theodur and Dexamethasone for itchy skin. My question is that my dog exhibits none of the classis hypothyroid symptoms like Obesity, lethargy, poor hair coat, in fact is quite opposite, having lost weight, and is not lethargic. His skin and coat are fine with the exception of allergy-type symptoms and itchiness. Is it possible that he is NOT hyperthyroid and there is something else going on to give a low thyroid reading? Other signi! figant history: chronic valvular disease (compensated, diagnosed 2/95) Fecal neg, U/A showed traces of blood. Currently taking 62.5 mg Clavamox BID x 14.omo
The three things of which I would be suspicious causing weight loss despite a voracious appetite (with normal bloodwork) are a dietary imbalance related to the prolonged use of u/d, cardiac cachexia due to chronic valvular disease, and infiltrative disease causing either poor absorption, or poor utilization of the food. I would consider gradually switching to a higher quality diet, and having x-rays taken to rule out other internal disorders. I will comment further on hypothyroidism if you can tell me the results of the free t4 and TSH tests. You are right though, he is not manifesting any classic signs of hypothyroidism,and the thyroid supplementation maybe unnecessary. Another empiric change you should consider is ading a digestive enzyme to his food to increase nutrient utilization.