Friday, November 22, 2013

Difficult Swallowing in Cats with Hyperthyroidism


We have a 13-year old male cat named Balki with hyperthyroidism and moderate renal disease. He has a history of diabetes, but that has been in remission for the latter for several months.

Balki's main problem at the moment is trouble eating. My veterinarian just puts it down to the renal disease. However, it seems he wants to eat, but has difficulty swallowing. It has progressively gotten worse, to the point where he is now barely eating.

He also has had several episodes of reverse sneezing. When trying to eat, he extends his neck and gulps, then turns away from the food being offered. He also sometimes drools, and often spits out the food. He has most difficulty with dry food.

Can you give any advice on what might be causing this, and what tests he might need to find out, and how to help him to be able to eat?

My Response:

The typical hyperthyroid cat eats well (usually an increased appetite). These cats almost never develop anorexia, and difficulty swallowing (dysphagia) never occurs as a direct result of hyperthyroidism (1-4).

Most cats with moderate to severe renal disease will develop a decreased appetite as a result of their uremia, but they don't show signs of dysphagia (5). Most likely, your cat has disease either in the caudal pharygeal (throat) region or esophagus that is causing some obstruction to the food eaten (6-10). With the history of reverse sneezing, I'd say the problem is most likely in the caudal pharynx.

I'd recommend starting with a good oral examination (under sedation) to look for a lesion or mass in the pharygeal area. If nothing is seen, then endoscopy may be needed. Radiography or other imaging (e.g., CT scan) may also be required to help define the extent of your cat's disease (9-11).

Could thyroid tumors ever grow large enough to compress the esophagus and produce signs of dysphagia? That would be extremely unlikely, since even cats with large thyroid carcinomas almost always continue to eat well and don't have any problems swallowing.  However, I have had two cats in my career that had thyroid carcinoma which invaded the esophagus, leading to signs of esophagitis and esophageal obstruction. In any case, the chance of that being the problem in your cat would be about 1 in a million; again, that would best be diagnosed with endoscopy and CT imaging.

References:
  1. Baral R, Peterson ME. Thyroid gland disorders In: Little SE, ed. The Cat: Clinical Medicine and Management. Philadelphia: Elsevier Saunders, 2012;571-592.
  2. Mooney CT, Peterson ME. Feline hyperthyroidism In: Mooney CT, Peterson ME, eds. Manual of Canine and Feline Endocrinology Fourth ed. Quedgeley, Gloucester: British Small Animal Veterinary Association, 2012;199-203.
  3. Peterson ME. Hyperthyroidism in cats In: Rand JS, Behrend E, Gunn-Moore D, et al., eds. Clinical Endocrinology of Companion Animals. Ames, Iowa Wiley-Blackwell, 2013;295-310.
  4. Peterson ME. Top 10 signs of hyperthyroidism in cats. Animal Endocrine Clinic blog post. March 21, 2011.
  5. DiBartola SP, Rutgers HC, Zack PM, et al. Clinicopathologic findings associated with chronic renal disease in cats: 74 cases (1973-1984). J Am Vet Med Assoc 1987;190:1196-1202. 
  6. Watrous BJ. Clinical presentation and diagnosis of dysphagia. Vet Clin North Am Small Anim Pract 1983;13:437-459.  
  7. Vos JH, van der Gaag I. Canine and feline oral-pharyngeal tumours. Zentralbl Veterinarmed A 1987;34:420-427.
  8. Mattson A. Pharyngeal disorders. Vet Clin North Am Small Anim Pract 1994;24:825-854. 
  9. Gengler W. Gagging. In: Ettinger SJ, Feldman EC, eds.The Textbook of Veterinary Internal Medicine. St Louis, Mo, USA: Saunders Elsevier; 2010:189–191.  
  10. Jergens AE. Diseases of the esophagus. In: Ettinger SJ, Feldman EC, eds. The Textbook of Veterinary Internal Medicine. St Louis, Mo, USA: Saunders Elsevier; 2010:1487–1499. 
  11.  Pollard RE. Imaging evaluation of dogs and cats with dysphagia. ISRN Vet Sci 2012;2012:238505. 

4 comments:

Unknown said...

My cat developed a similar problem after coming home from the vet when diagnosed with hyperthyroidism. She previously was eating voraciously, which I understand is a symptom of that disease. But after the vet visit, her appetite significantly decreased, and she started acting like she was having trouble chewing and swallowing her dry food. It was a dramatic change. She also started with sporadic vomiting. Just as these issues were beginning to improve somewhat, I had to take her back to the vet for x-rays in advance of her scheduled I-131 appointment. Now, she's back to having difficulty swallowing dry food and has very little appetite. I have to coax her to eat.

Any thoughts on what may be happening? The 1-131 treatment in scheduled for 11 days from now.

Dr. Mark E. Peterson said...

If the difficulty in swallowing is from hyperthyroidism, it must be a large invasive thyroid cancer. Most likely, it's not related at all. I would not treat your cat with radioiodine without first evaluating a thyroid scintiscan (scintigraphy). Otherwise, you haven't ruled out invasive cancer and the I-131 dose might not even be high enough to do anything. Talk to your vet.

Cluth64 said...

I have a 17 year old female who has hyperthyroidism and has been treated for 27 months. Recently, she has started having difficulties swallowing her food. I've started giving her kitten milk to drink, which she likes but I wish I could find a food that she could eat given her difficulty swallowing.

I know she is probably at the end stages of this disease, but want to make her as comfortable as I can as long as I can. She is in good spirits, and enjoys being around her family, and purrs constantly.

Any suggestions for food?

Dr. Mark E. Peterson said...

This is probably not caused by hyperthyroidism or a thyroid tumor. I'd recommend that you see your vet to best figure this out. Obviously, a soft food or liquid gruel may be easier to swallow.