Question of the Day

Test for acetylcholine receptor antibodies to rule out myasthenia gravis, which is a cause of acquired megaesophagus in older dogs. 

The megaesophagus is outlined with yellow arrows in the image below. There is also evidence of a patchy alveolar pattern in the ventral lung fields suggestive of aspiration pneumonia, a common finding in dogs with megaesophagus.   
 

Edrophonium (Tensilon^®) can be given as a clinical test for myasthenia gravis. However, since this dog is not weak it would not be useful.  

Megaesophagus can be idiopathic or secondary to other systemic disease such as heavy metal toxicity, atypical hypoadrenocorticism, and any lower motor neuron disease.  

Image courtesy of Dr Kalumet.