Reasons Regarding Regurgitation

Please excuse my alliteration in the title, but it just sounded fun.  Here's an email from Stefanie....

I have recently taken on a second foster dog. She is only about a year old and is a border collie cross. A high energy dog - which is fine - I'm learning how to channel her energy. I've noticed though that she will glurp out water as she is walking or running around. She also even glurped (my non-technical term for regurgitation) out dog food and water about 6 hours after her last meal. It's not a lot and while she has actually vomited a couple of times - it's been different objects she's chewed on around the house - it's more the regurgitation that has me puzzled.
Is regurgitation a few times a day enough to warrant a vet visit? She doesn't have any other symptoms other than what I've described - still has plenty of energy and is bright-eyed. I am fostering for a rescue so ultimately the decision to take her to the vet is at their discretion, but your advice on when to have her examined is greatly appreciated.
 
I would most certainly take her to the vet, and plan on having x-rays taken.  As you've indicated, regurgitation is different than vomiting.  The former is passive, with the stomach or esophageal contents spilling out because of a lack of tone in the sphincters or muscle walls.  Vomiting is active, involving contractions of the abdomen and stomach.  There are very different indications for each, so we can't treat them similarly.
 
The biggest concern I would have for chronic regurgitation would be megaesophagus.  This condition occurs when the esophagus is significantly dilated for some reason.  Anything swallowed can sit in this expanded area rather than passing into the stomach, and after a period of time can suddenly "glurp" back out.  In younger dogs this is most commonly caused as the result of a birth defect where a vascular arch near the heart stays around the esophagus, essentially causing a stricture and eventually dilation of the esophagus.  There are causes of megaesophagus that are more acquired than a vascular abnormality, but they are not as common.  A hiatal hernia or problem with the cardiac sphincter of the stomach (the one between the stomach or esophagus) could cause similar problems.  But I would consider megaesophagus until shown otherwise.
 
Megaesophagus is a big concern, as there is a high risk of food or water running backwards through the esophagus getting down the trachea and into the lungs, causing what we call aspiration pneumonia.  This kind of pneumonia can be life-threatening and the risk shouldn't be ignored, even if it hasn't happened yet.  Even if it's not megaesophagus, anything being regurgitated can be aspirated into the lungs and therefore should be checked out.
 
There is no cure for megaesophagus, so efforts are put to management.  I have known dogs successfully managed for many years, but it involves being very careful about feeding and drinking.  These dogs always need to have elevated bowls so they do not have their heads down while they are trying to swallow.  Essentially we are letting gravity work with us rather than against us.
 
So see a vet about this before something worse happens.  Good luck, Stefanie!
 
By the way, I love the word "glurp" and may use it myself, if you don't mind!