Dog vomits clear liquid

[theSp00ner]

I have two bully mix doges, they are 4 years old, they are siblings, and one of them keeps vomiting small amounts of clear liquid.  
She has a history of upset stomach problems but this is different.  She has seen the vet twice since this has begun.   Here is some background info:

She has no abdominal pain or tenderness
The first visit to the vet she gave a urine sample, there was bacteria
She was treated for a UTI and the follow-up urinalysis was clean
On the first visit she was also diagnosed with a back sprain, muscle relaxants and anti inflammatories solved that
She has been wetting her bed at night
She is currently on Proin for incontinence
She was always a fast eater, now her appetite is not that great
Even after she does eat a bowl of food she still vomits only clear liquid
She is active and by all other aspects normal. Though she is losing weight and vomiting clear liquid at random times.
Chances of an obstruction are low, she chew up toys and spits them out as little pieces

She happy most of the time but nothing like she usually was,  I feel so bad and she is was always lean but is getting even skinnier.  
Any insight is helpful

Thank you

[candy412]

Hi i just saw this i have something that my help your dog to want to eat  its adite from a vet that i got when my dog had parov and she pulled throught it with this food it is fresh and you cook it your self,you would want one bag of white rice,four chicken brust,one can of peas.frist boil the rice as on pk then just befour done add the peas,in a pot boil the chicken till done then cool to cut up and then add to the rice mix feed to your dog to or three time a day,they will love it my stell eat it  now it is put in with thire food i hope this helps you and one more thing for the voitiming try babys pedlight it will help that to.

[theSp00ner]

Thank you for your comments.

Her BMs haves been normal the whole time, maybe a bit less volume because she is eating less.  but still solid.

Your right that it is not really a vomit.  She doesn't heave and pulse to though up.  Most of the time its a cough then clear slimy goo, or sometimes she just opens up and some goo comes out without coughing.

I suppose it happens after she drinks but not always

[Margot49]

Agree with The above regarding possible obstruction, especially since she eats things.  She may not be passing something.  Another cause could be pancreas, liver or kidney issues, which may be suspect since she had that UTI.  Would be concerned since her activity level us going down and she is thin.
If it were me, I would take her back to the Vet for a complete blood work up, including thyroid and get some abdominal x-rays and take in stool samples to test for parasites.  
Wish I could be if more help but the combined and continuing symptoms would concern me.
Please keep us updated and hope you can find the cause.

[ArtstOest]

Are you sure this is vomiting?  Does she cough and wretch, or does she have the full stomach spasms and full body involvement associated with vomiting?  If it is actually vomiting, she may be drinking water too quickly.  If it's wretching/coughing it may be the throat, lungs or esophagus. A major concern with loss of appetite and vomiting would be bloat or obstruction.  Obstruction can happen even with food, if she has a history of digestive problems.  You didn't mention if she's having normal bowel movements.