Cysts and Rapid Weight Loss

So when my dog was 6 months old he developed this big, fatty cyst on his shoulder and in a week dropped about 5kg (leaving him at 15kg when he was previously 20kg).  We had sort of prepared for the worst because it was so fast and the lump was so weird, but our local vet basically said no it’s just a bump it’ll go on it’s own. So I went to get a second opinion. They popped it for a biopsy & it was fluid so they just drained it and said they didn’t know what was wrong. Since then we’ve had health issues from excessive peeing (even when nothing’s coming out - he doesn’t mark, he was neutered very young). Anyway, he’s just turned 17 months and I had to take a trip to london so he went into boarding with a lady I trust very much (he’s very reactive so it’s always a tight circle) from Thursday until yesterday (Monday). Since dropping him off he has gone from around 25kg to 22kg and has a weird, small, rock-solid lump on his elbow. I called to let them know and they said he’s probably fine and that I worry too much, and perhaps I should feed him more so it stops happening (he eats an ungodly amount of food to the point where people are shocked that he isn’t obese). I want to switch vets again because I’m upset and I’m convinced there’s something wrong with my dog but they just won’t look. Surely it’s not normal for a young dog like this to be coming up in scary bumps all the time and losing so much weight so quickly?  

*excessive peeing to rapid changes in behaviour (including snapping at me in the face randomly once which was entirely unexpected and he’s never done anything like it before or since).

Hello!   So you're telling me that your dog has lost weight, is urinating excessively and eats a lot of food, to the point that he 'should' be obese, but he isn't.   When was he last seen by the vet?  In general, such signs should always be checked quickly, in order to rule out diabetes for example, which can be done using a urine sample and blood test.  A urine test (you could catch one for them in a previously clean, dry container) tells clinicians a lot about the water balance in an animals' body.  Many vets will offer you same-day consultation for this, especially if you pet appears to be unwell in themselves, so it's worth calling your vet now if you haven't.  Perhaps you could ask that an emergency vet or nurse goes over these symptoms with you for triage.  Regarding the lump on the elbow:  is this the same on both sides?  If so, then it may be a bony landmark protruding as a result of weight-loss.  If not, then it sounds as though that ought to be looked into too but it's the urinating and weight loss that worry me in the short term.  Please speak to the vet as soon as possible and let us know how you get on.  

Hmmm having reread your first message, I am not sure whether your dog is marking a lot or trying to urinate, but it's excessive urination that I would be worried about here.  If he is not producing a lot of actual urine, I am less concerned about diabetes.   Even so, I think that the best plan would be to make a list of the symptoms (signs / unusual things) that your dog is showing, and ask that a vet or nurse assesses when would be the best time-scale for an appointment.

5kg is a lot of weight to lose - it's 1/4 of his bodyweight.  Whatever the cause, I am concerned about your dog and think that both the weight loss and the lump should be checked out.

With some urgency - please explain the scale and speed of his weight loss on the phone.

With some urgency - please explain the scale and speed of his weight loss on the phone.