Ask a Dog Vet and Get Answers to Your Dog Veterinary Questions
I am sorry to hear you are worried about Monster. It must be scary to see him pass out; no wonder you are worried. My name is Rebecca. I am a veterinarian and will do my best to help.
Has he had a physical examination recently? The first thing I would check for if he were mine is an irregular heart beat, or a heart murmur. The most likely cause of his passing out with exercise is a heart problem, where his heart can't pump enough blood to his brain when he is running hard, a condition called syncope. If it is his heart, there may be medications that will help his heart beats stronger, or treat for an irregular heart beat.
If it happens again, check his gums the moment he passes out. If his gums appear pale or white, this is probably syncope, and is probably due to a heart problem.
Let me know what else I can help with or answer.
That is another possibility. I have not seen many dogs actually pass out from a collapsing trachea, but it is possible. Usually dogs with a collapsing trachea have a honking cough that gradually gets worse with time. A chest Xray would tell you if he has a collapsing trachea, or an enlarged heart.
Heart disease can cause coughing as well.
The lumps on his chest are probably not causing this problem. Most lumps on or just under the skin are benign in dogs, about 85%.
A good physical exam is where I would start. A chest Xray might also be a good idea.
Let me know what other questions you have, and kindly consider rating my answer so the website knows to credit me for helping you. You can still ask more questions, or get back to me with updates after rating. Please do let me know how he is doing and what you find out. Rebecca
Yes, there may be. First you have to get a diagnosis: irregular or slow heart rate, congestive heart disease, collapsing trachea. The treatment would be different depending on what the diagnosis is. I could learn so much just by looking at his gums, feeling his pulses, and listening to his chest with a stethoscope.
Let me know what else I can answer and what I can do to earn a good rating from you. I will be online a short time longer tonight, and back again tomorrow morning. Rebecca
How is Monster doing?