Are you aware of any disease that causes intermittent distention of the left external jugular vein? I am a 66 y/o man who plays tennis and bikes weekly. MRI and MRA of head and neck and chest are normal. Angio CT of chest was normal. Stress echo EKG was also normal. I was recently treated for bizarre, chronically progressive GI symptoms that promptly resolved on treatment for H. pylori. Blood work turned up early Hashimoto s with low T4 and elevated TPO antiobodies, so I started thyroid 4 days ago. I seem to feel better already, although perhaps it s a placebo effect, as nowhere do I read that thyroid works that fast. What s left undiagnosed is this bizarre sensation of fullness and pulsation (or muscle twitch?) in my left neck that corresponds to distention of the left external jugular. The right external jugular is completely normal. I ve Googled it, but find nothing in terms of a differential dx. The distention is not related to exercise or anything else that I ve tried to associate with it.