The question is what is coming first. Is the nausea causing the dizziness or the dizziness causing the nausea. You have had an ENT referral with a workup for the dizziness. It would seem reasonable at this time for a GI referral to evaluate if there is any cause for the nausea.
Tests such as an upper GI series or upper endoscopy can be comprehensive in finding GI sources for nausea - including ulcers, GERD, or inflammation of the esophagus or stomach. I would also suggest a blood test to look for H Pylori, a bacteria that is associated with inflammation.
If the GI tests are negative, then the brain MRI can be performed to further look for neurological causes of dizziness.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Thanks,
Kevin, M.D.