HI, thanks for using healthcare magic
I agree with you, that it cannot be dismissed so easily.
Dizziness, light headed sensation and
nausea often go together.
There are different possible causes: (1) it can be related to the
inner ear and there are 3 main conditions that affect the inner ear eg meniere's disease,
vestibular neuronitis, benign paroxysmal positional vertigo
(2)side effect of medication
(3)low blood pressure
(4)lesion in the brain such as the brain stem or cerebellum
(5)certain types of migraines
(6)
dehydration or electrolyte disorders
If her present doctor is not willing to assess and investigate, she may need to consider seeing another doctor.
A thorough history and physical examination should reveal the cause of the symptoms.
Based on these findings, additional investigations may or may not be needed.
I hope this helps