Hello and welcome to you and to your wife
It sounds like your wife (and you) have had a really miserable time I hope things improve soon!
When I read your post, the vomiting and hiccups/hiccoughs made me think of something in the paper that outlines the most up to date diagnostic criteria for MS. I’ll copy and paste what it says at the end.
Obviously I’m not a neuro and this may be a total red herring, especially if she doesn’t have any symptoms that would be associated with spinal lesions (i.e. weakness or strange sensations anywhere below the neck), but the fact that your wife had these symptoms and now has optic neuritis makes me wonder if she should be tested for NMO (also known as Devic’s disease) - a condition that is easily confused with MS.
These vomiting/hiccough type symptoms can and do happen in MS, they’re just not all that common so it might be worth asking your GP or neuro about the NMO blood test (for AQP4 antibodies), especially if your wife’s brain scan is inconclusive? The neuro may well be running it anyway, but it’s not exactly unheard of for things to get missed!
I hope you don’t have too long to wait for the MRI appointment and results - waiting is often harder than knowing!
“In its current review, the Panel focused specifically on the often-problematic differential diagnosis for MS of neuromyelitis optica (NMO) and NMO spectrum disorders. There is increasing evidence of relapsing CNS demyelinating disease characterized by involvement of optic nerves (unilateral or bilateral optic neuritis), often severe myelopathy with MRI evidence of longitudinally extensive spinal cord lesions, often normal brain MRI (or with abnormalities atypical for MS), and serum aquaporin-4 (AQP4) autoantibodies. There was agreement that this phenotype should be separated from typical MS because of different clinical course, prognosis, and underlying pathophysiology and poor response to some available MS disease-modifying therapies. The Panel recommends that this disorder should be carefully considered in the differential diagnosis of all patients presenting clinical and MRI features that are strongly suggestive of NMO or NMO spectrum disorder, especially if (1) myelopathy is associated with MRI-detected spinal cord lesions longer than 3 spinal segments and primarily involving the central part of the spinal cord on axial sections; (2) optic neuritis is bilateral and severe or associated with a swollen optic nerve or chiasm lesion or an altitudinal scotoma; and (3) **intractable hiccough or nausea/****vomiting is present for >**2 days with evidence of a periaqueductal medullary lesion on MRI. In patients with such features, AQP4 serum testing should be used to help make a differential diagnosis between NMO and MS to help avoid misdiagnosis and to guide treatment.” http://onlinelibrary.wiley.com/doi/10.1002/ana.22366/abstract (Click on “get pdf” to download a full copy of the article. This extract is from the second page, page number 293.)