How do you approach the workup of transverse myelitis without any abnormality on spine MRI?  

If you are highly suspecting TM on clinical features, and other etiologies seem unlikely, then consider LP, checking labs (autoimmune, demyelinating, infectious, metabolic, etc), starting immunotherapy (if infection is unlikely, maybe check with Infectious Disease on that decision), and then in a fe...

Agree with all the above. Just want to mention a case I saw just after Thanksgiving. The lady came with transverse myelitis symptoms and very distressed. I ordered MRI thoracic immediately and follow her closely. However, because of her life style, I suspected drug use and finally she admitted inhal...

Great discussion, few more points: MOG-antibody myelitis often hits the CONUS and can be MRI negative at onset-something to remember. Timing from the onset of symptoms to nadir is important in ddx of myelopathy when MRI is negative-infarct usually reaches nadir in <6 hours, myelitis is typica...

If myelopathy is not clearly associated with evidence of inflammation in the CSF, I would also take care to rule out dural AV fistula - a common mimic that can get WORSE with steroids.