Removing the “idiopathic” from transverse myelitis
In neurology, there’s an excess of conditions which we would call idiopathic. Bell’s palsy, for instance, is often idiopathic. Headaches, very idiopathic. Epilepsy–you guessed it. 20-30% of all strokes are also idiopathic, but we call them cryptogenic. Idiopathic is everywhere in neurology, and it’s not necessarily because we aren’t clever enough to reach the diagnosis, or we lack the sophistication in imaging or diagnostic testing to identify the cause of the neurologic problem. Neurology, like all fields in medicine, is advancing rapidly. We’re discovering more and more genetic markers for diseases, more and more antibodies and other biomarkers. Sometimes it’s just hard to keep up with all of it.
This week I am joined by Dr. Clyde Markowitz, Director of the MS center at the University of Pennsylvania. Clyde was on our show in 2016 to talk about the radiologically isolated syndrome, and he returns this week to discuss idiopathic transverse myelitis. In its essence, Clyde says, “transverse myelitis is an inflammation of the spinal cord in the axial plane.” So it can affect a variety of multiple fiber types or cell bodies, resulting in a constellation of symptoms ranging from numbness to weakness to incontinence or urinary retention, dysautonomia, pain, and sometimes a sensory level. Transverse myelitis is a syndrome that can be caused by many disease states (see below).
Timing of symptoms can be informative. Acute transverse myelitis where symptoms are maximal around time of onset can be more suggestive of a spinal cord infarct. Conversely, symptoms that progress slowly over minutes to hours suggest an inflammatory or parainfectious process. And in a patient who complains of symptoms over weeks or longer, maybe even stepwise, you should be thinking structural, nutritional, or neoplastic. Or a dural AV fistula. Whatever the suspected cause, we often begin the workup with neuroimaging.
Additional neurodiagnostic testing recommendations by experts include the following:
There was a paper I came across in Neurology that was published in January 2018, which gave me the idea for this talk. It was published out of the Mayo Clinic and it was titled, “Evaluation of idiopathic transverse myelitis revealing specific myelopathy diagnoses”. Basically, 226 patients who were referred to Mayo Clinic with the diagnosis of idiopathic transverse myelitis were retrospectively studied. 91% of them had been seen and/or treated by a neurologist and given their idiopathic diagnosis. The authors reported that of the 226 patients, only 41 of them left Mayo with that diagnosis (18%). And I think this highlights the fact that medicine and neurodiagnostics are accelerating so rapidly that subspecialty care really is necessary in certain circumstances. Giving 82% of patients without a clear diagnosis a new, clear diagnosis is not trivial. Knowing that you actually have multiple sclerosis (in 75 cases from the study), or spinal cord infarction (37 patients) has the potential to change clinical management. 27 of the patients (12%) didn’t even have a myelopathy, and yet they were given a diagnosis of ITM.
It becomes more and more apparent, as the interview continues, that the diagnosis of idiopathic transverse myelitis is becoming somewhat outdated. As we become more knowledgeable about the condition, fewer and fewer patients are going home without questions answered. And while transverse myelitis or multiple sclerosis or neurosarcoidosis are certainly not easy to live with, I get the feeling that patients are feeling more and more reasurred as they arm themselves with this information.
The BrainWaves podcast and online content are intended for medical education and entertainment purposes only and should not be used in routine clinical decision making. The featured image from this week’s blog entry is from Jacob & Weinshenker, 2008. It identifies a dural AV fistula (3rd image is an MRA which points out the serpiginous vessel).
- Zalewski NL, Flanagan EP and Keegan BM. Evaluation of idiopathic transverse myelitis revealing specific myelopathy diagnoses. Neurology. 2018;90:e96-e102.
- Bevan CJ and Cree BA. Fulminant Demyelinating Diseases of the Central Nervous System. Semin Neurol. 2015;35:656-66.
- Greenberg BM and Frohman EM. Immune-mediated myelopathies. Continuum (Minneap Minn). 2015;21:121-31.
- Kimbrough DJ, Mealy MA, Simpson A and Levy M. Predictors of recurrence following an initial episode of transverse myelitis. Neurol Neuroimmunol Neuroinflamm. 2014;1:e4.
- Cobo Calvo A, Mane Martinez MA, Alentorn-Palau A, Bruna Escuer J, Romero Pinel L and Martinez-Yelamos S. Idiopathic acute transverse myelitis: outcome and conversion to multiple sclerosis in a large series. BMC Neurol. 2013;13:135.
- Jacob A and Weinshenker BG. An approach to the diagnosis of acute transverse myelitis. Semin Neurol. 2008;28:105-20.
- West TW, Hess C and Cree BA. Acute transverse myelitis: demyelinating, inflammatory, and infectious myelopathies. Semin Neurol. 2012;32:97-113.
- Goh C, Desmond PM and Phal PM. MRI in transverse myelitis. J Magn Reson Imaging. 2014;40:1267-79.