DeSena et al. published a paper in 2014 in JAMA Neurology describing a case series of five children (aged 29 months to 14 years) who had clinical characteristics that are not normally seen in transverse myelitis (TM) or acute disseminated encephalomyelitis (ADEM). All 5 children presented with flaccid paralysis to the University of Texas Southwestern Medical Center between 2009 and 2012 and were initially diagnosed with either TM, TM with brainstem involvement, or ADEM, but further magnetic resonance imaging (MRI) indicated that these children had inflammation in either the proximal ventral nerveroot or the cauda equina. A spinal nerve root, like the ventral nerve root, is the beginning portion of a nerve as it leaves the spinal cord and goes towards the muscles. The cauda equina is a group of spinal nerves and spinal nerve roots that innervate the pelvic organs and lower extremities, including motor innervation of the hips, knees, ankles, feet, internal anal sphincter and external anal sphincter, and sensory innervation of the perineum and some parasympathetic innervation of the bladder (source: http://en.wikipedia.org/wiki/Cauda_equina).
Nerve root and spinal nerve involvement as seen in these five children is unusual because in most cases of TM or ADEM, only the wires in the brain and/or spinal cord are affected, and not the wires after they leave the cord and go towards the muscles (there is more information about this topic a recent TMA blog post – https://myelitis.org/resources/tma-blog/reported-cases-polio-like-illness-relationship-transverse-myelitis). The nerve root or cauda equina involvement was discovered in imaging that was done after the initial diagnosis, so it is unclear if nerve root inflammation in patients with TM or ADEM represents a different disease mechanism than classic TM or ADEM, or if more people with classic TM or ADEM have nerve root involvement that was not caught in their initial imaging. Interestingly, the five cases described in this article all presented with TM/ADEM symptoms in the mid to late summer, and the authors note that this suggests that there may be a common viral or bacterial cause to these cases. Furthermore, nerve conduction studies were conducted on all five children as part of their diagnostic testing; nerve conduction studies measure nerve and muscle function in the body. Three of the patients’ nerve conduction results showed “evidence of possible axonal loss,” or damage to the nerves going into the muscles. Other studies have indicated that abnormal nerve conduction results are associated with a greater chance of incomplete motor return. The authors note that it is possible that some individuals who are diagnosed with TM and ADEM who do not recover may actually have nerve root involvement, so they suggest that all individuals who have nerve root inflammation and/or demyelination should have neuroimaging. They also argue that patients with TM who do not respond to treatment should have imaging redone to rule out nerve root involvement. The authors conclude that they believe that these patients are a separate category within the TM family of diseases, but that more studies are needed to better understand people with these clinical characteristics.
This summary was written by Gabrielle (GG) deFiebre, Research Associate at a Public Health non-profit in New York who was diagnosed with Transverse Myelitis in 2009. GG volunteers with the Transverse Myelitis Association.
Original research: DeSena A, Graves D, Morriss MC, Greenberg BM. Transverse myelitis plus syndrome and acute disseminated encephalomyelitis plus syndrome: A case series of 5 children. JAMA Neurol. 2014; E1-E6. doi: 10.1001/jamaneurol.2013.5323