|Classification and external resources|
Myelopathy refers to pathology of the spinal cord. When due to trauma, it is known as (acute) spinal cord injury. When inflammatory, it is known as myelitis. Disease that is vascular in nature is known as vascular myelopathy. The most common form of myelopathy in human is caused by degenerative changes in the cervical spine, which cause chronic compression of the spinal cord. Arthritic changes (spondylosis) of the cervical spine results in narrowing of the spinal canal (spinal stenosis) and can cause compression of the spinal cord. In Asian populations, spinal cord compression often occurs due to a different, inflammatory process affecting the posterior longitudinal ligament.
Clinical signs and symptoms depend on which spinal cord level (cervical, thoracic or lumbar) is affected and the extent (anterior, posterior or lateral) of the pathology, and may include:
- upper motor neuron signs (weakness, spasticity, clumsiness, altered tonus)
- lower motor neurone signs (weakness, clumsiness in the muscle group that innervated at the level of spinal cord compromise
- pathological hyperreflexia and inverted Plantar reflex (positive Babinski sign)
- sensory deficits
- bowel/bladder symptoms and sexual dysfunction.
Differential diagnosis of chronic myelopathy is extensive.
Myelopathy is primarily diagnosed by clinical examination. Once myelopathy has been diagnosed, the cause of myelopathy needs to be investigated using imaging, and especially Magnetic Resonance Imaging (MRI). The presence and severity of myelopathy can be evaluated by means of Transcranial Magnetic Stimulation (TMS), a neurophysiological method that allows the measurement of the time required for a neural impulse to cross the pyramidal tracts, starting from the cerebral cortex and ending at the anterior horn cells of the cervical, thoracic or lumbar spinal cord. This measurement is called Central Conduction Time (CCT). TMS can aid physicians to:
- determine whether myelopathy exists
- identify the level of the spinal cord where myelopathy is located. This is especially useful in cases where more than two lesions may be responsible for the clinical symptoms and signs, such as in patients with two or more cervical disc hernias
- follow-up the progression of myelopathy in time, for example before and after cervical spine surgery
TMS can also help in the differential diagnosis of different causes of pyramidal tract damage.
- "myelopathy" at Dorland's Medical Dictionary
- "Myelopathy.org - Home". www.myelopathy.org. Retrieved 2015-10-05.
- "The Science of CSM - Myelopathy.org". www.myelopathy.org. Retrieved 2015-10-05.
- Myelopathy differential diagnosis web site
- Chen R, Cros D, Curra A, Di Lazzaro V, Lefaucheur JP, Magistris MR, Mills K, Rösler KM, Triggs WJ, Ugawa Y, Ziemann U. The clinical diagnostic utility of transcranial magnetic stimulation: report of an IFCN committee. Clin Neurophysiol. 2008 Mar;119(3):504-32.
- Deftereos SN, et al. (April–June 2009). "Localisation of cervical spinal cord compression by TMS and MRI". Funct Neurol 24 (2): 99–105. PMID 19775538.
- Chen R, Cros D, Curra A, et al. (March 2008). "The clinical diagnostic utility of transcranial magnetic stimulation: report of an IFCN committee". Clin Neurophysiol 119 (3): 504–32. doi:10.1016/j.clinph.2007.10.014. PMID 18063409.