From the Guidelines
Upper motor neuron (UMN) lesions can indeed be located in the spinal cord, specifically affecting the lateral corticospinal tracts. UMN lesions refer to damage to the motor neurons that originate in the motor cortex of the brain and extend through the corticospinal tract. These lesions can result from various conditions such as spinal cord injury, multiple sclerosis, or spinal cord tumors. When UMN lesions occur in the spinal cord, they produce characteristic symptoms including increased muscle tone (spasticity), hyperreflexia, and the presence of pathological reflexes like Babinski sign, as noted in the evaluation of myelopathy 1.
Key Characteristics of UMN Lesions in the Spinal Cord
- Increased muscle tone (spasticity)
- Hyperreflexia
- Presence of pathological reflexes like Babinski sign
- Result from conditions such as spinal cord injury, multiple sclerosis, or spinal cord tumors
It's essential to distinguish UMN lesions from lower motor neuron (LMN) lesions, which affect the anterior horn cells in the spinal cord or peripheral nerves and present with different clinical features such as flaccid paralysis and muscle atrophy. The diagnosis and evaluation of UMN lesions in the spinal cord can be facilitated by imaging techniques like MRI, which is useful for evaluating the spinal cord and its contents, as well as surrounding structures 1.
Diagnostic Evaluation
- MRI is the preferred imaging modality for evaluating the spinal cord
- MRI can show signal alteration in the spinal cord earlier after symptom onset compared to T2-weighted images
- Diffusion-weighted imaging should be included when considering spinal cord ischemia 1
From the Research
UMN Lesion Location
- The location of an Upper Motor Neurone (UMN) lesion can be in the cerebrum or the spinal cord 2.
- UMN lesions can cause spasticity, which is a sign of the upper motor neurone syndrome 3.
- The clinical syndrome resulting from a UMN lesion depends on its location and extent, as well as the time since it occurred 3.
Spinal Cord Involvement
- Spasticity can be characterized as spinal cord spasticity or supraspinal spasticity, with spinal cord spasticity being characterized by spasms 4.
- UMN lesions in the spinal cord can cause severe untreatable spasticity, making movement, sitting, and hygiene difficult or impossible 4.
- Intrathecal baclofen therapy can be effective in treating severe spasticity in patients with UMN lesions in the spinal cord 4, 5.
Management of UMN Lesions
- Management of UMN lesions and resulting spasticity should be multimodal and include physiotherapy or exercise 2.
- Oral medications such as baclofen and tizanidine can be used to manage spasticity, but have limited efficacy and considerable side effects 2, 6.
- Intrathecal baclofen infusion and botulinum toxin injections can be used to treat severe spasticity in patients with UMN lesions 4, 6, 5.