From the Guidelines
Upper motor neuron signs in back pain indicate potential serious neurological involvement that requires urgent medical attention, and immediate imaging, preferably MRI, is necessary to assess for spinal cord compression or other serious conditions. These signs include hyperreflexia (exaggerated reflexes), clonus (rhythmic muscle contractions), Babinski sign (upward movement of the big toe when the sole is stimulated), increased muscle tone or spasticity, and weakness that follows a pyramidal pattern. When these signs appear in a patient with back pain, they suggest compression of the spinal cord rather than just nerve root involvement, which can be caused by central disc herniation, spinal canal stenosis, tumors, abscesses, or fractures causing cord compression 1.
This represents a potential medical emergency as prolonged cord compression can lead to permanent neurological damage. The presence of upper motor neuron signs distinguishes potentially dangerous central cord pathology from more common radicular syndromes that typically present with lower motor neuron signs. According to the most recent guidelines, MRI lumbar spine without IV contrast is the preferred initial study for evaluating suspected cauda equina syndrome or progressive neurologic deficits, due to its ability to accurately depict soft-tissue pathology, assess vertebral marrow, and assess the spinal canal patency 1.
Treatment depends on the underlying cause but may include high-dose corticosteroids to reduce inflammation while definitive treatment is arranged. Surgical decompression is frequently required, especially in cases of trauma, tumor, or severe disc herniation causing cord compression. Key points to consider in the evaluation and management of upper motor neuron signs in back pain include:
- Urgent MRI assessment to evaluate for spinal cord compression or other serious conditions
- Consideration of high-dose corticosteroids to reduce inflammation
- Potential need for urgent neurosurgical consultation
- Importance of distinguishing between central cord pathology and more common radicular syndromes.
From the Research
Upper Motor Neuron Signs in Back Pain
- Upper motor neuron signs can be associated with back pain, as seen in cases of anterior spinal cord herniation (aSCH) 2.
- aSCH is a rare cause of myelopathy that may present as a pure motor syndrome and mimic other degenerative diseases of the spinal cord.
- In some cases, diagnosis may be impeded by equivocal imaging results and mistaken for evolving upper motor neuron disease.
- A history of truncal pain and MRI findings of a ventrally displaced spinal cord can be indicative of aSCH 2.
- Upper motor neuron signs can also be a symptom of adult motor neuron disease, such as amyotrophic lateral sclerosis (ALS) 3.
- ALS is a neurodegenerative disorder characterized by loss of motor neurons in the cortex, brain stem, and spinal cord, manifested by upper and lower motor neuron signs and symptoms.
- However, not all studies are relevant to upper motor neuron signs in back pain, such as research on histidine transport in the Ehrlich cell 4.