Question
A patient presents with progressive back pain and weakness in both lower limbs. Which findings would NOT support the diagnosis of compressive myelopathy?
| A. |
Hypotonia
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| B. |
Babinski sign
|
| C. |
Ankle and knee clonus
|
| D. |
Normal cremasteric reflex
|
Show Answer
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Correct Answer � D
Explanation
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|
– Compressive myelopathy affects the spinal cord, leading to upper motor neuron (UMN) signs below the level of the lesion.
– UMN signs include increased tone (spasticity), positive Babinski sign, and hyperactive reflexes such as ankle and knee clonus.
– Hypotonia is typically seen in lower motor neuron lesions or acute spinal shock but not in chronic compressive myelopathy where spasticity develops.
– Babinski sign and clonus are classic UMN signs supporting compressive myelopathy.
– The cremasteric reflex, mediated by spinal segments L1-L2, is usually diminished or absent in compressive myelopathy involving these segments.
– Therefore, a normal cremasteric reflex argues against significant cord compression at those levels and hence does not support compressive myelopathy.
Reasons to rule out other options:
– A. Hypotonia: May be present early in acute injury but not persistent in compressive myelopathy.
– B. Babinski sign: Positive in compressive myelopathy due to UMN involvement.
– C. Ankle and knee clonus: Indicative of UMN lesion, consistent with compressive myelopathy.
