A patient presents to the OPD with the complaint of back pain and weakness in both lower limbs. Which of the following findings would suggest compressive myelopathy?

1. A

   Hypotonia

2. B

   Absent Babinski sign

3. C

   Normal cremasteric reflex

4. D

   Knee clonus

Appeared in: AIIMS Nagpur NO- 2020

Explanation

• Compressive myelopathy damages the descending corticospinal tracts in the spinal cord, leading to Upper Motor Neuron (UMN) signs below the level of the lesion.
• Knee clonus is a classic UMN sign, representing severe hyperreflexia (exaggerated tendon reflexes).
• It is characterized by rhythmic, involuntary contractions of the quadriceps muscle in response to a sudden stretch, indicating a loss of inhibitory signals from the brain.
• The presence of clonus is a strong indicator of significant neurological pathology affecting the central nervous system, such as spinal cord compression.

Why Other Options Were Wrong

• Option A: Hypotonia, or decreased muscle tone, is a characteristic sign of a Lower Motor Neuron (LMN) lesion, which affects the peripheral nerves, not the spinal cord itself in this context.
• Option B: An absent Babinski sign indicates a normal plantar reflex (toes flex downward). The sign indicative of a UMN lesion is a positive Babinski sign (toes extend upward).
• Option C: The cremasteric reflex is often absent in UMN lesions that are located above the L1-L2 spinal level. A normal reflex does not support the diagnosis of compressive myelopathy.

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to Clinical signs of Upper Motor Neuron (UMN) lesions, specifically in the context of compressive myelopathy to guide bedside assessment, documentation, and the next nursing action.
• Nurses must be able to recognize UMN signs like clonus, as they indicate a serious neurological issue like spinal cord compression, which is a medical emergency requiring prompt intervention to prevent permanent paralysis.
• A thorough neurological assessment, including testing reflexes and the plantar response, is a critical nursing skill for patients presenting with back pain and weakness.
• What if? If the patient presented with weakness, hypotonia, and absent reflexes in the lower limbs, the nurse should suspect a Lower Motor Neuron (LMN) pathology, such as cauda equina syndrome or Guillain-Barré syndrome, which also requires urgent medical evaluation.

How to Approach the Question

• First, identify the core clinical problem: The patient has symptoms (back pain, leg weakness) suggesting a spinal cord issue.
• Next, understand the question: It asks for a finding that suggests compressive myelopathy.
• Recall or deduce that compressive myelopathy is a disease of the spinal cord, which is part of the central nervous system, and therefore causes Upper Motor Neuron (UMN) signs.
• Evaluate each option against the characteristics of a UMN lesion.
• Eliminate options that describe normal findings (Absent Babinski sign, Normal cremasteric reflex) or LMN signs (Hypotonia).
• Identify the option that is a classic UMN sign (Knee clonus) as the correct answer.

Concept Tested & Keywords

• Concept Tested: Clinical signs of Upper Motor Neuron (UMN) lesions, specifically in the context of compressive myelopathy.
• Stem keywords: back pain, weakness in both lower limbs, compressive myelopathy
• Lead-in keywords: findings would suggest
• Clinical cues: The combination of back pain and bilateral lower limb weakness points towards a spinal cord pathology.

Question ID

QD2UQaHdQ8xVPf2UZqwT2Y

Copy ID

Reference Book

E6 Anatomy Grays 43e Vol 1 Part 3 pp. 80-82, 81-83