Practice questions › MBBS / Medicine › Neurology
Investigative Studies MCQs
Neurology · MBBS / Medicine · 27 practice questions
- Lumbar Puncture - Analysis of Results
- Lumbar Puncture - Indications
- Lumbar Puncture - Contraindications
- Lumbar Puncture - Pressure Interpretation
- Lumbar Puncture - Unsuccessful Tap
- Lumbar Puncture - Preparation
- Lumbar Puncture - Procedure Technique
- Lumbar Puncture - Complications
1. A patient with a known spinal cord mass lesion requires CSF analysis. If lumbar puncture is deemed necessary, what modification to the standard technique should be made to minimize risk?
- APerform the puncture in the seated position only
- BCollect the full 10 mL required for cytology regardless of mass effect
- CRemove only a small quantity of CSF to avoid a pressure differential
- DUse a larger bore needle to speed collection
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C. Remove only a small quantity of CSF to avoid a pressure differential With a suspected spinal cord mass lesion, only a small quantity of CSF should be removed to avoid creating a pressure differential that could worsen spinal cord compression.
2. A lumbar puncture is performed on a patient with suspected subarachnoid hemorrhage. The CSF is bloody in the first tube but clears markedly by the last tube collected, and the supernatant after centrifugation is colorless. What is the most likely explanation?
- ACNS hemorrhage with delayed xanthochromia
- BTraumatic tap
- CPseudotumor cerebri with elevated protein
- DSubarachnoid hemorrhage with rapid clearance
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B. Traumatic tap A marked decrease in red cell count between first and last tubes, along with a colorless supernatant on centrifugation, supports a traumatic tap rather than true subarachnoid hemorrhage.
3. A clinician is performing a lumbar puncture and needs to select the interspace to minimize risk of spinal cord injury. Which anatomic landmark corresponds to the L3-L4 interspace commonly used for puncture?
- ALevel of the posterior superior iliac crests
- BLevel of the twelfth rib
- CLevel of the sacral hiatus
- DLevel of the scapular tips
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A. Level of the posterior superior iliac crests The L3-L4 interspace corresponds to the level of the posterior iliac crests, a standard landmark for lumbar puncture.
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