Critical Care Registered Nurse (CCRN) Practice Exam

What complication can occur from a rapid decrease in intracranial pressure after a lumbar puncture?

1. Tonsillar herniation

2. Seizures

3. Vasospasm

4. Stroke

The correct answer is: Tonsillar herniation

A rapid decrease in intracranial pressure (ICP) following a lumbar puncture can lead to tonsillar herniation, which is a serious complication. When ICP is decreased too quickly, the brain can collapse downwards into the foramen magnum due to the sudden reduction in pressure on the brain tissue. This herniation occurs as the brainstem and cerebellar tonsils are pushed down through the foramen magnum, potentially compressing vital structures and disrupting cerebral blood flow. The risk is particularly notable in patients who already have elevated ICP, as they may have compensatory changes that could make them more susceptible to shifts in pressure. The rapid drop in pressure creates an imbalance, leading to these dangerous shifts. Recognition of this complication is crucial, as it can lead to life-threatening outcomes if not promptly addressed, including neurological deficits and possibly death. Other options, though important in different contexts, do not directly relate to the specific mechanism of tonsillar herniation as a result of rapid ICP changes after lumbar puncture.