During a lumbar puncture, which measurement is commonly obtained to assess intracranial pressure?

• A. Opening pressure.
• B. CSF glucose only.
• C. Blood glucose.
• D. CSF chloride.

Answer: (A)

Opening pressure is the measurement obtained during a lumbar puncture to gauge intracranial pressure. It’s read by connecting a manometer to the needle as CSF first enters the subarachnoid space, with the patient in a suitable position (often lateral decubitus or sitting). This value directly reflects the pressure inside the skull and helps identify elevated intracranial pressure, guiding management in conditions like suspected mass effect, hydrocephalus, or meningitis. Other measurements like CSF glucose, blood glucose, or CSF chloride are useful for diagnosing infections or metabolic issues, but they do not indicate intracranial pressure.