In intrathecal injection, medicine is administrated in :

Question

Question

This question was previously asked in

KGMU Nursing Officer 2023 Memory-Based Previous Year Paper

Answer 1

Correct Answer: Subarachnoid space

Rationale:

An intrathecal injection is a medical procedure in which a drug is delivered directly into the cerebrospinal fluid (CSF) within the subarachnoid space. The subarachnoid space lies between the arachnoid membrane and the pia mater, which is one of the protective layers (meninges) surrounding the brain and spinal cord.
This method is used for delivering medications such as anesthetics, chemotherapy drugs, or pain-relief medicines to bypass the blood-brain barrier and achieve direct access to the central nervous system (CNS).
Since the subarachnoid space contains cerebrospinal fluid, it is the ideal location for delivering drugs intended for CNS effects. This ensures rapid and efficient drug action.

Additional Information:

Intrathecal injections are commonly used in spinal anesthesia, the management of chronic pain, and for specific treatments such as baclofen therapy for spasticity or methotrexate for certain cancers.
This approach minimizes systemic side effects, as the drug acts locally within the CNS.

Explanation of Other Options:

Ventricles

Rationale: The ventricles are spaces within the brain filled with cerebrospinal fluid. While intraventricular injections can be performed to deliver medication directly to the brain, these are not the same as intrathecal injections, which specifically target the subarachnoid space.

Epidural space

Rationale: The epidural space is located outside the dura mater, the outermost layer of the meninges. Medications delivered here (such as epidural anesthesia) do not directly access the CSF and therefore are not considered intrathecal injections.

Subdural space

Rationale: The subdural space lies between the dura mater and the arachnoid membrane. While it is a potential space that may fill with fluid or blood in pathological conditions (such as subdural hematomas), it is not the target for intrathecal injections.

Conclusion:

Among the options provided, the subarachnoid space is the correct answer for intrathecal injections, as it is the specific location where cerebrospinal fluid circulates and allows for direct drug delivery to the CNS. Other options like ventricles, epidural space, and subdural space are not used for this purpose.