An Intrathecal injection administers a drug through the?

JODHPUR AIIMS SNO-2018

Pharmacology

Easy

Appeared in: JODHPUR AIIMS SNO-2018

Explanation

An intrathecal injection delivers medication directly into the subarachnoid space, which is located within the spinal canal.
This space contains cerebrospinal fluid (CSF), which surrounds the spinal cord and brain.
The term 'intrathecal' literally means 'within the theca,' referring to the thecal sac (a membrane formed by the dura mater) that encloses the spinal cord.
This route is specifically chosen when drugs need to bypass the blood-brain barrier to act directly on the central nervous system, such as for spinal anesthesia, certain types of chemotherapy, or management of chronic pain.

Option A: This describes a peripheral intravenous (IV) injection. It delivers medication into the systemic circulation via a vein near the skin's surface, not into the central nervous system.
Option B: This is a general term for an intravenous (IV) injection, which delivers drugs into the bloodstream for systemic effects. An intrathecal injection targets the spinal fluid, a separate compartment.
Option C: This describes an intracardiac injection, a high-risk emergency procedure where medication is injected directly into the heart muscle or chambers.

Clinical Relevance

Nursing practice connection: Knowing Routes of Drug Administration: Intrathecal Injection helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must monitor patients closely after an intrathecal procedure for signs of complications, such as post-dural puncture headache (PDPH), infection (meningitis), or neurological changes (e.g., numbness, weakness).
Strict aseptic (sterile) technique is paramount when assisting with the procedure to prevent the introduction of pathogens into the central nervous system, which can lead to life-threatening meningitis.
What if? If a patient develops a severe, positional headache (worse when upright, better when lying down) after the procedure, the nurse should suspect a CSF leak. The immediate nursing action is to have the patient lie flat, encourage fluid intake, and notify the provider, as a blood patch may be required.

How to Approach the Question

First, identify the key term in the question: 'Intrathecal injection'.
Recall the meaning of medical prefixes and roots. 'Intra-' means 'within' and 'theca' refers to the thecal sac that surrounds the spinal cord.
Connect this definition to the corresponding anatomical location. The thecal sac is an integral part of the spinal column.
Evaluate the options based on this understanding. 'Vein' and 'Superficial vein' relate to intravenous routes. 'Cardiac area' relates to the heart.
Conclude that 'Spine' is the only option that correctly corresponds to the location of the thecal sac for an intrathecal injection.

Concept Tested & Keywords

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