Regional Anesthesia — MCQs

A 25 year old male with roadside accident underwent debridement and reduction of fractured both bones right forearm under axillary block. On the second postoperative day the patient complained of persistent numbness and paresthesia in the right forearm and the hand. The commonest cause of this neurological dysfunction could be all of the following except :

Q176

Subarachnoid block as anaesthesia is contraindicated in –

Q177

For spinal anesthesia, lignocaine is used as

Q178

Epidural anaesthesia is preferred over spinal anaesthesia because:

Q179

Best site for administering spinal anesthesia is the intervertebral space between.

Q180

Intravenous regional anesthesia is suitable for :

Regional Anesthesia Indian Medical PG Practice Questions and MCQs

Question 171: Which is not true about spinal anesthesia?

A. Useful for lower limb surgery
B. It produces more hemodynamic alteration than epidural anesthesia
C. Produces complete sensory and motor paralysis below the level (Correct Answer)
D. Autonomic fibers are affected above the sensory level

Explanation: ***Produces complete sensory and motor paralysis below the level*** - While spinal anesthesia produces significant sensory and motor blockade, it is rarely a **complete paralysis** below the level of injection, especially in terms of all muscle groups and deep sensation. - The degree of blockade depends on the **dose of anesthetic**, the patient's individual anatomy, and the spread of the drug within the cerebrospinal fluid, leading to a variable rather than absolute "complete" paralysis. *Useful for lower limb surgery* - Spinal anesthesia is **highly effective** and commonly used for lower limb surgeries as it provides excellent surgical anesthesia and postoperative analgesia. - It targets the nerve roots innervating the lower extremities, successfully blocking sensation and motor function, which is ideal for procedures like **knee or hip replacements**. *It produces more hemodynamic alteration than epidural anesthesia* - Spinal anesthesia typically causes a more **rapid and profound sympathetic blockade** than epidural anesthesia, due to direct and rapid diffusion of local anesthetic into the cerebrospinal fluid (CSF). - This rapid blockade often leads to a more significant and faster decrease in **blood pressure and heart rate** due to widespread vasodilation and reduced venous return. *Autonomic fibers are affected above the sensory level* - Sympathetic (autonomic) fibers are typically smaller and unmyelinated, making them **more susceptible to local anesthetic blockade** than sensory or motor fibers. - Therefore, the **sympathetic blockade** often extends two to three dermatomes higher than the sensory block, resulting in vasodilation and potential hemodynamic changes in areas above the perceived sensory level.

Question 172: Most common injection site infection in spinal anaesthesia

A. Bacteroides
B. Staphylococcus (Correct Answer)
C. Pseudomonas
D. Streptococcus

Explanation: **Staphylococcus** - **_Staphylococcus_** species, particularly methicillin-sensitive _Staphylococcus aureus_ (MSSA) and methicillin-resistant _Staphylococcus aureus_ (MRSA), are the **most common culprits** in post-procedural infections like those following spinal anesthesia due to their presence on the skin. - These bacteria can cause various infections, from **superficial cellulitis** at the injection site to more serious complications like **meningitis** or an **epidural abscess**. *Bacteroides* - **_Bacteroides_** species are **anaerobic bacteria** commonly found in the gut flora, making them less likely to cause skin-puncture infections unless there is bowel injury or contamination. - While they can cause serious infections, they are **not typically associated** with superficial skin contamination leading to spinal anesthesia infections. *Pseudomonas* - **_Pseudomonas aeruginosa_** is known for causing opportunistic infections, especially in healthcare settings and in contact with water sources, but it is **not the most common cause** of injection site infections following spinal procedures. - Infections with **_Pseudomonas_** often present with a distinctive **grape-like odor** and a blue-green pus, which is not the typical presentation for initial injection site infections. *Streptococcus* - **_Streptococcus_** species can cause skin infections, but they are generally **less common than _Staphylococcus_** in injection site infections after spinal anesthesia. - While **Group A _Streptococcus_** can cause severe skin and soft tissue infections, it typically presents with **rapidly spreading cellulitis** rather than focal injection site issues.

Question 173: Centrineuraxial anaesthesia is not contraindicated in:

A. Patient on anticoagulants
B. Raised intracranial pressure
C. Patient on aspirin (Correct Answer)
D. Platelets <80,000

Explanation: ***Patient on aspirin*** - Aspirin is an **antiplatelet agent** that irreversibly inhibits cyclooxygenase, affecting platelet function but typically does not significantly increase the risk of **epidural hematoma** to contraindicate neuraxial anesthesia. - While careful consideration is needed, especially if combined with other anticoagulants, aspirin alone usually presents a **lower bleeding risk** compared to other anticoagulants. *Patient on anticoagulants* - Use of therapeutic anticoagulants (e.g., heparin, warfarin, novel oral anticoagulants) significantly increases the risk of **spinal or epidural hematoma**, which can lead to neurological deficits. - Therefore, these medications are generally considered a **contraindication** until they are stopped and coagulation parameters are within acceptable limits. *Raised intracranial pressure* - Centrineuraxial anesthesia can decrease spinal fluid pressure, potentially exacerbating a pressure gradient and leading to **brain herniation** in patients with raised intracranial pressure. - This is a serious and potentially fatal complication, making it a **strong contraindication**. *Platelets <80,000* - A platelet count below 80,000 cells/µL indicates significant **thrombocytopenia**, increasing the risk of bleeding. - Neuraxial anesthesia is generally regarded as **contraindicated** when platelet counts are below this threshold due to the heightened risk of spinal hematoma.

Question 174: Spinal anesthesia should be injected into the space between:

A. L3–L4 (Correct Answer)
B. L5–S1
C. T12–L1
D. L1–L2

Explanation: ***L3–L4*** - The **spinal cord** typically ends at the level of L1 or L2 in adults, making the L3–L4 interspace a safe region for injection. - Injecting at this level minimizes the risk of **direct spinal cord trauma** while allowing for effective drug delivery into the cerebrospinal fluid. *L5–S1* - While below the termination of the spinal cord, injection at L5-S1 is technically more challenging due to the **angle of the spinous processes** and depth of the interspace. - The wider interspinous space at L3-L4 generally makes it a more accessible and preferred site for spinal anesthesia. *T12–L1* - This interspace is above or at the typical **termination of the spinal cord**, making injection here carry a significant risk of **spinal cord injury**. - Direct trauma to the spinal cord can lead to severe neurological deficits. *L1–L2* - This interspace is at or very close to the **conus medullaris** (the end of the spinal cord) in most adults. - Injecting here poses a higher risk of **spinal cord damage** compared to lower lumbar interspaces, making it a less safe option.

Question 175: A 25 year old male with roadside accident underwent debridement and reduction of fractured both bones right forearm under axillary block. On the second postoperative day the patient complained of persistent numbness and paresthesia in the right forearm and the hand. The commonest cause of this neurological dysfunction could be all of the following except :

A. Tourniquet pressure
B. Crush injury to the hand and lacerated nerves
C. A tight cast or dressing
D. Systemic toxicity of local anaesthetics (Correct Answer)

Explanation: ***Systemic toxicity of local anaesthetics*** - This typically presents with **acute neurological symptoms** (e.g., seizures, metallic taste, tinnitus) or **cardiovascular collapse** during or immediately after local anesthetic administration. - Persistent numbness and paresthesia on the second postoperative day are **not characteristic** of systemic local anesthetic toxicity, which is a transient effect. *Tourniquet pressure* - **Prolonged or excessively high tourniquet pressure** can lead to nerve ischemia and damage, causing paresthesia and numbness in the limb distal to the tourniquet. - These symptoms often persist for some time post-operatively, consistent with the patient's presentation. *Crush injury to the hand and lacerated nerves* - The initial **roadside accident** involving a severely injured limb could directly cause **nerve lacerations or crush injuries**, leading to immediate and persistent neurological deficits like numbness and paresthesia. - Such direct nerve trauma would manifest immediately and continue post-operatively, aligning with the patient's complaints. *A tight cast or dressing* - A **tight cast or dressing** applied to the forearm can compress nerves, leading to **ischemia and neuropathy**. - This mechanical compression can cause persistent numbness and paresthesia, which might become more noticeable as swelling increases post-surgery.

Question 176: Subarachnoid block as anaesthesia is contraindicated in –

A. Atherosclerotic gangrene
B. Diabetic gangrene
C. Buerger's disease
D. Hemophilia (Correct Answer)

Explanation: ***Hemophilia*** - Subarachnoid block, which involves puncturing the dura, is contraindicated in patients with **hemophilia** due to the high risk of **spinal hematoma**. - A spinal hematoma can lead to **cord compression** and devastating neurological deficits. *Atherosclerotic gangrene* - This condition involves **peripheral vascular disease** and tissue necrosis, but does not inherently contraindicate subarachnoid block. - In fact, subarachnoid block can be beneficial by providing **sympathectomy**, improving blood flow to the affected limb. *Diabetic gangrene* - Similar to atherosclerotic gangrene, **diabetic gangrene** is a manifestation of peripheral vascular disease often complicated by neuropathy and infection. - There is no direct contraindication to subarachnoid block for this condition itself, provided there are no concurrent coagulopathies or active infections at the needle insertion site. *Buerger's disease* - **Buerger's disease** (thromboangiitis obliterans) is an inflammatory vasculitis of small and medium-sized arteries and veins, primarily in the limbs. - Subarachnoid block may even be indicated to improve blood flow by inducing **sympathectomy**, helping relieve ischemic pain or prevent further tissue damage.

Question 177: For spinal anesthesia, lignocaine is used as

A. 2 % solution (Correct Answer)
B. 0.5 % solution
C. 1 % solution
D. 5% solution

Explanation: ***2 % solution*** - **Lignocaine (lidocaine)** is commonly used in a **2% solution** for spinal anesthesia to achieve adequate sensory and motor block. - This concentration typically provides a rapid onset and sufficient duration for many surgical procedures. *0.5 % solution* - A **0.5% solution** of lignocaine is generally too dilute to provide an adequate or reliable spinal anesthetic effect for most surgical procedures. - While it may be used for some local infiltration or peripheral nerve blocks, it is not standard for subarachnoid injection. *5% solution* - A **5% solution** of lignocaine is considered too concentrated for routine spinal anesthesia, increasing the risk of **neurotoxicity** and adverse effects. - High concentrations can cause severe neurological complications, making it unsafe for intrathecal use. *1 % solution* - A **1% solution** of lignocaine might provide a less intense or shorter duration of block than desired for many spinal anesthesia applications. - It could be used in specific scenarios requiring a lighter block, but **2%** is more standard for reliable surgical anesthesia.

Question 178: Epidural anaesthesia is preferred over spinal anaesthesia because:

A. Less incidence of epidural hematoma
B. Cheaper
C. Less incidence of intravascular injection
D. Prolonged duration of effect (Correct Answer)

Explanation: ***Prolonged duration of effect*** - Epidural anesthesia allows for **continuous infusion** or **repeated boluses** of local anesthetic through an epidural catheter, providing a prolonged duration of effect suitable for extended procedures or postpartum analgesia. - This **catheter-based technique** ensures sustained pain relief, which is a major advantage over the relatively shorter, fixed duration of a single-shot spinal anesthetic. *Less incidence of epidural hematoma* - The incidence of **epidural hematoma** is generally similar or slightly higher with epidural anesthesia compared to spinal anesthesia, especially in patients with coagulopathies. - Both procedures carry risks of hematoma, but the presence of an epidural catheter for a prolonged period can increase this risk. *Cheaper* - Epidural anesthesia often involves more equipment (e.g., epidural sets, infusion pumps) and potentially longer monitoring, making it generally **more expensive** than a single-shot spinal anesthetic. - The use of sophisticated drug delivery systems and extended hospital stays for epidural administration contribute to higher costs. *Less incidence of intravascular injection* - **Intravascular injection** is a significant risk with epidural anesthesia due to the proximity of large blood vessels within the epidural space. - Test doses and careful aspiration are essential to mitigate this risk, whereas spinal anesthesia directly injects into the cerebrospinal fluid, largely avoiding this particular concern.

Question 179: Best site for administering spinal anesthesia is the intervertebral space between.

A. L1 - L2
B. L2 - L3
C. L3 - L4 (Correct Answer)
D. L5 - S1

Explanation: ***L3 - L4*** - The **spinal cord** typically ends at the level of **L1-L2** in adults, making the L3-L4 intervertebral space a safe choice to avoid inadvertent cord injury. - This interspace is easily identified by drawing an imaginary line between the highest points of the **iliac crests**, which usually intersects the L4 vertebra or the L3-L4 interspace. *L1 - L2* - This interspace is generally considered too high for routine spinal anesthesia due to the risk of directly puncturing the **spinal cord**, which often extends to this level in adults. - Puncturing the spinal cord can lead to severe neurological complications, so it is usually avoided. *L2 - L3* - While safer than L1-L2, the **L2-L3 interspace** is still relatively high and carries a slightly increased risk of spinal cord injury compared to lower levels. - The **L3-L4** or **L4-L5** interspaces are generally preferred as they offer a wider margin of safety. *L5 - S1* - The **L5-S1 interspace** is often difficult to access due to the angulation of the **vertebrae** and the presence of the **iliac crests**, making needle insertion challenging. - While anatomically safe in terms of spinal cord termination, the technical difficulty makes it a less preferred site for routine lumbar punctures or spinal anesthesia.

Question 180: Intravenous regional anesthesia is suitable for :

A. Caesarian section
B. Head and neck surgery
C. Orthopedic manipulation on the upper limb (Correct Answer)
D. Vascular surgery on the lower limb

Explanation: ***Orthopedic manipulation on the upper limb*** - **Intravenous regional anesthesia (IVRA)**, also known as a Bier block, is ideal for **short-duration procedures on the extremities**, especially the upper limb. - The technique involves isolating the limb with a **tourniquet** and injecting a local anesthetic intravenously, making it suitable for procedures like **orthopedic manipulations** that are typically less than an hour. *Caesarian section* - A Caesarian section requires **widespread anesthesia** to the lower abdomen and uterus, which cannot be achieved with IVRA. - It is typically performed under **spinal or epidural anesthesia**, or general anesthesia. *Head and neck surgery* - **IVRA** is a regional technique limited to the extremities below the tourniquet; it cannot provide anesthesia for the **head and neck region**. - Procedures in this area usually require **general anesthesia** or sometimes regional blocks like cervical plexus blocks. *Vascular surgery on the lower limb* - While IVRA can be used on the lower limb, **vascular surgery** often involves **longer durations** and may require more profound muscle relaxation and sensory blockade than IVRA can reliably provide. - Additionally, the use of a **tourniquet for extended periods** in vascular surgery patients can be contraindicated due to potential ischemic complications.

Practice by Chapter

Neuraxial Anatomy

Practice Questions

Spinal Anesthesia

Practice Questions

Epidural Anesthesia

Practice Questions

Combined Spinal-Epidural Anesthesia

Practice Questions

Peripheral Nerve Blocks: Upper Extremity

Practice Questions

Peripheral Nerve Blocks: Lower Extremity

Practice Questions

Truncal Blocks

Practice Questions

Ultrasound-Guided Regional Anesthesia

Practice Questions

Complications of Regional Anesthesia

Practice Questions

Regional Anesthesia in Pediatric Patients

Practice Questions

Regional Anesthesia in Obstetrics

Practice Questions

Continuous Peripheral Nerve Catheters

Practice Questions

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