Regional Anesthesia Practice Questions

Q: The segmental level of spinal anesthesia depends on which of the following factors?

All of the above. The level of a spinal block (the dermatomal spread of local anesthetic within the subarachnoid space) is determined by a complex interplay of drug characteristics, patient factors, and procedural techniques. **Explanation of Factors:** 1. **Specific Gravity (Baricity):** This is the most critical factor. The relationship between the density of the local anesthetic and the density of cerebrospinal fluid (CSF) determines how the drug moves. **Hyperbaric** solutions (denser than CSF, usually containing glucose) sink to dependent areas, while **hypobaric** solutions rise. 2. **Posture of the Patient:** Because of baricity, the patient's position during and immediately after injection dictates the spread. For example, if a hyperbaric drug is injected while the patient is sitting, it will settle toward the sacral fibers (Saddle block). If the patient is placed in the Trendelenburg position, the drug will spread cephalad (toward the head). 3. **Volume and Dose:** While baricity is dominant, the total volume and dose of the local anesthetic also influence the height of the block. A larger volume creates a greater pressure gradient and physical displacement within the fixed space of the spinal canal, typically leading to a higher level. **High-Yield Clinical Pearls for NEET-PG:** * **Most Important Factor:** Baricity (Specific Gravity) is considered the single most important factor for determining spread. * **CSF Volume:** Low CSF volume (seen in obesity, pregnancy, or the elderly) is associated with a higher level of block for a given dose. * **Site of Injection:** Unlike epidural anesthesia, the site of injection (e.g., L3-L4 vs. L4-L5) has a minimal effect on the final level of spinal anesthesia. * **Drug Concentration:** Concentration alone does not affect the level of spread, but it does affect the **quality and duration** of the motor and sensory block.

Q: All of the following are signs of successful stellate ganglion block, except:

Mydriasis. **Explanation:** A **Stellate Ganglion Block (SGB)** involves injecting local anesthetic near the stellate ganglion (formed by the fusion of the inferior cervical and first thoracic sympathetic ganglia). This procedure results in a **sympathetic blockade** of the head, neck, and upper extremity. **Why Mydriasis is the Correct Answer:** The sympathetic nervous system is responsible for pupillary dilation (mydriasis). When the stellate ganglion is blocked, sympathetic outflow is interrupted, leading to the dominance of parasympathetic activity. This results in **Miosis** (constriction of the pupil), not mydriasis. Miosis is a hallmark component of **Horner’s Syndrome**, which signifies a successful block. **Analysis of Incorrect Options:** * **Flushing of the face (A):** Sympathetic blockade causes vasodilation of the cutaneous blood vessels in the head and neck, leading to facial flushing and increased skin temperature. * **Conjunctival congestion (B):** Vasodilation of the conjunctival vessels occurs due to the loss of sympathetic vasoconstrictor tone. * **Nasal stuffiness (D):** Also known as **Guttman’s sign**, this occurs due to the engorgement of the nasal mucosa following sympathetic blockade. **High-Yield Clinical Pearls for NEET-PG:** * **Horner’s Syndrome Tetrad:** Miosis (constricted pupil), Ptosis (drooping eyelid), Anhidrosis (lack of sweating), and Enophthalmos (apparent sinking of the eyeball). * **Anatomical Landmark:** The block is typically performed at the level of the **C6 transverse process (Chassaignac’s tubercle)**. * **Complications:** Accidental vertebral artery injection (seizures), phrenic nerve block (diaphragmatic palsy), and recurrent laryngeal nerve block (hoarseness).

Q: What is the vasopressor of choice in hypotension produced during subarachnoid block?

Ephedrine. **Explanation:** Hypotension during **Subarachnoid Block (SAB)** is primarily caused by a sympathetic blockade, leading to venous pooling (decreased preload) and arterial vasodilation (decreased systemic vascular resistance). **Why Ephedrine is the Correct Choice:** Ephedrine is traditionally considered the drug of choice because it is a **mixed-acting sympathomimetic** (direct and indirect action on $\alpha$ and $\beta$ receptors). 1. **$\beta_1$ activity:** Increases heart rate and cardiac contractility. 2. **$\alpha_1$ activity:** Causes peripheral vasoconstriction. Crucially, in obstetric anesthesia, Ephedrine is preferred because it maintains **uteroplacental blood flow** better than pure alpha-agonists, although recent trends are shifting toward Phenylephrine in specific maternal contexts. **Analysis of Incorrect Options:** * **Mephenteramine:** Similar to Ephedrine but less potent. While commonly used in Indian clinical practice, Ephedrine remains the standard textbook answer for exams. * **Adrenaline:** A potent catecholamine used for cardiac arrest or anaphylaxis. It is too potent for routine post-spinal hypotension and can cause dangerous tachycardia and arrhythmias. * **Dopamine:** Requires infusion and is typically reserved for cardiogenic or septic shock; its onset is too slow for the acute management of spinal-induced hypotension. **High-Yield Clinical Pearls for NEET-PG:** * **Phenylephrine** is now often considered the "gold standard" for spinal hypotension in **obstetric patients** to avoid fetal acidosis, but **Ephedrine** remains the classic "choice" in general surgical scenarios and standard MCQ patterns. * The first-line management for post-spinal hypotension is **fluid pre-loading or co-loading** (crystalloids/colloids). * If hypotension is accompanied by **bradycardia** (due to block of T1-T4 cardioaccelerator fibers), Ephedrine or Atropine is mandatory.

Q: Post dural puncture headache is typically located in which region?

Occipital. **Explanation:** Post-Dural Puncture Headache (PDPH) is a common complication following spinal anesthesia or accidental dural puncture during epidural placement. **Why Occipital is Correct:** The underlying mechanism of PDPH is the leakage of Cerebrospinal Fluid (CSF) through the dural hole, leading to **low CSF pressure**. This loss of buoyancy causes the brain to sag in the upright position, stretching pain-sensitive structures like the dura mater and cranial nerves (V, IX, and X). The pain is characteristically **positional** (worsens on standing, relieved by lying flat) and is most commonly felt in the **occipital and frontal regions**, often radiating to the neck and shoulders. In the context of standard medical examinations, the **occipital** region is the classic hallmark location. **Analysis of Incorrect Options:** * **A & B (Retro-orbital and Frontal):** While PDPH can involve the frontal region, it is rarely isolated to the retro-orbital area. The occipital distribution is more specific to the traction on the tentorium cerebelli. * **D (Temporal):** Temporal pain is more characteristic of conditions like giant cell arteritis or tension headaches, rather than the gravitational traction seen in PDPH. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Treatment:** Epidural Blood Patch (EBP) – 15-20 ml of autologous blood is injected into the epidural space. * **Risk Factors:** Young age, female gender, pregnancy, and the use of large-bore/cutting needles (e.g., Quincke). * **Prevention:** Use of small-gauge, non-cutting (pencil-point) needles like **Whitacre** or **Sprotte**. * **Associated Symptom:** Diplopia due to **6th Cranial Nerve (Abducens)** palsy is the most common cranial nerve involvement.

Q: Which of the following is NOT true about post-spinal headache?

Old age is a risk factor.. **Explanation:** Post-Dural Puncture Headache (PDPH) occurs due to the leakage of cerebrospinal fluid (CSF) through a dural hole, leading to low CSF pressure and compensatory cerebral vasodilation. **Why Option D is the Correct Answer (The False Statement):** Contrary to the option, **old age is a protective factor**, not a risk factor. PDPH is most common in young adults (20–40 years), particularly pregnant women. In the elderly, the dura is less elastic and the epidural space is more fibrotic, which helps the dural puncture site seal more quickly, reducing the incidence of headache. **Analysis of Other Options:** * **Option A:** PDPH is characteristically **positional**. It worsens within seconds of sitting or standing and is significantly relieved by lying flat (supine). * **Option B:** The pain is typically bilateral and most commonly felt in the **frontal or occipital** regions, sometimes radiating to the neck and shoulders. * **Option C:** Using a **small-bore needle** (e.g., 25G–27G) and non-cutting "pencil-point" needles (e.g., Sprotte or Whitacre) significantly reduces the risk by creating a smaller, more easily healed dural defect. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Treatment:** Epidural Blood Patch (EBP) is the most effective treatment for persistent PDPH. * **Needle Type:** Pencil-point needles (Whitacre/Sprotte) have a lower incidence of PDPH compared to cutting-tip needles (Quincke). * **Orientation:** If using a cutting needle, the bevel should be kept parallel to the longitudinal fibers of the dura to minimize damage. * **Conservative Management:** Includes bed rest, aggressive hydration, and oral/IV caffeine (which causes cerebral vasoconstriction).

Question 1

A patient presents with trismus. Which of the following techniques will block the mylohyoid nerve, incisive nerve, and long buccal nerve?

Accepted Answer

Akinosi technique

Answer

Gow-Gates technique

Answer

V-block technique

Answer

Conventional inferior alveolar nerve block

Question 2

A 48-year-old male with triple vessel disease and longstanding diabetes developed gangrene in his left lower foot. Which is the best mode of anesthesia?

Accepted Answer

Popliteal block

Answer

Sciatic block

Answer

Femoral block

Answer

Saphenous nerve block

Question 3

The segmental level of spinal anesthesia depends on which of the following factors?

Accepted Answer

All of the above

Answer

Volume of the local anesthetic injected

Answer

Specific gravity of the local anesthetic solution

Answer

Posture of the patient

Question 4

A 20-year-old man complains of headache after spinal anesthesia. Which of the following is the likely cause?

Accepted Answer

Cerebrospinal fluid leak

Answer

Raised intracranial pressure

Answer

Meningitis

Answer

Encephalitis

Question 5

All of the following are signs of successful stellate ganglion block, except:

Accepted Answer

Mydriasis

Answer

Flushing of face

Answer

Conjunctival congestion

Answer

Nasal stuffiness

Question 6

What is the vasopressor of choice in hypotension produced during subarachnoid block?

Accepted Answer

Ephedrine

Answer

Mephenteramine

Answer

Adrenaline

Answer

Dopamine

Question 7

Post dural puncture headache is typically located in which region?

Accepted Answer

Occipital

Answer

Retro-orbital

Answer

Frontal

Answer

Temporal

Question 8

For which of the following is continuous epidural anaesthesia used?

Accepted Answer

Postoperative analgesia

Answer

Extending the duration of surgery

Answer

General anaesthesia

Answer

Use in children

Question 9

What is true regarding a bilateral mandibular block?

Accepted Answer

It is not contraindicated.

Answer

It is dangerous because the patient may swallow their tongue.

Answer

It will lead to a space infection.

Answer

It should rarely be performed.

Question 10

Which of the following is NOT true about post-spinal headache?

Accepted Answer

Old age is a risk factor.

Answer

It is relieved by lying down.

Answer

It is typically frontal or occipital.

Answer

It can be prevented by using a small bore needle.

Regional Anesthesia — MCQs

Regional Anesthesia — MCQs

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