Multimodal Analgesia — MCQs

10 questions

Which of the following anaesthetic agent lacks analgesic effect? A) N2O B) Thiopentone C) Methohexitone D) Ketamine E) Fentanyl

Which is the intravenous anesthetic agent that contributes to good analgesia?

Primary afferent fibers secrete which nociceptive substance at the dorsal horn?

Which of the following is the FIRST-LINE antiemetic drug most commonly used for post-operative nausea and vomiting (PONV) prophylaxis?

Which of the following anesthetic agents have good analgesic property? a) Ketamine b) Nitrous oxide c) Thiopentone d) Propofol e) Midazolam

Which of the following cannot be given by epidural anaesthesia?

Which nerve is targeted in the nasociliary nerve block?

Which intravenous anaesthetic agent has analgesic effect also

Q10Easy

Which of the following is true about allodynia?

Multimodal Analgesia Indian Medical PG Practice Questions and MCQs

Question 1: Which of the following anaesthetic agent lacks analgesic effect? A) N2O B) Thiopentone C) Methohexitone D) Ketamine E) Fentanyl

A. N2O
B. Methohexitone
C. Ketamine
D. Fentanyl
E. Thiopentone (Correct Answer)

Explanation: ***Thiopentone*** - Thiopentone is a **barbiturate** anesthetic primarily used for inducing anesthesia. - It provides significant **hypnosis** and sedation but lacks intrinsic **analgesic properties**, meaning it does not relieve pain. *N2O* - **Nitrous oxide** (N2O) is an inhalation anesthetic that provides good **analgesia** at sub-anesthetic concentrations. - It is often used as an adjunct to other anesthetic agents to enhance pain relief during procedures. *Methohexitone* - Methohexitone is another **barbiturate** similar to thiopentone, used for induction of anesthesia. - While it provides rapid **hypnosis**, it also lacks significant **analgesic effects**. *Ketamine* - Ketamine is a **dissociative anesthetic** known for its potent **analgesic properties**. - It works by blocking **NMDA receptors**, providing pain relief even at sub-anesthetic doses. *Fentanyl* - Fentanyl is a powerful **opioid analgesic** that is commonly used in anesthesia for its strong pain-relieving effects. - It acts on **opioid receptors** in the central nervous system to reduce pain perception.

Question 2: Which is the intravenous anesthetic agent that contributes to good analgesia?

A. Ketamine (Correct Answer)
B. Thiopentone
C. Propofol
D. Etomidate

Explanation: ***Ketamine*** - **Ketamine** is unique among intravenous anesthetics for its significant **analgesic properties**, primarily acting as an **NMDA receptor antagonist**. - It produces a state of **dissociative anesthesia**, where the patient appears "awake" but is unresponsive to pain. *Thiopentone* - **Thiopentone** is a barbiturate that induces rapid unconsciousness but offers no significant **analgesia**. - It works by potentiation of **GABA-A receptors** leading to central nervous system depression. *Propofol* - **Propofol** is a widely used intravenous anesthetic for induction and maintenance, providing rapid onset and recovery, but it lacks **analgesic effects**. - Its mechanism of action also involves potentiation of **GABA-A receptors**. *Etomidate* - **Etomidate** is an intravenous anesthetic known for its **cardiovascular stability**, making it suitable for patients with cardiac compromise, but it provides no analgesia. - It is another **GABA-A receptor agonist** that causes rapid induction of anesthesia.

Question 3: Primary afferent fibers secrete which nociceptive substance at the dorsal horn?

A. Substance P (Correct Answer)
B. Acetylcholine
C. Norepinephrine
D. Epinephrine

Explanation: ***Substance P*** - **Substance P** is a neuropeptide released by **C fibers** and **A-delta fibers** (primary afferent nociceptors) in the dorsal horn of the spinal cord. - It acts as a **neurotransmitter** and **neuromodulator**, contributing to the transmission and amplification of pain signals. *Acetylcholine* - **Acetylcholine** is a primary neurotransmitter in the **neuromuscular junction** and the autonomic nervous system. - While it has some roles in the CNS, it is not the primary nociceptive substance secreted by afferent fibers in the dorsal horn. *Norepinephrine* - **Norepinephrine** (noradrenaline) is a neurotransmitter involved in the **fight-or-flight response** and mood regulation. - It can modulate pain, but it is not directly released by primary afferent fibers as a nociceptive substance in the dorsal horn. *Epinephrine* - **Epinephrine** (adrenaline) is a hormone and neurotransmitter primarily associated with the **sympathetic nervous system** and stress response. - It does not serve as a direct nociceptive transmitter released by primary afferent fibers in the spinal cord.

Question 4: Which of the following is the FIRST-LINE antiemetic drug most commonly used for post-operative nausea and vomiting (PONV) prophylaxis?

A. Lorazepam
B. Metoclopramide
C. Promethazine
D. Ondansetron (Correct Answer)

Explanation: ***Ondansetron*** - **Ondansetron** is a **5-HT3 receptor antagonist** and is considered a first-line agent due to its high efficacy and favorable side effect profile in preventing PONV. - It works by blocking serotonin receptors in the **chemoreceptor trigger zone** and the **gastrointestinal tract**, reducing the sensation of nausea and vomiting. *Lorazepam* - **Lorazepam** is a **benzodiazepine** primarily used for its **anxiolytic** and **sedative effects**, and sometimes as an adjunct for refractory nausea, but not as a first-line antiemetic for PONV prophylaxis. - While it can help indirectly by reducing anxiety, it does not directly target the key pathways involved in PONV as effectively as 5-HT3 antagonists. *Phenytoin* - **Phenytoin** is an **anticonvulsant** medication used to prevent seizures and has no role in the direct treatment or prophylaxis of PONV. - It primarily acts on voltage-gated sodium channels in neurons and does not possess antiemetic properties. *Metoclopramide* - **Metoclopramide** is a **dopamine D2 receptor antagonist** and a **prokinetic agent** that can be used for PONV, particularly when gastric stasis is a concern. - However, it is generally considered a second-line agent due to the risk of **extrapyramidal side effects**, especially with higher doses or prolonged use. *Promethazine* - **Promethazine** is a **first-generation antihistamine** with **antidopaminergic** and **anticholinergic properties** that can be effective for nausea and vomiting. - It is often used as a rescue antiemetic or in combination therapy, but its sedative effects and potential for extrapyramidal symptoms make it less preferable as a first-line prophylactic agent compared to ondansetron.

Question 5: Which of the following anesthetic agents have good analgesic property? a) Ketamine b) Nitrous oxide c) Thiopentone d) Propofol e) Midazolam

A. Ketamine and Nitrous oxide (Correct Answer)
B. Ketamine only
C. Nitrous oxide and Thiopentone
D. Ketamine and Propofol
E. Midazolam only

Explanation: ***Ketamine and Nitrous oxide*** - **Ketamine** is a dissociative anesthetic with potent **analgesic properties** secondary to its action as an **NMDA receptor antagonist**. - **Nitrous oxide** is an inhalational anesthetic known for its mild to moderate **analgesic effects**, making it useful for sedation and pain relief. *Ketamine only* - While **ketamine** has excellent analgesic properties, this option is incomplete as **nitrous oxide** also contributes significant analgesia among the choices. - Excluding other agents with analgesic properties makes this option less comprehensive than the correct answer. *Ketamine and Propofol* - **Ketamine** possesses strong analgesic effects, but **propofol** is a sedative-hypnotic agent with no significant intrinsic **analgesic properties**. - Propofol provides anesthesia and sedation but typically requires co-administration with opioids for pain control. *Nitrous oxide and Thiopentone* - **Nitrous oxide** provides analgesia, but **thiopentone** (a barbiturate) is primarily an anesthetic and sedative with **no significant analgesic properties**. - Thiopentone can induce unconsciousness rapidly but does not relieve pain. *Midazolam only* - **Midazolam** is a benzodiazepine primarily used for sedation, anxiolysis, and amnesia, with **no intrinsic analgesic properties**. - Its effects can reduce stress and perception of pain, but it does not directly act as an analgesic.

Question 6: Which of the following cannot be given by epidural anaesthesia?

A. Morphine
B. Remifentanil (Correct Answer)
C. Alfentanil
D. Fentanyl

Explanation: ***Remifentanil*** - **Remifentanil** is specifically designed for **intravenous administration** and is rapidly metabolized by plasma esterases, making it unsuitable for epidural use. - Due to its short half-life and rapid metabolism, epidural administration would provide inconsistent and fleeting analgesia, and its breakdown products are not inert in the epidural space, potentially causing **neurotoxicity**. *Morphine* - **Morphine** is a commonly used opioid for **epidural analgesia** due to its hydrophilicity, allowing for prolonged action in the cerebrospinal fluid. - It provides effective **postoperative pain relief** and has a relatively slow onset but long duration of action when administered epidurally. *Alfentanil* - **Alfentanil** is a synthetic opioid that has been used for **epidural analgesia**, though less commonly than fentanyl or sufentanil, sometimes in conjunction with local anesthetics. - It has a faster onset and shorter duration of action compared to morphine, but still provides effective **analgesia** when administered epidurally. *Fentanyl* - **Fentanyl** is a widely used lipophilic opioid for **epidural analgesia**, often combined with local anesthetics, for both surgical and obstetric pain. - Its lipophilicity allows for rapid absorption and a relatively quick onset of action, providing effective **segmental analgesia**.

Question 7: Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |

A. A-1, B-3, C-2, D-4
B. A-4, B-1, C-3, D-2 (Correct Answer)
C. A-3, B-2, C-4, D-1
D. A-2, B-4, C-1, D-3

Explanation: ***A-4, B-1, C-3, D-2*** - **Morphine** is contraindicated in **head injury** as it can increase intracranial pressure and mask neurological symptoms. - **Amiodarone** is contraindicated in patients with **QT prolongation** due to its risk of inducing more severe arrhythmias like Torsades de Pointes. - **Vigabatrin** is contraindicated during **pregnancy** due to its potential for teratogenicity and adverse effects on fetal development. - **Estrogen preparations** are contraindicated in patients with a history of **thromboembolism** due to their increased risk of blood clot formation. *A-1, B-3, C-2, D-4* - This option incorrectly matches **Morphine** with QT prolongation and **Estrogen preparations** with head injury, which are not their primary contraindications. - It also incorrectly links **Vigabatrin** with thromboembolism and **Amiodarone** with pregnancy. *A-3, B-2, C-4, D-1* - This choice incorrectly associates **Morphine** with pregnancy and **Vigabatrin** with head injury, which are not the most critical or direct contraindications. - It also misaligns **Amiodarone** with thromboembolism and **Estrogen preparations** with QT prolongation. *A-2, B-4, C-1, D-3* - This option incorrectly matches **Morphine** with thromboembolism and **Amiodarone** with head injury, which are not their most significant contraindications. - It also incorrectly links **Vigabatrin** with QT prolongation and **Estrogen preparations** with pregnancy.

Question 8: Which nerve is targeted in the nasociliary nerve block?

A. Greater palatine nerve
B. Sphenopalatine nerve
C. Anterior ethmoidal nerve
D. Nasociliary nerve (Correct Answer)

Explanation: ***Nasociliary nerve*** - A nasociliary nerve block specifically targets the **nasociliary nerve** itself. - This block is used to anesthetize the sensory innervation of structures supplied by the nasociliary nerve, such as parts of the **nasal cavity**, **eyeball**, and **skin of the nose**. *Greater palatine nerve* - The **greater palatine nerve** supplies sensation to the posterior hard palate and is targeted in a **greater palatine nerve block**. - This nerve is a branch of the **maxillary nerve** and is primarily involved in dental and palatal anesthesia. *Sphenopalatine nerve* - The **sphenopalatine nerve**, or pterygopalatine ganglion, contains sensory fibers for the nasal cavity, palate, and pharynx, and its block is distinct from a nasociliary block. - A **sphenopalatine ganglion block** is mainly used for conditions like cluster headaches and facial pain, not for direct eyeball sensation. *Anterior ethmoidal nerve* - The **anterior ethmoidal nerve** is a branch of the nasociliary nerve, but a nasociliary nerve block targets the main trunk, which includes all its branches. - While the anterior ethmoidal nerve supplies the anterior part of the nasal septum and lateral wall, it is a **component** of the nasociliary innervation rather than the sole target.

Question 9: Which intravenous anaesthetic agent has analgesic effect also

A. Thiopentone
B. Ketamine (Correct Answer)
C. Propofol
D. Etomidate

Explanation: ***Ketamine*** - Ketamine acts as an **N-methyl-D-aspartate (NMDA) receptor antagonist**, providing significant **analgesia** in addition to its anaesthetic effects. - It induces a state of **dissociative anaesthesia**, where the patient appears awake but is unresponsive to pain, making it unique among intravenous anaesthetics. *Thiopentone* - Thiopentone is a **barbiturate** that acts as a potent hypnotic and anaesthetic but provides no significant analgesic properties. - It can even cause **anti-analgesia** (hyperalgesia) at sub-hypnotic doses, increasing sensitivity to pain. *Propofol* - Propofol is a potent intravenous anaesthetic that works primarily as a **GABA-A receptor agonist**, but it lacks intrinsic analgesic properties. - While it can cause some sedation and reduced pain perception due to CNS depression, it does not directly modulate pain pathways in the way an analgesic would. *Etomidate* - Etomidate is a hypnotic agent highly valued for its **cardiovascular stability**, making it suitable for patients with compromised cardiac function. - Like propofol and thiopentone, etomidate primarily acts on **GABA-A receptors** to induce unconsciousness and offers no significant analgesic effects.

Question 10: Which of the following is true about allodynia?

A. Hyperalgesia
B. Loss of sensory sensations
C. Perception of a non-painful stimulus as pain (Correct Answer)
D. Hyperesthesia

Explanation: **Explanation:** **Allodynia** is defined by the International Association for the Study of Pain (IASP) as **pain due to a stimulus that does not normally provoke pain**. It is a hallmark of neuropathic pain and central sensitization. In this condition, the threshold for pain is lowered such that innocuous stimuli (like a light touch, the brush of clothing, or a breeze) are perceived as painful. **Analysis of Options:** * **Option C (Correct):** This directly matches the definition. It involves a change in the *quality* of sensation, where a non-noxious stimulus triggers a pain response. * **Option A (Incorrect):** **Hyperalgesia** is an *increased* response to a stimulus that is *normally* painful (e.g., a pinprick feeling like a stab). While both involve sensitization, allodynia involves a non-painful trigger, whereas hyperalgesia involves a painful one. * **Option B (Incorrect):** Loss of sensory sensation is termed **anesthesia** or **hypesthesia**. Allodynia is a positive sensory phenomenon (gain of function), not a loss. * **Option D (Incorrect):** **Hyperesthesia** is a broad term referring to increased sensitivity to any stimulus (touch, thermal, etc.), not specifically the conversion of a non-painful stimulus into pain. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Allodynia is primarily mediated by **A-beta fibers** (normally responsible for light touch) "shunting" signals into the pain pathways due to central sensitization in the spinal cord dorsal horn. * **Dynamic vs. Static:** Allodynia can be **mechanical** (moving a cotton wisp) or **thermal** (mild warmth feeling like a burn). * **Common Clinical Scenarios:** Post-herpetic neuralgia, Migraine (scalp tenderness), and Complex Regional Pain Syndrome (CRPS).

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