Pain Management — MCQs

Pain Management Indian Medical PG Practice Questions and MCQs

Question 31: Which scale is primarily used for assessing the pain rating index?

A. Faces scale
B. Visual analogue scale
C. McGill questionnaire (Correct Answer)
D. CHEOPS scale

Explanation: **Explanation:** The **McGill Pain Questionnaire (MPQ)** is the correct answer because it is a multidimensional tool designed to measure the sensory, affective, and evaluative aspects of pain. Unlike simple intensity scales, it provides a **Pain Rating Index (PRI)** based on 78 descriptive adjectives (e.g., throbbing, shooting, exhausting) categorized into 20 groups. It also includes a Present Pain Intensity (PPI) score on a scale of 0-5. **Analysis of Incorrect Options:** * **Faces Pain Scale (Wong-Baker):** Primarily used in **pediatrics** (children >3 years) or patients with communication barriers. It assesses pain intensity through facial expressions but does not provide a Pain Rating Index. * **Visual Analogue Scale (VAS):** A 10 cm line where the patient marks their pain level from "no pain" to "worst imaginable pain." It is a **unidimensional** scale measuring only intensity, not the quality or index of pain. * **CHEOPS Scale (Children's Hospital of Eastern Ontario Pain Scale):** A behavioral scale used to assess **postoperative pain in young children** (ages 1–7). It evaluates parameters like crying, facial expression, and torso movement. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for Intensity:** Visual Analogue Scale (VAS) is the most commonly used tool in clinical research for subjective pain intensity. * **Neuropathic Pain:** Tools like **LANSS** or **DN4** are specifically used for screening neuropathic components. * **Neonatal Pain:** The **CRIES** score or **NIPS** (Neonatal Infant Pain Scale) are the preferred assessment tools. * **Chronic Pain:** The McGill Questionnaire is particularly useful for chronic pain syndromes where the emotional and sensory qualities are as important as the intensity.

Question 32: What is the reaction to a stimulus that is normally not painful called?

A. Allodynia (Correct Answer)
B. Hypoalgesia
C. Hypoesthesia
D. None of the above

Explanation: ### Explanation **Correct Answer: A. Allodynia** **1. Why Allodynia is correct:** 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**. In this condition, the threshold for pain is lowered to the point where non-noxious stimuli (like a light touch, the brush of clothing, or a breeze) are perceived as painful. It is a hallmark of neuropathic pain and is often mediated by "central sensitization," where second-order neurons in the spinal cord become hypersensitive to normal input from A-beta fibers. **2. Why the other options are incorrect:** * **B. Hypoalgesia:** This refers to a **diminished pain response** to a stimulus that is normally painful. It is the opposite of hyperalgesia. * **C. Hypoesthesia:** This is a broader term referring to **decreased sensitivity to any cutaneous stimulation**, including touch, pressure, or temperature (not specifically pain). **3. High-Yield Clinical Pearls for NEET-PG:** * **Hyperalgesia:** An *increased* response to a stimulus that is *normally* painful (e.g., a pinprick feeling like a stab). * **Hyperpathia:** An explosive, painful reaction to a stimulus, especially a repetitive one, often with an increased threshold. * **Dysesthesia:** An unpleasant, abnormal sensation, whether spontaneous or evoked. * **Paresthesia:** An abnormal sensation (like "pins and needles") that is **not** necessarily unpleasant or painful. * **Mechanism Tip:** Allodynia involves a change in the *quality* of sensation (non-painful becomes painful), whereas hyperalgesia involves a change in the *intensity* of sensation.

Question 33: Which monoclonal antibody against Nerve growth factor has been approved for chronic pain in patients with osteoarthritis and chronic low back pain?

A. Denosumab
B. Tanezumab (Correct Answer)
C. Alirocumab
D. Romosozumab

Explanation: **Explanation:** **Tanezumab** is a humanized monoclonal antibody that binds to and inhibits **Nerve Growth Factor (NGF)**. NGF levels are elevated in injured or inflamed tissues; it sensitizes nociceptors and contributes to the "wind-up" phenomenon in chronic pain states. By neutralizing NGF, Tanezumab prevents it from binding to its receptors (TrkA and p75) on pain-sensing neurons, effectively reducing pain signaling in conditions like osteoarthritis and chronic low back pain. **Analysis of Incorrect Options:** * **Denosumab (Option A):** A monoclonal antibody against **RANKL**. It inhibits osteoclast formation and is used for osteoporosis and giant cell tumors of the bone, not direct pain modulation. * **Alirocumab (Option C):** A **PCSK9 inhibitor** used to lower LDL cholesterol levels in patients with hypercholesterolemia. * **Romosozumab (Option D):** An anti-**sclerostin** antibody used to increase bone formation and decrease bone resorption in severe postmenopausal osteoporosis. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Tanezumab represents a non-opioid, non-NSAID approach to chronic pain management. * **Adverse Effect:** A significant concern during clinical trials was **Rapidly Progressive Osteoarthritis (RPOA)**, especially when used concurrently with NSAIDs. * **Target:** NGF is a key mediator of **peripheral sensitization**. * **Mnemonic:** Remember "**Tane**zumab for **Tame**-ing pain."

Question 34: The WHO Ladder is used for the rational titration of which type of therapy?

A. Oral analgesia (Correct Answer)
B. Chemotherapy
C. Radiotherapy
D. Antidepressants

Explanation: The **WHO Analgesic Ladder** was originally developed in 1986 as a framework to provide adequate pain relief for cancer patients. Its primary principle is the rational, sequential titration of **oral analgesics** based on the intensity of pain. ### **Explanation of the Correct Answer** The ladder emphasizes the "By the Mouth" principle, advocating for the oral route whenever possible. It consists of three main steps: 1. **Step 1 (Mild Pain):** Non-opioids (e.g., NSAIDs, Paracetamol) ± Adjuvants. 2. **Step 2 (Moderate Pain):** Weak opioids (e.g., Codeine, Tramadol) ± Non-opioids ± Adjuvants. 3. **Step 3 (Severe Pain):** Strong opioids (e.g., Morphine, Fentanyl) ± Non-opioids ± Adjuvants. The goal is to move up the ladder if pain persists or increases, ensuring rational titration to achieve a pain-free state. ### **Why Other Options are Incorrect** * **B & C (Chemotherapy/Radiotherapy):** While these are used in cancer management, they are definitive treatments for the underlying pathology, not the titrated symptomatic relief framework defined by the WHO Ladder. * **D (Antidepressants):** These are considered "adjuvants" within the ladder (especially for neuropathic pain), but the ladder itself is not designed for the titration of antidepressant therapy alone. ### **High-Yield Clinical Pearls for NEET-PG** * **The "Fourth Step":** Recent modifications include a 4th step involving **interventional techniques** (e.g., epidurals, nerve blocks, or PCA pumps) for refractory pain. * **Administration Principles:** The ladder follows the rules: *By the mouth, By the clock (fixed intervals), By the ladder, and For the individual.* * **Drug of Choice:** Morphine remains the "gold standard" strong opioid for Step 3. * **Ceiling Effect:** Non-opioids (Step 1) have a "ceiling effect" (increasing dose beyond a point doesn't increase analgesia), whereas pure opioid agonists (Step 3) do not.

Question 35: Which of the following opioids is used via the transdermal route for malignancy-associated pain?

A. Fentanyl (Correct Answer)
B. Morphine
C. Codeine
D. Oxycodone

Explanation: **Explanation:** **Fentanyl** is the correct answer because it possesses the specific physicochemical properties required for effective transdermal delivery: **high lipid solubility** and **low molecular weight**. These characteristics allow it to penetrate the stratum corneum easily. In malignancy-associated chronic pain, the Fentanyl transdermal patch (Durogesic) provides a stable plasma concentration over 72 hours, offering a non-invasive alternative for patients with dysphagia or persistent nausea. **Why the other options are incorrect:** * **Morphine:** It is the gold standard for cancer pain (WHO Step 3) but is **hydrophilic**. Its poor lipid solubility makes it unsuitable for transdermal absorption; it is primarily administered orally or intravenously. * **Codeine:** A weak opioid (WHO Step 2) used for mild-to-moderate pain. It is a prodrug converted to morphine and is administered orally. * **Oxycodone:** A potent semi-synthetic opioid used for severe pain. While available in controlled-release oral formulations, it is not standardly used via the transdermal route. **High-Yield Clinical Pearls for NEET-PG:** * **Buprenorphine** is the only other opioid commonly used via a transdermal patch in clinical practice. * **Fentanyl Patch Timing:** It takes **12–24 hours** to reach peak plasma concentration; therefore, it is used for *chronic* stable pain, never for *acute* or breakthrough pain. * **Potency:** Fentanyl is approximately **75–100 times more potent** than Morphine. * **Safety:** Fentanyl is preferred over Morphine in patients with **renal failure** as it has no active metabolites (unlike Morphine-6-glucuronide).

Question 36: Severe pain after injury or sectioning of a peripheral sensory nerve is called:

A. Complex regional pain syndrome. (Correct Answer)
B. Neuralgia.
C. Neuritis.
D. Temporal arteritis.

Explanation: **Explanation:** The correct answer is **Complex Regional Pain Syndrome (CRPS)**. Specifically, this description refers to **CRPS Type II** (formerly known as **Causalgia**). **1. Why CRPS is correct:** CRPS is a chronic pain condition characterized by autonomic and inflammatory features. It is divided into two types: * **Type I (Reflex Sympathetic Dystrophy):** Occurs after a minor injury or fracture *without* a definable nerve lesion. * **Type II (Causalgia):** Develops specifically after **injury or sectioning of a peripheral sensory nerve**. The pain is typically "burning" in nature, out of proportion to the inciting event, and associated with allodynia, hyperalgesia, and vasomotor instability (changes in skin temperature/color). **2. Why other options are incorrect:** * **Neuralgia:** Refers to sharp, paroxysmal pain radiating along the distribution of a specific nerve (e.g., Trigeminal neuralgia) without necessarily involving a sectioned nerve or autonomic changes. * **Neuritis:** This is the inflammation of a nerve, often due to infection or autoimmune processes, rather than a traumatic sectioning. * **Temporal Arteritis:** A form of vasculitis involving large and medium-sized arteries (typically the temporal artery). It presents with headaches and jaw claudication, not peripheral nerve injury pain. **High-Yield Clinical Pearls for NEET-PG:** * **Budapest Criteria:** The gold standard for clinical diagnosis of CRPS. * **Key Symptoms:** The "STAMP" mnemonic—**S**ensory (allodynia), **T**rophic (skin/nail changes), **A**utonomic (sweating), **M**otor (weakness), and **P**ain. * **Management:** Multimodal approach including physical therapy (most important), neuropathic agents (Gabapentin/Pregabalin), and Sympathetic Nerve Blocks (e.g., Stellate ganglion block for upper limbs).

Question 37: Who proposed the gate control theory of pain?

A. Lofgren
B. Melzack and Wall (Correct Answer)
C. Alexander Beunet
D. William Halsted

Explanation: **Explanation:** The **Gate Control Theory of Pain**, proposed by **Ronald Melzack and Patrick Wall in 1965**, is a fundamental concept in pain physiology. It suggests that the spinal cord contains a neurological "gate" (specifically in the **Substantia Gelatinosa** of the dorsal horn) that either blocks pain signals or allows them to continue to the brain. According to this theory, stimulation of large-diameter myelinated **A-beta fibers** (carrying touch/vibration) activates inhibitory interneurons that "close the gate," preventing pain signals from small-diameter **C and A-delta fibers** from reaching the brain. This explains why rubbing a bumped knee or using a TENS unit reduces the sensation of pain. **Analysis of Incorrect Options:** * **Lofgren (Nils Löfgren):** A Swedish chemist famous for synthesizing **Lidocaine** (Xylocaine) in 1943, the first amino-amide local anesthetic. * **Alexander Bennett:** A Scottish physician credited with the first clinical description of leukemia; he is not associated with pain theories. * **William Halsted:** A pioneer of modern surgery known for introducing the **Halstedian principles** and performing the first regional nerve block using cocaine. **High-Yield Clinical Pearls for NEET-PG:** * **Site of the "Gate":** Substantia Gelatinosa (Rexed Lamina II) of the dorsal horn. * **Clinical Application:** This theory forms the physiological basis for **TENS (Transcutaneous Electrical Nerve Stimulation)** and **Spinal Cord Stimulators**. * **First Local Anesthetic:** Cocaine (introduced by Koller for ophthalmology; Halsted for nerve blocks). * **First Synthetic Local Anesthetic:** Procaine (Novocaine) by Einhorn.

Question 38: Which drug is commonly used for outpatient department (OPD) analgesia?

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

Explanation: **Explanation:** The choice of an analgesic for Outpatient Department (OPD) or day-care procedures is primarily governed by the drug's **pharmacokinetic profile**, specifically a rapid onset and a very short duration of action to allow for early discharge. **Why Alfentanil is Correct:** Alfentanil is a potent phenylpiperidine derivative (analogue of fentanyl). It is the preferred choice for short, painful OPD procedures because: * **Rapid Onset:** It has a low pKa (6.5), meaning a higher fraction of the drug is non-ionized at physiological pH, allowing it to cross the blood-brain barrier almost instantly (onset within 1 minute). * **Short Duration:** It has a small volume of distribution and a short elimination half-life (approx. 90 minutes), leading to rapid recovery and minimal "hangover" effect, which is ideal for ambulatory (day-care) surgery. **Analysis of Incorrect Options:** * **Morphine:** It has a slow onset (low lipid solubility) and a long duration of action (3–4 hours). It carries a higher risk of postoperative nausea, vomiting (PONV), and respiratory depression, making it unsuitable for quick OPD discharge. * **Pethidine:** It has a moderate duration of action but produces a toxic metabolite, **normeperidine**, which can cause seizures. It is rarely used for routine OPD analgesia. * **Fentanyl:** While used in OPD, it has a longer duration of action than Alfentanil due to its larger volume of distribution and tendency to redistribute into fat stores, which can lead to delayed respiratory depression. **High-Yield Clinical Pearls for NEET-PG:** * **Potency Ratio:** Remifentanil > Fentanyl (100x Morphine) > Alfentanil (1/4th to 1/10th of Fentanyl) > Morphine (1) > Pethidine (1/10th of Morphine). * **Remifentanil:** Even shorter-acting than Alfentanil because it is metabolized by **non-specific plasma esterases**, but Alfentanil remains a classic answer for OPD "bolus" analgesia. * **Context-Sensitive Half-Time:** Alfentanil has a shorter context-sensitive half-time than fentanyl for infusions lasting up to 8 hours.

Question 39: What is the preferred route of administration for analgesics in cancer patients?

A. Oral (Correct Answer)
B. Intravenous
C. Topical
D. Sublingual

Explanation: **Explanation:** The management of cancer pain is primarily guided by the **WHO Analgesic Ladder**, which emphasizes the principle: **"By the mouth, by the clock, and by the ladder."** **1. Why Oral is Correct:** The **oral route** is the preferred method of administration because it is non-invasive, cost-effective, and allows for the greatest patient autonomy. It provides consistent plasma drug levels, which is essential for managing chronic cancer pain. It avoids the complications associated with needles (infection, hematoma) and is the most practical for long-term outpatient care. **2. Why Other Options are Incorrect:** * **Intravenous (IV):** While IV administration has the fastest onset, it is reserved for acute crises, titration in hospitalized patients, or when the patient cannot swallow. It is not ideal for long-term maintenance due to the need for venous access and risk of systemic complications. * **Topical:** Transdermal patches (e.g., Fentanyl) are useful for stable pain, but they are generally considered second-line to oral medications due to slow titration and absorption variability. * **Sublingual:** This route is typically reserved for "breakthrough pain" rather than baseline maintenance therapy. **Clinical Pearls for NEET-PG:** * **WHO Ladder Steps:** Step 1 (Non-opioids like Paracetamol/NSAIDs) → Step 2 (Weak opioids like Codeine/Tramadol) → Step 3 (Strong opioids like Morphine). * **Morphine** remains the gold standard for Step 3 cancer pain. * **Breakthrough Pain:** Always prescribe a "rescue dose" (usually 1/6th of the total daily dose) alongside the regular "by the clock" regimen. * **Constipation:** This is the only opioid side effect to which patients do **not** develop tolerance; always co-prescribe a stimulant laxative.

Question 40: Which parameter is most widely measured using the Visual Analogue Scale (VAS)?

A. Sleep
B. Sedation
C. Pain intensity (Correct Answer)
D. Depth of anaesthesia

Explanation: **Explanation:** The **Visual Analogue Scale (VAS)** is a validated, subjective psychometric tool used primarily to measure **Pain Intensity**. It typically consists of a 10 cm (100 mm) horizontal line with two anchors representing the extremes of the sensation: "No pain" at the 0 cm mark and "Worst imaginable pain" at the 10 cm mark. The patient marks a point on the line that represents their current pain level, and the distance from the start to the mark is measured in millimeters to provide a numerical value. Its simplicity and sensitivity to change make it the "gold standard" for assessing acute and chronic pain in clinical research and postoperative settings. **Analysis of Incorrect Options:** * **A. Sleep:** Sleep quality is usually assessed using the Pittsburgh Sleep Quality Index (PSQI) or the Epworth Sleepiness Scale. * **B. Sedation:** Sedation levels in anesthesia and ICU are measured using the **Ramsey Sedation Scale** or the **Richmond Agitation-Sedation Scale (RASS)**. * **D. Depth of Anaesthesia:** This is monitored using objective electroencephalographic (EEG) parameters, most commonly the **Bispectral Index (BIS)** or Entropy. **High-Yield Clinical Pearls for NEET-PG:** * **VAS vs. NRS:** The Numerical Rating Scale (NRS) is a verbal version (0–10) often preferred in clinical practice for ease of use, while VAS is preferred in research for its continuous data. * **Pediatric Pain:** For children (usually >3 years), the **Wong-Baker FACES Pain Rating Scale** is used. * **FLACC Scale:** Used for infants and non-verbal patients (Face, Legs, Activity, Cry, Consolability). * **Minimum Clinically Significant Difference:** A change of approximately **13 mm** on the 100 mm VAS is generally considered clinically meaningful.

Practice by Chapter

Pain Physiology and Pathways

Practice Questions

Acute Pain Management

Practice Questions

Chronic Pain Syndromes

Practice Questions

Neuropathic Pain

Practice Questions

Multimodal Analgesia

Practice Questions

Opioid Pharmacology

Practice Questions

Non-opioid Analgesics

Practice Questions

Adjuvant Analgesics

Practice Questions

Patient-Controlled Analgesia

Practice Questions

Interventional Pain Procedures

Practice Questions

Cancer Pain Management

Practice Questions

Perioperative Pain Management

Practice Questions

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