NEET-PG 2015 Practice Questions

Q: What is the composition of soda lime?

4% NaOH, 80% Ca(OH)2, trace elements, 15% H2O. ***4% NaOH, 80% Ca(OH)2, trace elements, 15% H2O*** - **Soda lime** is primarily composed of **calcium hydroxide (Ca(OH)2)**, typically around 80%, which acts as the main absorbent. - It also contains **sodium hydroxide (NaOH)**, around 4%, which serves as an activator, along with approximately 15% **water (H2O)** to facilitate the reaction, and **trace elements** like potassium hydroxide. *4% NaOH, 90% Ca(OH)2, 1% KOH, 5% H2O* - This option shows a higher percentage of **calcium hydroxide (90%)** and a lower percentage of **water (5%)** than the standard composition. - The reduced water content might impair the efficiency of **carbon dioxide absorption**. *4% NaOH, 80% Ca(OH)2, 1% KOH, 15% H2O* - While the percentages of NaOH, Ca(OH)2, and H2O are closer to correct, this option specifically mentions **potassium hydroxide (KOH)** as a distinct component at 1%, rather than general trace elements. - The standard composition usually encompasses trace elements more broadly, and specific percentages for KOH are not always highlighted as a primary component. *15% NaOH, 80% Ca(OH)2, trace elements, 4% H2O* - This composition incorrectly suggests a significantly higher percentage of **sodium hydroxide (15%)** and a critically low percentage of **water (4%)**. - A higher NaOH concentration can increase the risk of **carbon monoxide formation** from halogenated anesthetics, and inadequate water reduces absorptive capacity.

Q: In cobalamin deficiency which is not seen

Microcytic anemia. Microcytic anemia - Cobalamin deficiency typically leads to macrocytic anemia due to impaired DNA synthesis, not microcytic anemia [1]. - Microcytic anemia is usually associated with iron deficiency, thalassemia, or anemia of chronic disease [1]. Long tract signs - Long tract signs are common in cobalamin deficiency due to posterior column and corticospinal tract involvement leading to symptoms like spasticity. - They indicate involvement of pathways that are affected by vitamin B12 deficiency. Loss of proprioception - Loss of proprioception can occur in cobalamin deficiency due to damage to the dorsal columns of the spinal cord. - It is a common clinical finding indicating the involvement of sensory pathways. Rhomberg sign - A positive Rhomberg sign indicates impaired proprioception, which can happen in cobalamin deficiency. - It reflects difficulty maintaining balance, emphasizing sensory dysfunction associated with the deficiency.

Q: Which of the following conditions is most commonly associated with cauda equina syndrome?

Herniated disc. ***Herniated disc*** - A **large central disc herniation**, especially at the L4-L5 or L5-S1 level, often compresses multiple nerve roots of the **cauda equina** [1]. - This compression leads to the characteristic symptoms of **saddle anesthesia**, **bowel/bladder dysfunction**, and **bilateral leg weakness**. *Trauma* - While **severe trauma** to the lumbar spine (e.g., fractures, dislocations) can cause cauda equina syndrome, it is a less common cause than disc herniation [1]. - Trauma typically involves an acute, high-energy injury, distinct from the more gradual onset seen with disc pathology. *Tumor* - **Spinal tumors**, both primary and metastatic, can compress the cauda equina, but they are relatively rare compared to disc herniations [1]. - Tumor-related cauda equina syndrome often presents with more insidious symptom progression and may include systemic symptoms or a history of malignancy. *Spinal stenosis* - **Spinal stenosis** can cause compression of nerve roots, typically leading to neurogenic claudication. - While severe stenosis can contribute to cauda equina symptoms, it generally involves diffuse narrowing over multiple levels and is less likely to cause acute, severe cauda equina syndrome than a single, large disc herniation.

Q: Suxamethonium primarily acts on which type of receptors?

Nicotinic acetylcholine receptors. ***Nicotinic acetylcholine receptors*** - **Suxamethonium** is a depolarizing muscle relaxant that acts as an **agonist at nicotinic acetylcholine receptors** at the neuromuscular junction. - This initial activation leads to muscle fasciculations followed by prolonged depolarization, causing **flaccid paralysis**. *Potassium channels* - While some drugs may affect potassium channels to alter neuronal excitability, suxamethonium's primary mechanism of action is not on these channels. - Blocking potassium channels is characteristic of drugs like **certain antiarrhythmics** or **sulfonylureas**. *Calcium channels* - **Calcium channels** play a role in muscle contraction, but they are not the primary target of suxamethonium. - Drugs like **dihydropyridines** (e.g., nifedipine) target calcium channels for their antihypertensive effects. *Chloride channels* - Chloride channels are involved in maintaining resting membrane potential and inhibitory neurotransmission. - Drugs such as **benzodiazepines** indirectly enhance GABA-mediated chloride influx, which is distinct from suxamethonium's action.

Q: Which of the following is not considered a contraindication for undergoing an MRI?

Ryle's tube. ***Ryle's tube*** - A **Ryle's tube** is a form of nasogastric tube made of radiopaque plastic, which is entirely **MRI-safe** and does not interact with magnetic fields. - It is made from inert materials that are **non-ferromagnetic**, posing no risk during an MRI scan. *Cardiac pacemaker* - **Cardiac pacemakers** contain metallic components that can malfunction, demagnetize, or migrate due to the strong magnetic fields and radiofrequency pulses of an MRI. - This can lead to **arrhythmias**, **pacemaker failure**, or **heating of leads**, posing a significant risk to the patient. *Cochlear implant* - **Cochlear implants** contain strong magnets and electronic components that can be damaged or displaced by the MRI's magnetic field. - This can cause **pain**, **implant damage**, or **hearing loss** for the patient. *Metallic splinter in eye* - A **metallic splinter in the eye** is a severe contraindication because the strong magnetic field can cause the metal fragment to move. - This movement can lead to **tissue damage**, **hemorrhage**, or **blindness** if it dislodges in the delicate structures of the eye.

Q: All are done to minimize radiation exposure to the patient under fluoroscopy, except which of the following?

Increasing fluoroscopic time. ***Increasing fluoroscopic time*** - **Increasing fluoroscopic time** directly leads to a greater cumulative dose of radiation received by the patient. - This action goes against the principle of **ALARA (As Low As Reasonably Achievable)** for radiation safety. *Decreasing fluoroscopic time* - **Decreasing fluoroscopic time** reduces the total duration of X-ray exposure, thereby minimizing the radiation dose to the patient. - This is a fundamental practice in radiation protection. *Using low dose of radiation* - Employing **low-dose radiation protocols** means using the minimum amount of radiation necessary to obtain diagnostic images. - This directly reduces the patient's exposure while maintaining image quality for diagnosis. *Decrease in field of view* - A **decrease in the field of view** (collimation) restricts the X-ray beam to only the area of interest, limiting irradiation of surrounding healthy tissues. - This targeted approach significantly reduces the overall radiation dose to the patient.

Q: Substance used for PET scan is

18F-FDG. ***18F-FDG*** - **18F-FDG (Fluorodeoxyglucose)** is a glucose analog labeled with a **positron-emitting radioisotope**, fluorine-18 (18F). - It is the most commonly used radiotracer in PET scans, as it accumulates in cells with high metabolic activity, particularly **cancer cells** and activated brain cells. *Gadolinium* - **Gadolinium** is a paramagnetic contrast agent primarily used in **MRI scans** to enhance the visualization of blood vessels and abnormal tissues. - It does not emit positrons and is therefore not suitable for PET imaging. *Gastrografin* - **Gastrografin** is an oral, water-soluble contrast agent containing **iodine**, typically used in **X-rays** and **CT scans** of the gastrointestinal tract. - It is not a radioactive tracer and has no application in PET imaging. *Iodine* - **Iodine** in various forms can be used as a contrast agent in **X-rays** and **CT scans**, or as a radioactive isotope (e.g., **I-131**) for **thyroid imaging** and treatment. - While some isotopes of iodine are radioactive, they are not typically used for PET imaging, which relies on positron emission.

Q: In which of the following cancers is intraoperative radiotherapy (IORT) applicable?

All of the options. ***All of the options*** - **Intraoperative radiotherapy (IORT)** is applicable to all three cancers listed: gastric cancer, colon carcinoma, and pancreatic carcinoma. - IORT is a technique where a **single, high dose of radiation** is delivered to the tumor bed during surgery to improve local control and reduce late toxicity to surrounding healthy tissues. - All three cancers benefit from IORT due to their **high risk of local recurrence** and the ability to directly target the tumor bed while sparing adjacent critical organs. **Gastric cancer:** - IORT addresses **high rates of local recurrence** after conventional surgery, especially in locally advanced stages - Allows direct radiation of potentially involved regional lymph nodes or margins difficult to eradicate surgically - Particularly useful when complete surgical clearance carries excessive morbidity risk **Colon carcinoma:** - IORT considered in **locally advanced or recurrent disease**, particularly when tumors invade adjacent structures - Beneficial after resections with positive or close margins - Delivers high dose to microscopic residual disease in the tumor bed, avoiding damage to vital organs from external beam radiotherapy **Pancreatic carcinoma:** - High propensity for **local invasion and recurrence** makes IORT particularly relevant - Delivers high dose directly to tumor bed following resection when microscopic residual disease is suspected - Overcomes limitations of external beam radiation due to proximity of critical organs (duodenum, stomach, kidneys)

Q: Precisely directed high dose radiation is used in which of the following therapies?

Stereotactic radiosurgery. ***Stereotactic radiosurgery*** - **Stereotactic radiosurgery (SRS)** is a highly precise radiation therapy that uses focused, high-dose radiation beams to target small tumors or abnormalities with **sub-millimeter accuracy**. - It delivers **very high doses per fraction** (typically 15-24 Gy in a single session) using stereotactic guidance systems. - Commonly used for **brain metastases, AVMs, acoustic neuromas**, and other small intracranial targets. *IMRT* - **Intensity-modulated radiation therapy (IMRT)** is an advanced form of 3D-conformal radiation therapy that modulates beam intensity to conform to tumor shape. - While IMRT is precise, it uses **conventional fractionation** (1.8-2 Gy per fraction over many treatments), not the high-dose approach of SRS. *EBRT* - **External beam radiation therapy (EBRT)** is a general term for radiation delivered from outside the body. - It encompasses various techniques but *does not specifically indicate the **stereotactic precision and high-dose per fraction** characteristic of SRS*. *Brachytherapy* - **Brachytherapy** involves placing radioactive sources **directly inside or next to the tumor**. - While it delivers high doses locally, it is not "precisely directed high-dose radiation" from external beams like SRS.

Q: Which condition is characterized by a specific appearance on CT scans that resembles small centrilobular nodules with branching linear structures?

Pulmonary tuberculosis. ***Pulmonary tuberculosis*** - This description ("small centrilobular nodules with **branching linear structures**") is characteristic of the **tree-in-bud pattern** seen on CT scans, which is a hallmark finding in active **endobronchial spread of tuberculosis**. - The tree-in-bud pattern results from the impaction of tuberculous **granulomas** and caseous material in the terminal and respiratory bronchioles. *Silicosis* - Characterized by multiple small, well-defined **nodules** (often in the upper lobes) that tend to calcify, but typically lacks the fine **branching linear structures**. - It’s associated with occupational exposure to **silica dust** and may progress to **massive progressive fibrosis**. *Pulmonary hydatid cyst* - Presents as a well-defined, usually **single, large cystic lesion** on CT, often with internal membranes if ruptured (water lily sign or crumpled membrane sign). - It does not typically manifest with small centrilobular nodules or branching linear structures. *Small cell carcinoma* - Usually appears as a **large central mass**, often with mediastinal lymphadenopathy, and sometimes associated with obstructive pneumonitis. - It does not typically present as diffuse small centrilobular nodules with branching patterns.

Question 1

What is the composition of soda lime?

Accepted Answer

4% NaOH, 80% Ca(OH)2, trace elements, 15% H2O

Answer

4% NaOH, 90% Ca(OH)2, 1% KOH, 5% H2O

Answer

15% NaOH, 80% Ca(OH)2, trace elements, 4% H2O

Answer

4% NaOH, 80% Ca(OH)2, 1% KOH, 15% H2O

Question 2

In cobalamin deficiency which is not seen

Accepted Answer

Microcytic anemia

Answer

Loss of proprioception

Answer

Rhomberg sign

Answer

Long tract signs

Question 3

Which of the following conditions is most commonly associated with cauda equina syndrome?

Accepted Answer

Herniated disc

Answer

Trauma

Answer

Tumor

Answer

Spinal stenosis

Question 4

Suxamethonium primarily acts on which type of receptors?

Accepted Answer

Nicotinic acetylcholine receptors

Answer

Potassium channels

Answer

Calcium channels

Answer

Chloride channels

Question 5

Which of the following is not considered a contraindication for undergoing an MRI?

Accepted Answer

Ryle's tube

Answer

Cardiac pacemaker

Answer

Cochlear implant

Answer

Metallic splinter in eye

Question 6

All are done to minimize radiation exposure to the patient under fluoroscopy, except which of the following?

Accepted Answer

Increasing fluoroscopic time

Answer

Decreasing fluoroscopic time

Answer

Using low dose of radiation

Answer

Decrease in field of view

Question 7

Substance used for PET scan is

Accepted Answer

18F-FDG

Answer

Gadolinium

Answer

Gastrografin

Answer

Iodine

Question 8

In which of the following cancers is intraoperative radiotherapy (IORT) applicable?

Accepted Answer

All of the options

Answer

Gastric cancer

Answer

Colon carcinoma

Answer

Pancreatic carcinoma

Question 9

Precisely directed high dose radiation is used in which of the following therapies?

Accepted Answer

Stereotactic radiosurgery

Answer

EBRT

Answer

IMRT

Answer

Brachytherapy

Question 10

Which condition is characterized by a specific appearance on CT scans that resembles small centrilobular nodules with branching linear structures?

Accepted Answer

Pulmonary tuberculosis

Answer

Silicosis

Answer

Pulmonary hydatid cyst

Answer

Small cell carcinoma

NEET-PG 2015

Anesthesiology

Internal Medicine

Orthopaedics

Pharmacology

Radiology