NEET-PG 2019
294 Previous Year Questions with Answers & Explanations
Anesthesiology
1 questionsWhich of the following intravenous agents is known to cause pain upon injection?
NEET-PG 2019 - Anesthesiology NEET-PG Practice Questions and MCQs
Question 1: Which of the following intravenous agents is known to cause pain upon injection?
- A. Ketamine
- B. Propofol (Correct Answer)
- C. Etomidate
- D. Methohexital
Explanation: ***Propofol*** - **Propofol** is notoriously known to cause significant **pain upon injection**, especially when administered into smaller veins. - This is attributed to its **lipid emulsion formulation** and activation of **TRPA1 receptors** on sensory neurons. *Methohexital* - While **methohexital** can cause localized pain and venous irritation, it is generally less pronounced and less frequent than with propofol. - It is known more for causing **hiccups** and **muscle twitching** upon induction, rather than severe injection pain. *Ketamine* - **Ketamine** typically causes minimal to no pain upon intravenous injection. - Its side effects are often related to its **dissociative anesthetic** properties, such as psychomimetic effects and increased sympathetic activity. *Etomidate* - **Etomidate** is generally considered to be low in causing injection site pain. - Its primary concern is the potential for **adrenocortical suppression** and a high incidence of **myoclonus**.
Biochemistry
2 questionsWhich of the following is true about alpha-1 antitrypsin?
Which of the following is not the source of cytosolic NADPH ?
NEET-PG 2019 - Biochemistry NEET-PG Practice Questions and MCQs
Question 1: Which of the following is true about alpha-1 antitrypsin?
- A. Inhibits elastase (Correct Answer)
- B. Inhibits trypsin
- C. Inhibits chymotrypsin
- D. Inhibits trypsinogen activation
Explanation: ***Inhibits elastase*** - Alpha-1 antitrypsin (A1AT) primarily serves to **inhibit elastase**, a protease that can damage lung tissue, helping to protect the lungs from destruction [1]. - Deficiency of A1AT leads to **emphysema** and liver disease due to unchecked activity of elastase [1][2]. *Inhibits trypsin* - A1AT specifically does not primarily inhibit **trypsin**, which is involved in protein digestion in the intestine. - Although A1AT affects proteases, its main function is related to **elastase**, not trypsin [1]. *Inhibits trypsinogen activation in pancreas* - A1AT does not have a significant role in the **inhibition of trypsinogen activation** within the pancreas. - Instead, pancreatic enzyme regulation involves other mechanisms that do not involve A1AT's function. *Inhibits chymotrypsin* - A1AT is not known for inhibiting **chymotrypsin**, a serine protease derived from trypsinogen in the gut. - It specifically targets **elastase** and similar enzymes rather than chymotrypsin [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 856-858. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 683-684.
Question 2: Which of the following is not the source of cytosolic NADPH ?
- A. Malic enzyme
- B. G6PD
- C. Isocitrate dehydrogenase
- D. ATP citrate lyase (Correct Answer)
Explanation: ***ATP citrate lyase*** - **ATP citrate lyase** is an enzyme involved in the synthesis of **acetyl-CoA** from citrate in the cytosol, which is then used for **fatty acid synthesis**. It does not generate NADPH. - While the **acetyl-CoA** produced is used in pathways that require NADPH, ATP citrate lyase itself does not directly produce NADPH. *Isocitrate dehydrogenase* - Cytosolic **isocitrate dehydrogenase** catalyzes the oxidative decarboxylation of **isocitrate** to alpha-ketoglutarate, producing **NADPH**. - This reaction is an important source of **cytosolic NADPH**, especially in non-photosynthetic tissues. *Malic enzyme* - **Malic enzyme** catalyzes the oxidative decarboxylation of **malate** to pyruvate, simultaneously reducing **NADP+ to NADPH**. - This enzyme is a significant source of **cytosolic NADPH** in various tissues, contributing to fatty acid synthesis and other reductive processes. *G6PD* - **Glucose-6-phosphate dehydrogenase (G6PD)** is the rate-limiting enzyme in the **pentose phosphate pathway** (PPP). - It catalyzes the first step of the PPP, converting **glucose-6-phosphate** to 6-phosphogluconolactone and producing **NADPH** as a crucial coenzyme.
Ophthalmology
3 questionsEsotropia is most commonly associated with:
What conditions can be diagnosed using the cover-uncover test?
Esotropia is commonly seen in which type of refractive error?
NEET-PG 2019 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 1: Esotropia is most commonly associated with:
- A. Hyperopia (Correct Answer)
- B. Presbyopia
- C. Astigmatism
- D. Myopia
Explanation: ***Hyperopia*** - **Hyperopia** (farsightedness) requires greater accommodative effort to focus on distant and near objects, which is coupled with **convergence**. This excessive convergence can lead to **esotropia** (inward turning of the eye). - Accommodative esotropia is a common type of strabismus directly linked to uncorrected hyperopia. *Presbyopia* - **Presbyopia** is an age-related loss of the eye's ability to focus on nearby objects due to stiffening of the lens, typically occurring after age 40. - It affects accommodation but does not primarily cause esotropia; rather, it makes near work difficult, and patients may prefer to hold objects further away to see them. *Astigmatism* - **Astigmatism** is a refractive error where the eye does not focus light evenly onto the retina due to an irregularly shaped cornea or lens, leading to blurred or distorted vision at all distances. - While it can cause visual discomfort and eye strain, it is not directly associated with the development of esotropia. *Myopia* - **Myopia** (nearsightedness) is a refractive error where distant objects appear blurry because light focuses in front of the retina. - High myopia can sometimes be associated with **exotropia** (outward turning of the eye) due to divergence excess, rather than esotropia.
Question 2: What conditions can be diagnosed using the cover-uncover test?
- A. Eye alignment disorders including strabismus and heterophoria (Correct Answer)
- B. Convergent strabismus (Esotropia)
- C. Latent misalignment (Heterophoria)
- D. Strabismus (Squint)
Explanation: ***Eye alignment disorders including strabismus and heterophoria*** - The **cover-uncover test** is a clinical procedure used to detect and differentiate both **strabismus** (manifest deviation) and **heterophoria** (latent deviation) by observing eye movements when vision is occluded and then re-exposed. - This test is a fundamental tool for assessing **ocular alignment** and binocular vision, revealing if an eye deviates and how it recovers. - **This is the most comprehensive answer** as it includes both manifest and latent deviations. *Convergent strabismus (Esotropia)* - Although the cover-uncover test can diagnose **esotropia** (a type of strabismus where the eye turns inward), this option is **too specific** and does not cover all the conditions assessable by this test. - The test can diagnose **all types of strabismus** (esotropia, exotropia, hypertropia, hypotropia) and heterophoria, not just convergent strabismus. - Esotropia is characterized by the **deviating eye failing to spontaneously realign** when uncovered, as it is a constant, manifest deviation. *Latent misalignment (Heterophoria)* - While the cover-uncover test **can detect heterophoria**, this option is **incomplete** as it does not include strabismus (manifest deviation). - Heterophoria manifests when the covered eye deviates and then **refixes** when uncovered, indicating a latent deviation normally controlled by fusion. - The alternate cover test is more sensitive for detecting heterophoria, but the cover-uncover test can identify it as well. *Strabismus (Squint)* - The cover-uncover test is used to diagnose **strabismus**, but this option is **incomplete** and does not include **heterophoria**, which is also diagnosable by the test. - Strabismus is identified when the eye that was *not* covered deviates, or the covered eye does not refixate upon uncovering, indicating a manifest turn. - This option only covers manifest deviations and misses latent deviations.
Question 3: Esotropia is commonly seen in which type of refractive error?
- A. Myopia
- B. Hypermetropia (Correct Answer)
- C. Astigmatism
- D. Presbyopia
Explanation: ***Hypermetropia*** - **Esotropia**, or convergent strabismus, is commonly associated with **uncorrected hypermetropia**, especially in children. - The constant effort to **accommodate** to see clearly for hypermetropic individuals can lead to excessive convergence, causing the eye to turn inward. *Myopia* - Myopia, or **nearsightedness**, rarely causes esotropia. - In some cases, high myopia can be associated with **exotropia** (divergent strabismus) due to reduced accommodative effort. *Astigmatism* - **Astigmatism** causes blurry vision at all distances due to an irregularly shaped cornea or lens, but it is not directly linked to specific forms of strabismus like esotropia or exotropia. - While it can contribute to **amblyopia** if severe and uncorrected, it does not typically cause the eyes to turn inward. *Presbyopia* - **Presbyopia** is an age-related loss of the eye's ability to focus on nearby objects due to stiffening of the lens. - It affects accommodation but does not cause strabismus such as esotropia; it typically begins around age 40.
Pathology
1 questionsFish mouth stenosis in rheumatic heart disease is due to which of the following mechanisms?
NEET-PG 2019 - Pathology NEET-PG Practice Questions and MCQs
Question 1: Fish mouth stenosis in rheumatic heart disease is due to which of the following mechanisms?
- A. Calcification and fibrosis bridging across valvular commissures (Correct Answer)
- B. Fibrinoid necrosis
- C. Acute inflammation leading to valvular damage
- D. Myxomatous degeneration of the valve, which can occur in rheumatic heart disease
Explanation: ***Calcification and fibrosis bridging across valvular commissures*** - In rheumatic heart disease, **calcification and fibrosis** occur as a result of chronic inflammation, leading to **stenosis** of the mitral valve, often described as "fish mouth" appearance [1]. - This mechanism is due to **post-inflammatory scarring** that restricts opening and closing of the valve, characteristic of chronic rheumatic changes [1][2]. *Myxomatous degeneration of the valve* - Myxomatous degeneration primarily affects the **mitral valve** and may cause **prolapse**, but it does not lead to **stenosis**. - This process involves **thinning and elongation** of the valve leaflets, contrasting with the fibrotic changes seen in rheumatic heart disease. *Acute inflammation leading to valvular damage* - Acute inflammation due to **rheumatic fever** typically causes **valvulitis**, not chronic stenosis, which is a late consequence of chronic damage. - This mechanism leads to **valvular regurgitation** rather than stenosis, hence it's not associated with "fish mouth" stenosis. *Fibrinoid necrosis* - Fibrinoid necrosis is seen in **acute rheumatic fever** but does not directly cause **valvular stenosis**; it represents an acute inflammatory response. - This is more related to **immune complex deposition** rather than the chronic fibrotic changes leading to fish mouth morphology in rheumatic heart disease. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 566-567. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Cardiovascular Disease, pp. 293-294.
Pharmacology
3 questionsWhich of the following statements is true regarding a fixed-dose combination of drugs?
Carbapenem with the maximum seizure risk is:
Which of the following best demonstrates the variability in drug responsiveness among individuals?
NEET-PG 2019 - Pharmacology NEET-PG Practice Questions and MCQs
Question 1: Which of the following statements is true regarding a fixed-dose combination of drugs?
- A. The adverse effect of one drug may be mitigated by the other drug. (Correct Answer)
- B. The dose of one drug can be adjusted independently.
- C. Adverse effects can be attributed solely to one drug.
- D. Combining two drugs with different pharmacokinetics is straightforward.
Explanation: ***The adverse effect of one drug may be mitigated by the other drug.*** - Fixed-dose combinations are often designed such that the **therapeutic effect of one drug is enhanced**, or its **adverse effects are counteracted** by the other drug(s) in the combination. For example, a drug that causes gastrointestinal upset might be combined with one that reduces such side effects. - This synergistic or mitigating effect is a key rationale for developing certain fixed-dose combinations, aiming to improve **tolerability** and **patient adherence**. *The dose of one drug can be adjusted independently.* - In a **fixed-dose combination**, the doses of all drugs are predetermined and cannot be individually altered by the prescriber or patient. - This inflexibility is a major limitation, necessitating a separate prescription if **dose titration** for a single component is required. *Adverse effects can be attributed solely to one drug.* - When adverse effects occur with a fixed-dose combination, it is often challenging to definitively attribute them to a **single component**, as the pharmacodynamic and pharmacokinetic interactions between the drugs can be complex. - This makes managing side effects difficult, as stopping or reducing one drug is not possible without affecting the others. *Combining two drugs with different pharmacokinetics is straightforward.* - Combining drugs with **dissimilar pharmacokinetic profiles** (e.g., different absorption rates, half-lives, or metabolic pathways) can complicate fixed-dose formulations. - Achieving **optimal therapeutic windows** for both drugs concurrently can be challenging, potentially leading to suboptimal drug levels for one or both at various times.
Question 2: Carbapenem with the maximum seizure risk is:
- A. Imipenem (Correct Answer)
- B. Meropenem
- C. Doripenem
- D. Ertapenem
Explanation: ***Imipenem*** - **Imipenem** is primarily associated with a higher risk of seizures due to its ability to inhibit **GABAergic neurotransmission** in the central nervous system. - This effect is dose-dependent and more pronounced in patients with **renal impairment** or pre-existing CNS disorders, where drug accumulation occurs. *Meropenem* - While meropenem can also cause seizures, its **GABA antagonistic effect** is less potent than imipenem, resulting in a lower incidence of this adverse event. - It is generally considered safer than imipenem for patients at risk of seizures. *Ertapenem* - Ertapenem has an even lower propensity for causing seizures compared to imipenem and meropenem. - It is often preferred in outpatient settings due to its **once-daily dosing** and favorable safety profile regarding CNS adverse effects. *Doripenem* - Doripenem also has a **low seizure potential**, similar to meropenem and ertapenem. - Its **pharmacokinetic profile** and CNS penetration differ, but it is not associated with the same high risk as imipenem.
Question 3: Which of the following best demonstrates the variability in drug responsiveness among individuals?
- A. Potency
- B. Quantal Dose Response Curve (Correct Answer)
- C. Efficacy
- D. Graded Dose Response Curve
Explanation: ***Quantal Dose Response Curve*** - A **quantal dose-response curve** plots the percentage of individuals exhibiting a discrete, all-or-none effect against the log dose of a drug. - This curve directly illustrates the **variability in drug responsiveness** within a population by showing the range of doses required to produce a specific effect in different individuals. *Efficacy* - **Efficacy** refers to the maximum effect a drug can produce, regardless of the dose. - While efficacy is an important pharmacological parameter, it describes the drug's overall therapeutic potential, not the **individual variability** in response. *Potency* - **Potency** is a measure of the amount of drug needed to produce an effect of given intensity. - It relates to the absolute dose required for a particular effect but does not directly demonstrate the **inter-individual differences** in biological response. *Graded Dose Response Curve* - A **graded dose-response curve** depicts the relationship between the dose of a drug and the **magnitude of the effect** in a **single biological unit** (e.g., an individual, a tissue, or a cell). - This curve reflects the relationship between drug concentration and effect intensity, but not the **variability in response among different individuals** in a population.