NEET-PG 2015 Practice Questions

Q: Which subtype of Acute Myeloid Leukemia (AML) is associated with the best prognosis?

Acute promyeloblastic leukemia (M3). ***Acute promyeloblastic leukemia (M.3)*** [1] - **Best prognosis** in acute myeloid leukemia (AML) is associated with acute promyeloblastic leukemia due to its responsiveness to **all-trans retinoic acid (ATRA)** treatment. [1] - This type often presents with a **prominent coagulopathy**, but successful treatment can lead to **long-term remission**. *Acute monocytic leukemia* - Generally associated with **poor prognosis** and is characterized by a high white blood cell count and organ infiltration. - It lacks the favorable features seen in acute promyeloblastic leukemia, such as effective treatment outcomes. *Erythroleukemia* - Known for having a **poor prognosis** due to its aggressive nature and frequent association with complex chromosomal abnormalities. [1] - Treatment responses are often suboptimal compared to that of acute promyeloblastic leukemia. *Acute myelomonocytic leukemia* - Typically has an **intermediate prognosis** [1] and presents with a mixture of myeloid and monocytic features. - It does not have the same treatment responsiveness and favorable outcomes as seen in acute promyeloblastic leukemia.

Q: In the context of ventricular tachycardia, what do extra systoles appear as on an electrocardiogram (ECG)?

QRS complex. ***QRS complex*** - Extra systoles, particularly **premature ventricular contractions (PVCs)**, originate in the ventricles and result in a **wide and bizarre QRS complex** on an ECG [2]. - The QRS complex represents **ventricular depolarization**, and in ventricular tachycardia, the *ventricular activity* dominates the ECG tracing [2]. *P wave* - The **P wave** represents **atrial depolarization** and is typically either absent or dissociated from the QRS complex in ventricular tachycardia [1], [2]. - Its presence or absence helps differentiate supraventricular from ventricular arrhythmias. *T wave* - The **T wave** represents **ventricular repolarization**, which typically follows the QRS complex [1]. - While it will be present, it often appears abnormal or discordant in ventricular tachycardia due to the altered ventricular depolarization. *R wave* - The **R wave** is part of the QRS complex, specifically the first positive deflection. - While an R wave is present within the QRS complex of an extrasystole, referring to the entire **QRS complex** is more accurate as it encompasses the complete ventricular depolarization in an abnormal morphology.

Q: All are true about anaerobic infections except:

Exudates and swabs are ideal for culture. ***Exudates and swabs are ideal for culture.*** - **Swabs exposed to air** are generally **not ideal** for anaerobic culture because oxygen exposure can kill obligate anaerobes, leading to false-negative results. - Optimal anaerobic specimen collection requires techniques that **minimize oxygen exposure**, such as aspirates or tissue biopsies placed in anaerobic transport media. *Most infections are endogenous* - Anaerobic infections commonly arise from **one's own commensal flora**, which becomes pathogenic under specific conditions like tissue damage or impaired blood supply. - These bacteria are part of the normal microbiota of various body sites, including the gastrointestinal tract, oral cavity, and skin. *Specimen for UTI is suprapubic aspiration* - For **suspected anaerobic urinary tract infections (UTIs)**, suprapubic aspiration is considered the gold standard for specimen collection. - This method bypasses potential contamination from urethral flora and ensures a sterile, oxygen-free sample for accurate anaerobic culture. *They are found normally on skin and GIT* - **Anaerobic bacteria** are a significant component of the normal flora of the **skin and gastrointestinal tract (GIT)**, as well as the oral cavity and genitourinary tract. - Their presence in these sites is crucial for maintaining normal physiological functions and preventing the overgrowth of pathogens.

Q: HIV envelope is formed by:

Both. ***Both (Correct Answer)*** - The HIV envelope is a **composite structure** derived from both host and viral components - The **lipid bilayer** is acquired from the **host cell membrane** during viral budding - **Viral glycoproteins (gp120 and gp41)** encoded by the viral genome are inserted into this host-derived membrane - This makes the envelope a true hybrid structure essential for viral infectivity *Host cell (Incomplete)* - While the **lipid bilayer** of the envelope comes from the host cell membrane during budding, this alone does not form a functional envelope - The host cell provides the membrane scaffold but lacks the viral glycoproteins necessary for receptor binding and cell entry - Without viral proteins, the envelope cannot mediate infection *Virus (Incomplete)* - The virus encodes essential **envelope glycoproteins** (gp120 for receptor binding, gp41 for membrane fusion) - However, the virus does **not synthesize the lipid bilayer** itself - The viral genome lacks genes for lipid synthesis; the membrane must be acquired from the host *None of the options* - This is incorrect as the HIV envelope clearly requires contributions from **both** the host cell (lipid membrane) and the virus (glycoproteins)

Q: In Rideal-Walker method, plates are incubated for?

2-3 days. ***2-3 days*** - The **Rideal-Walker coefficient test** involves incubating plates for **2 to 3 days**, typically at a temperature of **37°C**, to allow for microbial growth and observation of disinfectant efficacy. - This incubation period is crucial for determining the **minimum inhibitory concentration** or bactericidal effect of a disinfectant against a test organism. *Less than 2 days* - An incubation period of less than **2 days** may not be sufficient for adequate microbial growth, potentially leading to **false-negative results** regarding disinfectant activity. - Insufficient growth time could prevent the full expression of the disinfectant's effect, making it difficult to accurately assess its **germicidal properties**. *6 to 8 days* - Incubation for **6 to 8 days** is typically **too long** for the Rideal-Walker method, as it risks overgrowth of microorganisms and potential changes in the test conditions. - Prolonged incubation can lead to **metabolic changes** in the bacteria or degradation of the disinfectant, compromising the validity of the results. *More than 10 days* - Incubation periods exceeding **10 days** are far too long and would render the results of the Rideal-Walker method **invalid**. - Such extended periods are not standard for assessing disinfectant efficacy due to issues like **nutrient depletion**, pH changes, and disinfectant instability.

Q: Lattice phenomenon is seen in which of the following?

Precipitation test. ***Precipitation test*** - The **lattice phenomenon** describes the formation of an interconnected network of antigen-antibody complexes, which is essential for visible precipitation to occur. - This phenomenon dictates that optimal precipitation requires a specific **antigen-to-antibody ratio**; an excess of either can lead to false-negative results due to soluble immune complexes (prozone or postzone effects). *Complement fixation test* - This test relies on the **binding of complement** to antigen-antibody complexes, leading to the lysis of indicator red blood cells if complement is not fixed. - It is a **two-stage test** that measures the consumption of complement, not the direct observation of a lattice. *None of the options* - This option is incorrect because the **precipitation test** clearly demonstrates the lattice phenomenon. - The formation of a visible precipitate is a direct result of antigen-antibody lattice formation. *Neutralization reaction* - Neutralization involves antibodies binding to toxins or viruses, **blocking their biological activity** rather than forming a visible precipitate. - It is a **functional assay** that measures the ability of antibodies to inhibit harmful effects, not the formation of large immune complexes.

Q: During cell death, myelin figures are derived from which of the following?

Cell membrane (lipid bilayer). ***Cell membrane (lipid bilayer)*** - **Myelin figures** are whorled phospholipid masses formed during cell injury and death from the breakdown of **cellular membranes**, particularly the plasma membrane and **endoplasmic reticulum**. - These structures represent damaged membrane lipids (phospholipids) that undergo structural rearrangement into concentric lamellar (layered) configurations resembling myelin. - The term "cell membrane" encompasses both the plasma membrane and lipid-rich intracellular membranes, making this the most accurate answer among the options provided. - They are a characteristic morphologic feature of **irreversible cell injury** and can be seen with electron microscopy. *Cytoplasmic components* - While cytoplasmic proteins and organelles do degrade during cell death, they do not form the organized **phospholipid structures** characteristic of myelin figures. - Cytoplasmic breakdown produces different morphologic changes such as cytoplasmic eosinophilia and loss of ribosomes. *Mitochondrial structures* - Mitochondria have their own membranes that are damaged during cell death (leading to release of cytochrome c and other apoptotic factors). - However, mitochondrial membranes are not the primary source of **myelin figures**, which predominantly arise from ER and plasma membranes. *Nuclear membrane* - The nuclear envelope does fragment during cell death, contributing to nuclear changes like **karyopyknosis, karyorrhexis, and karyolysis**. - While technically a membrane structure, the nuclear envelope is not the primary source of myelin figures, which are mainly derived from the more abundant plasma and ER membranes.

Q: Which of the following is a type of small vessel vasculitis?

Granulomatosis with polyangiitis (GPA). ***Granulomatosis with polyangiitis (GPA)*** - GPA is a prototypic **ANCA-associated small vessel vasculitis** characterized by necrotizing granulomas and vasculitis [1], [2]. - It commonly involves the **upper and lower respiratory tracts** and the **kidneys** with necrotizing granulomatous inflammation [1], [2]. - Classified as small vessel vasculitis according to the **Chapel Hill Consensus Conference** classification. *Classical PAN* - This refers to **Polyarteritis Nodosa (PAN)**, which is a **medium-sized vessel vasculitis**. - PAN is characterized by multifocal inflammatory and necrotizing lesions of medium-sized muscular arteries, **not small vessels**. *Giant cell arteritis* - **Giant cell arteritis (GCA)** is a **large vessel vasculitis** that primarily affects the aorta and its major branches, particularly the temporal artery [3]. - Symptoms include headache, jaw claudication, and visual disturbances, reflecting the involvement of larger blood vessels [3]. *None of the options* - This option is incorrect because Granulomatosis with polyangiitis (GPA) is a clear example of a small vessel vasculitis. - There is a correct answer among the provided choices. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 519-520. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 536-537. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 515-516.

Q: Post-streptococcal glomerulonephritis (PSGN) is an example of which type of hypersensitivity?

Type -3 hypersensitivity. ***Type -3 hypersensitivity*** - Post-streptococcal glomerulonephritis (PSGN) is caused by **immune complex deposition**, a hallmark of type III hypersensitivity reactions [1][2][3]. - It involves the formation of **antigen-antibody complexes** following a streptococcal infection, leading to inflammation in the kidneys [1][2]. *Type -1 hypersensitivity* - Characterized by **IgE-mediated** reactions, such as allergies and anaphylaxis, which do not apply to PSGN. - It typically involves **mast cells** and histamine release, notably absent in PSGN cases. *Type -4 hypersensitivity* - Involves **T-cell mediated** responses and is related to delayed-type reactions, not applicable to PSGN. - Common examples include **contact dermatitis** and graft-versus-host disease, differing fundamentally from PSGN's mechanism. *Type -2 hypersensitivity* - Characterized by **antibody-mediated cytotoxicity**, such as in hemolytic anemia, unrelated to immune complexes in PSGN. - Typically involves direct damage to cells, contrasting with the immune complex mechanism observed in PSGN [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 214-215. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 910-915. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 215-216.

Q: Which antithyroid drug is preferred during the first trimester of pregnancy due to relatively lower placental transfer?

Propylthiouracil. ***Propylthiouracil*** - **Propylthiouracil (PTU)** is the preferred antithyroid drug during the **first trimester** of pregnancy because it crosses the placenta less readily than methimazole/carbimazole. - While it still crosses the placenta, its lower placental transfer and association with fewer fetal anomalies in early pregnancy make it a safer initial choice, especially to minimize the risk of **fetal embryopathy** associated with methimazole. *Carbimazole* - **Carbimazole** (which is metabolized to methimazole) can cross the placenta more easily than PTU and has been associated with **fetal anomalies**, particularly in the first trimester. - Its use is generally avoided during the first trimester due to concerns about congenital malformations such as **aplasia cutis** and **esophageal atresia**. *Both* - While both drugs can cross the placenta to some extent, their safety profiles and recommended use during pregnancy differ significantly. - Carbimazole (methimazole) has a higher risk of teratogenicity in the first trimester compared to PTU. *None of the options* - This option is incorrect because propylthiouracil is indeed known to cross the placenta and is commonly used in pregnancy, especially during the first trimester. - The choice of antithyroid drug is a critical consideration in managing hyperthyroidism in pregnancy.

Question 1

Which subtype of Acute Myeloid Leukemia (AML) is associated with the best prognosis?

Accepted Answer

Acute promyeloblastic leukemia (M3)

Answer

Acute myelo monocytic leukemia.

Answer

Acute monocytic leukemia.

Answer

Erythro leukemia

Question 2

In the context of ventricular tachycardia, what do extra systoles appear as on an electrocardiogram (ECG)?

Accepted Answer

QRS complex

Answer

P wave

Answer

T wave

Answer

R wave

Question 3

All are true about anaerobic infections except:

Accepted Answer

Exudates and swabs are ideal for culture

Answer

Specimen for UTI is suprapubic aspiration

Answer

They are found normally on skin and GIT

Answer

Most infections are endogenous

Question 4

HIV envelope is formed by:

Accepted Answer

Both

Answer

Host cell

Answer

Virus

Answer

None of the options

Question 5

In Rideal-Walker method, plates are incubated for?

Accepted Answer

2-3 days

Answer

Less than 2 days

Answer

6 to 8 days

Answer

More than 10 days

Question 6

Lattice phenomenon is seen in which of the following?

Accepted Answer

Precipitation test

Answer

Complement fixation test

Answer

None of the options

Answer

Neutralization reaction

Question 7

During cell death, myelin figures are derived from which of the following?

Accepted Answer

Cell membrane (lipid bilayer)

Answer

Cytoplasmic components

Answer

Mitochondrial structures

Answer

Nuclear membrane

Question 8

Which of the following is a type of small vessel vasculitis?

Accepted Answer

Granulomatosis with polyangiitis (GPA)

Answer

Classical PAN

Answer

Giant cell arteritis

Answer

None of the options

Question 9

Post-streptococcal glomerulonephritis (PSGN) is an example of which type of hypersensitivity?

Accepted Answer

Type -3 hypersensitivity

Answer

Type -1 hypersensitivity

Answer

Type -2 hypersensitivity

Answer

Type -4 hypersensitivity

Question 10

Which antithyroid drug is preferred during the first trimester of pregnancy due to relatively lower placental transfer?

Accepted Answer

Propylthiouracil

Answer

Carbimazole

Answer

Both

Answer

None of the options

NEET-PG 2015

Internal Medicine

Microbiology

Pathology

Pharmacology