Forensic Medicine
1 questionsWhat is the diagnostic sign of antemortem drowning?
NEET-PG 2013 - Forensic Medicine NEET-PG Practice Questions and MCQs
Question 631: What is the diagnostic sign of antemortem drowning?
- A. Emphysema aquosum
- B. Water in esophagus
- C. Weeds and grass in clenched hands
- D. Paltauf's hemorrhage (Correct Answer)
Explanation: ***Paltauf's hemorrhage*** - These are **subpleural ecchymoses** (petechial hemorrhages) found on the surface of the lungs that represent the **definitive diagnostic sign** of antemortem drowning. - They result from rapid changes in **pulmonary pressure** and vascular permeability due to active breathing efforts and water aspiration during the drowning process. *Emphysema aquosum* - This refers to **overdistention of lungs** with frothy fluid in airways, commonly seen in drowning cases. - It represents a **morphological change** rather than a specific diagnostic sign and can occur in various types of asphyxial deaths. *Water in esophagus* - Water presence in the esophagus occurs due to **swallowing during immersion** or passive post-mortem water entry. - This finding **cannot differentiate** between antemortem and post-mortem drowning as water can enter passively after death. *Weeds and grass in clenched hands* - While **cadaveric spasm** with vegetation indicates the person was alive during immersion and actively struggling, it is **not the diagnostic sign** of antemortem drowning. - This finding confirms **vital reaction** at the time of immersion but does not specifically diagnose the drowning mechanism itself.
Internal Medicine
1 questionsWhich of the following is true about Hepatitis A virus?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 631: Which of the following is true about Hepatitis A virus?
- A. Causes chronic hepatitis
- B. Helps HDV replication
- C. Causes cirrhosis
- D. Common cause of hepatitis in children (Correct Answer)
Explanation: ***Common cause of hepatitis in children*** - **Hepatitis A virus (HAV)** infection is often acquired in childhood, particularly in areas with poor sanitation, and many infections are **asymptomatic** or mild in children [1]. - Due to their developing immune systems and often exposure in daycare or school settings, children are a highly susceptible population for HAV transmission [1]. *Causes cirrhosis* - **HAV infection** is an **acute self-limiting illness** and typically does not lead to chronic liver disease or cirrhosis [1]. - **Cirrhosis** is primarily associated with chronic viral hepatitis (e.g., HBV, HCV), alcohol-related liver disease, or certain autoimmune conditions. *Helps HDV replication* - **Hepatitis D virus (HDV)** is a **defective virus** that requires the presence of **Hepatitis B virus (HBV)** surface antigen (HBsAg) for its replication and assembly [1]. - **HAV** has no role in the replication or pathogenesis of **HDV** [1]. *Causes chronic hepatitis* - **HAV infection** results in an **acute inflammatory response** in the liver that resolves spontaneously in most cases [1]. - Unlike **HBV** and **HCV**, **HAV** does not establish a persistent infection and, therefore, does not cause chronic hepatitis [1].
Microbiology
5 questionsWhat are the changes in the variable region of immunoglobulins?
Macrophage tropic strains of HIV use which co-receptor?
How many segments of RNA does the Influenza virus have?
Which gene of Hepatitis B virus (HBV) is most commonly associated with mutations causing antiviral drug resistance?
Rosette formation with sheep RBCs (SRBCs) indicates functioning of -
NEET-PG 2013 - Microbiology NEET-PG Practice Questions and MCQs
Question 631: What are the changes in the variable region of immunoglobulins?
- A. Isotype
- B. Epitope
- C. Allotype
- D. Idiotype (Correct Answer)
Explanation: ***Idiotype*** - **Idiotype** refers to the unique set of antigenic determinants in the **variable region** of an antibody molecule, specifically within the **hypervariable regions (complementarity-determining regions, CDRs)**. - These unique determinants allow antibodies to recognize specific antigens and are generated by the specific **V(D)J gene rearrangements** in B cells. *Isotype* - **Isotype** refers to the constant region of an antibody, determining its class (e.g., **IgG, IgM, IgA, IgD, IgE**). - This region defines the antibody's effector functions and has nothing to do with the antigen-binding variability. *Allotype* - **Allotype** refers to minor genetic variations within the **constant region** of an antibody molecule within a species. - These variations are due to different alleles inherited from parents and are not associated with the variable region that binds to antigens. *Epitope* - An **epitope** is the specific part of an **antigen** that an antibody or T-cell receptor recognizes and binds to. - It is a feature of the antigen, not a change within the variable region of the immunoglobulin itself.
Question 632: Macrophage tropic strains of HIV use which co-receptor?
- A. CCR5 (Correct Answer)
- B. CXCR4
- C. CCR3
- D. CCR2
Explanation: ***CCR5*** - **Macrophage-tropic** HIV strains, also known as **R5 strains**, primarily use the **CCR5 co-receptor** to enter target cells. - These strains are typically involved in the **initial infection** and transmission of HIV. - CCR5-tropic viruses are usually the **predominant strains transmitted** during sexual transmission. *CXCR4* - **T-cell-tropic** HIV strains, or **X4 strains**, preferentially utilize the **CXCR4 co-receptor** for cell entry. - These strains are associated with a **more rapid decline in CD4+ T-cell counts** during later stages of HIV infection. - Emergence of X4 strains is linked to **disease progression**. *CCR3* - While a chemokine receptor, **CCR3** is not a primary co-receptor used by common HIV strains for entry into macrophages or T cells. - CCR3 is primarily involved in **eosinophil chemotaxis** and allergic responses. *CCR2* - **CCR2** is another chemokine receptor but is **not a major co-receptor** for HIV entry. - While some laboratory-adapted strains may show minor usage, it is not clinically significant for macrophage-tropic HIV strains.
Question 633: How many segments of RNA does the Influenza virus have?
- A. 5 segments of single-stranded RNA
- B. 8 segments of double-stranded DNA
- C. 8 segments of single-stranded DNA
- D. 8 segments of single-stranded RNA (Correct Answer)
Explanation: ***8 segments of single-stranded RNA*** - The **Influenza virus** is characterized by its segmented genome, which consists of **eight distinct negative-sense single-stranded RNA (ssRNA)** molecules. - This segmentation is crucial for its high mutation rate and ability to undergo **antigenic shift** and **antigenic drift**, leading to new strains. *5 segments of single-stranded RNA* - This option is incorrect because the Influenza virus specifically has **eight segments**, not five. - While it is a single-stranded RNA virus, the number of segments is a key characteristic. *8 segments of double-stranded DNA* - This option is incorrect as Influenza is an **RNA virus**, not a DNA virus, and its genetic material is single-stranded, not double-stranded. - No known influenza viruses have a **double-stranded DNA genome**. *8 segments of single-stranded DNA* - This option is incorrect because Influenza is an **RNA virus**, not a DNA virus. - Its genetic material is composed of **RNA**, specifically negative-sense single-stranded RNA.
Question 634: Which gene of Hepatitis B virus (HBV) is most commonly associated with mutations causing antiviral drug resistance?
- A. X gene
- B. S gene
- C. C gene
- D. P gene (Correct Answer)
Explanation: ***P gene*** - The **P gene** (polymerase gene) of HBV encodes the viral reverse transcriptase which is essential for viral replication. - Mutations in the P gene can lead to **antiviral drug resistance**, particularly to nucleos(t)ide analogues. *X gene* - The **X gene** encodes the X protein (HBx), a **transcriptional transactivator** involved in viral replication and pathogenesis. - While important for viral function, it is not the primary target for antiviral therapy, and mutations are less frequently associated with drug resistance. *S gene* - The **S gene** encodes the **surface antigens (HBsAg)**, which are crucial for viral entry and immune evasion. - Mutations in the S gene can lead to **vaccine escape mutants** or alter HBsAg detection, but not directly responsible for antiviral resistance. *C gene* - The **C gene** encodes the **core protein (HBcAg)** and the precore protein (HBeAg). - These proteins are involved in **viral particle assembly** and immune modulation, but mutations in this gene are not typically associated with resistance to antiviral drugs.
Question 635: Rosette formation with sheep RBCs (SRBCs) indicates functioning of -
- A. T-cells (Correct Answer)
- B. B-cells
- C. Neutrophils
- D. Monocytes
Explanation: ***T-cells*** - **T-cells** possess specific receptors, like **CD2** on their surface, that can bind to ligands on sheep red blood cells (SRBCs). - This binding leads to the formation of characteristic **rosettes**, where SRBCs cluster around the T-lymphocytes, indicating functional T-cells. *B-cells* - **B-cells** primarily function in **humoral immunity** by producing antibodies and do not typically form rosettes with sheep RBCs. - While B-cells have surface receptors, they are not CD2 and thus do not facilitate this specific type of rosette formation. *Neutrophils* - **Neutrophils** are **phagocytic cells** involved in innate immunity, primarily combating bacterial and fungal infections. - They lack the specific surface receptors (like CD2) required to form rosettes with sheep RBCs. *Monocytes* - **Monocytes** are precursors to macrophages and dendritic cells, involved in phagocytosis and antigen presentation. - They do not possess the necessary surface markers to form rosettes with sheep RBCs.
Pediatrics
2 questionsAt what age does clinically significant IgG production begin?
A 3-month-old infant with no chest indrawing and a respiratory rate of 52/minute. The diagnosis is:
NEET-PG 2013 - Pediatrics NEET-PG Practice Questions and MCQs
Question 631: At what age does clinically significant IgG production begin?
- A. Around 6 months (Correct Answer)
- B. Around 1 year
- C. Around 2 years
- D. Around 3 years
Explanation: ***Around 6 months*** - Maternal IgG levels, which provide **passive immunity**, decrease significantly by 3-6 months of age. - Infants begin to produce their own **clinically significant** levels of IgG around this time, coinciding with the "physiologic nadir" of IgG. *Around 1 year* - While IgG production continues to mature, significant production has already begun by 6 months to replace declining maternal antibodies. - By 1 year, the immune system is more robust, but the initial critical transition occurs earlier. *Around 2 years* - By this age, children generally have a robust adaptive immune response, and the period of vulnerability due to low IgG has passed. - This option is too late for the beginning of clinically significant IgG production. *Around 3 years* - This age is far past the point where children start producing their own significant levels of IgG. - The immune system is well-developed by 3 years, and initial IgG production started much earlier.
Question 632: A 3-month-old infant with no chest indrawing and a respiratory rate of 52/minute. The diagnosis is:
- A. Severe pneumonia
- B. Pneumonia (Correct Answer)
- C. No pneumonia
- D. Very severe disease
Explanation: ***Pneumonia*** - A respiratory rate of 52/minute in a 3-month-old infant **meets the age-specific threshold for tachypnea** (respiratory rate ≥ 50 breaths/minute for infants 2-12 months according to IMCI guidelines). - In the **absence of chest indrawing**, the presence of fast breathing (tachypnea) alone classifies this as **pneumonia** per IMCI classification. - This requires **outpatient management with oral antibiotics** and close follow-up. *No pneumonia* - This diagnosis would apply if the respiratory rate was **< 50 breaths/minute** for this age group with no chest indrawing. - Since the respiratory rate is 52/minute (≥ 50/minute), this rules out "no pneumonia." *Severe pneumonia* - This diagnosis requires the presence of **chest indrawing** in addition to fast breathing. - The question explicitly states **"no chest indrawing,"** which excludes severe pneumonia. - Severe pneumonia would require **hospitalization and parenteral antibiotics**. *Very severe disease* - This diagnosis involves **danger signs** such as inability to drink or breastfeed, persistent vomiting, convulsions, lethargy, unconsciousness, or severe malnutrition. - None of these critical signs are mentioned in the clinical scenario. - Very severe disease requires **urgent hospitalization and injectable antibiotics**.
Pharmacology
1 questionsWhich drug is contraindicated in G6PD deficiency?
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 631: Which drug is contraindicated in G6PD deficiency?
- A. Primaquine (Correct Answer)
- B. Chloroquine
- C. Quinine
- D. All of the options
Explanation: ***Primaquine*** - **Primaquine** is an antimalarial drug that generates **severe oxidative stress** in red blood cells. - It is **definitively contraindicated** in **G6PD deficiency** as it consistently causes **acute hemolytic anemia**. - Among antimalarials, primaquine poses the **highest risk** and should **never be used** in G6PD-deficient patients. - It is used for radical cure of P. vivax and P. ovale malaria, but alternative regimens must be used in G6PD deficiency. *Chloroquine* - **Chloroquine** can cause hemolysis in **G6PD deficiency**, though the risk is **lower than primaquine**. - It is **not considered fully safe** and should be used with **caution** in G6PD-deficient patients. - At standard doses, the risk is moderate, but hemolysis can occur, especially in certain G6PD variants. - However, it is not absolutely contraindicated and may be used when benefits outweigh risks with close monitoring. *Quinine* - **Quinine** can also cause **hemolysis** in patients with **G6PD deficiency**. - The risk varies with G6PD variant severity and dosage. - In **severe G6PD deficiency**, quinine should be avoided when alternatives are available. - While less consistently problematic than primaquine, it still requires caution and monitoring. *All of the options* - This option is incorrect in the context of this question because **primaquine** is the **most consistently and severely contraindicated** drug. - While chloroquine and quinine can cause hemolysis, they have **variable risk profiles** and may be used cautiously in some situations, unlike primaquine which is **absolutely contraindicated**. - The question asks for "which drug" (singular), indicating primaquine as the primary answer due to its consistent and severe risk.