Internal Medicine
4 questionsWhat is the PRIMARY evidence-based intervention for preventing catheter-associated urinary tract infections (CAUTIs)?
Buboes form is which stage of LGV?
ABO non- secretors are more prone to ?
What is the primary cause of Common Variable Immunodeficiency (CVID)?
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 621: What is the PRIMARY evidence-based intervention for preventing catheter-associated urinary tract infections (CAUTIs)?
- A. Use of face mask during catheter insertion
- B. Prophylactic antibiotics are effective
- C. Early catheter removal when clinically appropriate
- D. Closed drainage technique to minimize bacterial entry (Correct Answer)
Explanation: ***Closed drainage technique to minimize bacterial entry*** - Maintaining a **closed drainage system** prevents the entry of bacteria into the urinary tract, which is a primary cause of CAUTIs. - This technique involves ensuring the connection between the catheter and the drainage bag remains sealed at all times, minimizing **environmental contamination**. *Prophylactic antibiotics are effective* - **Prophylactic antibiotics** are generally not recommended for routine CAUTI prevention due to concerns about **antibiotic resistance** and limited evidence of effectiveness [1]. - Their use is typically reserved for specific high-risk procedures or patient populations. *Use of face mask during catheter insertion* - While maintaining **asepsis** during catheter insertion is crucial, the use of a face mask specifically addresses **respiratory droplet transmission**, which is not the primary route of bacterial entry into the urinary system during catheterization. - **Sterile gloves** and a **sterile field** are more directly relevant for preventing contamination during insertion [1]. *Early catheter removal when clinically appropriate* - While **early catheter removal** is a critical strategy for CAUTI prevention by reducing dwell time, the question asks for the *primary* evidence-based intervention [1]. A **closed drainage system** directly addresses the mechanism of bacterial entry while the catheter is in place. - Reducing catheter duration minimizes risk, but the closed system ensures safety during the necessary period of catheterization.
Question 622: Buboes form is which stage of LGV?
- A. Secondary (Correct Answer)
- B. Tertiary
- C. Latent
- D. Primary
Explanation: ***Secondary*** - Buboes, which are swollen, painful lymph nodes, are a hallmark of the **secondary stage** of **Lymphogranuloma Venereum (LGV)** [1]. - This stage typically develops weeks after the initial infection, following the unnoticed or transient primary lesion. *Primary* - The primary stage of LGV is characterized by a **small, painless papule or ulcer** at the site of inoculation, which often goes unnoticed. - **Buboes are not formed** during this initial, often asymptomatic, phase. *Tertiary* - The tertiary stage of LGV involves **chronic inflammation** and **tissue destruction**, leading to complications like **genital elephantiasis**, rectal strictures, and fistulas. - While there is chronic lymphedema, the acute, painful buboes are characteristic of the secondary stage, not this late, destructive phase. *Latent* - The concept of a latent stage is not typically used to describe the progression of LGV in the same way as other infections like syphilis. - LGV progresses through distinct symptomatic primary, secondary, and potentially tertiary stages without a prolonged asymptomatic latency period between symptom presentations.
Question 623: ABO non- secretors are more prone to ?
- A. Increased risk of infections (Correct Answer)
- B. Autoimmune diseases
- C. Cardiovascular diseases
- D. Cancer
Explanation: Increased risk of infections - Non-secretors of ABO antigens exhibit an increased susceptibility to a variety of infections, particularly bacterial and viral pathogens. - This is thought to be due to the absence of ABO antigens in secretions, which typically act as decoy receptors to prevent pathogen adhesion to host cells. Autoimmune diseases - While some associations between ABO blood groups and autoimmune diseases exist, non-secretor status is not consistently linked to a higher overall risk of autoimmune conditions. Cardiovascular diseases - ABO blood groups have been associated with cardiovascular risk, with non-O blood types generally having a slightly higher risk of certain cardiovascular events. - However, secretor status (the ability to secrete ABO antigens into bodily fluids) itself is not a prominent independent risk factor for cardiovascular diseases. Cancer - There are some documented associations between specific ABO blood types and certain types of cancer (e.g., non-O blood types with pancreatic cancer), but this is distinct from secretor status. - Being an ABO non-secretor is not a primary, broadly recognized risk factor for developing cancer.
Question 624: What is the primary cause of Common Variable Immunodeficiency (CVID)?
- A. Defective B cell function
- B. Absent B cells
- C. Reduced number of B cells
- D. Defective B cell differentiation (Correct Answer)
Explanation: ***Defective B cell differentiation*** - CVID is characterized primarily by a failure of **B cells** to differentiate into **plasma cells**, which are responsible for producing antibodies [1]. - This defective differentiation leads to **hypogammaglobulinemia**, or low levels of immunoglobulins [1]. *Absent B cells* - Complete absence of B cells is characteristic of severe combined immunodeficiency (SCID) or X-linked agammaglobulinemia (XLA), not CVID [1]. - In CVID, B cells are typically present, but they are dysfunctional. *Reduced number of B cells* - While some patients with CVID may have reduced B cell numbers, this is not the primary or defining defect. - The key issue is the inability of existing B cells to mature and produce antibodies effectively. *Defective B cell function* - While B cell function is indeed defective in CVID, the root cause of this malfunction is specifically the **failure of differentiation** into mature plasma cells. - The B cells are unable to perform their primary function of antibody production due to this arrest in their development.
Microbiology
5 questionsIn a patient presenting with fever and suspected systemic infection, which of the following specimens is the most appropriate for the isolation of microorganisms in laboratory diagnosis?
In human infections, the morula form is seen in which of the following organisms?
A child presents with vomiting and abdominal pain 5 hours after eating. The most likely causative organism is:
In Rideal-Walker method, plates are incubated for?
CD3 is a marker for which type of cells?
NEET-PG 2015 - Microbiology NEET-PG Practice Questions and MCQs
Question 621: In a patient presenting with fever and suspected systemic infection, which of the following specimens is the most appropriate for the isolation of microorganisms in laboratory diagnosis?
- A. Blood culture for isolation of bacteria (Correct Answer)
- B. Stool sample in cases of gastroenteritis
- C. Throat swab for suspected pharyngitis
- D. Urine sample for urinary tract infection
Explanation: ***Blood culture for isolation of bacteria*** - For **systemic infection** and **fever**, **blood culture** is the most direct method to isolate and identify the causative microorganism disseminated throughout the body. - It helps guide **appropriate antibiotic therapy** by determining the pathogen's **susceptibility profile**. *Stool sample in cases of gastroenteritis* - This specimen is appropriate for diagnosing **gastrointestinal infections** where the pathogen primarily affects the digestive tract. - It is not the primary choice for suspected **systemic infection** unless GI symptoms are prominent and dissemination is suspected. *Throat swab for suspected pharyngitis* - A throat swab is specific for diagnosing **pharyngitis** or upper **respiratory tract infections**, localizing the infection to the pharynx. - It would not sufficiently identify a **systemic infection**, as the pathogen may not be present in the throat in such cases. *Urine sample for urinary tract infection* - A urine sample is indicated for diagnosing **urinary tract infections (UTIs)**, where the pathogen is concentrated in the urinary system. - While a UTI can lead to systemic symptoms, a urine sample alone is insufficient to confirm a generalized systemic infection unless the infection has specifically localized there.
Question 622: In human infections, the morula form is seen in which of the following organisms?
- A. Chlamydiae
- B. Bartonella quintana
- C. Mycoplasma hominis
- D. Ehrlichia (Correct Answer)
Explanation: ***Correct: Ehrlichia*** - *Ehrlichia* species are **obligate intracellular bacteria** that replicate in host immune cells, forming distinctive microcolonies known as **morulae** (mulberry-like clusters). - The presence of morulae within the cytoplasm of **white blood cells** (monocytes or granulocytes) is the **key diagnostic feature** for ehrlichiosis. - The term "morula" comes from Latin for "mulberry," describing the characteristic clustered appearance visible on microscopy. *Incorrect: Chlamydiae* - *Chlamydiae* are obligate intracellular parasites with a unique developmental cycle involving elementary bodies (infectious form) and reticulate bodies (replicative form). - They form **intracytoplasmic inclusions** within vacuoles, but these are **not morulae**. *Incorrect: Bartonella quintana* - *Bartonella quintana* is a fastidious gram-negative bacillus associated with **trench fever** and bacillary angiomatosis. - Typically seen as individual or small clusters of bacteria, but **does not form morulae** within host cells. *Incorrect: Mycoplasma hominis* - *Mycoplasma hominis* is a small, **wall-less bacterium** that can cause genitourinary infections. - It is an extracellular pathogen or adheres to host cells but **does not invade or form intracytoplasmic morulae**.
Question 623: A child presents with vomiting and abdominal pain 5 hours after eating. The most likely causative organism is:
- A. Bacillus cereus (Correct Answer)
- B. Cl. perfringens
- C. V. cholerae
- D. Cl. botulinum
Explanation: ***Bacillus cereus*** - This organism produces **emetogenic toxins** such as cereulide, which cause **short-incubation food poisoning** characterized by vomiting and abdominal pain, typically within 1-6 hours after consumption. - Common sources include **fried rice** and other starchy foods that have been improperly re-heated, allowing spore germination and toxin production. *Cl. perfringens* - This bacterium produces an **enterotoxin** that causes diarrheal illness with a longer incubation period, usually 8-16 hours, and is characterized more by **abdominal cramps and diarrhea** rather than prominent vomiting. - It is typically associated with consumption of contaminated meat and poultry. *V. cholerae* - This bacterium causes **cholera**, an acute diarrheal illness characterized by **profuse watery diarrhea** and severe dehydration, with an incubation period of 2 hours to 5 days. - Vomiting can occur but is secondary to the severe fluid loss and is not the primary symptom in short-incubation cases with abdominal pain. *Cl. botulinum* - This bacterium produces **botulinum neurotoxin**, which causes botulism, a rare but severe illness characterized by **flaccid paralysis**. - While gastrointestinal symptoms like vomiting can occur, the hallmark feature is **neurological dysfunction**, and the incubation period is typically 12-36 hours, not 5 hours with isolated vomiting and abdominal pain.
Question 624: In Rideal-Walker method, plates are incubated for?
- A. 2-3 days (Correct Answer)
- B. Less than 2 days
- C. 6 to 8 days
- D. More than 10 days
Explanation: ***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.
Question 625: CD3 is a marker for which type of cells?
- A. B - cells
- B. T - cells (Correct Answer)
- C. NK - cells
- D. Monocytes
Explanation: ***T - cells*** - **CD3** is a complex of proteins that is universally expressed on the surface of all **T lymphocytes** (T cells). - It plays a crucial role in **T cell activation** by transducing signals from the T cell receptor (TCR) to the cell's interior. *B - cells* - **B cells** are characterized by the expression of unique surface markers like **CD19**, **CD20**, and surface **immunoglobulins**, not CD3. - Their primary function is to produce **antibodies** and present antigens. *NK - cells* - **Natural Killer (NK) cells** are a type of lymphocyte that lacks both CD3 and a T cell receptor (TCR), differentiating them from T cells. - They express markers such as **CD16** and **CD56** and are involved in innate immunity, particularly against viral infections and tumor cells. *Monocytes* - **Monocytes** are myeloid cells, not lymphocytes, and are characterized by markers such as **CD14** and **CD68**. - They differentiate into macrophages and dendritic cells, playing a significant role in phagocytosis and antigen presentation.
Pharmacology
1 questionsIn primary open-angle glaucoma, pilocarpine eye drops lower intraocular pressure primarily by acting on which of the following?
NEET-PG 2015 - Pharmacology NEET-PG Practice Questions and MCQs
Question 621: In primary open-angle glaucoma, pilocarpine eye drops lower intraocular pressure primarily by acting on which of the following?
- A. All of the options
- B. Trabecular meshwork
- C. Ciliary epithelium
- D. Longitudinal fibres of the ciliary muscle (Correct Answer)
Explanation: ***Longitudinal fibres of the ciliary muscle***- Pilocarpine is a **muscarinic agonist** that contracts the **longitudinal fibers of the ciliary muscle** [1, 3].- This contraction pulls on the **scleral spur**, separating the **trabecular meshwork** sheets, which increases conventional **aqueous humor outflow** [2, 3].*Trabecular meshwork*- While the **trabecular meshwork** is the site where aqueous humor exits the eye, pilocarpine primarily acts on the ciliary muscle to **indirectly affect** the meshwork's outflow facility [2, 3].- Pilocarpine does not directly alter the structure or function of the trabecular meshwork cells.*Ciliary epithelium*- The **ciliary epithelium** is responsible for **aqueous humor production** [1, 2].- Pilocarpine primarily affects **outflow**, not production, through its action on the ciliary muscle [1, 2].*All of the options*- Pilocarpine does not act on **all** these structures; its primary mechanism is through the ciliary muscle to enhance outflow.- It has no direct significant effect on **ciliary epithelium** or direct action on the **trabecular meshwork** itself.