Community Medicine
1 questionsWhich indicator best measures the operational efficiency of a malaria control programme?
NEET-PG 2013 - Community Medicine NEET-PG Practice Questions and MCQs
Question 681: Which indicator best measures the operational efficiency of a malaria control programme?
- A. Infant parasite rate
- B. Slide positivity rate
- C. Mosquito bite rate
- D. Annual blood examination rate (Correct Answer)
Explanation: ***Annual blood examination rate*** - The **Annual Blood Examination Rate (ABER)** directly reflects the proportion of the population that has been tested for malaria, indicating the reach and effectiveness of surveillance activities. - A high ABER suggests that active case detection and diagnosis are being effectively implemented, which is crucial for operational efficiency in identifying and managing cases. *Infant parasite rate* - The **infant parasite rate** measures the prevalence of malaria infection among infants, serving as an indicator of recent transmission intensity. - While important for assessing disease burden and transmission, it doesn't directly measure the operational effectiveness of interventions like testing or treatment programs. *Slide positivity rate* - The **slide positivity rate (SPR)** is the proportion of positive malaria slides among all slides examined, indicating the likelihood of an individual seeking testing to actually have malaria. - While SPR helps understand disease activity among tested individuals, it doesn't reflect the full operational reach of a program in the general population or the overall testing effort. *Mosquito bite rate* - The **mosquito bite rate** measures the number of mosquito bites per person per night, indicating the level of human exposure to malaria vectors. - This is an entomological indicator of transmission risk and the impact of vector control, but it does not directly assess the operational efficiency of human-centric interventions like diagnosis and treatment programs.
Internal Medicine
1 questionsPseudomembranous colitis, all are true except:
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 681: Pseudomembranous colitis, all are true except:
- A. Blood in stools is a common feature (Correct Answer)
- B. Toxin A is responsible for clinical manifestation
- C. Summit lesions are early histopathological findings
- D. Toxin B is responsible for clinical manifestation
Explanation: ***Blood in stools is a common feature*** - While diarrhea is a hallmark of **pseudomembranous colitis**, **bloody stools** are uncommon and, if present, suggest severe disease or an alternative diagnosis [1]. - The typical presentation involves **watery diarrhea**, abdominal cramps, and fever, not usually overt bleeding [1]. *Toxin A is responsible for clinical manifestation* - **Toxin A (TcdA)** is one of the primary exotoxins produced by *Clostridioides difficile* and contributes significantly to the **inflammation** and fluid secretion seen in pseudomembranous colitis. - It acts as an **enterotoxin**, causing fluid secretion and mucosal damage in the colon [1]. *Summit lesions are early histopathological findings* - **Summit lesions**, also known as "summit pseudomembranes" or **"volcano lesions"**, refer to characteristic histological findings where inflammatory exudates effuse from the tips of damaged crypts. - These are typical early findings in pseudomembranous colitis, demonstrating the focal nature of the **mucosal injury**. *Toxin B is responsible for clinical manifestation* - **Toxin B (TcdB)** is another key exotoxin produced by *Clostridioides difficile*, and it is considered even more **cytotoxic** than Toxin A [1]. - It causes significant **cell damage** and **apoptosis**, playing a crucial role in the development of the pseudomembranes and clinical symptoms [1].
Microbiology
4 questionsWhich of the following bacteria does not exhibit bipolar staining?
Pseudomonas is which type of bacteria?
What is the typical bacterial count in the duodenum?
Which of the following is not a sporicidal agent?
NEET-PG 2013 - Microbiology NEET-PG Practice Questions and MCQs
Question 681: Which of the following bacteria does not exhibit bipolar staining?
- A. Haemophilus influenzae (Correct Answer)
- B. Yersinia pestis
- C. Calymmatobacterium granulomatis
- D. Francisella tularensis
Explanation: ***Haemophilus influenzae*** - *Haemophilus influenzae* is a **pleomorphic coccobacillus** that typically stains uniformly and does not exhibit characteristic **bipolar staining**. - Its presence is often identified by Gram stain showing small, Gram-negative rods, but without the distinctive safety pin appearance. *Calymmatobacterium granulomatis* - *Calymmatobacterium granulomatis* (now *Klebsiella granulomatis*) is known to exhibit **bipolar staining**, often described as a **"safety pin" appearance**, especially in tissue smears from granuloma inguinale lesions. - This characteristic staining is due to the concentration of stain at the ends of the rod-shaped bacteria. *Yersinia pestis* - *Yersinia pestis*, the causative agent of plague, is classically described as having **bipolar staining**, giving it a distinctive **"safety pin" appearance** under a microscope. - This finding is a key diagnostic feature, particularly when observed in Gram-stained smears of clinical samples. *Francisella tularensis* - *Francisella tularensis* is a small, Gram-negative coccobacillus that is known to exhibit **bipolar staining**, though it may be less prominent than in *Yersinia pestis*. - This characteristic can assist in the microscopic identification of the bacterium, which causes tularemia.
Question 682: Pseudomonas is which type of bacteria?
- A. Anaerobic
- B. Aerobic (Correct Answer)
- C. Microaerophilic
- D. Obligate anaerobe
Explanation: ***Aerobic*** - **Pseudomonas aeruginosa** is a classic example of an **aerobic bacterium**, meaning it requires oxygen for growth and metabolism. - Its ability to thrive in aerobic environments contributes to its prevalence in hospital settings and its capacity to cause a wide range of infections. *Anaerobic* - Anaerobic bacteria grow in the absence of oxygen and often die in its presence. **Pseudomonas** does not exhibit this characteristic. - Examples of anaerobic bacteria include *Clostridium* species. *Microaerophilic* - Microaerophilic bacteria require oxygen but only in low concentrations (5-10%), higher concentrations are inhibitory. - **Pseudomonas** grows optimally in atmospheric oxygen levels, not restricted to low concentrations. *Obligate anaerobe* - Obligate anaerobes are severely inhibited or killed by oxygen. - This is the opposite of **Pseudomonas**, which strictly requires oxygen for survival.
Question 683: What is the typical bacterial count in the duodenum?
- A. 10^2 per gram (Correct Answer)
- B. 10^1 per gram
- C. 10^10 per gram
- D. 10^5 per gram
Explanation: ***10^2 per gram*** - The duodenum has a **relatively low bacterial count** (typically 10^2-10^4 CFU/gram) due to the **acidic environment** from gastric acid and **rapid transit** of contents. - A count of **10^2 CFU/gram** represents the **lower end of the normal range** for the proximal duodenum, where gastric acid effects are strongest. - This sparse bacterial population contrasts sharply with the dense colonization seen in the distal gut. *10^1 per gram* - This represents an **extremely low count** more characteristic of the **stomach**, not the duodenum. - Such minimal bacterial presence is due to the **hostile acidic environment** (pH 1-3) in the stomach. - The duodenum, while having low counts, consistently has higher bacterial densities than this. *10^5 per gram* - This count is characteristic of the **distal small intestine (ileum)**, where bacterial concentrations progressively increase. - A bacterial count of **10^5 per gram in the duodenum** would be considered **abnormal** and suggest **small intestinal bacterial overgrowth (SIBO)**. - SIBO occurs when colonic-type bacteria colonize the small intestine inappropriately. *10^10 per gram* - This bacterial density is typical of the **colon** (which harbors 10^11-10^12 CFU/gram), the most densely colonized part of the human gut. - Such a high count in the duodenum would indicate **severe bacterial overgrowth** or gross contamination. - The colon's anaerobic environment supports this massive bacterial population.
Question 684: Which of the following is not a sporicidal agent?
- A. Formaldehyde
- B. Glutaraldehyde
- C. Ethylene oxide
- D. Isopropyl alcohol (Correct Answer)
Explanation: ***Isopropyl alcohol*** - Isopropyl alcohol is an **antiseptic** and **disinfectant** that works by denaturing proteins and dissolving lipids, but it is not effective against bacterial spores. - Its efficacy against microbes is primarily for **vegetative bacteria**, fungi, and enveloped viruses. *Formaldehyde* - Formaldehyde is a potent **sporicide** that cross-links proteins and nucleic acids, making it effective for high-level disinfection and sterilization. - It is often used in solutions or as a gas for sterilizing heat-sensitive medical equipment. *Glutaraldehyde* - Glutaraldehyde is a **high-level disinfectant** and **sterilant** that works by alkylating protein and nucleic acid components, effectively killing spores. - It's commonly used for sterilizing endoscopic instruments and other heat-sensitive devices. *Ethylene oxide* - Ethylene oxide is a gaseous sterilant that **alkylates proteins** and nucleic acids, making it highly effective against all microorganisms, including spores, bacteria, and viruses. - It is frequently used for sterilizing heat-sensitive and moisture-sensitive medical devices.
Pharmacology
4 questionsAn Englishman travels to a place which is resistant to chloroquine and mefloquine. What should he take as prophylaxis?
Drug that binds bile acids in the intestine and prevents their return to liver via the enterohepatic circulation?
What is the mechanism of action of clofibrate in lipid metabolism?
All of the following are adverse effects of nicotinic acid except:
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 681: An Englishman travels to a place which is resistant to chloroquine and mefloquine. What should he take as prophylaxis?
- A. Primaquine
- B. Atovaquone-proguanil (Correct Answer)
- C. Doxycycline
- D. Proguanil
Explanation: ***Atovaquone-proguanil*** - This combination, known as **Malarone**, is the most appropriate prophylactic agent for areas with **multi-drug resistant malaria**, including resistance to chloroquine and mefloquine [1], [2]. - It targets multiple stages of the parasite life cycle, providing excellent protection and is generally well-tolerated with specific **WHO and CDC recommendations** for chloroquine and mefloquine resistant areas [1], [3]. *Primaquine* - **Primaquine** is primarily used for **causal prophylaxis** against *P. vivax* and *P. ovale* to prevent relapse, not as primary prophylaxis [2]. - It is not typically recommended as the primary prophylactic agent in areas with **chloroquine and mefloquine resistance** and requires **G6PD testing** due to risk of hemolysis [1]. *Proguanil* - While proguanil is used for malaria prophylaxis, **proguanil alone** is not effective enough for prophylaxis in areas with multi-drug resistant malaria. - It is typically used in **combination with atovaquone** rather than as monotherapy for effective protection [3]. *Doxycycline* - **Doxycycline** is also an effective prophylactic agent for areas with **chloroquine and mefloquine-resistant malaria** and is commonly recommended [1], [2]. - While effective, it can cause **photosensitivity** and **gastrointestinal upset**, making atovaquone-proguanil the preferred first-line choice.
Question 682: Drug that binds bile acids in the intestine and prevents their return to liver via the enterohepatic circulation?
- A. Niacin
- B. Fenofibrate
- C. Cholestyramine (Correct Answer)
- D. Gugulipid
Explanation: ***Cholestyramine*** - **Cholestyramine** is a **bile acid-binding resin** that sequesters bile acids in the intestine, preventing their reabsorption. - This interruption of the **enterohepatic circulation** leads to increased synthesis of new bile acids from cholesterol in the liver, thus lowering plasma LDL cholesterol. *Niacin* - **Niacin (nicotinic acid)** reduces the hepatic synthesis and secretion of **VLDL**, which in turn lowers LDL and triglyceride levels. - It works primarily through mechanisms related to fat metabolism in the liver and adipose tissue, not direct bile acid binding in the intestine. *Fenofibrate* - **Fenofibrate** is a **PPAR-α agonist** that primarily reduces triglyceride levels by increasing fatty acid oxidation and lipoprotein lipase activity, and secondarily increases HDL. - Its main action is on lipid metabolism in the liver and peripheral tissues, not by binding bile acids in the gut. *Gugulipid* - **Gugulipid** is a phytosterol derived from the guggul tree, sometimes used in traditional medicine for cholesterol management. - Its purported mechanism involves increasing **bile acid excretion** and inhibiting cholesterol biosynthesis, but it does not directly bind bile acids in the same manner as resins like cholestyramine.
Question 683: What is the mechanism of action of clofibrate in lipid metabolism?
- A. Inhibits lipolysis in adipose tissue.
- B. Inhibits HMG CoA reductase.
- C. Binds bile acids and bile salts in the small intestine.
- D. Increases lipoprotein lipase activity through PPAR alpha, leading to enhanced lipolysis of triglycerides. (Correct Answer)
Explanation: ***Increases lipoprotein lipase activity through PPAR alpha, leading to enhanced lipolysis of triglycerides.*** - Clofibrate, a **fibrat**e, acts as an agonist for **peroxisome proliferator-activated receptor alpha (PPAR-α)**. - Activation of PPAR-α leads to increased synthesis of **lipoprotein lipase (LPL)**, which enhances the breakdown of **triglycerides** in VLDL particles. *Inhibits lipolysis in adipose tissue.* - This mechanism is characteristic of **niacin (nicotinic acid)**, which reduces the release of free fatty acids from adipose tissue. - Clofibrate's primary action is not focused on inhibiting lipolysis in adipose tissue. *Inhibits HMG CoA reductase.* - This is the mechanism of action for **statins** (e.g., simvastatin, atorvastatin), which are used to reduce cholesterol synthesis. - Clofibrate does not directly inhibit HMG CoA reductase. *Binds bile acids and bile salts in the small intestine.* - This mechanism is characteristic of **bile acid sequestrants** (e.g., cholestyramine, colestipol). - These drugs prevent the reabsorption of bile acids, leading to increased cholesterol conversion to bile acids in the liver.
Question 684: All of the following are adverse effects of nicotinic acid except:
- A. Liver dysfunction
- B. Vasodilation
- C. Hyperpigmentation
- D. Pancreatitis (Correct Answer)
Explanation: ***Pancreatitis*** - **Pancreatitis** is not a commonly reported adverse effect of nicotinic acid (niacin) therapy. - While other gastrointestinal side effects like nausea and vomiting can occur, pancreatic inflammation is not characteristic. *Vasodilation* - **Cutaneous flushing** and **vasodilation** are very common adverse effects of nicotinic acid, mediated by prostaglandin release. - This effect can cause a sensation of warmth, redness, and itching, especially at the start of therapy. *Liver dysfunction* - **Liver dysfunction**, including elevated liver enzymes and rare cases of **hepatotoxicity**, can occur with high doses of nicotinic acid. - Regular monitoring of liver function tests is recommended for patients on niacin therapy. *Hyperpigmentation* - **Hyperpigmentation**, particularly **acanthosis nigricans**, is a known cutaneous side effect of nicotinic acid. - This typically presents as dark, velvety patches on the skin, especially in skin fold areas.