NEET-PG 2012 Practice Questions

Q: What does the Dibucaine number indicate in clinical practice?

Atypical acetylcholinesterase activity. ***Atypical acetylcholinesterase activity*** - The **Dibucaine number** quantifies the inhibition of **pseudocholinesterase (butyrylcholinesterase)** by the local anesthetic dibucaine. - A low Dibucaine number (e.g., < 20-30) indicates a genetically determined **atypical variant** of pseudocholinesterase, leading to prolonged duration of action of drugs like succinylcholine. *Potency of muscle relaxants* - The potency of muscle relaxants is typically assessed by the **ED95**, which is the dose required to produce 95% suppression of twitch response. - While Dibucaine is a local anesthetic that can cause muscle relaxation, the **Dibucaine number** specifically evaluates an enzyme's activity, not the strength of the relaxant itself. *Potency of general anesthetics* - The potency of general anesthetics is primarily measured by the **Minimum Alveolar Concentration (MAC)** required to prevent movement in 50% of patients in response to a noxious stimulus. - The Dibucaine number is unrelated to the mechanism or potency of general anesthetic agents. *None of the options* - This option is incorrect because **Atypical acetylcholinesterase activity** accurately describes what the Dibucaine number indicates. - The Dibucaine number is a specific laboratory test used to identify genetic variations in butyrylcholinesterase, which has significant clinical implications for drug metabolism.

Q: Which of the following is not associated with subcortical dementia?

Alzheimer's disease. ***Alzheimer's disease*** - Alzheimer's disease is primarily a **cortical dementia**, characterized by global cognitive decline, specifically affecting memory, language, and executive functions. - It involves the accumulation of **amyloid plaques** and **neurofibrillary tangles** predominantly in the cerebral cortex. *Parkinsonism* - Parkinsonism, particularly Parkinson's disease dementia, is a common cause of **subcortical dementia**. - It presents with prominent **motor symptoms** (bradykinesia, rigidity, tremor) along with cognitive impairment affecting executive function and attention. *Wilson's disease* - Wilson's disease is a genetic disorder leading to **copper accumulation**, which can cause significant damage to the basal ganglia and other subcortical structures. - This often results in a **subcortical dementia** characterized by motor symptoms, psychiatric disturbances, and cognitive decline. *Huntington's chorea* - Huntington's chorea is a neurodegenerative genetic disorder primarily affecting the **basal ganglia**, a key subcortical structure. - It is a classic example of **subcortical dementia**, presenting with characteristic choreiform movements, psychiatric disturbances, and cognitive impairment.

Q: What is the typical pH of the vagina in a pregnant woman?

4.0. ***4.0*** - The typical vaginal pH in a pregnant woman is **acidic**, generally ranging from 3.5 to 4.5, with **4.0 being the most commonly cited average value** during pregnancy. - This **acidic environment** is crucial for maintaining a healthy vaginal flora, primarily dominated by **Lactobacillus species**, which produce lactic acid from glycogen deposits in vaginal epithelium. - The increased estrogen levels during pregnancy promote glycogen deposition, supporting lactobacilli growth and maintaining this acidic pH. *4.5* - While 4.5 is **also within the normal range** (3.5-4.5) for pregnant women, it represents the **upper limit** of normal vaginal pH during pregnancy. - Although still physiologic, **4.0 is more commonly referenced** as the typical value in obstetric literature, making it the best answer for "typical" pH. - A pH consistently at 4.5 or trending upward may warrant monitoring, though it is not necessarily pathological. *5* - A pH of 5 is considered **elevated** and is typically associated with conditions like **bacterial vaginosis** (BV) or **trichomoniasis**, which increase the risk of preterm labor and other complications. - A pH of 5 in pregnancy would raise suspicion and warrant further investigation, as it indicates a **less acidic** environment and disruption of normal lactobacilli-dominated flora. - This elevated pH suggests loss of the protective acidic environment. *>5* - A pH greater than 5 is **abnormal** for a pregnant woman and strongly suggests the presence of a **vaginal infection**, such as bacterial vaginosis, trichomoniasis, or aerobic vaginitis. - This **alkaline shift** favors the growth of pathogenic bacteria over beneficial lactobacilli, significantly increasing the risk of adverse pregnancy outcomes including preterm birth and chorioamnionitis. - Requires prompt evaluation and treatment.

Q: Which structures are most commonly involved in a ciliary staphyloma?

Ciliary body and sclera. ***Ciliary body and sclera*** - A **staphyloma** is a localized bulging of the outer coat of the eye (sclera or cornea) lined internally by uveal tissue. - A **ciliary staphyloma** specifically involves the **ciliary body** and **sclera** at the region of the ciliary body, typically presenting as a dark bluish bulge at the limbal or perilimbal area. - This occurs due to weakening and ectasia of the sclera with prolapse of the underlying ciliary body, commonly seen following scleritis, perforating injuries, or surgeries. *Choroid and sclera* - This combination describes a **posterior staphyloma**, which occurs at the posterior pole of the eye, commonly seen in pathological myopia. - While medically accurate for posterior type, it does not describe a **ciliary staphyloma**. *Iris and sclera* - An **anterior staphyloma** primarily involves bulging of the **cornea** with incarceration of iris tissue, rather than sclera alone. - It occurs after corneal perforation with iris prolapse. *Cornea and conjunctiva* - This does not describe a staphyloma. Bulging of the cornea alone is termed **keratectasia** or **keratoconus**. - The **conjunctiva** is a superficial membrane and is not a structural component of staphyloma formation.

Q: A 3-month-old infant presents with an abdominal palpable mass and non-bilious vomiting. What is the most likely diagnosis?

Hypertrophic pyloric stenosis. ***Hypertrophic pyloric stenosis*** - The classic presentation includes **projectile non-bilious vomiting** and a palpable **olive-shaped mass** in the epigastrium of an infant typically between 3 weeks and 6 months of age. - The vomiting is non-bilious because the obstruction is proximal to the ampulla of Vater. *Intussusception* - While it can present with an **abdominal mass** and vomiting, the vomiting is often **bilious** and the classic stool is **'currant jelly'**, which is not mentioned here. - It usually presents with sudden onset of severe, **colicky abdominal pain** and occurs more commonly in slightly older infants (6-12 months). *Tracheoesophageal fistula* - This condition presents at birth with symptoms such as **choking, coughing**, and **cyanosis** during feeding. - It usually causes respiratory distress and feeding difficulties from the first days of life, not a palpable abdominal mass and non-bilious vomiting at 3 months. *Duodenal atresia* - This is a congenital obstruction that typically presents with **bilious vomiting** (as the obstruction is distal to the ampulla of Vater) within the first 24-48 hours of life. - Imaging usually shows a **“double bubble” sign** on abdominal X-ray, and an abdominal mass is not typically palpable.

Q: What is the drug of choice for listeria meningitis?

Ampicillin. ***Ampicillin*** - **Ampicillin** is the **drug of choice** for *Listeria monocytogenes* meningitis due to its excellent in vitro activity and good central nervous system penetration. - It is often used in combination with an **aminoglycoside** (e.g., gentamicin) for synergistic bactericidal activity, especially in severe cases, though gentamicin does not penetrate the CSF well. *Cefotaxime* - **Third-generation cephalosporins** like cefotaxime have poor activity against *Listeria monocytogenes* due to the organism's intrinsic resistance to these agents. - While effective against many other bacterial causes of meningitis (e.g., *S. pneumoniae*, *N. meningitidis*), it is not appropriate for *Listeria*. *Ceftriaxone* - Similar to cefotaxime, **ceftriaxone** is a third-generation cephalosporin and is **ineffective** against *Listeria monocytogenes* due to the lack of penicillin-binding protein (PBP) affinity. - Its use for *Listeria* meningitis would lead to treatment failure. *Ciprofloxacin* - **Ciprofloxacin**, a fluoroquinolone, is generally **not recommended** as a first-line treatment for *Listeria* meningitis, despite some in vitro activity. - Its use is typically reserved for patients with severe allergies to penicillins, and even then, **trimethoprim-sulfamethoxazole** is usually preferred as an alternative to ampicillin.

Q: What does Pica refer to?

An appetite for non-nutritive substances. ***An appetite for non-nutritive substances*** - Pica is an eating disorder characterized by a persistent and compulsive craving for and consumption of **non-nutritive, non-food substances** for at least one month. - Common ingested substances include **dirt, clay, ice, hair, paint chips, and laundry starch**, often associated with **nutritional deficiencies** like iron deficiency anemia or **developmental disabilities**. *Ice sucking* - While **pagophagia (ice craving)** is a specific form of Pica, it represents only one manifestation and not the overarching definition of the disorder. - Isolated ice sucking can sometimes be a sign of **iron deficiency anemia**. *Thumb sucking* - **Thumb sucking** is a common habit, especially in infants and young children, typically associated with self-soothing and comfort. - It is not considered an eating disorder and does not involve the consumption of non-nutritive substances. *None of the options* - This option is incorrect because "An appetite for non-nutritive substances" accurately defines Pica.

Q: What is the treatment of choice for anal carcinoma?

Chemoradiation. ***Chemoradiation*** - This combined modality is the **standard of care** for most anal carcinomas, achieving high cure rates while preserving sphincter function. - The combination of **chemotherapy** (e.g., 5-fluorouracil and mitomycin C) and **external beam radiation** works synergistically to destroy cancer cells. *Chemotherapy alone* - **Chemotherapy alone** is generally insufficient as a primary treatment for anal carcinoma. - It is often used in combination with radiation or for **metastatic disease**, but not as a monotherapy for curative intent in localized disease. *APR combined with radiotherapy* - **Abdominoperineal resection (APR)** combined with radiotherapy is typically reserved for **recurrent** or **persistent anal carcinoma** after failed chemoradiation, or for very advanced tumors. - APR is a highly morbid surgery leading to a **permanent colostomy**, and primary chemoradiation aims to avoid this outcome. *All of the options* - As **chemoradiation** is the preferred first-line treatment and other options are either inadequate or reserved for specific situations, stating "all of the options" is incorrect. - The treatment strategy for anal carcinoma involves a nuanced approach, prioritizing **organ preservation** with effective cancer control.

Question 1

What does the Dibucaine number indicate in clinical practice?

Accepted Answer

Atypical acetylcholinesterase activity

Answer

Potency of muscle relaxants

Answer

Potency of general anesthetics

Answer

None of the options

Question 2

All following are at-risk group adults meriting Hepatitis B vaccination in low endemic areas except for which of the following?

Accepted Answer

Diabetics on insulin

Answer

Medical/nursing personnel

Answer

Patients with chronic liver disease

Answer

Patients on chronic hemodialysis

Question 3

Which of the following is not associated with subcortical dementia?

Accepted Answer

Alzheimer's disease

Answer

Wilson's disease

Answer

Huntington's chorea

Answer

Parkinsonism

Question 4

Which of the following is a characteristic of Yellow-nail syndrome?

Accepted Answer

Pleural effusion and lymphedema, associated with discolored nails

Answer

Knee joint effusion and lymphedema, associated with discolored nails

Answer

Pericardial effusion and lymphedema, associated with discolored nails

Answer

Peritoneal effusion and lymphedema, associated with discolored nails

Question 5

What is the typical pH of the vagina in a pregnant woman?

Accepted Answer

4.0

Answer

4.5

Answer

5

Answer

>5

Question 6

Which structures are most commonly involved in a ciliary staphyloma?

Accepted Answer

Ciliary body and sclera

Answer

Choroid and sclera

Answer

Cornea and conjunctiva

Answer

Iris and sclera

Question 7

A 3-month-old infant presents with an abdominal palpable mass and non-bilious vomiting. What is the most likely diagnosis?

Accepted Answer

Hypertrophic pyloric stenosis

Answer

Tracheoesophageal fistula

Answer

Duodenal atresia

Answer

Intussusception

Question 8

What is the drug of choice for listeria meningitis?

Accepted Answer

Ampicillin

Answer

Cefotaxime

Answer

Ciprofloxacin

Answer

Ceftriaxone

Question 9

What does Pica refer to?

Accepted Answer

An appetite for non-nutritive substances

Answer

Ice sucking

Answer

Thumb sucking

Answer

None of the options

Question 10

What is the treatment of choice for anal carcinoma?

Accepted Answer

Chemoradiation

Answer

Chemotherapy alone

Answer

APR combined with radiotherapy

Answer

All of the options

NEET-PG 2012

Anesthesiology

Community Medicine

Internal Medicine

Obstetrics and Gynecology

Ophthalmology

Pediatrics

Pharmacology

Psychiatry

Surgery