NEET-PG 2012 Practice Questions

Q: What is the recommended amount of bleaching powder necessary to disinfect stools contaminated with cholera?

50 gm/liter. ***50 gm/liter*** - For effective disinfection of stools contaminated with cholera, a concentration of **50 gm of bleaching powder per liter** of stool is recommended to ensure the destruction of **Vibrio cholerae**. - This concentration typically provides a sufficient amount of available **chlorine** to inactivate the bacteria within a reasonable contact time. *75 gm/liter* - While this concentration would certainly disinfect, it is **higher than necessary** for routine cholera stool disinfection and leads to inefficient resource use. - Using excess bleaching powder can also create a **stronger odor** and possibly increase the risk of skin or respiratory irritation. *90 gm/liter* - This concentration is **excessive** and not the standard recommendation for cholera stool disinfection. - Higher concentrations contribute to **waste of resources** and do not offer significantly improved efficacy over the recommended dose for this specific application. *100 gm/liter* - This concentration is significantly **higher than required** for effective disinfection of cholera-contaminated stools. - Using such a high amount is **economically inefficient** and offers no additional benefit in terms of disinfection for this specific pathogen and application.

Q: Which contraceptive method has the lowest pregnancy failure rate (typical use)?

Intrauterine Contraceptive Device (IUCD). ***Intrauterine Contraceptive Device (IUCD)*** - **IUCDs** are highly effective, with a **pregnancy failure rate of less than 1%** in typical use due to their long-acting and reversible nature, requiring no daily action from the user. - They are **fit-and-forget methods**, eliminating user error inherent in other forms of contraception, leading to very low typical use failure rates. *Diaphragm* - The **diaphragm** has a significantly higher typical use failure rate (around 12-16%) because its effectiveness depends on **correct placement** and consistent use with spermicide before each intercourse. - It is a **user-dependent method**, making its efficacy susceptible to improper use or non-use during sexual activity. *Condom* - **Condoms** have a typical use failure rate of about 13-18%, largely due to **incorrect use**, breakage, or slippage. - Their effectiveness relies heavily on **consistent and proper application** with every act of intercourse. *Oral Contraceptive Pills (OCP)* - **Oral Contraceptive Pills (OCPs)** have a typical use failure rate of approximately 7-9%, primarily because effectiveness is dependent on **daily adherence** at roughly the same time. - **Missed pills** are a common reason for failure, significantly increasing the risk of pregnancy compared to methods that do not require daily action.

Q: Which of the following is not a source of environmental radiation?

CO. ***CO*** - **Carbon monoxide (CO)** is a toxic gas produced by incomplete combustion, but it is **not radioactive** and thus not a source of environmental radiation. - Its danger comes from its ability to bind to **hemoglobin**, preventing oxygen transport, not from emitting radiation. *Radium* - **Radium** is a highly **radioactive element** found naturally in the environment as a decay product of uranium and thorium. - It emits **alpha and gamma radiation**, contributing significantly to natural background radiation. *Uranium* - **Uranium** is a naturally occurring **radioactive element** found in rocks, soil, and water. - It decays through a series of steps, emitting **alpha, beta, and gamma radiation**, and is a primary source of environmental background radiation. *Radon* - **Radon** is a **radioactive gas** that is formed from the decay of uranium in soil and rocks. - It is a significant source of **indoor environmental radiation exposure** and a known cause of lung cancer.

Q: Which of the following statements about the population pyramid of India is incorrect?

India has narrow base. ***Correct Answer: India has narrow base*** - A **narrow base** in a population pyramid indicates a **low birth rate** and a small proportion of young people. - This statement is **INCORRECT for India**, as India's population pyramid has a **broad base** due to high birth rates and a large proportion of children and young people. - This is the correct answer because the question asks for the incorrect statement. *Incorrect Option: India has narrow apex* - A **narrow apex** signifies a **smaller proportion of older individuals**, indicating lower life expectancy. - This is TRUE for India's population pyramid, making it an incorrect answer choice. *Incorrect Option: Developing countries have bulge in the center* - A **bulge in the center** represents a larger cohort of working-age adults in developing countries undergoing demographic transition. - This reflects improvements in childhood survival and declining (but still substantial) birth rates. - This is TRUE, making it an incorrect answer choice. *Incorrect Option: India has broad base* - A **broad base** indicates a **high birth rate** and large proportion of young children in the population. - This is TRUE and characteristic of India's population structure, making it an incorrect answer choice.

Q: Which of the following is not a risk factor for angle closure glaucoma?

Small lens. ***Correct Answer: Small lens*** - A smaller lens would lead to a **deeper anterior chamber**, reducing the likelihood of iridotrabecular contact and angle closure. - In contrast, a **large or thick lens** is a well-established risk factor for angle closure glaucoma as it pushes the iris forward, causing pupillary block. - Small lens size is **NOT a risk factor** for angle closure glaucoma. *Incorrect: Small eye* - A small eye (e.g., in **nanophthalmos**) is associated with a relatively large lens in proportion to the eye size, which can push the iris forward and narrow the angle. - This anatomical configuration makes individuals more prone to **pupillary block** and angle closure. *Incorrect: Hypermetropia* - **Hyperopic eyes** tend to be shorter with reduced axial length, which often results in a shallower anterior chamber and a relatively crowded anterior segment. - This shallow anterior chamber increases the risk of the iris occluding the **trabecular meshwork**, predisposing to angle closure. *Incorrect: Small cornea* - A small corneal diameter can be indicative of a generally smaller anterior segment, often correlating with a **shallow anterior chamber**. - A smaller cornea contributes to a more crowded anterior segment, predisposing to **angle closure glaucoma**.

Q: When should surgery be performed for congenital cataracts with visual disturbances?

As soon as possible (within 6-10 weeks). ***As soon as possible (within 6-10 weeks)*** - **Early surgical intervention** (within the first few weeks of life) is crucial for congenital cataracts to prevent **irreversible visual deficits**, such as **amblyopia**. - The brain's visual pathways develop rapidly in infancy, and prolonged visual deprivation from cataracts can lead to **permanent impairment**. *After 2 months* - This time frame represents a delay that can increase the risk of **amblyopia** and poorer visual outcomes. - The critical period for visual development is very early in life, making immediate intervention vital. *After 4 months* - A delay of four months significantly increases the likelihood of **dense amblyopia** and **strabismus**, making complete visual rehabilitation much more challenging. - At this age, the potential for achieving good vision post-surgery dramatically decreases due to entrenched abnormal visual processing. *After 1 year* - Performing surgery at one year or later for congenital cataracts is generally considered too late, often resulting in **profound and irreversible amblyopia**. - The visual system will have already established abnormal connections, making significant improvement in visual acuity unlikely.

Q: What is the most common cause of anterior uveitis?

Idiopathic. ***Idiopathic*** - In a significant proportion of cases of **anterior uveitis**, a specific cause cannot be identified, leading to a diagnosis of idiopathic uveitis. - This highlights the multifactorial nature of the condition, where various triggers or underlying predispositions may not always be evident. *CMV* - **Cytomegalovirus (CMV)** typically causes a **posterior uveitis** or **retinitis**, especially in immunocompromised individuals. - While CMV can rarely cause anterior uveitis, it is not the most common cause. *Toxoplasma* - **Toxoplasmosis** is a frequent cause of **posterior uveitis** or **chorioretinitis**, characterized by focal necrotic lesions in the retina. - It is not a common cause of isolated anterior uveitis, although anterior chamber inflammation can occur secondary to posterior disease. *Ankylosing spondylitis* - **Ankylosing spondylitis** is a well-known systemic condition associated with **acute anterior uveitis**. - However, while a significant association exists, it is not the single most common cause when considering all cases of anterior uveitis, many of which remain idiopathic.

Q: What is the first clinical sign observed in a patient with anterior uveitis?

Presence of aqueous flare. ***Presence of aqueous flare*** - **Aqueous flare** is considered the **earliest clinical sign** of anterior uveitis, representing increased protein content in the anterior chamber due to breakdown of the **blood-aqueous barrier**. - It is detected as a visible "haze" when a **slit lamp beam** passes through the anterior chamber, similar to observing dust particles in a light beam. *Presence of hypopyon* - **Hypopyon** is a more severe sign, indicating a **layer of white blood cells** in the anterior chamber, representing a more advanced inflammatory process. - While it can occur in severe anterior uveitis, it is not typically the **first or earliest** clinical manifestation. *Presence of miosis* - **Miosis** (pupillary constriction) can be present in anterior uveitis due to **iris inflammation** and irritation of the sphincter muscle. - However, it is an indirect sign and typically occurs *after* the initial signs of inflammation in the aqueous humor, such as flare. *Presence of keratic precipitates* - **Keratic precipitates (KPs)** are deposits of inflammatory cells on the **endothelium of the cornea**. - These deposits are a result of sustained inflammation and typically appear *after* the initial inflammatory changes in the aqueous humor, such as flare, have already occurred.

Q: Among the following organisms, which is the most common cause of postoperative endophthalmitis following corneal transplantation?

Staph epidermidis. ***Staph epidermidis*** - **Coagulase-negative Staphylococcus** (CoNS), including *S. epidermidis*, is the most frequent cause of **postoperative endophthalmitis** after both cataract surgery and corneal transplantation due to its presence on the normal ocular flora. - These organisms can form **biofilms on intraocular lenses** or transplanted corneal tissue, making eradication difficult. *Streptococcus* - While *Streptococcus* species can cause endophthalmitis, they are associated with a **more virulent and rapid onset** of severe inflammation and are not the most common causative agents of postoperative endophthalmitis compared to *S. epidermidis*. - They tend to cause more aggressive infections with often **poorer visual outcomes**. *Propionibacterium acnes* - *Propionibacterium acnes* can cause a **late-onset, indolent form of endophthalmitis**, typically months or even years after surgery. - While it is a recognized cause, it is far **less common** than *Staphylococcus epidermidis* in immediate or early postoperative cases. *Pseudomonas* - **Pseudomonas aeruginosa** is an aggressive and rapid-onset pathogen often associated with **severe keratitis** or **post-traumatic endophthalmitis**. - Although it can cause postoperative endophthalmitis, it is **much less common** than coagulase-negative staphylococci due to its infrequency on normal conjunctival flora.

Question 1

Which of the following is not considered an occupational cancer?

Accepted Answer

Breast

Answer

Lung

Answer

Liver

Answer

Bladder

Question 2

What is the recommended amount of bleaching powder necessary to disinfect stools contaminated with cholera?

Accepted Answer

50 gm/liter

Answer

75 gm/liter

Answer

90 gm/liter

Answer

100 gm/liter

Question 3

Which contraceptive method has the lowest pregnancy failure rate (typical use)?

Accepted Answer

Intrauterine Contraceptive Device (IUCD)

Answer

Diaphragm

Answer

Condom

Answer

Oral Contraceptive Pills (OCP)

Question 4

Which of the following is not a source of environmental radiation?

Accepted Answer

CO

Answer

Uranium

Answer

Radon

Answer

Radium

Question 5

Which of the following statements about the population pyramid of India is incorrect?

Accepted Answer

India has narrow base

Answer

India has narrow apex

Answer

Developing countries have bulge in the center

Answer

India has broad base

Question 6

Which of the following is not a risk factor for angle closure glaucoma?

Accepted Answer

Small lens

Answer

Small eye

Answer

Small cornea

Answer

Hypermetropia

Question 7

When should surgery be performed for congenital cataracts with visual disturbances?

Accepted Answer

As soon as possible (within 6-10 weeks)

Answer

After 2 months

Answer

After 4 months

Answer

After 1 year

Question 8

What is the most common cause of anterior uveitis?

Accepted Answer

Idiopathic

Answer

CMV

Answer

Toxoplasma

Answer

Ankylosing spondylitis

Question 9

What is the first clinical sign observed in a patient with anterior uveitis?

Accepted Answer

Presence of aqueous flare

Answer

Presence of hypopyon

Answer

Presence of miosis

Answer

Presence of keratic precipitates

Question 10

Among the following organisms, which is the most common cause of postoperative endophthalmitis following corneal transplantation?

Accepted Answer

Staph epidermidis

Answer

Streptococcus

Answer

Pseudomonas

Answer

Propionibacterium acnes

NEET-PG 2012

Community Medicine

Ophthalmology