NEET-PG 2012 Practice Questions

Q: In the context of epidemiology, what is the denominator used for calculating incidence?

Population at risk. ***Population at risk*** - Incidence measures the **rate of new cases** of a disease in a population over a specified period. - The denominator for calculating incidence must exclude individuals who are **already diseased** or are **immune** and thus not susceptible to developing the condition. - This is the **most accurate and theoretically correct** denominator as it represents only those who can actually develop the disease. *Mid year population* - While often used as a **practical approximation** in epidemiological calculations when the exact population at risk is difficult to determine. - However, it includes individuals who may not be at risk (e.g., already have the disease or are immune), making it **less precise** than using the actual susceptible population. - For the **theoretical definition** of incidence rate, population at risk is the correct denominator. *Total number of cases* - This value represents the **numerator** for incidence calculations, as it counts the number of new events or diseases occurring. - It cannot serve as the denominator, as the denominator must reflect the pool of individuals from which these **new cases arose**. *Total number of deaths* - This is a measure of **mortality**, not incidence, and is used to calculate death rates. - The denominator for mortality rates is typically the **population at risk of death**, not specifically the population at risk of developing a disease.

Q: What substance is measured in the vitreous humor to estimate the time since death?

Potassium. ***Potassium*** - **Potassium** concentration in the vitreous humor increases predictably after death due to the breakdown of cellular membranes and passive diffusion from cells. - This consistent post-mortem rise makes it a reliable marker for estimating the **post-mortem interval** (PMI) or time since death. *Sodium* - While sodium is present in the vitreous humor, its post-mortem changes are not as consistent or predictable as potassium for estimating the **time since death**. - Sodium levels tend to decrease slightly after death, but this decline is influenced by various factors and is less reliable for **PMI determination**. *Proteins* - **Proteins** are generally stable in the vitreous humor for some time post-mortem, but their levels do not show a consistent or predictable change that can be used to accurately estimate the **time since death**. - Measuring protein levels is more useful in assessing specific eye pathologies rather than **PMI**. *Chloride* - **Chloride** concentrations in the vitreous humor exhibit post-mortem changes, but like sodium, they are not as precise or reliable as potassium for estimating the **post-mortem interval**. - Its diffusion out of the vitreous humor can be more variable and less consistently linear than potassium's influx.

Q: Madarosis is seen in ?

Hypothyroidism. ***Hypothyroidism*** - **Madarosis**, specifically the loss of the **outer third of the eyebrows**, is a classic sign of **hypothyroidism** due to decreased thyroid hormone levels affecting hair follicle growth [1]. - Other common symptoms include **fatigue**, **weight gain**, **cold intolerance**, and **dry skin**. *Addison's disease* - This condition involves **adrenal insufficiency**, primarily causing symptoms like **hyperpigmentation**, low blood pressure, and fatigue. - **Hair loss** is generally not a prominent feature, and madarosis is not typically seen. *Acromegaly* - Characterized by excessive **growth hormone** production, leading to enlargement of hands, feet, and facial features. - While it can cause some changes in hair texture, **madarosis** is not a common clinical manifestation. *None of the options* - This option is incorrect because **Hypothyroidism** is a direct cause of madarosis due to its impact on **hair follicle metabolism** [1]. - The other conditions listed do not typically present with this specific type of eyebrow hair loss.

Q: Who discovered the malarial parasite?

Charles Louis Alphonse Laveran. ***Charles Louis Alphonse Laveran*** - **Charles Louis Alphonse Laveran** was a French physician who, in **1880**, observed parasites in the blood of a malaria patient. - He was awarded the **Nobel Prize in Physiology or Medicine in 1907** for his discovery of the role of protozoa in causing diseases, specifically recognizing the malarial parasite. *Ronald Ross* - **Ronald Ross** was a British physician who, in **1897**, demonstrated that **malaria is transmitted by mosquitoes**. - While he elucidated the **transmission cycle**, it was Laveran who first identified the parasite itself in human blood. - He received the **Nobel Prize in 1902** for this work. *Paul Muller* - **Paul Muller** was a Swiss chemist who was awarded the **Nobel Prize in Physiology or Medicine in 1948** for his discovery of the insecticidal properties of **DDT (dichlorodiphenyltrichloroethane)**. - His work was significant in combating insect-borne diseases like malaria, but he was not involved in the discovery of the malarial parasite. *Pampania* - This name does not correspond to any recognized figure in the discovery of the malarial parasite or its transmission. - This is a distractor option in the original examination question.

Q: Which of the following statements about trematodes is true?

Two hosts required. ***Two hosts required (Correct)*** - Trematodes typically require at least **two hosts** to complete their life cycle: an intermediate host (usually a **snail**) and a definitive host (a vertebrate). - This complex lifecycle involving multiple hosts is a characteristic feature of **flukes**. - This is a fundamental distinguishing feature that separates trematodes from some other helminths. *Segmented (Incorrect)* - Trematodes (flukes) have **unsegmented, leaf-shaped or cylindrical bodies**, unlike cestodes (tapeworms) which are segmented. - The absence of body segmentation is a key morphological distinction from other helminths. *Anus present (Incorrect)* - Trematodes have an **incomplete digestive system** with a mouth and an esophagus, but **no anus**. - Waste products are expelled back through the **mouth**. - This blind-ending gut is characteristic of the class Trematoda. *Body cavity present (Incorrect)* - Trematodes are **acoelomates**, meaning they lack a true fluid-filled body cavity (coelom). - Their internal organs are embedded in **parenchymatous tissue** filling the space between body wall and organs.

Q: Which of the following statements is false regarding yersiniosis?

Caused by Yersinia pestis. ***Caused by Yersinia pestis*** - **Yersinia pestis** is the causative agent of **plague**, not typical yersiniosis affecting the gastrointestinal tract. - Yersiniosis generally refers to infections caused by other *Yersinia* species like *Y. enterocolitica* and *Y. pseudotuberculosis*. *Gram-negative bacillus* - *Yersinia* species, including *Y. enterocolitica* and *Y. pseudotuberculosis*, are indeed **Gram-negative bacilli**. - This characteristic is fundamental to their classification and bacterial structure. *Caused by Yersinia pseudotuberculosis* - **Yersinia pseudotuberculosis** is a recognized cause of **yersiniosis**, particularly affecting children. - It can cause symptoms such as **abdominal pain** and **mesenteric lymphadenitis**, mimicking appendicitis. *Caused by Yersinia enterocolitica* - **Yersinia enterocolitica** is the **most common cause of yersiniosis** in humans. - It is responsible for a range of symptoms including **gastroenteritis**, **acute enteritis**, and **mesenteric lymphadenitis**.

Q: What type of deposit is commonly associated with age-related macular degeneration?

Drusen. ***Drusen*** - **Drusen** are yellow deposits of extracellular material that accumulate beneath the **retinal pigment epithelium (RPE)**. - Their presence is a hallmark sign of **age-related macular degeneration (AMD)** and can lead to vision loss by disrupting retinal function. *Iron* - While iron can accumulate in ocular tissues in conditions like **siderosis bulbi** (due to retained intraocular foreign bodies), it is not a characteristic deposit of macular degeneration. - Ocular iron deposition typically causes different pathologies, such as retinal dysfunction or glaucoma, rather than AMD. *Lipochrome* - **Lipochrome** refers to a class of pigments, including **lipofuscin**, which can accumulate in cells as a byproduct of cellular metabolism and aging. - Although lipofuscin buildup occurs in the RPE with age, **drusen** are the specific, organized extracellular deposits pathognomonic for macular degeneration. *Hemosiderine* - **Hemosiderin** is an iron-storage complex formed from the breakdown of hemoglobin, found in situations of hemorrhage or chronic bleeding. - It is not a typical deposit found in macular degeneration; its presence in the retina usually indicates a history of retinal hemorrhage.

Q: Which of the following conditions is least likely to be associated with neovascular glaucoma?

Open angle glaucoma. ***Open angle glaucoma*** ✓ - **Open-angle glaucoma** is a primary **neurodegenerative disease** of the optic nerve, characterized by progressive loss of **retinal ganglion cells** and their axons, leading to characteristic **optic neuropathy** and visual field defects. - It does **NOT** directly cause **neovascularization** or increased VEGF production, which are the underlying mechanisms for **neovascular glaucoma**. - This is the **least likely** association among the given options. *Diabetes* - **Diabetic retinopathy** is a **major cause** of **neovascularization** due to retinal ischemia and increased production of **vascular endothelial growth factor (VEGF)**, which can lead to **neovascular glaucoma**. - **Neovascularization** on the iris (rubeosis iridis) and angle can block aqueous outflow, causing a severe, rapidly progressing form of secondary glaucoma. *CRVO (Central Retinal Vein Occlusion)* - **CRVO** leads to significant retinal ischemia and subsequent release of **VEGF**, which prompts the growth of new, fragile blood vessels. - These new vessels (neovascularization) can grow in the iris and angle, obstructing aqueous humor outflow and causing **neovascular glaucoma**. - **Ischemic CRVO** is one of the **most common causes** of neovascular glaucoma. *Eale's disease* - **Eale's disease** is an **idiopathic occlusive vasculitis** primarily affecting the **peripheral retinal veins**, leading to **retinal ischemia**. - This ischemia stimulates **neovascularization** and the production of **VEGF**, increasing the risk of **neovascular glaucoma** due to the formation of new blood vessels in the anterior chamber.

Q: Which diuretic exhibits paradoxical antidiuretic activity in diabetes insipidus?

Thiazide diuretics. ***Thiazide diuretics*** - Thiazides cause a modest **volume depletion**, leading to increased proximal tubular reabsorption of water and solutes [1]. - They also lower the **glomerular filtration rate**, further reducing the amount of fluid delivered to the collecting ducts, thus paradoxically reducing urine output in diabetes insipidus [2]. - This effect is particularly useful in **nephrogenic diabetes insipidus**, where the kidneys cannot respond to ADH [2]. *Potassium-sparing diuretics (Triamterene)* - Triamterene is a **potassium-sparing diuretic** that blocks epithelial sodium channels in the late distal tubule and collecting duct. - It increases sodium and water excretion, which would worsen, not improve, the polyuria of diabetes insipidus. *Aldosterone antagonists (Spironolactone)* - Spironolactone is a **mineralocorticoid receptor antagonist** that increases sodium and water excretion while conserving potassium in the collecting duct. - Its primary action is to counteract aldosterone, and it does not exhibit the paradoxical antidiuretic effect seen with thiazides in diabetes insipidus. *Loop diuretics (Furosemide)* - Loop diuretics like furosemide act on the **thick ascending limb of the loop of Henle** to inhibit sodium, potassium, and chloride reabsorption. - They cause significant diuresis and would **exacerbate the polyuria** in patients with diabetes insipidus, rather than improving it.

Question 1

In the context of epidemiology, what is the denominator used for calculating incidence?

Accepted Answer

Population at risk

Answer

Mid year population

Answer

Total number of cases

Answer

Total number of deaths

Question 2

What substance is measured in the vitreous humor to estimate the time since death?

Accepted Answer

Potassium

Answer

Sodium

Answer

Proteins

Answer

Chloride

Question 3

An 86-year-old lady presented with severe constipation. She was a known hypertensive on medications for 10 years. In clinic, her BP was 157/98 mm Hg with a heart rate of 58/min. On taking her BP in the supine position, it was found to be 90/60 mm Hg. She had a recent history of depression. She is taking atenolol, thiazide, imipramine, haloperidol, and docusate. What is the next best step in the management?

Accepted Answer

Change imipramine and haloperidol to fluoxetine and risperidone and add bisacodyl for constipation

Answer

Change atenolol and thiazide to calcium channel blocker and ACE inhibitor and add bisacodyl for constipation

Answer

Only add bisacodyl for constipation and continue rest of the medications

Answer

Discontinue all her medications and start her on steroids

Question 4

Madarosis is seen in ?

Accepted Answer

Hypothyroidism

Answer

None of the options

Answer

Addison's disease

Answer

Acromegaly

Question 5

Who discovered the malarial parasite?

Accepted Answer

Charles Louis Alphonse Laveran

Answer

Ronald Ross

Answer

Paul Muller

Answer

Pampania

Question 6

Which of the following statements about trematodes is true?

Accepted Answer

Two hosts required

Answer

Segmented

Answer

Anus present

Answer

Body cavity present

Question 7

Which of the following statements is false regarding yersiniosis?

Accepted Answer

Caused by Yersinia pestis

Answer

Gram-negative bacillus

Answer

Caused by Yersinia pseudotuberculosis

Answer

Caused by Yersinia enterocolitica

Question 8

What type of deposit is commonly associated with age-related macular degeneration?

Accepted Answer

Drusen

Answer

Iron

Answer

Lipochrome

Answer

Hemosiderine

Question 9

Which of the following conditions is least likely to be associated with neovascular glaucoma?

Accepted Answer

Open angle glaucoma

Answer

Diabetes

Answer

CRVO

Answer

Eale's disease

Question 10

Which diuretic exhibits paradoxical antidiuretic activity in diabetes insipidus?

Accepted Answer

Thiazide diuretics

Answer

Aldosterone antagonists (Spironolactone)

Answer

Loop diuretics (Furosemide)

Answer

Potassium-sparing diuretics (Triamterene)

NEET-PG 2012

Community Medicine

Forensic Medicine

General Medicine

Internal Medicine

Microbiology

Ophthalmology

Pharmacology