Anatomy
1 questionsUnilateral lacrimal gland destruction may be caused by?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 531: Unilateral lacrimal gland destruction may be caused by?
- A. Fracture of roof of orbit (Correct Answer)
- B. Inferior orbital fissure fracture
- C. Fracture of lateral wall
- D. Fracture of sphenoid
Explanation: ***Fracture of roof of orbit*** - The **lacrimal gland** is situated in the **lacrimal fossa** on the anterior-lateral part of the **orbital roof**. A fracture in this specific area can directly damage the gland. - Trauma to the **orbital roof** can lead to laceration, avulsion, or compression of the lacrimal gland, resulting in its destruction and impairing tear production. *Inferior orbital fissure fracture* - The **inferior orbital fissure** transmits nerves and vessels to the orbit but is located inferior to the lacrimal gland, making direct injury unlikely. - Fractures here are more associated with **infraorbital nerve damage** or disruption of orbital contents into the maxillary sinus, not lacrimal gland destruction. *Fracture of lateral wall* - The **lateral wall of the orbit** forms the outer boundary and protects structures deeper within the orbit, but the lacrimal gland is situated superiorly and anteriorly. - While significant trauma to the lateral wall can impact orbital contents, it is less likely to directly cause unilateral lacrimal gland destruction compared to a direct roof fracture. *Fracture of sphenoid* - Fractures of the **sphenoid bone** are typically more posterior and central, affecting structures like the **optic canal** or **cavernous sinus**. - While it can indirectly affect orbital function, it is not a direct cause of isolated lacrimal gland destruction due to its anatomical location.
Community Medicine
2 questionsWhat is the most commonly reported bacterial sexually transmitted infection?
What does a highly sensitive test imply about its false negative rate?
NEET-PG 2012 - Community Medicine NEET-PG Practice Questions and MCQs
Question 531: What is the most commonly reported bacterial sexually transmitted infection?
- A. HSV
- B. HIV
- C. Syphilis
- D. Chlamydia (Correct Answer)
Explanation: ***Correct: Chlamydia*** - **Chlamydia trachomatis** is the most frequently reported bacterial STI in many countries, often being **asymptomatic** and thus easily spread - Its high prevalence is due to efficient transmission and the widespread use of sensitive diagnostic tests that detect infections in asymptomatic individuals - Accounts for the majority of reported bacterial STI cases globally *Incorrect: HSV* - **Herpes Simplex Virus (HSV)** is a **viral STI**, not bacterial, and is characterized by recurrent outbreaks of **genital ulcers** or sores - While common, it does not qualify as a bacterial infection and is often not laboratory-confirmed due to mild or subclinical presentations *Incorrect: HIV* - **Human Immunodeficiency Virus (HIV)** is also a **viral STI**, not bacterial, that attacks the immune system leading to AIDS - Although highly impactful, HIV is not a bacterial infection and has lower incidence rates compared to Chlamydia *Incorrect: Syphilis* - **Syphilis**, caused by the bacterium **Treponema pallidum**, is a serious bacterial STI that can have long-term complications if untreated - While its incidence has been increasing in some regions, it is significantly less common than **Chlamydia** in terms of overall reported cases
Question 532: What does a highly sensitive test imply about its false negative rate?
- A. High false positive rate
- B. Low false negative rate (Correct Answer)
- C. High true negative rate
- D. High true positive rate
Explanation: ***Low false negative rate*** - A highly **sensitive test** is good at identifying true positives, meaning it correctly identifies most people who have the disease. - Sensitivity = TP/(TP+FN), so high sensitivity mathematically means few false negatives. - This characteristic directly translates to a **low false negative rate**, as few people with the disease will be missed. *High false positive rate* - A high **false positive rate** relates to **specificity**, not sensitivity. - False positive rate = FP/(FP+TN), which measures how many healthy people are incorrectly identified as diseased. - While some sensitive tests may have lower specificity (higher FP rate), this is not a direct implication of high sensitivity. *High true negative rate* - A high **true negative rate** is a characteristic of a highly **specific** test, which correctly identifies people who do **not** have the disease. - True negative rate = TN/(TN+FP) = Specificity. - **Sensitivity** and **specificity** are independent measures, so high sensitivity does not imply a high true negative rate. *High true positive rate* - High **true positive rate** is actually another term for high sensitivity (Sensitivity = TPR = TP/(TP+FN)). - While this is true of a sensitive test, the question specifically asks about the implication for the **false negative rate**. - The **most direct answer** regarding false negatives is "low false negative rate" rather than describing the true positive rate.
Internal Medicine
1 questionsAmong the following, most reliable test for screening of diabetes mellitus?
NEET-PG 2012 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 531: Among the following, most reliable test for screening of diabetes mellitus?
- A. Urine sugar
- B. Random sugar
- C. Fasting sugar (Correct Answer)
- D. Glucose tolerance test
Explanation: ***Fasting sugar*** - A **fasting plasma glucose** (FPG) test is the most common and reliable initial test for screening for **diabetes mellitus** because it measures blood glucose after an overnight fast (typically 8-12 hours), providing a baseline level unaffected by recent food intake [1]. - A fasting glucose level of **≥ 126 mg/dL** (7.0 mmol/L) on two separate occasions is diagnostic of diabetes, making it an excellent screening tool for identifying individuals with impaired glucose metabolism [1]. *Random sugar* - A random plasma glucose test can be used to diagnose diabetes if the level is **≥ 200 mg/dL** (11.1 mmol/L) in a symptomatic individual, but it is less reliable for screening asymptomatic individuals due to its variability depending on recent food intake [1]. - Because it can be measured at any time of day without regard to the last meal, it has a **lower sensitivity** for detecting early stages of diabetes compared to fasting glucose. *Glucose tolerance test* - An **oral glucose tolerance test** (OGTT) is highly sensitive and specific for diagnosing diabetes and impaired glucose tolerance, but it is more cumbersome and time-consuming, involving multiple blood draws over two hours after consuming a sugary drink. - While it is a definitive diagnostic test, its complexity makes it **less practical for routine screening** in large populations compared to simpler tests like fasting plasma glucose. *Urine sugar* - The presence of glucose in urine (glycosuria) indicates that blood glucose levels have exceeded the **renal threshold** (typically around 180 mg/dL), meaning the kidneys are unable to reabsorb all the glucose. - This is a **less sensitive and specific** method for screening, as it only becomes positive once blood glucose is significantly elevated, and it does not detect milder forms of impaired glucose metabolism or early diabetes.
Ophthalmology
5 questionsWhich type of cataract is specifically associated with decreased reading ability?
Which type of congenital cataract is commonly associated with significant visual defects?
Bilateral ptosis is seen in all except which of the following?
Most common malignant tumour of eyelid is ?
In which condition is the swinging light test positive?
NEET-PG 2012 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 531: Which type of cataract is specifically associated with decreased reading ability?
- A. Blue dot cataract
- B. Nuclear cataract (Correct Answer)
- C. Fusiform cataract
- D. Punctate cataract
Explanation: ***Nuclear cataract*** - **Nuclear cataracts** cause progressive hardening and yellowing of the lens nucleus with increased refractive index - This produces a **myopic shift** that initially causes **"second sight"** (temporary improvement in near vision) - However, as the cataract progresses, the increasing opacity leads to **overall visual decline affecting both distance and near vision**, including reading ability - Among the given options, nuclear cataract is the most common age-related cataract that significantly impairs vision including reading *Blue dot cataract* - **Blue dot cataracts** (cerulean cataracts) are small, bluish peripheral opacities, usually congenital and stationary - They rarely cause significant visual impairment and do not affect reading ability *Fusiform cataract* - **Fusiform cataracts** are congenital spindle-shaped opacities along the visual axis - While they can affect vision if dense, they are rare and not typically associated with progressive reading difficulty *Punctate cataract* - **Punctate cataracts** are small, scattered dot-like opacities in the lens - They are often congenital or age-related and cause minimal visual disturbance - Not specifically associated with decreased reading ability
Question 532: Which type of congenital cataract is commonly associated with significant visual defects?
- A. Punctate Cataract
- B. Blue dot cataract
- C. Fusiform cataract
- D. Nuclear cataract (Correct Answer)
Explanation: ***Nuclear cataract*** - It involves the **nucleus** of the lens, which is the central and most visually critical part. - This type of cataract can cause **significant visual impairment** due to its central location and density, impacting early visual development. *Punctate Cataract* - These are **small, dot-like opacities** that are usually clinically insignificant and do not typically cause significant visual defects. - They are often **peripheral** or very fine, thus not obstructing the central visual axis. *Blue dot cataract* - Also known as **cerulean cataract**, this type consists of small, bluish opacities in the lens cortex. - While congenital, it often has **minimal impact on vision** and is frequently observed incidentally. *Fusiform cataract* - This cataract forms in the shape of a **spindle or needle**, usually along the visual axis. - While it can sometimes cause minor visual compromise, its impact is generally **less severe** compared to a dense nuclear cataract.
Question 533: Bilateral ptosis is seen in all except which of the following?
- A. Trauma
- B. Hyperthyroidism (Graves' disease) (Correct Answer)
- C. Congenital
- D. Myotonic dystrophy
Explanation: ***Hyperthyroidism (Graves' disease)*** - **Hyperthyroidism** causes eyelid retraction, leading to a **stare** or **lid lag**, rather than **ptosis**. - **Graves' ophthalmopathy** can cause proptosis (bulging eyes) and conjunctival injection, but does not typically manifest as ptosis. *Congenital* - **Congenital ptosis** is often present at birth due to improper development of the **levator palpebrae superioris muscle**. - It can be **bilateral** and is usually isolated, without other systemic symptoms. *Trauma* - **Traumatic ptosis** can occur if the **levator muscle**, **aponeurosis**, or **third cranial nerve** is damaged. - This can be **bilateral** depending on the nature and extent of the head trauma. *Myotonic dystrophy* - **Myotonic dystrophy** is a **hereditary muscle disorder** characterized by progressive muscle weakness. - **Bilateral ptosis** is a very common early sign of **myotonic dystrophy**, often accompanied by **facial weakness** and **myotonia**.
Question 534: Most common malignant tumour of eyelid is ?
- A. Basal cell carcinoma (Correct Answer)
- B. Malignant melanoma
- C. Squamous cell carcinoma
- D. Sebaceous gland carcinoma
Explanation: ***Basal cell carcinoma*** - **Basal cell carcinoma (BCC)** accounts for approximately 85-95% of all eyelid malignancies, making it the most common type. - It often presents as a **pearly nodule** with telangiectatic vessels, frequently affecting the lower eyelid. *Squamous cell carcinoma* - **Squamous cell carcinoma (SCC)** is the second most common eyelid malignancy, but it is significantly less frequent (5-10%) than BCC. - SCC has a **higher metastatic potential** compared to BCC. *Malignant melanoma* - **Malignant melanoma** is a rare but highly aggressive eyelid tumor, accounting for less than 1% of all eyelid malignancies. - It is characterized by its **pigmented appearance** and rapid growth pattern. *Sebaceous gland carcinoma* - **Sebaceous gland carcinoma** is a relatively uncommon, but aggressive, tumor of the eyelid, comprising about 1-5% of cases. - It often mimics benign lesions like a **chalazion** or chronic blepharitis, leading to delayed diagnosis.
Question 535: In which condition is the swinging light test positive?
- A. Conjunctivitis
- B. Glaucoma
- C. Keratoconus
- D. Optic neuritis (Correct Answer)
Explanation: ***Optic neuritis*** - The swinging light test (also known as the **Marcus Gunn pupil** or relative afferent pupillary defect, RAPD) is positive when there is a significant **asymmetry in the afferent visual pathway** between the two eyes. - In optic neuritis, the **optic nerve** is inflamed and demyelinated, impairing the transmission of light signals to the brain, which leads to a paradoxical pupillary dilation when the light is swung from the unaffected to the affected eye. *Conjunctivitis* - This is an **inflammation of the conjunctiva**, the membrane lining the eyelid and sclera, which primarily affects the ocular surface. - It does not involve the optic nerve or afferent pupillary pathways, so the swinging light test would be **negative**. *Glaucoma* - Glaucoma is a condition characterized by **progressive optic nerve damage**, often associated with elevated intraocular pressure, leading to peripheral vision loss. - While it causes optic neuropathy, a positive swinging light test is typically seen only in **severe, asymmetric cases** and is not its primary diagnostic feature. *Keratoconus* - This is a non-inflammatory eye condition in which the normally round dome-shaped cornea **thins and bulges outward into a cone-like shape**. - It affects the **cornea's shape and vision quality**, but not the optic nerve or the afferent pupillary reflex pathway, thus the swinging light test would be negative.
Pharmacology
1 questionsWhich of the following medications does not interact with warfarin?
NEET-PG 2012 - Pharmacology NEET-PG Practice Questions and MCQs
Question 531: Which of the following medications does not interact with warfarin?
- A. Barbiturate
- B. Oral contraceptive
- C. Cephalosporins
- D. Benzodiazepines (Correct Answer)
Explanation: ***Benzodiazepines*** - **Benzodiazepines** are generally considered safe to use with warfarin as they are extensively metabolized in the liver, but they do not typically alter the **cytochrome P450 enzymes** responsible for warfarin metabolism. - They also do not interfere with **vitamin K recycling** or **platelet function**, which are key mechanisms through which other drugs interact with warfarin. *Barbiturate* - **Barbiturates** are **potent inducers of hepatic enzymes**, particularly CYP2C9, which is responsible for metabolizing warfarin. - This enzyme induction leads to **increased warfarin metabolism**, reducing its anticoagulant effect and necessitating higher warfarin doses. *Oral contraceptive* - **Oral contraceptives** can **reduce the anticoagulant effect of warfarin** by inducing clotting factors or inhibiting warfarin metabolism. - This interaction can increase the risk of **thromboembolic events** in patients on warfarin. *Cephalosporins* - Certain **cephalosporins**, especially those with a **methylthiotetrazole (MTT) side chain** (e.g., Cefamandole, Cefoperazone, Moxalactam), can **inhibit vitamin K epoxide reductase**. - This inhibition leads to a **decrease in vitamin K-dependent clotting factors**, thus potentiating the anticoagulant effect of warfarin and increasing bleeding risk.