NEET-PG 2013 Practice Questions

Q: Cystatin C levels are used for

Estimating GFR. ***Estimating GFR*** - **Cystatin C** is a **proteinase inhibitor** produced by all nucleated cells at a constant rate, and its level in the blood is inversely related to the **glomerular filtration rate (GFR)**. - Unlike **creatinine**, Cystatin C levels are less affected by **muscle mass, diet, or inflammation**, making it a more reliable marker for early and subtle changes in GFR, especially in certain populations. *Detecting UTI* - **Urinary tract infections (UTIs)** are primarily detected through **urinalysis** (presence of **leukocytes, nitrites**, and **bacteria**) and **urine culture**. - **Cystatin C** is a serum marker for renal function and has no direct role in detecting the presence of bacterial infection in the urinary tract. *Estimating difference between CRF and ARF* - Differentiating between **chronic renal failure (CRF)** and **acute renal failure (ARF)** typically involves assessing the **chronicity of symptoms**, trend in **creatinine levels**, and **kidney size** and **echogenicity** on ultrasound. - While Cystatin C can reflect current GFR, it doesn't inherently provide discriminatory power between acute and chronic processes without serial measurements or additional clinical context. *Screening for Renal Ca* - **Renal cell carcinoma (RCC)** screening is primarily done using **imaging techniques** like **ultrasonography, CT, or MRI**, especially in individuals with risk factors or symptoms like **hematuria**. - **Cystatin C** is a marker of kidney function and does not serve as a tumor marker for renal cancer.

Q: Mucoperichondrial flap in septoplasty is made on?

Septal cartilage. ***Septal cartilage*** - A mucoperichondrial flap is meticulously raised on the **septal cartilage** during septoplasty to access and correct deviations of the nasal septum. - This flap preserves the **perichondrium** and overlying mucosa, which is crucial for nutrient supply and healing of the septal cartilage. *Alar cartilage* - The alar cartilage forms the **lower lateral aspect** of the nose and is not involved in creating a mucoperichondrial flap for septal correction. - Procedures involving alar cartilage typically address **nasal tip projection** or alar rim deformities. *Maxillary spine* - The maxillary spine is a **bony prominence** at the anterior nasal floor and forms part of the underlying support for the septum. - While it can sometimes be a site of septal deviation, a mucoperichondrial flap is not primarily raised over the maxillary spine itself. *Sphenoid spine* - The sphenoid spine is a **bony projection** found on the sphenoid bone, located deep within the cranial base, posterior to the nasal cavity. - It is anatomically distant from the nasal septum and has no role in septoplasty or mucoperichondrial flap creation for septal surgical access.

Q: During functional endoscopic sinus surgery the position of the patient is

Reverse Trendelenburg. ***Reverse Trendelenburg*** - This position helps to reduce **venous congestion** in the surgical field, which is crucial for maintaining clear visibility during **functional endoscopic sinus surgery (FESS)**. - It minimizes **bleeding** by allowing gravity to drain blood away from the head and neck, improving surgical precision and safety. *Trendelenburg* - This position involves tilting the patient with the head lower than the feet, which would increase **venous pressure** in the head and neck. - Increased venous congestion would lead to significant **bleeding**, severely impairing visibility during FESS. *Lateral* - The lateral position is generally used for procedures involving the **side of the body**, such as kidney surgery or lung procedures. - It does not provide the optimal ergonomic access or venous drainage benefits required for **endoscopic sinus surgery**. *Lithotomy* - The lithotomy position is characterized by the patient lying on their back with hips and knees flexed and supported, primarily used for **pelvic or perineal procedures**. - This position is entirely inappropriate for **head and neck surgery** as it does not allow proper access to the sinus area.

Q: Which of the following is a sign of Bartter's syndrome?

Low potassium levels. ***Low potassium levels*** * Bartter's syndrome is characterized by **renal salt wasting** and subsequent volume depletion, which activates the **renin-angiotensin-aldosterone system** [1]. * This leads to increased aldosterone levels, causing increased potassium secretion in the collecting ducts, resulting in **hypokalemia** [2]. *High potassium levels* * **Hyperkalemia** is not a feature of Bartter's syndrome; instead, it is marked by persistent potassium loss [1]. * Conditions causing hyperkalemia typically involve impaired renal potassium excretion or increased potassium release from cells. *Acidic blood* * Bartter's syndrome usually presents with **metabolic alkalosis** due to hydrogen ion loss in the urine, not acidic blood [2]. * Acidic blood (**acidemia**) would imply a state of respiratory or metabolic acidosis. *High sodium levels* * Bartter's syndrome primarily involves **renal salt wasting**, leading to **normal or low sodium levels** rather than high sodium levels. * High sodium levels (**hypernatremia**) are usually due to inadequate water intake or excessive water loss.

Q: What is the primary brain region associated with ocular bobbing?

Pons. Pons - **Ocular bobbing** is a characteristic eye movement disorder strongly associated with **pontine lesions**, particularly infarctions or hemorrhages affecting the tegmentum. - The pons contains critical connections for vertical gaze control within the **brainstem**, and damage here disrupts these pathways [1]. *Midbrain* - While important for eye movements, particularly **vertical gaze centers**, injuries to the midbrain typically cause disorders like Parinaud syndrome (upgaze palsy), not classic ocular bobbing. - Midbrain lesions might cause other types of nystagmus or gaze palsies but not generally the rapid downward and slow upward movement seen in bobbing. *Medulla* - The medulla primarily controls vital functions like breathing and heart rate, as well as some ocular reflexes, but is less directly involved in the generation of sustained vertical eye movements. - Damage to the medulla is more likely to cause effects like **nystagmus** (e.g., downbeat nystagmus in some cases) or other brainstem signs, rather than ocular bobbing. *Cerebral cortex* - The cerebral cortex is responsible for voluntary eye movements and integration of visual information, but it does not directly generate or control the brainstem reflexes associated with ocular bobbing [1]. - Lesions in the cortex would typically manifest as **gaze preference**, apraxia, or other higher-level visual processing deficits, not involuntary brainstem driven eye movements like bobbing.

Q: XDR-TB is defined as resistance to which of the following drug combinations?

Fluoroquinolones plus INH plus rifampicin plus amikacin. **Fluoroquinolones plus INH plus rifampicin plus amikacin** - **Extensively drug-resistant tuberculosis (XDR-TB)** is defined by resistance to the most effective anti-TB drugs: **isoniazid (INH)**, **rifampicin**, any **fluoroquinolone**, and at least one of the three injectable second-line drugs (**amikacin**, **kanamycin**, or **capreomycin**). - This combination signifies a substantial therapeutic challenge due to limited treatment options and a high risk of treatment failure. *INH plus rifampicin* - Resistance to **INH** and **rifampicin** defines **multidrug-resistant tuberculosis (MDR-TB)**, which is a precursor to XDR-TB but not XDR-TB itself. - While serious, MDR-TB is not as extensively resistant as XDR-TB, as it doesn't include resistance to fluoroquinolones and second-line injectables. *Fluoroquinolones plus INH plus amikacin* - This combination is incomplete for the definition of XDR-TB because it omits **rifampicin** from the core definition. - XDR-TB specifically requires resistance to both **INH** and **rifampicin** (defining MDR-TB), in addition to resistance to a fluoroquinolone and one of the injectable second-line drugs. *Fluoroquinolones plus rifampicin plus kanamycin* - This combination is also incomplete for the definition of XDR-TB as it omits **isoniazid (INH)**, which is one of the two most crucial first-line drugs that characterize MDR-TB. - XDR-TB builds upon MDR-TB's resistance to both INH and rifampicin.

Q: Which of the following conditions is associated with ectopia lentis?

Homocystinuria. ***Homocystinuria*** - **Ectopia lentis** (lens dislocation) is a common and characteristic ocular manifestation of homocystinuria. - The lens typically dislocates **downward and inward**, differentiating it from Marfan syndrome. *Alport syndrome* - Characterized by **glomerulonephritis**, **sensorineural hearing loss**, and ocular abnormalities. - Ocular manifestations include **anterior lenticonus** (which can be mistaken for ectopia lentis in some descriptions), posterior polymorphous corneal dystrophy, and retinal flecks, but not classic ectopia lentis. *Lowe syndrome* - Also known as oculocerebrorenal syndrome of Lowe, it primarily affects the **eyes, brain, and kidneys**. - Ocular features include **congenital cataracts** and glaucoma, but not ectopia lentis. *Sulphite oxidase deficiency* - This is a rare metabolic disorder affecting the metabolism of sulfur-containing amino acids, leading to severe neurological symptoms. - While it can manifest with **cataracts** and **lens subluxation** in some cases, ectopia lentis is more characteristically associated with homocystinuria, and the overall clinical picture of sulphite oxidase deficiency is dominated by severe neurological impairment.

Q: What is the normal aqueous production rate in the human eye?

2 µl/min. ***2 µl/min*** - The ciliary body in the human eye continuously produces **aqueous humor** at a typical rate of approximately **2.0-3.0 µl/min**. - This rate is crucial for maintaining **intraocular pressure (IOP)** and providing nutrients to avascular eye structures like the **cornea** and **lens**. - This translates to approximately **3-4 ml per day** of aqueous humor production. *2 ml/min* - This rate is significantly **higher** than the actual production of aqueous humor, which is measured in microliters per minute. - Such a high production rate would lead to a rapid and severe increase in **intraocular pressure**, causing damage to the eye. *5 ml/min* - This value is an **excessively high** rate of fluid production and is not physiologically correct for aqueous humor. - It would result in unsustainable and damaging **intraocular pressure** levels. *5 µl/min* - While closer to the correct order of magnitude, **5 µl/min** is generally considered to be at the higher end or slightly above the average physiological range for aqueous humor production. - Most sources cite the normal range as being between **2-3 µl/min**.

Q: Which of the following is not a feature of hypothyroidism in infancy?

Premature closure of posterior fontanelle. ***Premature closure of posterior fontanelle*** - Delayed closure of fontanelles, particularly the **posterior fontanelle**, is a characteristic feature of **congenital hypothyroidism** due to impaired bone maturation. - Therefore, **premature closure** would be inconsistent with a diagnosis of hypothyroidism in infancy. *Coarse facies* - **Coarse facial features** such as a broad nasal bridge, puffy eyelids, and a protuberant tongue are common manifestations of **congenital hypothyroidism** due to the accumulation of glycosaminoglycans. - This is a direct consequence of the metabolic derangements caused by insufficient thyroid hormone. *Umbilical hernia* - An **umbilical hernia** is frequently observed in infants with hypothyroidism, resulting from generalized **hypotonia** and incomplete closure of the umbilical ring. - The reduced muscle tone characteristic of the condition contributes to this physical finding. *Constipation* - **Constipation** is a common gastrointestinal symptom in infants with hypothyroidism, caused by **decreased gut motility** secondary to reduced thyroid hormone levels. - This is a clinical indicator of the systemic metabolic slowing associated with the condition.

Q: In which condition is the Prehn sign typically positive?

Acute epididymitis. ***Acute epididymitis*** - **Prehn sign** is positive when lifting the scrotal sac alleviates pain, as it reduces pressure on the inflamed epididymis. - This sign is commonly used to differentiate **epididymitis** from **testicular torsion**, where pain typically worsens or remains unchanged with elevation. *Chronic epididymitis* - While potentially painful, **chronic epididymitis** usually presents with persistent, dull pain that is less likely to be acutely relieved by scrotal elevation. - The **Prehn sign** is primarily a diagnostic tool for **acute inflammatory conditions** of the epididymis. *Testicular torsion* - In **testicular torsion**, the pain is often sudden, severe, and typically **not relieved** by elevating the testicle; in fact, it may worsen. - This condition is a **surgical emergency** where blood flow to the testicle is compromised. *Acute scrotal pain due to other causes* - Other causes of **acute scrotal pain**, such as **trauma** or **incarcerated hernias**, generally do not exhibit a positive Prehn sign. - The **Prehn sign** is quite specific to the **inflammatory process** of epididymitis affecting pain perception.

Question 1

Cystatin C levels are used for

Accepted Answer

Estimating GFR

Answer

Detecting UTI

Answer

Screening for Renal Ca

Answer

Estimating difference between CRF and ARF

Question 2

Mucoperichondrial flap in septoplasty is made on?

Accepted Answer

Septal cartilage

Answer

Alar cartilage

Answer

Maxillary spine

Answer

Sphenoid spine

Question 3

During functional endoscopic sinus surgery the position of the patient is

Accepted Answer

Reverse Trendelenburg

Answer

Lateral

Answer

Lithotomy

Answer

Trendelenburg

Question 4

Which of the following is a sign of Bartter's syndrome?

Accepted Answer

Low potassium levels

Answer

High potassium levels

Answer

Acidic blood

Answer

High sodium levels

Question 5

What is the primary brain region associated with ocular bobbing?

Accepted Answer

Pons

Answer

Midbrain

Answer

Medulla

Answer

Cerebral cortex

Question 6

XDR-TB is defined as resistance to which of the following drug combinations?

Accepted Answer

Fluoroquinolones plus INH plus rifampicin plus amikacin

Answer

INH plus rifampicin

Answer

Fluoroquinolones plus INH plus amikacin

Answer

Fluoroquinolones plus rifampicin plus kanamycin

Question 7

Which of the following conditions is associated with ectopia lentis?

Accepted Answer

Homocystinuria

Answer

Alport syndrome

Answer

Lowe syndrome

Answer

Sulphite oxidase deficiency

Question 8

What is the normal aqueous production rate in the human eye?

Accepted Answer

2 µl/min

Answer

2 ml/min

Answer

5 ml/min

Answer

5 µl/min

Question 9

Which of the following is not a feature of hypothyroidism in infancy?

Accepted Answer

Premature closure of posterior fontanelle

Answer

Umbilical hernia

Answer

Constipation

Answer

Coarse facies

Question 10

In which condition is the Prehn sign typically positive?

Accepted Answer

Acute epididymitis

Answer

Chronic epididymitis

Answer

Testicular torsion

Answer

Acute scrotal pain due to other causes

NEET-PG 2013

Biochemistry

ENT

Internal Medicine

Microbiology

Ophthalmology

Pediatrics

Surgery