Biochemistry
2 questionsA patient complains of knee pain. Routine investigations are unremarkable and still, the patient is unsatisfied. Urine turns black on standing, what is the enzyme involved?
Vitamin B12 is found maximum in:
NEET-PG 2020 - Biochemistry NEET-PG Practice Questions and MCQs
Question 231: A patient complains of knee pain. Routine investigations are unremarkable and still, the patient is unsatisfied. Urine turns black on standing, what is the enzyme involved?
- A. Methylmalonyl-CoA mutase
- B. Homogentisate oxidase (Correct Answer)
- C. Xanthine oxidase
- D. Tyrosine hydroxylase
Explanation: ***Homogentisate oxidase*** - **Homogentisate oxidase** deficiency leads to **alkaptonuria**, where homogentisic acid accumulates and is excreted in urine, turning it black upon standing or exposure to air. The knee pain could be due to **ochronosis**, the deposition of oxidized homogentisic acid in cartilage and connective tissues. - The unremarkable routine investigations with persistent knee pain suggest a less common metabolic disorder, which is consistent with **alkaptonuria**'s chronic and insidious presentation. *Methylmalonyl-CoA mutase* - A deficiency in **methylmalonyl-CoA mutase** causes **methylmalonic acidemia**, a metabolic disorder typically presenting in infancy with neurological symptoms, feeding difficulties, and developmental delay. - It does not cause urine to turn black on standing or lead to specific joint pain like that seen in ochronosis. *Xanthine oxidase* - **Xanthine oxidase** is involved in purine metabolism, and its inhibition (e.g., by allopurinol) is used to treat **gout**. - While gout can cause knee pain, it is characterized by elevated uric acid and typically responds to conventional treatments and the urine does not turn black. *Tyrosine hydroxylase* - **Tyrosine hydroxylase** is the rate-limiting enzyme in catecholamine synthesis, converting tyrosine to L-DOPA. - Defects in this enzyme are rare and result in neurological disorders, such as **DOPA-responsive dystonia**, and do not cause urine to blacken or lead to direct joint damage.
Question 232: Vitamin B12 is found maximum in:
- A. Sunlight
- B. Green leafy vegetables
- C. Animal products (Correct Answer)
- D. Roots and tubers
Explanation: ***Animal products*** - **Vitamin B12**, or cobalamin, is primarily synthesized by bacteria and accumulates in animal tissues, making **meat, fish, poultry, eggs, and dairy** the richest dietary sources. - Humans generally cannot synthesize vitamin B12 and must obtain it from dietary sources, with **animal-derived foods** being the most concentrated and bioavailable forms. *Sunlight* - **Sunlight** is primarily critical for the synthesis of **Vitamin D** in the skin, not Vitamin B12. - Exposure to sunlight has no direct role in the production or absorption of **Vitamin B12**. *Green leafy vegetables* - **Green leafy vegetables** are excellent sources of nutrients like **folate, Vitamin K, and iron**, but they are generally devoid of naturally occurring **Vitamin B12**. - While some fortified plant-based foods may contain Vitamin B12, naturally, these vegetables do not provide it. *Roots and tubers* - **Roots and tubers** like potatoes, carrots, and sweet potatoes are good sources of carbohydrates, fiber, and various vitamins and minerals such as **Vitamin C and potassium**. - They do not contain significant amounts of **Vitamin B12**, as they are plant-based foods.
Community Medicine
1 questionsLiquid chemical waste is discarded in:
NEET-PG 2020 - Community Medicine NEET-PG Practice Questions and MCQs
Question 231: Liquid chemical waste is discarded in:
- A. Yellow bag (Correct Answer)
- B. Red bag
- C. White bag
- D. Blue bag
Explanation: ***Yellow bag*** - **Liquid chemical waste** including laboratory reagents, disinfectants, and expired chemicals must be segregated and collected in a **yellow bag or container** as per **Bio-Medical Waste Management Rules, 2016 (India)**. - Yellow bags are designated for **infectious and hazardous waste** including chemical waste, expired medicines, and anatomical waste. - This ensures proper handling through **incineration or chemical treatment** to prevent environmental contamination. *Red bag* - **Red bags** are used for **contaminated waste (recyclable)** including items contaminated with blood or body fluids that are not highly infectious. - This includes tubing, bottles, intravenous sets, and catheters that can be autoclaved and recycled. - Red bag waste undergoes **autoclaving/microwaving** followed by shredding before disposal. *White bag* - **White or translucent puncture-proof containers** are designated for **sharps waste** including needles, syringes, scalpels, and blades. - These containers prevent needlestick injuries and ensure safe handling of sharp objects. - Not suitable for liquid chemical waste which requires yellow bag disposal. *Blue bag* - **Blue/white puncture-proof containers** are used for **sharps including metallic body implants** and glassware that may cause injury. - In the Indian BMW system, blue and white containers serve similar purposes for sharps waste. - Not designated for liquid chemical waste, which belongs in yellow bags.
Internal Medicine
2 questionsA patient presented with weakness of the right side of the face. There is associated ipsilateral loss of pain and temperature of face and contralateral body. The lesion is most likely located at
A 26 year old female after her delivery develops features of headache, nausea, visual complaints, fatigue. What is the most probable diagnosis?
NEET-PG 2020 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 231: A patient presented with weakness of the right side of the face. There is associated ipsilateral loss of pain and temperature of face and contralateral body. The lesion is most likely located at
- A. Lateral medulla
- B. Medial pons
- C. Medial medulla
- D. Lateral pons (Correct Answer)
Explanation: ***Lateral pons*** - A lesion in the **lateral pons** would affect the **facial nerve nucleus** (VII) causing ipsilateral facial weakness. It would also damage the **spinal trigeminal nucleus** (V) leading to ipsilateral facial loss of pain and temperature [1]. - The involvement of the **spinothalamic tract** in the lateral pons would result in contralateral body loss of pain and temperature [1]. *Lateral medulla* - A lesion in the **lateral medulla** (Wallenberg syndrome) typically causes ipsilateral facial sensory loss (due to involvement of the spinal trigeminal nucleus), but would not affect the facial nerve nucleus directly to cause facial weakness [1]. - It also presents with **vertigo, nystagmus, ataxia**, and **dysphagia**, which are not mentioned in the patient's presentation. *Medial pons* - A lesion in the **medial pons** would primarily affect the **corticospinal tract** causing contralateral weakness and the **abducens nerve** (VI) causing ipsilateral gaze palsy, which are not described. - It would not typically involve the facial nerve directly to cause significant facial weakness or the spinal trigeminal nucleus for ipsilateral facial sensory loss. *Medial medulla* - A lesion in the **medial medulla** (Dejerine syndrome) usually affects the **pyramidal tract** causing contralateral hemiparesis and the **hypoglossal nerve** (XII) causing ipsilateral tongue deviation. - It does not explain the ipsilateral facial weakness or the ipsilateral facial loss of pain and temperature.
Question 232: A 26 year old female after her delivery develops features of headache, nausea, visual complaints, fatigue. What is the most probable diagnosis?
- A. Sheehan's syndrome (Correct Answer)
- B. Waterhouse-Friderichsen syndrome
- C. Hyperprolactinemia
- D. Pituitary adenoma
Explanation: ***Sheehan's syndrome*** - This syndrome is caused by **ischemic necrosis of the pituitary gland** due to severe postpartum hemorrhage or hypovolemic shock, leading to **pituitary dysfunction** [1]. - Symptoms like **headache, nausea, visual complaints, and fatigue** are consistent with panhypopituitarism developing after delivery, often presenting in the postpartum period due to the large, vulnerable pregnancy-enlarged pituitary [1]. *Waterhouse-Friderichsen syndrome* - This is a rare, life-threatening condition caused by overwhelming **bacterial infection (often meningococcal)**, leading to **adrenal gland hemorrhage** and acute adrenal insufficiency. - It presents with rapid onset of fever, petechial rash, hypotension, and shock, which are not described in the patient's symptoms. *Hyperprolactinemia* - While hyperprolactinemia can cause headaches and visual disturbances (if due to a pituitary tumor) [1], it typically presents with **galactorrhea**, **amenorrhea**, or **oligomenorrhea**, and is not directly linked to the postpartum period unless caused by a new or existing pituitary adenoma. - It does not account for the widespread pituitary failure implied by the patient's general fatigue and other symptoms after delivery, which is more characteristic of Sheehan's [2]. *Pituitary adenoma* - A pituitary adenoma can cause headaches, visual disturbances (due to **mass effect on the optic chiasm**) [1], and hormone deficiencies or excesses, but its onset is not specifically tied to the postpartum period like Sheehan's syndrome. - While it's a possibility for these symptoms, the history of recent delivery strongly points to Sheehan's syndrome over a newly symptomatic or pre-existing pituitary adenoma without specific features like galactorrhea or Cushing's symptoms that would hint at a specific type of adenoma.
Pediatrics
1 questionsA 5-year-old unvaccinated child presents to the OPD with fever, red eyes, and a maculopapular rash. What is the most likely complication associated with this condition?
NEET-PG 2020 - Pediatrics NEET-PG Practice Questions and MCQs
Question 231: A 5-year-old unvaccinated child presents to the OPD with fever, red eyes, and a maculopapular rash. What is the most likely complication associated with this condition?
- A. Acute myocarditis
- B. Acute nephritis
- C. Acute orchitis
- D. Pneumonia (Correct Answer)
Explanation: ***Pneumonia*** - **Pneumonia** is the **most common and most likely complication of measles**, occurring in approximately **1-6% of measles cases** - The clinical presentation of **fever, red eyes (conjunctivitis), and maculopapular rash** in an **unvaccinated child** is classic for **measles (rubeola)** - Pneumonia may be due to **direct viral pneumonitis** from measles virus or **secondary bacterial infection** (most commonly *Streptococcus pneumoniae*, *Staphylococcus aureus*, or *Haemophilus influenzae*) - It is a major cause of **measles-related mortality**, particularly in young children and immunocompromised individuals *Acute myocarditis* - **Acute myocarditis** is an extremely rare complication of measles - While myocardial involvement can theoretically occur with severe viral infections, it is **not a recognized characteristic or common complication** of measles - This is not the most likely complication when compared to pneumonia, otitis media, or diarrhea *Acute nephritis* - **Acute nephritis** is not a characteristic complication of measles - It is more commonly associated with **post-streptococcal glomerulonephritis** following Group A Streptococcus infection - Kidney involvement in measles is not a well-documented or common complication *Acute orchitis* - **Acute orchitis** is a recognized complication of **mumps** virus infection, particularly in post-pubertal males (occurring in 20-30% of infected males) - It is **not associated with measles infection** - This is a classic distractor testing knowledge of viral exanthems and their specific complications
Pharmacology
1 questionsWhich of the following drugs act by inhibiting DNA replication?
NEET-PG 2020 - Pharmacology NEET-PG Practice Questions and MCQs
Question 231: Which of the following drugs act by inhibiting DNA replication?
- A. Mitomycin C
- B. 6-Mercaptopurine (Correct Answer)
- C. Actinomycin D
- D. Asparaginase
Explanation: ***6-Mercaptopurine*** - This drug is a **purine analog** that acts as an **antimetabolite**, directly interfering with the **synthesis of purine nucleotides** required for DNA replication. - By inhibiting enzymes like **PRPP amidotransferase** and getting incorporated into DNA as a fraudulent nucleotide, it blocks the **de novo synthesis** pathway, preventing normal DNA replication. - This represents **direct inhibition of DNA synthesis** at the nucleotide building block level. *Mitomycin C* - This agent is an **alkylating agent** that **cross-links DNA** strands, causing DNA damage that prevents strand separation. - While it does prevent DNA replication, its mechanism is through **DNA damage and structural disruption** rather than inhibition of the DNA synthesis machinery itself. - It acts by damaging already-formed DNA rather than preventing new DNA synthesis. *Actinomycin D* - Actinomycin D is an **intercalating agent** that inserts itself between DNA base pairs, primarily **inhibiting RNA synthesis** by blocking RNA polymerase movement. - While it binds to DNA, its primary therapeutic action is on **transcription (RNA synthesis)**, not direct inhibition of DNA replication. *Asparaginase* - Asparaginase is an enzyme that **depletes asparagine** from the blood, which is an essential amino acid for certain cancer cells (e.g., leukemic cells). - Its mechanism is to starve cancer cells of asparagine, leading to **inhibition of protein synthesis**, not DNA replication.
Physiology
1 questionsSerum prolactin levels are highest
NEET-PG 2020 - Physiology NEET-PG Practice Questions and MCQs
Question 231: Serum prolactin levels are highest
- A. 24 hrs after parturition
- B. REM sleep
- C. In actively lactating mothers
- D. During third trimester of pregnancy (Correct Answer)
Explanation: ***Correct: During third trimester of pregnancy*** - **Serum prolactin levels reach their absolute highest** during the **third trimester of pregnancy**, rising progressively from normal levels (5-25 ng/mL) to peak values of **200-400 ng/mL** near term. - This represents the **highest physiological prolactin levels** observed in humans. - Despite these high levels, **lactation does not occur** during pregnancy because **estrogen and progesterone** block prolactin's action on mammary tissue. - The high prolactin prepares the breast for lactation but milk secretion is inhibited until delivery. *Incorrect: 24 hrs after parturition* - After delivery, prolactin levels actually begin to **decline** from their pregnancy peak, though they remain elevated (around 200 ng/mL). - While **lactogenesis II** (copious milk production) begins 24-72 hours postpartum, this is due to the **removal of estrogen/progesterone inhibition**, not because prolactin levels peak at this time. - The confusion arises from conflating **functional milk production** with **peak hormone levels**. *Incorrect: REM sleep* - Prolactin exhibits **circadian variation** with nocturnal rise during sleep, peaking in early morning hours. - However, these sleep-related peaks (typically 25-40 ng/mL) are **much lower** than pregnancy levels. - This physiological variation is unrelated to reproductive function. *Incorrect: In actively lactating mothers* - During established lactation, basal prolactin levels gradually decline over weeks to months. - Each **suckling episode** causes transient prolactin surges (2-10 fold increase), but these peaks are still **lower than third trimester levels**. - By 6 months postpartum, basal prolactin may return near pre-pregnancy levels despite continued lactation.
Radiology
2 questionsA radiograph is obtained from a child with scoliosis. What is the name of the angle used to measure spinal curvature?
Radiation Dose Monitoring in Occupational Workers is done by
NEET-PG 2020 - Radiology NEET-PG Practice Questions and MCQs
Question 231: A radiograph is obtained from a child with scoliosis. What is the name of the angle used to measure spinal curvature?
- A. Bohler's Angle
- B. Ferguson's Angle
- C. Cobb's Angle (Correct Answer)
- D. Pauwels' Angle
Explanation: **Cobb's Angle** - **Cobb's angle** is the primary method for measuring the severity of **scoliosis** on radiographs. - It is measured by drawing lines parallel to the superior endplate of the most tilted superior vertebra and the inferior endplate of the most tilted inferior vertebra of the curve; the angle between these two lines (or their perpendiculars) is the Cobb angle. *Bohler's Angle* - **Bohler's angle** is used in the assessment of **calcaneus fractures** and is measured on a lateral foot radiograph. - A decrease in this angle is indicative of a calcaneal fracture. *Ferguson's Angle* - **Ferguson's angle**, also known as the lumbosacral angle, measures the inclination of the sacrum relative to the horizontal in the standing position. - It is primarily used in the assessment of **spondylolisthesis** and other lumbosacral conditions. *Pauwels' Angle* - **Pauwels' angle** is used to classify **femoral neck fractures** based on the angle of the fracture line relative to the horizontal. - It helps determine the severity and stability of femoral neck fractures, guiding treatment decisions.
Question 232: Radiation Dose Monitoring in Occupational Workers is done by
- A. TLD Badge (Correct Answer)
- B. Collimators
- C. Grid
- D. Linear Accelerator
Explanation: ***TLD Badge (used for monitoring radiation exposure)*** - **Thermoluminescent Dosimeter (TLD) badges** are widely used for monitoring an individual's exposure to ionizing radiation over time. - They work by storing energy from radiation exposure and releasing it as **light when heated**, which is then measured to calculate the accumulated dose. *Collimators (used to shape radiation beams)* - **Collimators** are devices used in radiation therapy and diagnostic imaging to **restrict and shape the radiation beam**, ensuring it only targets the intended area. - They do not measure or monitor the dose received by an individual, but rather **control the spatial distribution** of the radiation. *Grid (used to reduce scatter in imaging)* - An **anti-scatter grid** is placed between the patient and the image receptor in radiography to **absorb scattered radiation**, which degrades image quality. - While essential for image quality, grids do not directly measure or monitor the radiation dose received by an occupational worker. *Linear Accelerator (used for delivering radiation therapy)* - A **linear accelerator (linac)** is a machine used to deliver **external beam radiation treatment** for cancer. - It generates high-energy X-rays or electrons, but it is a **source of radiation** for treatment, not a device for monitoring occupational exposure.