Biochemistry
1 questionsWhich vitamin deficiency is associated with night blindness?
NEET-PG 2018 - Biochemistry NEET-PG Practice Questions and MCQs
Question 51: Which vitamin deficiency is associated with night blindness?
- A. Biotin
- B. Vit. A (Correct Answer)
- C. Thiamine
- D. Riboflavin
Explanation: ***Vitamin A*** - **Vitamin A deficiency is THE classic cause of night blindness (nyctalopia)**, one of the earliest signs of deficiency - Vitamin A is essential for synthesis of **rhodopsin**, the photopigment in retinal rod cells responsible for vision in dim light - Deficiency leads to impaired dark adaptation and progressive loss of night vision - Other manifestations include **xerophthalmia, Bitot's spots, and keratomalacia** - This is a high-yield fact for NEET-PG examinations *Riboflavin (Vitamin B2)* - Riboflavin deficiency causes **oral-ocular-genital syndrome** - Clinical features include **angular stomatitis, cheilosis, glossitis, seborrheic dermatitis** - Eye manifestations include **corneal vascularization and photophobia**, NOT night blindness - Does NOT cause night blindness as a primary symptom *Thiamine (Vitamin B1)* - Thiamine deficiency causes **Beriberi** (wet and dry forms) and **Wernicke-Korsakoff syndrome** - Characterized by peripheral neuropathy, cardiac dysfunction, and CNS manifestations - Does NOT cause night blindness *Biotin (Vitamin B7)* - Biotin deficiency is rare and causes **dermatitis, alopecia, conjunctivitis** - Also causes neurological symptoms in severe deficiency - Does NOT cause night blindness
Community Medicine
1 questionsAccording to WHO classification, severe thinness is defined as a BMI below which value?
NEET-PG 2018 - Community Medicine NEET-PG Practice Questions and MCQs
Question 51: According to WHO classification, severe thinness is defined as a BMI below which value?
- A. 18
- B. 14
- C. < 16 (Correct Answer)
- D. 13
Explanation: ***Correct: < 16 kg/m²*** - The WHO classifies **BMI < 16 kg/m²** as **severe thinness (Grade 3 thinness)** - This represents critically low body weight with significant health risks - Values like 12, 13, 14, or 15 all fall into this severe thinness category *18* - BMI **18.5-24.9 kg/m²** is classified as **normal/healthy weight** by WHO - BMI **17.0-18.49 kg/m²** is classified as **mild thinness (Grade 1)** - 18 is not the threshold for severe thinness *14* - 14 kg/m² is **an example of a value** that falls within severe thinness - However, the question asks for the **threshold/cutoff value**, which is **16 kg/m²** - Any BMI below 16 (including 14, 13, 12) indicates severe thinness *13* - Like option 14, this is **a value within** the severe thinness range - The **defining threshold** is **< 16 kg/m²**, not 13 - The question asks for the classification cutoff, not an example value within the range
Internal Medicine
1 questionsWhich of the following is a cause of hypokalemic metabolic alkalosis with hypertension?
NEET-PG 2018 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 51: Which of the following is a cause of hypokalemic metabolic alkalosis with hypertension?
- A. Liddle syndrome (Correct Answer)
- B. Bartter syndrome
- C. Gitelman syndrome
- D. Renal tubular acidosis
Explanation: ***Liddle syndrome*** - It is an **autosomal dominant** disorder characterized by a mutation in the **ENaC channel**, leading to increased sodium reabsorption and potassium excretion, thus causing **hypokalemia**, **metabolic alkalosis**, and **hypertension**. [1] - This condition mimics **primary hyperaldosteronism** but has **low plasma renin activity** and **low aldosterone levels**. [1] *Bartter syndrome* - This is a genetic disorder affecting the **Na-K-2Cl cotransporter** in the **thick ascending limb** of the loop of Henle, leading to **salt wasting** and compensatory **renin-angiotensin-aldosterone system activation**. - It presents with **hypokalemia**, **metabolic alkalosis**, but typically with **normal or low blood pressure**, not hypertension. *Gitelman syndrome* - This is an autosomal recessive disorder affecting the **thiazide-sensitive Na-Cl cotransporter** in the **distal convoluted tubule**. - It causes **hypokalemic metabolic alkalosis**, hypomagnesemia, and hypocalciuria, but patients are typically **normotensive** or **hypotensive**, distinguishing it from Liddle syndrome. *Renal tubular acidosis* - This is a group of disorders characterized by the **kidneys' inability to excrete acid** or **reabsorb bicarbonate**, leading to **metabolic acidosis**. [2] - While it can cause electrolyte abnormalities, hypokalemia is a feature of certain types (e.g., RTA type 1 and 2), but the defining feature is **metabolic acidosis**, not metabolic alkalosis, and it is not typically associated with hypertension from the primary tubular defect. [2]
Microbiology
2 questionsWhich organism is the most common cause of acute bacterial prostatitis?
Acute Hemorrhagic Conjunctivitis is primarily caused by which type of Enterovirus?
NEET-PG 2018 - Microbiology NEET-PG Practice Questions and MCQs
Question 51: Which organism is the most common cause of acute bacterial prostatitis?
- A. Enterococcus
- B. Streptococcus viridans
- C. Peptostreptococcus
- D. E.coli (Correct Answer)
Explanation: ***E.coli*** - **E.coli** is the most common cause of **acute bacterial prostatitis**, accounting for a significant majority of cases. - It is a **gram-negative rod** commonly found in the gastrointestinal tract and can ascend into the urinary tract and prostate. *Enterococcus* - While **Enterococcus species** can cause urinary tract infections and, less commonly, prostatitis, they are a distant second to E.coli in frequency. - They are **gram-positive cocci** and are often associated with catheter-associated infections or healthcare-acquired infections. *Streptococcus viridans* - **Streptococcus viridans** group bacteria are typically commensals of the oral cavity and are more known for causing **endocarditis** or dental infections. - They are not a common cause of acute bacterial prostatitis. *Peptostreptococcus* - **Peptostreptococcus** is a genus of **anaerobic gram-positive cocci** commonly found in the normal flora of the mouth, gastrointestinal tract, and vagina. - They are typically involved in **polymicrobial anaerobic infections** but are not a primary or common cause of acute bacterial prostatitis.
Question 52: Acute Hemorrhagic Conjunctivitis is primarily caused by which type of Enterovirus?
- A. Enterovirus type 68
- B. Enterovirus type 69
- C. Enterovirus type 70 (Correct Answer)
- D. Enterovirus type 71
Explanation: ***Enterovirus type 70*** - **Enterovirus type 70** is the most common cause of **Acute Hemorrhagic Conjunctivitis (AHC)**, particularly in epidemic outbreaks. - AHC presents with rapid onset of **ocular pain**, **redness**, **swelling**, and **subconjunctival hemorrhages**. *Enterovirus type 68* - **Enterovirus D68 (EV-D68)** is primarily known for causing **respiratory illnesses**, ranging from mild to severe, and is associated with acute flaccid myelitis. - While it can cause respiratory symptoms, it is not a primary cause of **Acute Hemorrhagic Conjunctivitis**. *Enterovirus type 69* - **Enterovirus type 69** is a rare serotype and is not typically associated with specific human diseases or large-scale outbreaks. - Unlike EV70, it is not recognized as a significant cause of **conjunctivitis**. *Enterovirus type 71* - **Enterovirus A71 (EV-A71)** is a common cause of **hand, foot, and mouth disease (HFMD)**, especially in children, and can also lead to severe neurological complications. - While it causes various infections, it is not the primary cause of **hemorrhagic conjunctivitis**.
Obstetrics and Gynecology
3 questionsWhich of the following is not a high-risk pregnancy?
Best time to perform the quadruple test is:
What are the effects of Progesterone-only pills?
NEET-PG 2018 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 51: Which of the following is not a high-risk pregnancy?
- A. Age 25-30 years (Correct Answer)
- B. Diabetes mellitus
- C. Previous history of manual removal of placenta
- D. Anemia
Explanation: ***Age 25-30 years*** - An age of **25-30 years** is generally considered the optimal reproductive age range, and pregnancies within this bracket are typically classified as low-risk based on age alone. - This age range carries the lowest statistical risk for both maternal and fetal complications, assuming no other co-morbidities. *Previous history of manual removal of placenta* - A previous history of manual removal of the placenta indicates a risk factor for **recurrent placental retention** or **morbidly adherent placenta** in future pregnancies, making it a high-risk factor. - This history suggests an increased likelihood of complications such as **postpartum hemorrhage** and can influence the management of subsequent deliveries. *Anemia* - **Anemia** in pregnancy, especially severe iron deficiency anemia, is considered a high-risk factor due to increased maternal and fetal morbidity. - It can lead to complications such as **preterm delivery**, **low birth weight**, and difficulties tolerating blood loss during delivery. *Diabetes mellitus* - **Diabetes mellitus**, whether pre-existing or gestational, makes a pregnancy high-risk due to potential adverse effects on both the mother and the fetus. - Risks include **preeclampsia**, **macrosomia**, **neonatal hypoglycemia**, and **congenital anomalies**.
Question 52: Best time to perform the quadruple test is:
- A. 8-12 weeks
- B. 11-15 weeks
- C. 15-20 weeks (Correct Answer)
- D. 18-22 weeks
Explanation: ***15-20 weeks*** - The quadruple test measures levels of four substances (**alpha-fetoprotein**, **human chorionic gonadotropin**, **unconjugated estriol**, and **inhibin A**) in the mother's blood. - This window is optimal for detecting neural tube defects and chromosomal abnormalities like **Down syndrome** and **Trisomy 18**, allowing for timely counseling and further diagnostic testing if needed. *8-12 weeks* - This period is generally too early for the quadruple test to be accurate, as the levels of the markers would not be sufficiently distinct for reliable screening. - The **combined first-trimester screening** (nuchal translucency and blood tests for PAPP-A and hCG) is typically performed during this time. *11-15 weeks* - While some components might be detectable at the later end of this range, 15-20 weeks offers a more accurate window for all four markers of the quadruple test. - **Integrated screening**, which combines first and second-trimester markers, would involve blood draws around 10-14 weeks and then 15-20 weeks. *18-22 weeks* - This period is generally considered too late for optimal results of the quadruple test, as the fetal markers might be less indicative or diagnostic interventions options might be limited. - A **detailed ultrasound** for anatomical survey is usually performed around this time.
Question 53: What are the effects of Progesterone-only pills?
- A. All of the options may occur (Correct Answer)
- B. May suppress ovulation
- C. Thins the lining of the uterus
- D. Thickens cervical mucus
Explanation: ***All of the options may occur*** - Progesterone-only pills (POPs) work through **multiple complementary mechanisms** that collectively provide effective contraception. - All three effects occur simultaneously and contribute to the overall contraceptive efficacy of POPs. - Understanding these mechanisms helps explain why POPs are effective despite lower hormone doses compared to combined oral contraceptives. **Mechanism 1: May suppress ovulation** - POPs can **partially suppress ovulation**, preventing the release of an egg. - Traditional POPs suppress ovulation in approximately 40-60% of cycles, while newer desogestrel-containing POPs achieve higher rates (97-99%). - This effect depends on the dose and type of progestin used in the formulation. **Mechanism 2: Thins the lining of the uterus** - Progesterone causes **endometrial atrophy**, making the uterine lining thin and unsuitable for embryo implantation. - This hostile uterine environment acts as a backup contraceptive mechanism if ovulation and fertilization occur. - Endometrial changes occur consistently with POP use. **Mechanism 3: Thickens cervical mucus** - This is the **primary and most consistent mechanism** of POPs. - Progesterone significantly **increases cervical mucus viscosity** and reduces its quantity within hours of administration. - The thickened mucus creates a physical barrier that prevents sperm penetration, motility, and viability.
Pathology
1 questionsIn which type of Hodgkin's lymphoma are classical Reed-Sternberg cells most characteristically observed?
NEET-PG 2018 - Pathology NEET-PG Practice Questions and MCQs
Question 51: In which type of Hodgkin's lymphoma are classical Reed-Sternberg cells most characteristically observed?
- A. Lymphocyte depleted
- B. Nodular sclerosis
- C. Lymphocyte predominance
- D. Mixed cellularity Hodgkin (Correct Answer)
Explanation: ***Lymphocyte predominance*** - The **Hodgkin's lymphoma (HL) lymphocyte predominance** variant characteristically displays a predominance of lymphocytes in the cellular makeup [1]. - This subtype is often associated with a better prognosis and fewer symptoms than other types of HL [1]. *Lymphocyte depleted* - This subtype features a significant decrease in lymphocytes, leading to a **higher proportion of Reed-Sternberg cells** [3]. - It typically presents with a more aggressive clinical course, which contrasts with lymphocyte predominance [3]. *Mixed cellularity hodgkin* - Mixed cellularity shows a variety of cell types, including a significant number of **Reed-Sternberg cells**, but does not demonstrate **lymphocyte predominance** [2]. - This subtype is generally found in older patients and associated with advanced disease, unlike lymphocyte predominance [2]. *Nodular sclerosis* - Nodular sclerosis subtype is characterized by **collagen bands** and a particular architecture that is distinct from lymphocyte predominance [2]. - It primarily affects younger patients and can often involve mediastinal lymph nodes; however, it does not have the features of lymphocyte predominance [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 618. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 616-618. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 559-560.
Physiology
1 questionsWhat is the physiological response of the kidney during shock?
NEET-PG 2018 - Physiology NEET-PG Practice Questions and MCQs
Question 51: What is the physiological response of the kidney during shock?
- A. GFR decreases
- B. Perfusion of kidney decreases
- C. Afferent arteriole resistance increases
- D. Renal blood flow decreases (Correct Answer)
Explanation: ***Renal blood flow decreases*** - During shock, the **primary and most fundamental** physiological change affecting the kidney is a marked **reduction in renal blood flow (RBF)**. - Shock triggers intense **sympathetic activation** and **renin-angiotensin system (RAS) activation**, causing preferential **vasoconstriction** of renal vessels to redirect blood to vital organs (brain, heart). - RBF can drop to as low as **20-30% of normal** in severe shock, making this the hallmark renal response. - This reduction in RBF is the **upstream event** that triggers all other renal changes during shock. *Perfusion of kidney decreases* - While technically correct, "decreased perfusion" is **essentially synonymous** with decreased blood flow in this context. - The term "renal blood flow" is the **standard physiological terminology** used in medical literature to describe this phenomenon, making it the more precise answer. *Afferent arteriole resistance increases* - This is a **mechanism** by which RBF decreases, not the overall response itself. - Increased afferent arteriolar resistance is **secondary** to sympathetic activation and angiotensin II effects during shock. - It describes the "how" rather than the "what" of the kidney's response. *GFR decreases* - GFR reduction is a **consequence** of decreased RBF and increased afferent arteriolar resistance. - While clinically important (oliguria/acute kidney injury), it's a **downstream effect** rather than the primary physiological response. - The relationship: ↓RBF → ↓Glomerular hydrostatic pressure → ↓GFR