Biochemistry
1 questions3 beta hydroxysteroid dehydrogenase deficiency causes increased production of -
NEET-PG 2013 - Biochemistry NEET-PG Practice Questions and MCQs
Question 921: 3 beta hydroxysteroid dehydrogenase deficiency causes increased production of -
- A. DHEA (Correct Answer)
- B. Progesterone
- C. Deoxycortisol
- D. Estradiol
Explanation: ***DHEA*** - The enzyme **3 beta-hydroxysteroid dehydrogenase (3β-HSD)** is crucial for converting **delta-5 steroids (pregnenolone, 17-OH-pregnenolone, and DHEA)** into **delta-4 steroids (progesterone, 17-OH-progesterone, and androstenedione)**. - A **deficiency** in 3β-HSD leads to the accumulation of its substrates, particularly **DHEA (dehydroepiandrosterone)** and **17-OH-pregnenolone**, due to the impaired conversion in the steroid synthesis pathway. - Among the accumulated substrates, **DHEA** has weak androgenic activity, making it clinically significant in this enzyme deficiency. *Progesterone* - **Progesterone** is a delta-4 steroid, which is synthesized from **pregnenolone** via the action of **3β-HSD**. - A deficiency in this enzyme would **decrease** the production of progesterone, not increase it, as the enzyme is required for its synthesis. *Deoxycortisol* - **Deoxycortisol (11-deoxycortisol)** is a precursor to cortisol, formed later in the adrenal steroid synthesis pathway from **17-hydroxyprogesterone**. - Its production would be **decreased** by a 3β-HSD deficiency, as the pathway is blocked upstream, reducing the formation of downstream products like cortisol and its precursors. *Estradiol* - **Estradiol** is an estrogen, synthesized from androgens (like testosterone) via the enzyme **aromatase**. - A deficiency in 3β-HSD would impair the production of androgens like androstenedione and testosterone, which are precursors for estradiol, thereby leading to a **decrease** in estradiol levels, not an increase.
Internal Medicine
2 questionsWhich of the following conditions is associated with male pseudohermaphroditism?
Which of the following is NOT a feature of Refsum disease?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 921: Which of the following conditions is associated with male pseudohermaphroditism?
- A. 21-hydroxylase deficiency
- B. Androgen insensitivity syndrome
- C. 17-hydroxylase deficiency
- D. 5-alpha reductase deficiency (Correct Answer)
Explanation: ***5-alpha reductase deficiency*** - This deficiency prevents the conversion of **testosterone into dihydrotestosterone (DHT)**, which is essential for external male genitalia development. - Individuals with XY chromosomes are born with **ambiguous genitalia** that may appear female-like, leading to male pseudohermaphroditism. *21-hydroxylase deficiency* - This is the most common cause of **congenital adrenal hyperplasia (CAH)**, leading to overproduction of androgens. [1] - In XX individuals, it causes **virilization**, resulting in female pseudohermaphroditism, not male. [1] *17-hydroxylase deficiency* - This leads to impaired synthesis of **cortisol and sex steroids**, thus affecting adrenal and gonadal functions. [1] - XY individuals with this deficiency typically present with **female external genitalia** due to a lack of androgens, but it's a different mechanism than 5-alpha reductase deficiency. [1] *Androgen insensitivity syndrome* - In this condition, individuals with XY chromosomes have **non-functional androgen receptors**, making their bodies unable to respond to testosterone. [1] - They develop **female external genitalia** despite having testes and usually present as phenotypic females. [1]
Question 922: Which of the following is NOT a feature of Refsum disease?
- A. Retinitis pigmentosa
- B. Ataxia
- C. CCF (Correct Answer)
- D. Ichthyosis
Explanation: ***CCF*** - **Congestive cardiac failure (CCF)** is generally **not a primary feature** or common complication of Refsum disease. While some cardiac abnormalities can occur, severe CCF is rare. - Refsum disease is characterized by the accumulation of **phytanic acid**, which primarily affects the nervous system, skin, and eyes. *Ataxia* - **Cerebellar ataxia** is a very common and prominent neurological symptom in Refsum disease, due to damage to the cerebellum. - Patients often present with **unsteady gait and poor coordination**. *Ichthyosis* - **Ichthyosis** (dry, scaly skin) is a characteristic dermatological manifestation of Refsum disease, occurring in nearly all patients. - It is caused by the disruption of **lipid metabolism** in the skin due to phytanic acid accumulation. *Retinitis pigmentosa* - **Retinitis pigmentosa** is one of the classic ocular features of Refsum disease, leading to **night blindness** and progressive **visual field loss**. - It involves the degeneration of photoreceptor cells in the retina.
Obstetrics and Gynecology
2 questions34 week primigravida punjabi khatri comes with history of consanguineous marriage, with history of repeated blood transfusion to her sibling since 8 months of age. The first diagnostic test is -
Which of the following methods is used for prenatal diagnosis of Down Syndrome?
NEET-PG 2013 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 921: 34 week primigravida punjabi khatri comes with history of consanguineous marriage, with history of repeated blood transfusion to her sibling since 8 months of age. The first diagnostic test is -
- A. HPLC
- B. Bone marrow
- C. Blood smear
- D. Hb electrophoresis (Correct Answer)
Explanation: ***Hb electrophoresis*** - The patient's history of **consanguineous marriage**, a sibling requiring **repeated blood transfusions** since 8 months of age, and Punjabi Khatri ethnicity strongly suggest a **hemoglobinopathy**, likely **beta-thalassemia major or intermedia**. - **Hemoglobin electrophoresis** is the traditional gold standard for definitive diagnosis of various hemoglobin variants and thalassemia types, identifying and characterizing abnormal hemoglobin patterns (e.g., elevated HbF, HbA2). - It remains a primary diagnostic test for hemoglobinopathies, particularly useful for pattern recognition of various thalassemia syndromes. *HPLC* - **High-performance liquid chromatography (HPLC)** is an equally valid and increasingly preferred method for diagnosing hemoglobinopathies, offering automated, precise quantification of hemoglobin fractions (HbA, HbA2, HbF). - In modern practice, HPLC is often used as a first-line screening tool due to its accuracy, reproducibility, and ability to provide quantitative data crucial for thalassemia diagnosis. - Both HPLC and Hb electrophoresis are acceptable diagnostic approaches; the choice between them depends on laboratory availability and practice patterns. For this 2013 exam, Hb electrophoresis was considered the traditional first diagnostic test. *Blood smear* - A **peripheral blood smear** would show morphological changes like **microcytic hypochromic red blood cells**, **target cells**, **anisopoikilocytosis**, and **nucleated RBCs**, which are suggestive of thalassemia. - These findings are indicative but non-specific and require confirmatory tests like hemoglobin electrophoresis or HPLC to identify the specific hemoglobin disorder and establish a definitive diagnosis. *Bone marrow* - A **bone marrow** examination would show **erythroid hyperplasia** due to increased ineffective erythropoiesis in thalassemia but is an invasive procedure and not the initial diagnostic test for hemoglobinopathies. - It provides details about cellularity and maturation but does not directly identify hemoglobin abnormalities, making it unsuitable as the first diagnostic step in suspected hemoglobinopathies.
Question 922: Which of the following methods is used for prenatal diagnosis of Down Syndrome?
- A. Karyotyping for chromosomal analysis (Correct Answer)
- B. Non-invasive prenatal testing (NIPT) for cell-free DNA analysis
- C. Triple test for biomarker screening
- D. Fetal ultrasonography for physical feature assessment
Explanation: ***Karyotyping for chromosomal analysis*** - **Karyotyping** is the gold standard definitive diagnostic method for Down syndrome (trisomy 21) as it directly visualizes and counts all chromosomes, identifying the presence of an extra copy of chromosome 21. - This cytogenetic method provides a clear genetic diagnosis with 100% accuracy, confirming the chromosomal abnormality responsible for Down syndrome. - Karyotyping can be performed on cells obtained via amniocentesis or chorionic villus sampling (CVS). *Triple test for biomarker screening* - The **triple test** measures biochemical markers (alpha-fetoprotein, unconjugated estriol, and hCG) to assess the risk of Down syndrome, but it is a **screening tool**, not a diagnostic method. - It has a detection rate of approximately 69% with a 5% false-positive rate. - Abnormal results require confirmatory diagnostic testing with karyotyping or other chromosomal analysis methods. *Fetal ultrasonography for physical feature assessment* - Fetal ultrasonography can detect **soft markers** such as increased nuchal translucency, absent/hypoplastic nasal bone, echogenic intracardiac focus, or structural anomalies that raise suspicion for Down syndrome. - However, ultrasound findings are **not diagnostic** on their own and have limited sensitivity and specificity. - Positive findings necessitate genetic testing like karyotyping for definitive diagnosis. *Non-invasive prenatal testing (NIPT) for cell-free DNA analysis* - **NIPT** analyzes cell-free fetal DNA in maternal blood and has high sensitivity (>99%) and specificity (>99%) for detecting trisomy 21. - Despite its excellent screening performance, NIPT is still classified as a **screening test**, not a diagnostic test. - Positive NIPT results require confirmation with diagnostic testing (karyotyping) before making clinical decisions regarding the pregnancy.
Pediatrics
2 questionsOn USG, a mass was found in the abdomen which was displacing the kidney laterally in a 1-year-old child. What is the most likely diagnosis?
Which of the following is not a feature of hypothyroidism in infancy?
NEET-PG 2013 - Pediatrics NEET-PG Practice Questions and MCQs
Question 921: On USG, a mass was found in the abdomen which was displacing the kidney laterally in a 1-year-old child. What is the most likely diagnosis?
- A. Neuroblastoma (Correct Answer)
- B. Wilms' tumor
- C. Renal cell carcinoma
- D. All of the options
Explanation: ***Neuroblastoma*** - A retroperitoneal mass displacing the kidney laterally in an infant is highly characteristic of **neuroblastoma**, which originates from neural crest cells in the adrenal gland or sympathetic ganglia. - The key finding is **extrarenal origin** - the mass pushes the kidney aside rather than arising from within it. - Most common extrarenal abdominal mass in children under 2 years. *Wilms' tumor* - This is an **intrarenal mass** that originates within the kidney parenchyma. - Wilms' tumor **expands and distorts the kidney** rather than displacing it laterally from outside. - Most common renal tumor in children (peak age 3-4 years), presenting with abdominal mass, hematuria, and hypertension. *Renal cell carcinoma* - Exceedingly **rare in a 1-year-old child** - primarily an adult malignancy (typically >40 years). - Would be an intrarenal mass, not an extrarenal mass displacing the kidney laterally. *All of the options* - Incorrect because the specific imaging finding of **lateral kidney displacement** indicates an extrarenal origin, which is pathognomonic for neuroblastoma, not the intrarenal tumors listed.
Question 922: Which of the following is not a feature of hypothyroidism in infancy?
- A. Umbilical hernia
- B. Constipation
- C. Coarse facies
- D. Premature closure of posterior fontanelle (Correct Answer)
Explanation: ***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.
Psychiatry
1 questionsIn which condition is the presence of an extra pair of ribs sometimes observed?
NEET-PG 2013 - Psychiatry NEET-PG Practice Questions and MCQs
Question 921: In which condition is the presence of an extra pair of ribs sometimes observed?
- A. Down syndrome
- B. Turner syndrome (Correct Answer)
- C. Holt-Oram syndrome
- D. Fibrous dysplasia
- E. Klinefelter syndrome
Explanation: ***Turner syndrome*** - **Turner syndrome** (45,X) is often associated with skeletal abnormalities, including an extra pair of ribs (cervical ribs) in some cases. - Other common skeletal features include **short stature**, a **shield chest**, and **cubitus valgus**. *Down syndrome* - **Down syndrome** (trisomy 21) is characterized by specific facial features, intellectual disability, and congenital heart defects. - While it can manifest with various skeletal anomalies, an extra pair of ribs is not a characteristic feature. *Klinefelter syndrome* - **Klinefelter syndrome** (47,XXY) is characterized by hypogonadism, tall stature, gynecomastia, and learning difficulties. - Skeletal features may include long limbs and decreased bone density, but cervical ribs are not typically associated with this condition. *Holt-Oram syndrome* - **Holt-Oram syndrome** is a genetic disorder affecting heart and limb development, specifically the upper limbs (thumb abnormalities, phocomelia). - It does not typically involve the presence of an extra pair of ribs. *Fibrous dysplasia* - **Fibrous dysplasia** is a bone disorder where normal bone is replaced by fibrous tissue, leading to weakened bone and fractures. - It is a localized bone condition and does not involve the presence of supernumerary ribs.
Surgery
2 questionsIn which one of the following conditions is gas under the diaphragm typically seen?
Which of the following statements about Grisel syndrome is false?
NEET-PG 2013 - Surgery NEET-PG Practice Questions and MCQs
Question 921: In which one of the following conditions is gas under the diaphragm typically seen?
- A. Perforated duodenal ulcer (Correct Answer)
- B. Typhoid perforation
- C. After laparotomy
- D. Spontaneous rupture of oesophagus
Explanation: ***Perforated duodenal ulcer*** - A perforated duodenal ulcer creates a communication between the **lumen of the duodenum and the peritoneal cavity**, allowing air from the gastrointestinal tract to escape. - This free air, being lighter, rises and collects under the **diaphragm**, visible as **pneumoperitoneum** on an upright chest X-ray. - This is the **classic and most typical** presentation taught in medical education for gas under the diaphragm. - Occurs in approximately **70-75% of cases** of peptic ulcer perforation. *Typhoid perforation* - Typhoid perforation (typically affecting the **terminal ileum**) also causes pneumoperitoneum and can show gas under the diaphragm. - However, it is **less commonly encountered** in routine practice compared to peptic ulcer perforation in most settings. - The question asks for the **"typically seen"** condition, which refers to the classic teaching example: perforated duodenal ulcer. *After laparotomy* - It is normal to see a small amount of **residual intra-abdominal gas** for a few days to a week after a laparotomy, which can collect under the diaphragm. - However, this is a **post-surgical finding** and not a pathological condition leading to gas under the diaphragm in the same acute, diagnostic sense as a perforation. - Not the answer when considering pathological causes. *Spontaneous rupture of oesophagus* - Spontaneous oesophageal rupture (Boerhaave syndrome) leads to leakage of oesophageal contents into the **mediastinum or pleural cavity**, not the peritoneal cavity. - Presents with **mediastinal emphysema** (Hamman's sign) and pleural effusion rather than pneumoperitoneum. - **Subdiaphragmatic free air** indicative of pneumoperitoneum is not typically seen.
Question 922: Which of the following statements about Grisel syndrome is false?
- A. It can occur after adenoidectomy.
- B. It involves inflammation of cervical spine ligaments.
- C. A neurosurgeon is never needed. (Correct Answer)
- D. Conservative treatment is the first-line approach in most cases.
Explanation: ***A neurosurgeon is never needed.*** - This statement is false because severe cases of **Grisel syndrome** may require surgical intervention, necessitating consultation with a **neurosurgeon**. - Surgical management, such as **cervical fusion**, may be indicated in cases of irreducible subluxation or neurological compromise. *It can occur after adenoidectomy.* - This statement is true; **Grisel syndrome** is a rare complication that may occur following **adenoidectomy** or other head and neck surgeries. - The postulated mechanism involves inflammation spreading from the pharynx to the alar and transverse ligaments, leading to **atlantoaxial subluxation**. *It involves inflammation of cervical spine ligaments.* - This statement is true; **Grisel syndrome** is characterized by non-traumatic **atlantoaxial subluxation** resulting from inflammatory laxity of the cervical ligaments. - Specifically, the **transverse and alar ligaments** become inflamed and weakened, leading to instability between the atlas (C1) and axis (C2). *Conservative treatment is the first-line approach in most cases.* - This statement is true; initial management of **Grisel syndrome** typically involves conservative measures such as **neck immobilization**, pain control, and muscle relaxants. - Early diagnosis and conservative treatment are crucial to prevent progression and potential neurological complications.