NEET-PG 2019 Practice Questions

Q: In Zellweger syndrome, which of the following is absent?

Peroxisomes. ***Peroxisomes*** - **Zellweger syndrome** is an **autosomal recessive disorder** characterized by a severe reduction or absence of functional peroxisomes. - Peroxisomes are essential organelles involved in **lipid metabolism**, particularly the breakdown of very long-chain fatty acids (VLCFAs) and branched-chain fatty acids, leading to their accumulation in the blood and tissues. *Golgi apparatus* - The **Golgi apparatus** is an intact and functional organelle in Zellweger syndrome. - It plays a crucial role in modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles, functions that remain unaffected in this condition. *Mitochondria* - **Mitochondria**, responsible for cellular respiration and ATP production, are present and functional in Zellweger syndrome. - While metabolic disturbances occur, they are not due to primary mitochondrial dysfunction. *ER* - The **endoplasmic reticulum (ER)**, a network of membranes involved in protein and lipid synthesis, is also intact and functional. - It is not directly implicated in the pathogenesis of Zellweger syndrome.

Q: Glutamine is increased in CSF, blood & urine WITHOUT elevated orotic acid in which defect:

CPS-I. ***CPS-I*** - A deficiency in **Carbamoyl Phosphate Synthetase I (CPS-I)** leads to a severe block in the **urea cycle**, resulting in profound hyperammonemia. - The elevated ammonia is then shunted to produce more **glutamine** (via glutamine synthetase), which serves as a detoxification mechanism but also causes high levels of glutamine in CSF, blood, and urine. *Arginase* - **Arginase deficiency** primarily leads to elevated **arginine** levels and mild to moderate hyperammonemia, but not typically a dramatic increase in glutamine due to the block occurring later in the cycle. - Clinical features include progressive spasticity, growth retardation, and intellectual disability. *Argininosuccinate lyase deficiency* - This deficiency causes accumulation of **argininosuccinate** in body fluids, which is a diagnostic marker, rather than primarily increased glutamine. - It presents with severe hyperammonemia, neurological symptoms, and often hepatomegaly. *Arginosuccinate synthetase* - A deficiency in **argininosuccinate synthetase** (also known as citrullinemia type I) leads to a buildup of **citrulline** and severe hyperammonemia. - While hyperammonemia can indirectly increase glutamine, the primary diagnostic marker is elevated citrulline, and the glutamine increase is not as pronounced or directly symptomatic as in CPS-I deficiency. *OTC* - **Ornithine Transcarbamylase (OTC) deficiency** is the most common urea cycle disorder and leads to severe hyperammonemia, accompanied by elevated **orotic acid** due to carbamoyl phosphate shunting to pyrimidine synthesis. - While hyperammonemia drives glutamine synthesis, the presence of elevated orotic acid is a key differentiator from CPS-I deficiency, which does not have increased orotic acid.

Q: HIV patient presented with diarrhea. On stool examination, acid-fast organisms (Isospora belli) were seen. What is the drug of choice in this patient?

TMP-SMX. ***TMP-SMX*** - **Trimethoprim-sulfamethoxazole (TMP-SMX)** is the primary treatment for **Isospora belli** infections, especially in HIV-positive patients [1]. - It is highly effective in eradicating the parasite and preventing relapses in immunocompromised individuals [1]. *Niclosamide* - **Niclosamide** is an antihelminthic drug primarily used for treating **tapeworm infections** [2]. - It is not effective against protozoal parasites like *Isospora belli*. *Nitazoxanide* - **Nitazoxanide** is an antiparasitic drug that can be used for various protozoal and helminthic infections, including *Cryptosporidium* and *Giardia*. - While it has some efficacy against *Isospora belli*, it is generally considered a second-line agent, with **TMP-SMX** being the drug of choice [1]. *Primaquine* - **Primaquine** is an antimalarial drug specifically used to prevent relapse of **Plasmodium vivax** and **Plasmodium ovale** malaria by targeting hypnozoites. - It has no role in the treatment of **Isospora belli** infection.

Q: Which apolipoprotein is most strongly associated with increased risk of Alzheimer's disease?

APOE4. APOE4 - The APOE4 allele is the strongest genetic risk factor for late-onset Alzheimer's disease, increasing risk and lowering the age of onset in a gene-dose dependent manner. - Individuals with one copy of APOE4 have a 2-3 times increased risk, and those with two copies have an 8-12 times increased risk compared to those with APOE3. APOE3 - APOE3 is the most common allele and is considered a neutral risk factor for Alzheimer's disease. - It plays a normal role in lipid metabolism and brain function without significantly increasing or decreasing AD risk. APOC3 - APOC3 is involved in triglyceride metabolism and is primarily linked to cardiovascular disease risk, not Alzheimer's disease. - While it modulates lipid levels, it does not have a direct, strong genetic association with AD pathogenesis. APOE2 - APOE2 is associated with a reduced risk of Alzheimer's disease, offering a protective effect against its development. - It is thought to improve the clearance of amyloid-beta (A̠) plaques, a hallmark of AD pathology.

Q: A neonate was found to have cataract, deafness and cardiac defects. Which group of viruses was the mother infected with?

Togaviridae family (includes Rubella virus). ***Togaviridae family (includes Rubella virus)*** - The classic triad of **congenital rubella syndrome (CRS)** includes **cataracts**, **deafness**, and **cardiac defects** (e.g., patent ductus arteriosus, pulmonary artery stenosis). - Rubella virus is a member of the **Togaviridae family** and causes significant fetal damage if the mother is infected during the first trimester. *Flaviviridae family (includes Zika virus)* - While congenital Zika syndrome can cause severe birth defects, it is primarily associated with **microcephaly**, intracranial calcifications, and ocular abnormalities, not typically the classic rubella triad. - **Deafness** and **linear cataracts** are not characteristic features of congenital Zika infection. *Bunyaviridae family (includes Rift Valley fever virus)* - Rift Valley fever virus is primarily transmitted by mosquitoes and causes **febrile illness** in humans and livestock, with potential for **hemorrhagic fever** or **encephalitis**. - It is not known to cause congenital abnormalities resembling cataracts, deafness, and cardiac defects in neonates. *Arenaviridae family (includes Lassa fever virus)* - Lassa fever virus causes a severe **hemorrhagic fever** in humans, primarily through contact with infected rodents or person-to-person transmission. - It is not associated with congenital malformations such as cataracts, deafness, and cardiac defects.

Q: Flask-shaped ulcers in the intestine are caused by which of the following?

Entamoeba histolytica. ***Entamoeba histolytica*** - *Entamoeba histolytica* is a protozoan that causes **amoebiasis**, which is characterized by **flask-shaped (bottle-shaped) ulcers** in the colon - this is the **pathognomonic feature** of intestinal amoebiasis. - The trophozoites invade the intestinal mucosa and submucosa, creating a **narrow neck at the mucosal surface** and a **wider base in the submucosa**, giving them their unique flask-like appearance. - These ulcers are most commonly found in the **cecum and ascending colon**. *TB* - Intestinal tuberculosis typically causes **transverse ulcers** (perpendicular to the bowel axis) due to lymphatic spread and caseous necrosis, often in the ileocecal region. - These ulcers are usually associated with **granulomas** and acid-fast bacilli, which are histologically distinct from flask-shaped ulcers. *Giardia* - *Giardia lamblia* (or *intestinalis*) is a flagellate that causes **giardiasis**, primarily adhering to the small intestinal villi and causing malabsorption and diarrhea. - It is **non-invasive** and does not penetrate the intestinal wall or cause ulcer formation; its pathology is mainly due to **mucosal inflammation** and villous blunting. *Typhoid* - Typhoid fever, caused by *Salmonella Typhi*, commonly leads to **longitudinal ulcers** (parallel to the bowel axis) in the **Peyer's patches** of the ileum due to bacterial invasion and necrosis of lymphoid tissue. - These ulcers may perforate but do not present with the flask-shaped morphology characteristic of amoebiasis.

Q: A person working in an abattoir presented with malignant pustule on hand. What is the causative agent?

Bacillus anthracis. **Bacillus anthracis** - The presence of a **malignant pustule** on the hand, especially in an individual working in an **abattoir** (exposure to animals/animal products), is highly characteristic of **cutaneous anthrax**. - **Bacillus anthracis** is a **spore-forming bacterium** that causes anthrax, and the cutaneous form typically presents as a painless ulcer that develops into a black eschar. *Clostridium botulinum* - This bacterium causes **botulism**, a severe **neuroparalytic disease** characterized by flaccid paralysis. - It does not cause cutaneous lesions like a malignant pustule and is typically associated with **food poisoning** or wound infections leading to toxin production. *Streptococcus pyogenes* - This bacterium is a common cause of various infections, including **strep throat**, **impetigo**, **erysipelas**, and **necrotizing fasciitis**. - While it can cause skin infections, it does not typically present as a "malignant pustule" with the characteristic eschar seen in anthrax. *Clostridium perfringens* - This bacterium is a common cause of **gas gangrene** (myonecrosis) and **food poisoning**. - While it can cause severe tissue infections, it does not present as a malignant pustule.

Q: Tolvaptan is used for:-

SIADH. ***SIADH*** - **Tolvaptan** is a **vasopressin V2 receptor antagonist** that promotes water excretion without affecting sodium, making it ideal for treating **euvolemic and hypervolemic hyponatremia** associated with SIADH. - In **syndrome of inappropriate antidiuretic hormone secretion (SIADH)**, there is excessive **ADH** leading to water retention and dilutional hyponatremia; tolvaptan effectively counters this by blocking vasopressin's action. *Von Willebrand disease* - This is a **bleeding disorder** caused by a deficiency or dysfunction of **von Willebrand factor**, treated with **desmopressin** or factor replacement, not tolvaptan. - Tolvaptan has no role in coagulation pathways or the management of bleeding disorders. *Central DI* - **Central diabetes insipidus (DI)** results from reduced **ADH production** by the hypothalamus or posterior pituitary, leading to excessive water loss. - It is treated with **desmopressin** (synthetic ADH) to replace the deficient hormone, which is the opposite effect of tolvaptan. *Catecholamine resistant Shock* - **Catecholamine-resistant shock** is characterized by persistent hypotension despite high doses of **vasopressors**. - Treatment often involves agents like **vasopressin** (not tolvaptan) or corticosteroids to improve vascular tone, as tolvaptan would worsen the hypotension by promoting diuresis.

Q: Dohlman surgery in Zenker's diverticulum is:-

Endoscopic electrocautery technique. ***Endoscopic electrocautery technique*** - The **Dohlman procedure** (Dohlman-Mattsson procedure, 1960) is an **endoscopic electrosurgical technique** that uses **diathermy/electrocautery** to divide the cricopharyngeal muscle (the septum between the esophagus and the diverticulum). - This method creates a common cavity between the esophagus and the diverticulum, allowing food to pass freely and preventing pooling. - It is one of the **classic endoscopic approaches** for treating Zenker's diverticulum and remains widely used. *Endoscopic suturing of pouch* - Endoscopic suturing is not the primary technique for the Dohlman procedure. - The goal is to **divide the septum**, not to suture or reduce the pouch itself. *Laser division of pouch* - **Laser division** of the cricopharyngeal muscle is another endoscopic approach, often called **endoscopic laser diverticulostomy**. - While effective, this is a **different technique** from the Dohlman procedure, which specifically uses electrocautery. *Endoscopic stapling of septum* - **Endoscopic stapling** (using an endoscopic stapler to divide the septum) is associated with the **Collard-Peracchia technique** or endoscopic stapling diverticulostomy. - While this is a modern and effective approach, it is **not the Dohlman procedure**, which historically and traditionally refers to the electrocautery technique.

Question 1

In Zellweger syndrome, which of the following is absent?

Accepted Answer

Peroxisomes

Answer

Golgi apparatus

Answer

Mitochondria

Answer

ER

Question 2

Glutamine is increased in CSF, blood & urine WITHOUT elevated orotic acid in which defect:

Accepted Answer

CPS-I

Answer

Arginase

Answer

Argininosuccinate lyase deficiency

Answer

Arginosuccinate synthetase

Answer

OTC

Question 3

HIV patient presented with diarrhea. On stool examination, acid-fast organisms (Isospora belli) were seen. What is the drug of choice in this patient?

Accepted Answer

TMP-SMX

Answer

Niclosamide

Answer

Nitazoxanide

Answer

Primaquine

Question 4

Which apolipoprotein is most strongly associated with increased risk of Alzheimer's disease?

Accepted Answer

APOE4

Answer

APOE3

Answer

APOC3

Answer

APOE2

Question 5

A neonate was found to have cataract, deafness and cardiac defects. Which group of viruses was the mother infected with?

Accepted Answer

Togaviridae family (includes Rubella virus)

Answer

Flaviviridae family (includes Zika virus)

Answer

Bunyaviridae family (includes Rift Valley fever virus)

Answer

Arenaviridae family (includes Lassa fever virus)

Question 6

Flask-shaped ulcers in the intestine are caused by which of the following?

Accepted Answer

Entamoeba histolytica

Answer

TB

Answer

Giardia

Answer

Typhoid

Question 7

A person working in an abattoir presented with malignant pustule on hand. What is the causative agent?

Accepted Answer

Bacillus anthracis

Answer

Clostridium botulinum

Answer

Streptococcus pyogenes

Answer

Clostridium perfringens

Question 8

Which of the following is positive in Follicular lymphoma?

Accepted Answer

Bcl-2 protein

Answer

Cyclin D1 (Bcl-1)

Answer

Bcl-10 signaling protein

Answer

Bcl-6 transcription factor

Question 9

Tolvaptan is used for:-

Accepted Answer

SIADH

Answer

Von Willebrand disease

Answer

Central DI

Answer

Catecholamine resistant Shock

Question 10

Dohlman surgery in Zenker's diverticulum is:-

Accepted Answer

Endoscopic electrocautery technique

Answer

Endoscopic suturing of pouch

Answer

Laser division of pouch

Answer

Endoscopic stapling of septum

NEET-PG 2019

Biochemistry

Internal Medicine

Microbiology

Pathology

Pharmacology

Surgery