NEET-PG 2018 Practice Questions

Q: Which of the following is a cause of hypokalemic metabolic alkalosis with hypertension?

Liddle syndrome. ***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]

Q: Which of the following organisms is MOST associated with histamine production in scombroid fish poisoning?

Morganella morganii. ***Morganella morganii*** - ***Morganella morganii*** is the **MOST commonly implicated organism** in **scombroid fish poisoning** - It produces the enzyme **histidine decarboxylase**, which converts **histidine** (abundant in scombroid fish like tuna, mackerel, bonito) to **histamine** - When fish are stored at improper temperatures (>15°C), *M. morganii* proliferates and produces large amounts of **histamine** - Other histamine-producing bacteria include *Klebsiella*, *Proteus*, *Enterobacter*, and *Photobacterium* species - Symptoms mimic an **allergic reaction**: flushing, headache, palpitations, urticaria, diarrhea *Staphylococcus* - ***Staphylococcus aureus*** causes **staphylococcal food poisoning** through preformed **enterotoxins** (not histamine) - Associated with protein-rich foods left at room temperature - Causes rapid-onset nausea, vomiting, and abdominal cramps - **Not a significant cause** of scombroid fish poisoning *Salmonella* - ***Salmonella*** species cause **gastroenteritis** through direct infection and invasion of intestinal mucosa - Symptoms include **diarrhea**, **fever**, and **abdominal cramps** with longer incubation period (6-72 hours) - **Not associated** with histamine production or scombroid poisoning *P. aeruginosa* - ***Pseudomonas aeruginosa*** is an **opportunistic pathogen** causing hospital-acquired infections - Associated with wound infections, pneumonia, and UTIs in immunocompromised patients - **Not a cause** of foodborne histamine poisoning

Q: A boy presented with multiple non suppurative osteomyelitis with sickle cell anaemia. What will be the causative organism?

Salmonella. ***Salmonella*** - **Salmonella species** are a well-known cause of **osteomyelitis** in patients with **sickle cell anemia**, due to factors like gut mucosal damage and functional asplenia. [1] - The unique pathophysiology of sickle cell disease, including areas of bone infarction and compromised reticulendothelial system function, predisposes these patients to **Salmonella infections**. [1] *Staphylococcus aureus* - While **Staphylococcus aureus** is the most common cause of osteomyelitis in the general population, it is less likely to be the causative organism in patients with **sickle cell anemia** compared to Salmonella. - Its presence usually indicates other predisposing factors like trauma or prosthetic devices. *H. influenzae* - **Haemophilus influenzae** was a common cause of osteomyelitis in children before widespread vaccination but is now rare, especially with routine immunizations. - It is not specifically associated with a higher risk in patients with **sickle cell disease** for osteomyelitis compared to other pathogens. *Enterobacter species* - **Enterobacter species** can cause osteomyelitis, particularly in immunocompromised individuals or following surgery, but they are not uniquely associated with **sickle cell anemia** as a primary cause compared to Salmonella. - Their involvement in non-suppurative osteomyelitis in this specific patient population is less common.

Q: Identify the organism related to the blood smear image.

Plasmodium falciparum. ***Plasmodium falciparum*** - The image clearly displays multiple **ring-form trophozoites** within red blood cells, some of which are *appliqué* or *accolade* forms (rings on the periphery of the red blood cell) and **multiple rings per red blood cell**, which are characteristic of *P. falciparum*. - Presence of **multiple parasites per red blood cell** and various developmental stages including occasional **banana-shaped gametocytes**, though not prominent in this specific field, are key indicators of *P. falciparum* infection, differentiating it from other malarial species. - *P. falciparum* is the most dangerous malarial species and can cause **cerebral malaria** and other severe complications. *Salmonella Typhi* - This bacterium causes **typhoid fever** and is typically identified through **blood culture** or serological tests (Widal test), not by direct visualization within red blood cells on a peripheral blood smear. - *Salmonella Typhi* is an **intracellular bacterium** that primarily infects phagocytic cells (macrophages), not erythrocytes, and does not present as ring forms or other parasitic stages in blood smears. *Toxoplasma gondii* - This parasite causes **toxoplasmosis** and is typically found as **tachyzoites** or **bradyzoites** (within cysts) in tissue samples or less commonly in macrophages in disseminated disease, but not as ring forms within red blood cells on a peripheral blood smear. - Diagnosis usually involves **serological testing** for IgM/IgG antibodies or PCR, as opposed to direct visualization of unique forms in blood smears. *Treponema pallidum* - This is the spirochete responsible for **syphilis** and is too small and thin (0.1-0.2 μm diameter) to be seen with standard light microscopy on routine blood smears. - It is best identified using **dark-field microscopy** or serological tests (VDRL, RPR, TPPA, FTA-ABS) and does not infect red blood cells in the manner shown.

Q: Which of the following methods is known as a fimbriectomy procedure?

Kroener procedure. ***Kroener procedure*** - The **Kroener procedure** is a method of **tubal ligation** particularly known as a **fimbriectomy**, where the fimbriated end of the fallopian tube is removed. - This sterilization technique primarily involves excising the **fimbriae**, preventing **ovum capture** and subsequent fertilization. *Uchida procedure* - The **Uchida procedure** involves **injecting a sclerosing solution** under the serosa of the fallopian tube, then excising a small segment and ligating the ends. - This method aims to **bury the fimbriated end** within the broad ligament, but it is not a fimbriectomy. *Irving procedure* - The **Irving procedure** involves **tying and transecting the fallopian tube**, then burying the severed medial end into the posterior wall of the uterus. - This technique is designed to prevent **fistula formation** and recanalization but does not involve fimbriectomy. *Madlener procedure* - The **Madlener procedure** involves **crushing a section** of the fallopian tube, usually a knuckle, and then ligating it. - This method is simpler but has a **higher failure rate** compared to other sterilization techniques and does not involve removal of the fimbriae.

Q: What are the effects of Progesterone-only pills?

All of the options may occur. ***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.

Q: Best time to perform the quadruple test is:

15-20 weeks. ***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.

Q: What type of uterine anomaly is shown in this X-ray HSG image?

Unicornuate uterus. ***Unicornuate uterus*** - The image shows a single, elongated uterine horn with a single fallopian tube arising from it, consistent with a **unicornuate uterus**. - This congenital anomaly results from the **failure of one Müllerian duct to develop**, leading to an abnormally shaped uterus. *Septate uterus* - A **septate uterus** would show a normal uterine fundus with an internal septum dividing the uterine cavity. - This image clearly depicts only **one rudimentary horn** and no visible septum. *Uterus didelphys* - **Uterus didelphys** involves two completely separate uteri, each with its own cervix and vagina. - The image does not show evidence of a **second, separate uterine structure**. *Bicornuate uterus* - A **bicornuate uterus** is characterized by two distinct uterine horns, which fuse at the cervix or lower uterine segment, creating a heart-shaped appearance of the fundus. - The image shows a **single, long horn** rather than two distinct horns.

Q: Anaplasia is

Lack of differentiation. ***Lack of differentiation*** - Anaplasia refers to a **loss of differentiation** in cells, making them more primitive and less specialized [1]. - It is often seen in **malignant tumors**, indicating a poor prognosis and aggressive behavior [1]. *Morphological changes* - While anaplasia involves **morphological changes**, this term is too broad and can relate to various cellular alterations, not exclusively anaplasia [1]. - Anaplasia specifically emphasizes **lack of differentiation**, distinct from general changes in cell appearance [1]. *Changing one type of epithelium to another* - This describes a process known as **metaplasia**, where one adult cell type transforms into another, not anaplasia. - Anaplasia signifies a **de-differentiation** rather than a change to a different epithelial type [1]. *Nuclear chromatin* - While changes in **nuclear chromatin** can occur in anaplastic cells, this does not define anaplasia itself [1]. - Anaplasia primarily refers to **loss of cell differentiation**, making this option insufficient to describe the concept [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 276-280.

Q: What happens to gas exchange when the Va/Q ratio approaches infinity?

No exchange of O2 and CO2 occurs.. ***No exchange of O2 and CO2 occurs.*** - When the **Va/Q ratio approaches infinity**, it signifies a scenario of **ventilation without perfusion** (Q approaches zero). - This represents **alveolar dead space** - despite adequate ventilation, there is **no blood flow** to participate in gas exchange. - Therefore, **no O2 enters the blood** and **no CO2 leaves the blood**, making this the most accurate description of what happens to gas exchange. *Partial pressure of O2 becomes negligible.* - This statement is incorrect because with **no blood flow** (Q = 0), the alveolar air retains high O2 partial pressure. - O2 is being delivered via ventilation but not removed by blood, so **alveolar PO2** would approach that of **inspired air (~150 mmHg)**, not become negligible. *Partial pressure of CO2 becomes negligible.* - While this statement is technically true (alveolar PCO2 would approach zero/inspired air levels), it doesn't directly answer what happens to **gas exchange**. - With no blood flowing through the alveolus, no **CO2 from venous blood** can reach the alveolus to be excreted. - However, the question asks about **gas exchange** itself, not just partial pressures, making the first option more comprehensive. *Partial pressures of both CO2 and O2 remain normal.* - This statement is incorrect as the **Va/Q mismatch** significantly alters the partial pressures of both gases. - In infinite Va/Q scenario (dead space ventilation), **alveolar PO2 would be high** (approaching inspired air ~150 mmHg) and **alveolar PCO2 would be low** (approaching zero).

Question 1

Which of the following is a cause of hypokalemic metabolic alkalosis with hypertension?

Accepted Answer

Liddle syndrome

Answer

Bartter syndrome

Answer

Gitelman syndrome

Answer

Renal tubular acidosis

Question 2

Which of the following organisms is MOST associated with histamine production in scombroid fish poisoning?

Accepted Answer

Morganella morganii

Answer

P. aeruginosa

Answer

Staphylococcus

Answer

Salmonella

Question 3

A boy presented with multiple non suppurative osteomyelitis with sickle cell anaemia. What will be the causative organism?

Accepted Answer

Salmonella

Answer

H. influenzae

Answer

Enterobacter species

Answer

Staphylococcus aureus

Question 4

Identify the organism related to the blood smear image.

Accepted Answer

Plasmodium falciparum

Answer

Salmonella Typhi

Answer

Toxoplasma gondii

Answer

Treponema pallidum

Question 5

Which of the following methods is known as a fimbriectomy procedure?

Accepted Answer

Kroener procedure

Answer

Uchida procedure

Answer

Irving procedure

Answer

Madlener procedure

Question 6

What are the effects of Progesterone-only pills?

Accepted Answer

All of the options may occur

Answer

May suppress ovulation

Answer

Thins the lining of the uterus

Answer

Thickens cervical mucus

Question 7

Best time to perform the quadruple test is:

Accepted Answer

15-20 weeks

Answer

8-12 weeks

Answer

11-15 weeks

Answer

18-22 weeks

Question 8

What type of uterine anomaly is shown in this X-ray HSG image?

Accepted Answer

Unicornuate uterus

Answer

Septate uterus

Answer

Uterus didelphys

Answer

Bicornuate uterus

Question 9

Anaplasia is

Accepted Answer

Lack of differentiation

Answer

Changing one type of epithelium to another

Answer

Nuclear chromatin

Answer

Morphological changes

Question 10

What happens to gas exchange when the Va/Q ratio approaches infinity?

Accepted Answer

No exchange of O2 and CO2 occurs.

Answer

Partial pressure of O2 becomes negligible.

Answer

Partial pressure of CO2 becomes negligible.

Answer

Partial pressures of both CO2 and O2 remain normal.

NEET-PG 2018

Internal Medicine

Microbiology

Obstetrics and Gynecology

Pathology

Physiology