NEET-PG 2012 Practice Questions

Q: Calcium homeostasis disturbance is the predominant pathophysiological mechanism in

Malignant hyperthermia. ***Malignant hyperthermia*** - Malignant hyperthermia is caused by a genetic defect in the **ryanodine receptor (RYR1)** in skeletal muscle, leading to an uncontrolled release of **intracellular calcium** from the sarcoplasmic reticulum. - This excessive calcium release results in sustained muscle contraction, increased metabolism, and a rapid rise in body temperature. *Duchenne Muscular Dystrophy (DMD)* - DMD is primarily caused by a mutation in the **dystrophin gene**, which leads to the absence or severe deficiency of the **dystrophin protein**. - This deficiency results in muscle fiber fragility, cycles of degeneration and regeneration, and eventual replacement of muscle with fibrous and fatty tissue, rather than a primary calcium homeostasis disturbance. *Limb Girdle Muscular Dystrophy* - This group of disorders is characterized by progressive weakness and wasting of muscles, primarily affecting the **shoulders and hips**. - The pathophysiology involves genetic defects in various proteins that are crucial for muscle function and integrity, such as **sarcoglycans** or **calpain-3**, not primarily calcium dysregulation. *Tibial Muscular Dystrophy* - Tibial muscular dystrophy is a rare, late-onset disorder characterized by progressive weakness of the **anterior tibial muscles**. - It is typically caused by mutations in the **TTN gene**, encoding for the protein **titin**, which plays a vital role in muscle elasticity and structural integrity, rather than a primary calcium imbalance.

Q: In a patient with suspected vitamin B12 deficiency, which condition would result in an abnormal Schilling test?

Intrinsic factor deficiency. ***Intrinsic factor deficiency*** - The Schilling test assesses the absorption of **vitamin B12**. **Intrinsic factor** is crucial for B12 absorption in the ileum. - Deficiency of intrinsic factor, as seen in **pernicious anemia**, directly impairs B12 absorption, leading to an abnormal Schilling test result [1]. *Amylase deficiency* - **Amylase** is an enzyme involved in the digestion of carbohydrates, not vitamin B12 absorption [2]. - Its deficiency would primarily cause carbohydrate malabsorption symptoms, not an abnormal Schilling test. *Pancreatic endocrine insufficiency* - **Pancreatic endocrine function** relates to hormone production (e.g., insulin, glucagon), while exocrine function involves digestive enzymes. - Impairment of endocrine function does not directly affect vitamin B12 absorption or the Schilling test. *Lipase deficiency* - **Lipase** is an enzyme essential for the digestion of fats [2]. - Its deficiency would lead to fat malabsorption (steatorrhea) but would not affect vitamin B12 absorption or the Schilling test results.

Q: Secretory diarrhea is not typically associated with which of the following conditions?

Celiac disease. ***Celiac disease*** [1] - Characterized by **malabsorption** due to immune-mediated damage to the intestinal mucosa, leading to **osmotic diarrhea** rather than secretory diarrhea [1]. - Symptoms include **bloating**, **weight loss**, and **steatorrhea**, which are not consistent with secretory processes. *Cholera* - Caused by **Vibrio cholerae**, leading to **massive secretory diarrhea** due to the action of cholera toxin on intestinal epithelial cells. - Presents with **watery diarrhea**, potentially leading to **dehydration** and electrolyte imbalances. *Addison's Disease* - This condition may cause **diarrhea** but typically results in **non-secretory diarrhea**, often associated with adrenal insufficiency symptoms. - Presenting features include **fatigue**, **weight loss**, and **hyperpigmentation**, not primarily secretory processes. *Phenolphthalein* - A laxative that can induce **secretory diarrhea** through its stimulant effects on the bowel. - Its mechanism leads to increased fluid secretion in the intestines, thus contributing to secretory diarrhea.

Q: What is the daily temperature variation in remittent fever?

> 1.0 °C. ***> 1.0 °C*** - In **remittent fever**, the temperature fluctuates by **more than 1.0 °C** (or 2°F) over a 24-hour period. [1] - Despite the significant variation, the temperature **never returns to normal** during the day. [1] *< 0.5 °C* - A variation of less than 0.5 °C (or 1°F) is more characteristic of a **sustained or continuous fever**, where the temperature remains elevated with minimal fluctuation. [1] - This pattern is seen in conditions like **typhoid fever** or **pneumonia**. * 2.0 °C* - While a variation greater than 2.0 °C would certainly fall under the definition of remittent fever (as it's > 1.0 °C), the defining lower limit for remittent fever is typically **> 1.0 °C (or 2°F)**. - A larger fluctuation might occur, but > 1.0 °C is the minimum threshold.

Q: Investigation of choice in pheochromocytoma is:

Urinary catecholamines. ***Urinary catecholamines*** - Measurement of **24-hour urinary fractionated metanephrines and catecholamines** is the initial **biochemical test of choice**. - These biochemical tests are preferred over plasma levels due to the **episodic release** of hormones from a pheochromocytoma, which can lead to high false-negative rates in single plasma measurements. *CT scan* - While a **CT scan** is a crucial **imaging modality** for localizing a pheochromocytoma once the biochemical diagnosis is established [1], it is not the *initial* diagnostic investigation. - Imaging should be performed only after **biochemical confirmation** to avoid unnecessary investigations of incidental adrenal masses [1]. *MIBG scan* - An **MIBG scan** (metaiodobenzylguanidine scan) is a **functional imaging study** used primarily for **localizing metastatic pheochromocytomas** [1] or for cases where CT/MRI is equivocal. - It is not the initial investigation but rather a **secondary imaging test** [1]. *MRI Scan* - **MRI** is an alternative **imaging modality** to CT for localizing pheochromocytomas [1], especially in pregnant women or when radiation exposure is a concern. - Like CT, it serves as a **localization tool** after biochemical confirmation, not the diagnostic test itself.

Q: Which of the following medications is not typically used in the treatment of malignant malaria?

Quinolone. ***Quinolone*** - **Quinolone** antibiotics, while broad-spectrum, are not typically used as primary antimalarial agents due to limited efficacy against *Plasmodium falciparum* and potential for resistance. - Their use in malaria treatment is generally restricted to specific co-infections rather than direct antimalarial efficacy. *Quinine* - **Quinine** has been a cornerstone of severe malaria treatment for many years, especially in regions with limited access to newer artemisinin derivatives. - It works by interfering with the parasite's ability to detoxify heme, thus killing the parasites. *Doxycycline* - **Doxycycline** is an effective antimalarial, particularly as a prophylactic agent and in combination therapy for uncomplicated malaria or as an alternative for severe malaria when other agents are contraindicated. - It inhibits **protein synthesis** in the parasite. *Artesunate* - **Artesunate** is the recommended first-line treatment for severe malaria due to its rapid action and potent parasiticidal effects. - It is an **artemisinin derivative** that produces free radicals toxic to the parasite.

Q: How much length is increased in Z-plasty when it is done at 60 degrees?

75%. ***75%*** - A **60-degree Z-plasty** lengthens the central limb by approximately **75%** of its original length. This configuration provides a balance between length gain and flap viability. - The greater the angle of the Z-plasty limbs, the greater the theoretical lengthening, but also the larger the flaps and the increased risk of complications. *25%* - A **30-degree Z-plasty** typically provides about **25% lengthening** of the central limb. This angle offers less lengthening but is useful for smaller scars or when skin mobility is limited. - While it provides some lengthening, it falls significantly short of the length achieved with a 60-degree Z-plasty. *50%* - A **45-degree Z-plasty** generally results in approximately **50% lengthening**. This is an intermediate option, providing moderate lengthening. - This option does not match the significant lengthening associated with the larger 60-degree angle. *100%* - To achieve approximately **100% length gain**, larger angles such as **75 or 90-degree Z-plasty** might be considered. However, these angles are less commonly used due to increased flap size and tension at the base. - A standard 60-degree Z-plasty does not provide a 100% increase in length.

Q: What is the ideal angle for Z-plasty?

60°. ***60°*** - An angle of **60°** is considered ideal for Z-plasty because it provides the best balance between **lengthening the scar** and maintaining **tissue viability**. - This angle typically results in a **75% gain in length** along the central limb of the Z-plasty, while ensuring the flaps have a broad enough base for adequate blood supply. *90°* - While a **90°** angle would provide the most lengthening (around 100%), it creates very **thin, narrow flap tips** that are highly susceptible to **ischemia and necrosis** due to compromised blood supply. - This angle is generally avoided in Z-plasty due to the high risk of **flap complications**. *45°* - A **45°** angle results in less lengthening (approximately 50% gain) compared to a 60° angle, which may not be sufficient for significant release of scar contractures. - While it offers excellent flap viability due to wider bases, the **suboptimal lengthening** makes it less efficient for many Z-plasty applications. *75°* - An angle of **75°** would yield greater lengthening than 60°, but it also compromises flap viability making the flap susceptible to **necrosis**. - The benefits of increased length are often outweighed by the increased **risk of complications** when using this angle.

Q: What is the most common abdominal surgical procedure for complete rectal prolapse?

Rectopexy. ***Rectopexy*** - **Rectopexy** is the most common abdominal surgical procedure for full-thickness rectal prolapse - It involves fixing the rectum to the sacral promontory or presacral fascia (with sutures or mesh) to prevent prolapse - Various modifications exist including suture rectopexy, mesh rectopexy, ventral rectopexy, and resection rectopexy - **Abdominal approach** is preferred in fit patients with better long-term outcomes compared to perineal procedures *Rectal mucosal stapling* - This procedure refers to **stapled hemorrhoidopexy (PPH)** or **STARR procedure** - Primarily used for **internal mucosal prolapse** and hemorrhoids, not full-thickness external rectal prolapse - Involves excising redundant rectal mucosa using circular staplers - Does not address the full-thickness prolapse or provide proper fixation *Placation/wiring* - **Thiersch wiring** is a historical perineal procedure involving placement of a wire or suture around the anus to narrow the anal canal - Now largely abandoned due to high recurrence rates and complications - **Plication** refers to folding tissue but is not a standalone procedure name for rectal prolapse - This terminology is not standard in modern colorectal surgery *Mucosal resection* - Refers to **Delorme's procedure**, a perineal approach involving mucosal sleeve resection with underlying muscle plication - Used in elderly or high-risk patients who cannot tolerate abdominal surgery - Associated with higher recurrence rates compared to abdominal rectopexy - Does not provide the same level of fixation as abdominal procedures

Question 1

Calcium homeostasis disturbance is the predominant pathophysiological mechanism in

Accepted Answer

Malignant hyperthermia

Answer

Duchenne Muscular Dystrophy (DMD)

Answer

Limb Girdle Muscular Dystrophy

Answer

Tibial Muscular Dystrophy

Question 2

In a patient with suspected vitamin B12 deficiency, which condition would result in an abnormal Schilling test?

Accepted Answer

Intrinsic factor deficiency

Answer

Amylase deficiency

Answer

Pancreatic endocrine insufficiency

Answer

Lipase deficiency

Question 3

Secretory diarrhea is not typically associated with which of the following conditions?

Accepted Answer

Celiac disease

Answer

Phenolphthalein

Answer

Cholera

Answer

VIPoma

Question 4

What is the daily temperature variation in remittent fever?

Accepted Answer

> 1.0 °C

Answer

< 0.5 °C

Answer

< 1.0 °C

Answer

> 2.0 °C

Question 5

Investigation of choice in pheochromocytoma is:

Accepted Answer

Urinary catecholamines

Answer

CT scan

Answer

MIBG scan

Answer

MRI Scan

Question 6

Which of the following is a characteristic of Yellow-nail syndrome?

Accepted Answer

Pleural effusion and lymphedema, associated with discolored nails

Answer

Knee joint effusion and lymphedema, associated with discolored nails

Answer

Pericardial effusion and lymphedema, associated with discolored nails

Answer

Peritoneal effusion and lymphedema, associated with discolored nails

Question 7

Which of the following medications is not typically used in the treatment of malignant malaria?

Accepted Answer

Quinolone

Answer

Doxycycline

Answer

Artesunate

Answer

Quinine

Question 8

How much length is increased in Z-plasty when it is done at 60 degrees?

Accepted Answer

75%

Answer

50%

Answer

25%

Answer

100%

Question 9

What is the ideal angle for Z-plasty?

Accepted Answer

60°

Answer

90°

Answer

45°

Answer

75°

Question 10

What is the most common abdominal surgical procedure for complete rectal prolapse?

Accepted Answer

Rectopexy

Answer

Rectal mucosal stapling

Answer

Placation/wiring

Answer

Mucosal resection

NEET-PG 2012

Anesthesiology

Internal Medicine

Surgery