All of the following statements about the third heart sound (S3) are true, except:
Which components of cigarette smoke are known to contribute to coronary artery disease?
Most common cause of nephrotic syndrome in adults?
Which condition is most commonly associated with systemic amyloidosis?
What is the most common site of gastrointestinal stromal tumors (GISTs)?
Which of the following conditions is the classic example of acute intravascular hemolysis triggered by oxidative stress?
Creola bodies are seen in:
Progressive distal-to-proximal motor recovery following nerve regeneration is most characteristic of which type of nerve injury?
PNH patients have deficient surface proteins that normally protect red blood cells from activated complements. Which two surface proteins are deficient in these patients?
Which of the following is not typically associated with cystic fibrosis?
NEET-PG 2012 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 11: All of the following statements about the third heart sound (S3) are true, except:
- A. Seen in Atrial Septal Defect (ASD)
- B. Seen in Ventricular Septal Defect (VSD)
- C. Occurs due to rapid filling of the ventricles during early diastole.
- D. Seen in Constrictive Pericarditis (Correct Answer)
Explanation: ***Seen in Constrictive Pericarditis*** - While constrictive pericarditis can lead to a diastolic sound, it's typically a **pericardial knock**, which is sharper and occurs earlier than an S3, due to abrupt halting of ventricular filling. - A true S3 is a low-pitched sound caused by turbulent blood flow into an overly compliant or volume-overloaded ventricle, which is not the primary mechanism in constrictive pericarditis. *Occurs due to rapid filling of the ventricles during early diastole.* - The S3 heart sound is precisely caused by the **rapid inflow of blood** into a dilated or poorly compliant ventricle during the early, rapid filling phase of diastole [1]. - This rapid distension causes vibrations in the ventricular wall, audible as S3, and is often associated with conditions causing **volume overload** or **ventricular dysfunction**. *Seen in Atrial Septal Defect (ASD)* - Patients with a large ASD have increased blood flow through the tricuspid valve, leading to **right ventricular volume overload** [2]. - This increased volume can cause an **S3** sound, particularly a **right ventricular S3**, due to rapid filling of the overloaded right ventricle [2]. *Seen in Ventricular Septal Defect (VSD)* - A significant VSD leads to a **left-to-right shunt**, increasing blood flow to the pulmonary circulation and subsequently returning to the left atrium and left ventricle. - This **left ventricular volume overload** can result in an audible **left ventricular S3**, reflecting rapid filling of the dilated left ventricle.
Question 12: Which components of cigarette smoke are known to contribute to coronary artery disease?
- A. Nicotine, carbon monoxide, and tar (Correct Answer)
- B. Carbon monoxide and tar
- C. Carbon dioxide
- D. Tar and nicotine
Explanation: ***Nicotine, carbon monoxide, and tar*** - **Nicotine** directly affects the cardiovascular system by increasing **heart rate**, **blood pressure**, and causing **vasoconstriction**, as well as promoting atherogenesis [2]. - **Carbon monoxide** binds to hemoglobin with higher affinity than oxygen, forming **carboxyhemoglobin**, which reduces oxygen delivery to tissues, leading to **endothelial damage** and contributing to atherosclerosis [1]. - **Tar** contains various **carcinogens** and toxic chemicals that contribute to inflammation, oxidative stress, and lipid peroxidation, all of which are implicated in the development and progression of **atherosclerosis**. *Carbon monoxide and tar* - While both contribute significantly, this option **omits nicotine**, which is a major contributor to the cardiovascular effects of smoking. - Nicotine's direct impact on **vasoconstriction** and **atherogenesis** is a critical factor in coronary artery disease [2]. *Carbon dioxide* - **Carbon dioxide** is a product of respiration and combustion but is not considered a primary direct contributor to the pathogenesis of **coronary artery disease** from cigarette smoke in the same way as nicotine, carbon monoxide, and tar. - Its presence in smoke primarily relates to its role in **respiratory physiology** rather than direct vascular damage. *Tar and nicotine* - This option correctly identifies **tar** and **nicotine** as contributors but **omits carbon monoxide**, which plays a crucial role in reducing oxygen-carrying capacity and directly damaging the endothelium [1]. - The impact of **carbon monoxide** on cardiac oxygen supply is a significant mechanism in smoking-related cardiovascular disease [1].
Question 13: Most common cause of nephrotic syndrome in adults?
- A. Minimal change disease
- B. Acute GN
- C. Membranous glomerulonephritis
- D. Focal Segmental Glomerulosclerosis (FSGS) (Correct Answer)
Explanation: ***Membranous glomerulonephritis*** - Membranous glomerulonephritis is the **most common cause of nephrotic syndrome** in adults, often associated with **autoimmune diseases** or certain medications. [1] - Patients typically present with **heavy proteinuria**, edema, and a normal renal function in early stages. *Focal GN* - Focal glomerulosclerosis typically affects young individuals and may not usually present as nephrotic syndrome. - It is associated with **obesity** and **HIV**, often leading to more significant renal impairment compared to membranous glomerulonephritis. [1] *Acute GN* - Acute glomerulonephritis generally presents with **hematuria**, **hypertension**, and **renal failure**, rather than nephrotic syndrome. [1] - It can have different causes, such as infections or systemic diseases, but is not the primary condition leading to nephrotic syndrome in adults. *Minimal change disease* - Minimal change disease is more prevalent in **children** [1], and while it can occur in adults, it is less common as a cause of nephrotic syndrome in this demographic. - It is characterized by **responsive edema** to steroids, but its incidence is not as high as membranous glomerulonephritis in adults.
Question 14: Which condition is most commonly associated with systemic amyloidosis?
- A. Chronic Kidney Disease (Correct Answer)
- B. Multiple Myeloma
- C. Rheumatoid Arthritis
- D. Familial Mediterranean Fever
Explanation: Type II DM - Amyloidosis is commonly associated with **chronic diseases** like type II diabetes mellitus due to insulin resistance leading to amyloid deposition [4]. - The presence of **amiloid in the pancreas** often correlates with the complications of this type of diabetes [3]. *Maturity onset DM* - While maturity-onset diabetes can lead to complications, it is often synonymous with **type II DM**, making this distinction inaccurate regarding amyloidosis. - This term is less commonly used and does not emphasize the direct link to amyloidosis seen in type II diabetes. *HTN* - Hypertension itself is not a direct cause of amyloidosis; it typically results from other underlying conditions. - The association of amyloidosis with hypertension is usually **secondary**, not a primary condition leading to amyloid deposits [2]. *Type I DM* - Type I diabetes is primarily **autoimmune**, resulting in insulin-deficient states and does not strongly associate with amyloidosis like type II [1]. - The amyloid deposits seen in type I are much less common compared to type II or associated chronic conditions.
Question 15: What is the most common site of gastrointestinal stromal tumors (GISTs)?
- A. Ileum
- B. Esophagus
- C. Colon
- D. Stomach (Correct Answer)
Explanation: Stomach - The stomach is the most common site for gastrointestinal stromal tumors (GISTs), accounting for approximately 60-70% of cases. - GISTs in the stomach often present with symptoms like abdominal pain or bleeding and are associated with mutations in the KIT gene. Ileum - Although GISTs can occur in the ileum, they are far less common than those found in the stomach, representing about 10-15% of cases [1]. - GISTs in the ileum tend to present differently, often with intestinal obstruction or pain [1]. Esophagus - Esophageal GISTs are rare and account for only about 5% of GIST cases, making them an uncommon location. - Symptoms are usually related to dysphagia or chest pain, not typical for GISTs arising from more common sites. Colon - Although GISTs can occur in the colon, their frequency is much lower compared to the stomach and represents a small percentage of cases. - Clinical features in colonic GISTs can mimic other colorectal tumors, often causing obstruction or bleeding rather than classic GIST symptoms.
Question 16: Which of the following conditions is the classic example of acute intravascular hemolysis triggered by oxidative stress?
- A. Hereditary spherocytosis
- B. Sickle cell disease
- C. Acute G6PD deficiency (Correct Answer)
- D. None of the options
Explanation: ***b and c*** - Intravascular hemolysis is commonly associated with both **Acute G6PD deficiency** and **Hereditary spherocytosis**, leading to destruction of red blood cells in the bloodstream [1]. - These conditions are characterized by **high levels of hemoglobinuria** and **low haptoglobin**, indicative of intravascular hemolysis. *Sickle cell ds* - Sickle cell disease primarily causes **extravascular hemolysis** due to splenic sequestration rather than **intravascular** destruction [3]. - The clinical features include **vaso-occlusive crises** and splenic infarction rather than hemolysis within the blood vessels. *Acute G6PD* - While acute G6PD deficiency can lead to hemolysis, it is typically **triggered by oxidative stress** rather than occurring continuously [2]. - The hemolysis in G6PD deficiency occurs more in an **extravascular** manner unless acute stress occurs, which can result in **acute intravascular hemolysis, marked by anemia, hemoglobinemia, and hemoglobinuria** [4]. *Hereditary spherocytosis* - This condition primarily causes **extravascular hemolysis** through the spleen, where abnormal spherocytes are destroyed [1]. - Although it leads to anemia, the hallmark of hereditary spherocytosis is the **spleen's role** in hemocyte destruction rather than intravascular hemolysis.
Question 17: Creola bodies are seen in:
- A. Emphysema
- B. Chronic bronchitis
- C. Bronchiectasis
- D. Bronchial asthma (Correct Answer)
Explanation: ***Bronchial asthma*** - **Creola bodies** are clusters of **desquamated columnar epithelial cells** found in the sputum of patients with asthma. [1] - Their presence indicates ongoing **bronchial inflammation** and epithelial damage, characteristic of asthma exacerbations. *Chronic bronchitis* - Characterized by **mucus hypersecretion** and **chronic productive cough**, without the specific finding of Creola bodies. - Histologically, it involves **goblet cell hyperplasia** and **mucous gland enlargement**. *Emphysema* - Defined by irreversible enlargement of airspaces distal to the terminal bronchioles with **destruction of alveolar walls**, not specific cell aggregates. [1] - The primary defect is loss of **elastic recoil** and **airflow limitation**. *Bronchiectasis* - Involves **permanent abnormal dilation** of the bronchi due to destruction of the muscular and elastic components of the bronchial wall. [1] - Sputum typically contains inflammatory cells and bacteria, but Creola bodies are not a defining feature.
Question 18: Progressive distal-to-proximal motor recovery following nerve regeneration is most characteristic of which type of nerve injury?
- A. Axonotmesis (Correct Answer)
- B. Neurotmesis
- C. Neuropraxia
- D. Nerve injury
Explanation: ***Axonotmesis*** - Involves damage to the **axon** and myelin sheath, while the surrounding **epineurium** remains intact. - This preservation of the connective tissue allows for guided **regeneration** of axons from distal to proximal, leading to a good prognosis for recovery [1]. *Neurotmesis* - Refers to the **complete transection** of the nerve, including the axon, myelin, and all connective tissue sheaths. - Recovery is often **incomplete** or requires surgical repair, as significant misdirection of regenerating axons is common. *Neuropraxia* - Characterized by a **temporary block** in nerve conduction, typically due to **demyelination**, with the axon remaining intact. - Recovery is usually **rapid** and complete, occurring within days to weeks, as no axonal regeneration is needed. *Nerve injury* - This is a **general term** that encompasses all types of nerve damage, from mild to severe. - It does not specify a particular mechanism or pattern of recovery, making it less precise than the more specific classifications.
Question 19: PNH patients have deficient surface proteins that normally protect red blood cells from activated complements. Which two surface proteins are deficient in these patients?
- A. CD 55 and CD 58
- B. CD 45 and CD 55 (Correct Answer)
- C. CD 55 and CD 59
- D. CD 51 and CD 55
Explanation: ***CD 55 and CD 59*** - **CD 55 (decay accelerating factor)** and **CD 59 (protectin)** are crucial for inhibiting the complement system, protecting red blood cells from lysis in PNH. - Deficiencies in these proteins lead to increased **susceptibility** of red cells to **complement-mediated hemolysis**. *CD58 and CD 59* - **CD 58** is involved in T-cell interaction but does not solely protect red cells from complement. - While **CD 59** is a correct answer, the absence of **CD 55** makes this option incorrect for PNH. *CD 45 and CD 59* - **CD 45** is primarily a **leukocyte common antigen**, not involved in protecting red cells from complement activation. - This orrectly mentions **CD 59**, but lacks **CD 55**, making it unsuitable as an answer. *CD 51 and CD 59* - **CD 51** is associated with integrin functions and does not play a role in protecting red blood cells from complements. - Although **CD 59** is relevant, the deficiency in **CD 55** highlights the incompleteness of this option.
Question 20: Which of the following is not typically associated with cystic fibrosis?
- A. Infertility
- B. Azoospermia
- C. Nasal polyps
- D. Renal failure (Correct Answer)
Explanation: ***Renal failure*** - **Renal failure** is not a typical manifestation or complication of **cystic fibrosis (CF)**. The CFTR protein primarily affects epithelial cells in organs like the lungs, pancreas, liver, and intestines, not the kidneys. - While CF patients may experience **electrolyte imbalances** due to excessive salt loss, this rarely progresses to **kidney failure** as a direct result of the disease itself. *Infertility* - **Infertility** is commonly associated with CF, particularly in males due to **congenital bilateral absence of the vas deferens (CBAVD)**, which is found in over 95% of male CF patients [1]. - In females, CF can cause **viscous cervical mucus** and nutritional deficiencies, leading to challenges with conception [1]. *Azoospermia* - **Azoospermia**, specifically **obstructive azoospermia**, is a direct consequence of **congenital bilateral absence of the vas deferens (CBAVD)**, which is highly prevalent in male CF patients [1]. - This condition prevents sperm from reaching the ejaculate, despite normal sperm production in the testes. *Nasal polyps* - **Nasal polyps** are a common feature in patients with **cystic fibrosis**, often leading to **chronic rhinosinusitis** and nasal obstruction. - This is due to the dysfunctional CFTR protein leading to abnormal mucus production and inflammation in the nasal passages [1].