All of the following statements about the third heart sound (S3) are true, except:
In which condition is venous blood most commonly observed to have a high hematocrit in routine clinical practice?
What is the most common cause of dissecting hematoma?
Which type of fatty acids should be included in the diet to manage chyluria?
Creola bodies are seen in:
Which of the following is not typically associated with cystic fibrosis?
Which condition is commonly associated with Disseminated Intravascular Coagulation (D.I.C.)?
Which of the following complications is commonly associated with mitral valve prolapse?
Progressive distal-to-proximal motor recovery following nerve regeneration is most characteristic of which type of nerve injury?
Which of the following conditions is the classic example of acute intravascular hemolysis triggered by oxidative stress?
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: In which condition is venous blood most commonly observed to have a high hematocrit in routine clinical practice?
- A. Dehydration (Correct Answer)
- B. Anemia
- C. Hypervolemia
- D. Acute blood loss
Explanation: Dehydration - In **dehydration**, the total body water is reduced, leading to a decrease in plasma volume [1, 5]. This concentrates the red blood cells, resulting in a relatively **high hematocrit**. [3] - This is a common finding as the body attempts to conserve fluid, making it a primary cause of **elevated hematocrit** in clinical practice. *Anemia* - **Anemia** is characterized by a decrease in the number of red blood cells or a reduced hemoglobin concentration, which would lead to a **low hematocrit**, not a high one [2]. - This condition involves insufficient oxygen-carrying capacity due to a deficiency in red blood cells or hemoglobin [2]. *Hypervolemia* - **Hypervolemia** describes an excess of fluid in the blood, which would dilute the blood components, leading to a relatively **low hematocrit** [1]. - This condition is often associated with conditions like heart failure or kidney disease, where fluid retention is common. *Acute blood loss* - In **acute blood loss**, the loss of whole blood immediately after the event would initially reduce both red blood cells and plasma proportionally, not immediately raising hematocrit [2]. - As the body attempts to compensate by shifting extravascular fluid into the circulation, this would further dilute the blood, eventually leading to a **decreased hematocrit** [2].
Question 13: What is the most common cause of dissecting hematoma?
- A. Hypertension (Correct Answer)
- B. Marfan syndrome
- C. Iatrogenic causes
- D. Kawasaki disease
Explanation: ***Hypertension*** - **Chronic hypertension** is the most frequent cause of dissecting hematoma (aortic dissection) due to the constant high pressure stressing the arterial wall [1]. - It leads to **medial degeneration** and predisposition to intimal tear, allowing blood to enter the arterial wall [1]. *Marfan syndrome* - While Marfan syndrome is a significant risk factor for aortic dissection due to **connective tissue weakness** (cystic medial necrosis), it is much less common than hypertension [1]. - It primarily affects younger individuals with a genetic predisposition to **fibrillin-1 mutations**. *Iatrogenic causes* - These include complications from medical procedures like **cardiac catheterization** or surgery [1]. - Though a possible cause, iatrogenic dissection is relatively rare compared to spontaneous dissection due to hypertension [1]. *Kawasaki disease* - Kawasaki disease primarily causes **coronary artery aneurysms** in children. - It is not a common cause of aortic dissecting hematoma in adults.
Question 14: Which type of fatty acids should be included in the diet to manage chyluria?
- A. Short-chain fatty acids
- B. Medium-chain fatty acids (Correct Answer)
- C. Long-chain fatty acids
- D. Omega-3 fatty acids
Explanation: ***Medium-chain fatty acids*** - **Medium-chain fatty acids (MCFAs)** are absorbed directly into the **portal circulation** without being re-esterified to triglycerides or incorporated into chylomicrons [1]. This helps bypass the compromised lymphatic system. - In **chyluria**, the lymphatic system's integrity is disrupted, leading to leakage of **chyle** (lymphatic fluid rich in chylomicrons) into the urinary tract. MCFAs provide a source of fat that does not rely on the lymphatic pathway for transport [1]. *Short-chain fatty acids* - **Short-chain fatty acids (SCFAs)** are primarily produced by bacterial fermentation in the colon and are absorbed directly into the portal circulation. - While they do not rely on the lymphatic system, their dietary contribution as a significant energy source is limited, and they are not the primary fat source for patients with chyluria. *Long-chain fatty acids* - **Long-chain fatty acids (LCFAs)** are absorbed with the help of bile salts, re-esterified into triglycerides, and packaged into **chylomicrons** within the intestinal cells [2]. - These chylomicrons then enter the **lymphatic system** and eventually the bloodstream, which is precisely the pathway that is compromised in chyluria, making them unsuitable [2]. *Omega-3 fatty acids* - **Omega-3 fatty acids** are a type of **long-chain polyunsaturated fatty acid** that also follow the chylomicron-lymphatic pathway for absorption [3]. - While beneficial for other health aspects, they are not suitable for managing chyluria due to their reliance on the **lymphatic system** for transport, which is dysfunctional in this condition.
Question 15: 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 16: 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].
Question 17: Which condition is commonly associated with Disseminated Intravascular Coagulation (D.I.C.)?
- A. Acute myelomonocytic leukemia
- B. Chronic myeloid leukemia
- C. Autoimmune hemolytic anemia
- D. Acute promyelocytic leukemia (Correct Answer)
Explanation: ***Acute promyelocytic leukemia*** - **Disseminated Intravascular Coagulation (D.I.C.)** is commonly associated with acute promyelocytic leukemia due to the release of **tissue factor** from promyelocytes [1]. - Patients typically present with **severe bleeding** and coagulopathy [1], driven by the rapid proliferation of these abnormal cells. *Acute myelomonocytic leukemia* - While this type of leukemia presents with myelomonocytic features, it is less frequently associated with **D.I.C.** compared to acute promyelocytic leukemia. - This condition is often characterized by **monocytic infiltration** but does not typically cause the severe coagulopathy associated with D.I.C. *Autoimmune hemolytic anemia* - This condition causes **hemolysis** due to antibodies but is mainly associated with **anemia**, not a coagulation disorder like D.I.C. - **D.I.C.** involves widespread **consumption coagulopathy** [1], which is not a feature of autoimmune hemolytic anemia. *CMC* - CMC refers to **Chronic Myeloid Leukemia**, which does not commonly lead to **D.I.C.** and presents primarily with splenomegaly and **chronic symptoms**. - The coagulation profile in CMC tends to be stable, with no link to the acute coagulopathy seen in D.I.C.
Question 18: Which of the following complications is commonly associated with mitral valve prolapse?
- A. Ventricular arrhythmia
- B. Stroke
- C. Infective endocarditis (Correct Answer)
- D. Mitral stenosis
Explanation: Mitral valve prolapse (MVP) involves myxomatous degeneration of the mitral valve leaflets, which can create a rough surface predisposing to bacterial adhesion and subsequent infective endocarditis [1]. While the overall risk is low, patients with MVP and accompanying mitral regurgitation or thickened leaflets are at higher risk [1]. Patients with valvular heart disease are generally susceptible to bacterial endocarditis, often associated with procedures or dental hygiene [2]. Stroke - Although MVP can sometimes be associated with embolic events (e.g., from thrombi forming on the prolapsing valve), stroke is not considered a commonly associated complication. - The risk of stroke is generally higher in MVP patients with concomitant atrial fibrillation or other cardiovascular risk factors. Mitral stenosis - Mitral valve prolapse is characterized by the displacement of mitral valve leaflets into the left atrium during systole, which can lead to mitral regurgitation [3], not stenosis. - Mitral stenosis involves narrowing of the mitral valve orifice, usually due to rheumatic fever, which is a different pathophysiology [4]. Ventricular arrhythmia - While palpitations (often benign supraventricular ectopy) are common in MVP, clinically significant ventricular arrhythmias are less common. - Severe ventricular arrhythmias are more typically seen with significant underlying myocardial disease or severe mitral regurgitation causing left ventricular dysfunction.
Question 19: 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 20: 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.