Internal Medicine
8 questionsClicking noise in Pneumomediastinum is known as
Which of the following is least likely to be associated with emphysema?
What is the most common cause of lung abscess in comatose patients?
In the context of ventricular tachycardia, what do extra systoles appear as on an electrocardiogram (ECG)?
What is the most common arrhythmia in ICU patients?
A patient with first-degree heart block presents with dizziness. What is the most appropriate management for this patient?
Which of the following is not typically used for secondary prevention of myocardial infarction?
Which of the following is not recommended for patients with coronary artery disease?
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 631: Clicking noise in Pneumomediastinum is known as
- A. Hamman's sign (Correct Answer)
- B. Traube's sign
- C. Kussmaul's sign
- D. None of the options
Explanation: Hamman's sign - Hamman's sign is a crunching, bubbling, or clicking sound synchronous with the heartbeat, audible on auscultation over the precordium. - It is pathognomonic for pneumomediastinum, caused by the heart beating against air-filled tissues. Traube's sign - Traube's sign refers to a pistol-shot sound heard over the femoral artery in severe aortic regurgitation [1]. - It is a vascular sign and not related to pneumomediastinum. Kussmaul's sign - Kussmaul's sign is a paradoxical rise in jugular venous pressure (JVP) during inspiration. - It is typically seen in conditions like constrictive pericarditis or right ventricular infarction, not pneumomediastinum. None of the options - This option is incorrect because Hamman's sign accurately describes the clicking noise associated with pneumomediastinum. - The other options refer to different clinical phenomena unrelated to pneumomediastinum.
Question 632: Which of the following is least likely to be associated with emphysema?
- A. Associated with smoking
- B. Type I respiratory failure (Correct Answer)
- C. Barrel shaped chest
- D. Cyanosis
Explanation: **Type I respiratory failure** - **Emphysema** primarily causes **Type II respiratory failure** (hypercapnic) due to impaired gas exchange and CO2 retention resulting from alveolar destruction and air trapping [2][4]. - While hypoxemia can occur in severe emphysema, it is the more prominent **hypercapnia** that defines its typical respiratory failure pattern, making pure Type I less likely [3][4]. *Associated with smoking* - **Cigarette smoking** is the leading cause of emphysema, directly linked to the destruction of alveolar walls and loss of elastic recoil [1]. - The inhaled toxins trigger an inflammatory response in the lungs, leading to the release of proteases that break down lung tissue [1][2]. *Barrel shaped chest* - This is a classic sign of advanced emphysema, caused by **chronic air trapping** and subsequent hyperinflation of the lungs [2]. - The diaphragm flattens, and the ribs become more horizontal, increasing the anterior-posterior diameter of the chest. *Cyanosis* - Often seen in patients with severe emphysema (especially in a subgroup referred to as "blue bloaters" for chronic bronchitis overlap) due to **significant hypoxemia** [3]. - Impaired gas exchange leads to insufficient oxygenation of hemoglobin, causing a bluish discoloration of the skin and mucous membranes [3].
Question 633: What is the most common cause of lung abscess in comatose patients?
- A. Staph aureus
- B. Oral anaerobes (Correct Answer)
- C. Klebsiella
- D. Tuberculosis
Explanation: Oral anaerobes - **Comatose patients** are at high risk for **aspiration** of oropharyngeal flora, which predominantly consists of anaerobic bacteria. [1] - Aspiration of these organisms, especially in compromised lung tissue, frequently leads to **necrotizing pneumonia** and subsequent abscess formation. [1] *Staph aureus* - While *Staphylococcus aureus* can cause lung abscesses, particularly in the context of **hematogenous spread** (e.g., endocarditis) or nosocomial infections, it is not the most common cause in *comatose patients* who typically aspirate oral flora. [2] - *S. aureus* lung abscesses are often associated with multiple, smaller lesions rather than a single, large abscess from aspiration. *Klebsiella* - *Klebsiella pneumoniae* can cause severe, **rapidly progressive pneumonia** that may lead to abscess formation, especially in individuals with **alcoholism** or **diabetes**. - However, it is less common than oral anaerobes as the primary cause of abscess in the general population of comatose patients, whose main risk factor is aspiration of normal oral flora. [1] *Tuberculosis* - **Mycobacterium tuberculosis** can cause cavitary lung lesions, but these are typically chronic and result from primary or reactivated tuberculosis disease, not acute aspiration. [3] - Lung abscesses caused by tuberculosis are histologically distinct from pyogenic abscesses and are characterized by **granulomatous inflammation** and caseous necrosis.
Question 634: In the context of ventricular tachycardia, what do extra systoles appear as on an electrocardiogram (ECG)?
- A. P wave
- B. QRS complex (Correct Answer)
- C. T wave
- D. R wave
Explanation: ***QRS complex*** - Extra systoles, particularly **premature ventricular contractions (PVCs)**, originate in the ventricles and result in a **wide and bizarre QRS complex** on an ECG [2]. - The QRS complex represents **ventricular depolarization**, and in ventricular tachycardia, the *ventricular activity* dominates the ECG tracing [2]. *P wave* - The **P wave** represents **atrial depolarization** and is typically either absent or dissociated from the QRS complex in ventricular tachycardia [1], [2]. - Its presence or absence helps differentiate supraventricular from ventricular arrhythmias. *T wave* - The **T wave** represents **ventricular repolarization**, which typically follows the QRS complex [1]. - While it will be present, it often appears abnormal or discordant in ventricular tachycardia due to the altered ventricular depolarization. *R wave* - The **R wave** is part of the QRS complex, specifically the first positive deflection. - While an R wave is present within the QRS complex of an extrasystole, referring to the entire **QRS complex** is more accurate as it encompasses the complete ventricular depolarization in an abnormal morphology.
Question 635: What is the most common arrhythmia in ICU patients?
- A. Atrial flutter
- B. Atrial fibrillation (Correct Answer)
- C. Atrial Tachycardia
- D. Supraventricular Tachycardia
Explanation: ***Atrial fibrillation*** - **Atrial fibrillation (AF)** is the most prevalent arrhythmia in the general population [1], and its incidence is significantly higher in critically ill patients due to various stressors. - Factors like **sepsis**, **hypoxemia**, **electrolyte imbalances**, **myocardial ischemia**, and **inflammatory states** common in the ICU are known triggers for new-onset AF. *Atrial flutter* - While atrial flutter is a common arrhythmia, its overall incidence in the ICU setting is **less frequent than atrial fibrillation**. - It often involves a **re-entrant circuit** in the right atrium [2], leading to characteristic "sawtooth" waves on ECG. *Atrial Tachycardia* - Atrial tachycardia is a form of **supraventricular tachycardia (SVT)** that originates in the atria but is **less common** than AF in the ICU [2]. - It often presents as a **regular, narrow-complex tachycardia** with discrete P waves. *Supraventricular Tachycardia* - This is a broad term encompassing arrhythmias that originate **above the ventricles** [3], including AF, atrial flutter, and atrial tachycardia. - While SVT as a category is common, **atrial fibrillation is the single most frequent specific arrhythmia** within this group in the ICU.
Question 636: A patient with first-degree heart block presents with dizziness. What is the most appropriate management for this patient?
- A. Observation and investigation of other causes (Correct Answer)
- B. Pacemaker insertion
- C. Isoprenaline
- D. Atropine
Explanation: ***Observation and investigation of other causes*** - **First-degree heart block** is usually **asymptomatic** and benign, rarely causing dizziness or other symptoms. - The dizziness experienced by the patient is likely due to another underlying condition and warrants **further investigation** rather than direct intervention for the heart block [2], [3]. *Pacemaker insertion* - **Pacemaker insertion** is reserved for **symptomatic heart blocks** of higher degrees (e.g., Mobitz II or complete heart block) or those with significant hemodynamic compromise [1]. - Given that first-degree heart block is typically asymptomatic, inserting a pacemaker would be an **overtreatment** and unnecessary for this condition alone. *Isoprenaline* - **Isoprenaline** is a **beta-agonist** that increases heart rate and AV conduction, sometimes used in certain bradyarrhythmias. - However, for first-degree heart block, which is generally benign, pharmacologic intervention with agents like **isoprenaline** is not typically indicated and carries risks of adverse effects [2]. *Atropine* - **Atropine** is an anticholinergic drug used to **increase heart rate** by blocking vagal stimulation of the SA and AV nodes. - While it can improve AV conduction, it is not indicated for **asymptomatic first-degree heart block** or when symptoms like dizziness are unlikely to be directly caused by the block itself.
Question 637: Which of the following is not typically used for secondary prevention of myocardial infarction?
- A. Aspirin
- B. Statins
- C. Beta blockers
- D. Warfarin (Correct Answer)
Explanation: ***Warfarin*** - While Warfarin is an **anticoagulant**, its primary role is in preventing *thromboembolism* in conditions like **atrial fibrillation** [1] or **mechanical heart valves**, not routinely for general **secondary prevention of MI** unless specific indications exist. - Unlike the other options, it doesn't directly address the underlying plaque rupture or reduce the workload of the heart in the typical post-MI patient. *Aspirin* - **Aspirin** is a cornerstone of secondary prevention after MI due to its **antiplatelet** effects, which help prevent future clot formation [2]. - It reduces the risk of recurrent MI, stroke, and cardiovascular death by inhibiting **platelet aggregation** [2]. *Statins* - **Statins** are crucial for secondary prevention as they aggressively lower **LDL cholesterol** levels, stabilizing existing plaques and preventing further plaque progression. - They have pleiotropic effects beyond lipid lowering, including **anti-inflammatory** and **endothelial function improvement**. *Beta blockers* - **Beta blockers** reduce myocardial oxygen demand by decreasing heart rate and contractility, which helps prevent recurrent ischemic events and improves survival post-MI [3]. - They are particularly beneficial in patients with **left ventricular dysfunction** or **hypertension** following an MI [1].
Question 638: Which of the following is not recommended for patients with coronary artery disease?
- A. Vitamin E (Correct Answer)
- B. Potassium
- C. Statins
- D. Daily exercise
Explanation: ***Vitamin E*** - **Vitamin E supplements** are generally not recommended for patients with coronary artery disease (CAD) based on current evidence. Some studies suggest a potential link between high doses of vitamin E and an increased risk of **heart failure** or even **overall mortality**. - There is no convincing evidence that vitamin E supplements provide cardiovascular benefits in patients with established CAD, and they may interfere with the efficacy of other beneficial medications like **statins**. *Daily exercise* - **Regular physical activity** is a cornerstone of CAD management, improving cardiovascular fitness, reducing blood pressure, and aiding in weight control [1]. - It helps in preventing disease progression and reducing the risk of future cardiovascular events when performed under appropriate medical guidance [1]. *Potassium* - Maintaining adequate **potassium levels** is crucial for patients with CAD, especially those on diuretics, as it helps regulate **blood pressure** and prevents **cardiac arrhythmias**. - Dietary sources of potassium (fruits, vegetables) are preferred, and supplementation may be necessary for those with deficiencies, but always under medical supervision. *Statins* - **Statins** are a class of medications widely recommended for patients with CAD due to their ability to significantly lower **LDL cholesterol** levels and reduce cardiovascular events [1]. - They stabilize **atherosclerotic plaques** and reduce inflammation, playing a critical role in secondary prevention of heart attacks and strokes [1].
Pharmacology
1 questionsDigitalis is used in mitral stenosis to control the ventricular rate when the patient develops which condition?
NEET-PG 2015 - Pharmacology NEET-PG Practice Questions and MCQs
Question 631: Digitalis is used in mitral stenosis to control the ventricular rate when the patient develops which condition?
- A. Atrial fibrillation (Correct Answer)
- B. Right ventricular failure
- C. Acute pulmonary edema
- D. Myocarditis
Explanation: ***Atrial fibrillation*** - **Digitalis** (digoxin) is effective in **slowing the ventricular rate** in atrial fibrillation by increasing vagal tone and prolonging the refractory period of the AV node. - In **mitral stenosis**, an uncontrolled rapid ventricular rate due to atrial fibrillation can significantly reduce cardiac output and worsen symptoms. *Right ventricular failure* - While digitalis can improve contractility, its primary role in **RV failure** is not rate control; diuretics and afterload reduction are more commonly used. - A patient with isolated right ventricular failure due to mitral stenosis would not directly benefit from digitalis for rate control. *Acute pulmonary edema* - **Acute pulmonary edema** requires rapid diuresis, oxygen, and vasodilators to reduce preload and afterload. - Digitalis has a slower onset of action and is not the first-line treatment for acute pulmonary edema, especially if the cause is not related to a rapid ventricular rate. *Myocarditis* - **Myocarditis** is an inflammation of the heart muscle, and digitalis is generally avoided due to concerns about potentially worsening arrhythmias and myocardial damage in an inflamed heart. - Treatment for myocarditis focuses on supportive care and addressing the underlying cause, not rate control with digitalis unless specific arrhythmias develop.
Physiology
1 questionsWhat is the most common mechanism responsible for causing arrhythmias in the heart?
NEET-PG 2015 - Physiology NEET-PG Practice Questions and MCQs
Question 631: What is the most common mechanism responsible for causing arrhythmias in the heart?
- A. Re-entry (Correct Answer)
- B. Early after depolarization
- C. Late after depolarization
- D. Automaticity
Explanation: ***Re-entry*** - **Re-entry** is the most common mechanism for arrhythmias and involves a re-excitation of cardiac tissue due to a circulating electrical impulse. - This requires at least two pathways with differing conduction velocities and refractory periods, creating a path for the impulse to re-excite an area after its normal refractory period has ended. *Early after depolarization* - **Early afterdepolarizations (EADs)** occur during phase 2 or 3 of the action potential when repolarization is incomplete, often due to prolonged action potential duration. - They are typically associated with conditions like **long QT syndrome** and can trigger polymorphic ventricular tachycardia, but are less common than re-entry. *Late after depolarization* - **Late afterdepolarizations (DADs)** occur during phase 4 of the action potential, after repolarization is complete, due to excessive intracellular calcium. - They are often seen in conditions like **digoxin toxicity** or **catecholaminergic polymorphic ventricular tachycardia**, but are not the most prevalent mechanism. *Automaticity* - **Abnormal automaticity** refers to pacemaker activity arising in non-pacemaker cells or an acceleration of normal pacemaker activity. - While it can cause arrhythmias such as accelerated idioventricular rhythm, re-entry is far more frequently implicated in the etiology of clinical arrhythmias.