Syncope and Presyncope — MCQs
Which of the following features helps in distinguishing seizures from syncope?
A young female presents with chest pain not associated with exercise. Auscultation reveals multiple ejection clicks with a murmur. The most important investigation for diagnosis is:
A patient with new-onset syncope has a blood pressure of 110/95 mmHg and a harsh systolic ejection murmur at the base, radiating to both carotids. What finding may be revealed upon auscultation of the second heart sound at the base?
Neurogenic shock is characterized by:
Mobitz type 2 second degree AV block is seen in all except:
Which of the following is the most common cause of syncope in children?
In the context of ventricular tachycardia, what do extra systoles appear as on an electrocardiogram (ECG)?
A 38-year-old man presents with pain and shortness of breath. His pulse rate is 85 per minute, blood pressure is 180/80 mmHg, and the cardiac examination reveals an ejection systolic murmur. The ECG shows a LVH pattern and ST depression in the anterior leads. His Troponin T test is positive. Based on these findings, the echocardiogram is likely to reveal which of the following conditions?
What is the Lovibond angle?
Which of the following statements is true regarding digital clubbing?
Syncope and Presyncope Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following features helps in distinguishing seizures from syncope?
- A. Urinary incontinence
- B. Injury due to fall
- C. Physical weakness with clear sensorium (Correct Answer)
- D. Loss of consciousness
Explanation: ***Physical weakness with clear sensorium*** - This describes the **post-syncopal state**, where a patient typically feels weak but is fully aware and oriented immediately upon regaining consciousness, unlike the **post-ictal confusion** seen after a seizure [1]. - The rapid return to a clear sensorium is a key differentiating feature as syncope is a transient global cerebral hypoperfusion event without the sustained neuronal discharge of a seizure [1], [2]. *Urinary incontinence* - **Urinary incontinence** can occur in both severe syncopal episodes and seizures, making it a non-specific differentiator [1], [2]. - While more common and often tonic in seizures, brief bladder control loss can happen with significant hypotension in syncope. *Injury due to fall* - **Injury due to fall** can occur in both seizures and syncope, as both conditions involve a sudden loss of postural control [2]. - The nature of the injury might differ (e.g., specific injuries like posterior shoulder dislocation in seizures), but the fall itself is not distinctive. *Loss of consciousness* - Both **seizures** and **syncope** are characterized by a transient **loss of consciousness** [3]. - This symptom defines the core presentation of both conditions and therefore does not help in distinguishing between them.
Question 2: A young female presents with chest pain not associated with exercise. Auscultation reveals multiple ejection clicks with a murmur. The most important investigation for diagnosis is:
- A. ECG
- B. Thallium 201 scan
- C. Echocardiography (Correct Answer)
- D. Tc pyrophosphate scan
Explanation: ***Echocardiography*** - **Echocardiography** is the gold standard for visualizing cardiac structures and valve function, allowing direct assessment of **mitral valve prolapse (MVP)** [1]. - The presence of **multiple ejection clicks** and a murmur in a young female with non-exertional chest pain strongly suggests MVP, which can be confirmed by echocardiography [3]. *ECG* - An **ECG** can detect arrhythmias or signs of ischemia, but it cannot directly visualize the heart valves or diagnose **mitral valve prolapse** [2]. - While some MVP patients may have T-wave abnormalities or QT prolongation, these findings are non-specific and not diagnostic. *Thallium 201 scan* - A **Thallium 201 scan** is a nuclear imaging test primarily used to assess myocardial perfusion and detect areas of ischemia, usually in the context of **coronary artery disease** [4]. - It does not provide detailed anatomical information about heart valves or cardiac chamber morphology, making it unsuitable for diagnosing **mitral valve prolapse**. *Tc pyrophosphate scan* - A **Tc pyrophosphate scan** is primarily used to diagnose **amyloidosis** or evaluate myocardial infarction, particularly for detecting late-phase complications or right ventricular involvement. - It does not offer direct visualization of valvular structures and is not indicated for the diagnosis of **mitral valve prolapse**.
Question 3: A patient with new-onset syncope has a blood pressure of 110/95 mmHg and a harsh systolic ejection murmur at the base, radiating to both carotids. What finding may be revealed upon auscultation of the second heart sound at the base?
- A. It is accentuated.
- B. It is diminished. (Correct Answer)
- C. It is normal in character.
- D. It is widely split due to delayed ventricular ejection.
Explanation: ***It is diminished.*** - A **harsh systolic ejection murmur** radiating to the carotids, new-onset syncope, and a narrow pulse pressure (110/95 mmHg) are highly suggestive of **severe aortic stenosis** [1]. - In **severe aortic stenosis**, the aortic valve leaflets are rigid and fail to open properly, causing a significant reduction in the **aortic component of the second heart sound (A2)** due to decreased mobility and calcification [1], [2]. *It is accentuated.* - An **accentuated S2** (specifically A2) would indicate conditions like systemic hypertension or an increased closing pressure of the aortic valve, which is not consistent with severe aortic stenosis. - In **aortic stenosis**, the valve is *stiff* and *calcified*, leading to a weakened rather than an accentuated closing sound [1]. *It is normal in character.* - A **normal S2** would suggest that the aortic valve is functioning adequately or that any stenosis is mild and not significantly impacting valve closure, which contradicts the patient's symptoms and the harsh murmur. - The presence of **syncope** and a **harsh systolic murmur** strongly implies hemodynamically significant valvular disease [1]. *It is widely split due to delayed ventricular ejection.* - A **widely split S2** with delayed ventricular ejection is characteristic of **right bundle branch block** or **pulmonic stenosis**, neither of which fits the clinical picture of a harsh systolic ejection murmur radiating to the carotids. - In severe aortic stenosis, there can be a **paradoxical splitting of S2** (P2 preceding A2) due to prolonged left ventricular ejection time, but a widely split S2 due to delayed right ventricular ejection is incorrect.
Question 4: Neurogenic shock is characterized by:
- A. Hypotension and bradycardia (Correct Answer)
- B. Hypotension and tachycardia
- C. Hypertension and tachycardia
- D. Hypertension and bradycardia
Explanation: ***Hypotension and bradycardia*** - **Neurogenic shock** results from the loss of **sympathetic vascular tone**, leading to widespread vasodilation and subsequent **hypotension**. - The interruption of sympathetic innervation to the heart can also cause **bradycardia**, as parasympathetic tone becomes unopposed. *Hypotension and tachycardia* - This presentation is typical of other forms of shock, such as **hypovolemic** or **septic shock**, where the body attempts to compensate for low blood pressure with an increased heart rate. - In neurogenic shock, the sympathetic nervous system, which usually causes tachycardia, is dysfunctional. *Hypertension and tachycardia* - This combination is not characteristic of any form of shock; rather, it often indicates a **hyperadrenergic state** or certain types of **hypertensive crisis**. - Shock is fundamentally a state of inadequate tissue perfusion, which typically involves hypotension. *Hypertension and bradycardia* - This combination can be seen in conditions like **Cushing's reflex** (due to increased intracranial pressure) but is not a feature of neurogenic shock [1]. - Neurogenic shock is defined by a loss of sympathetic tone, which leads to vessel dilation and reduced blood pressure.
Question 5: Mobitz type 2 second degree AV block is seen in all except:
- A. Hypothyroidism
- B. Cushing syndrome (Correct Answer)
- C. Sarcoidosis
- D. Coronary Artery Disease
Explanation: Cushing syndrome - **Mobitz type 2 AV block** is not a characteristic cardiovascular manifestation of Cushing syndrome. - Cushing syndrome primarily leads to **hypertension**, hyperglycemia, and dyslipidemia, which can increase cardiovascular risk but typically do not cause direct conduction system disease. *Hypothyroidism* - Severe **hypothyroidism** can lead to various cardiovascular abnormalities, including **bradycardia** and impaired conduction, which can manifest as AV blocks. - Myxedematous involvement of the heart can directly affect the **conduction system**. *Coronary Artery Disease* - **Ischemia** or infarction affecting the AV node or His-Purkinje system can cause **Mobitz type 2 AV block** [1]. - Blockage of the **right coronary artery** (supplying the AV node in most cases) or the septal perforators can lead to these conduction disturbances [2]. *Sarcoidosis* - **Cardiac sarcoidosis** often involves the heart's conduction system, leading to various **arrhythmias** and blocks, including Mobitz type 2 AV block. - Granulomas can directly infiltrate and damage the **AV node** or His-Purkinje fibers.
Question 6: Which of the following is the most common cause of syncope in children?
- A. Breath holding spells
- B. Hypoglycemia
- C. Neurocardiogenic syncope (Correct Answer)
- D. Hypovolemia
Explanation: ***Neurocardiogenic syncope*** - This is the **most common cause of syncope** in children and adolescents, often triggered by prolonged standing, pain, or emotional stress. - It results from a **reflex-mediated drop in heart rate and blood pressure**, leading to temporary cerebral hypoperfusion. *Breath holding spells* - While common in infants and toddlers (6 months to 6 years), these are typically **self-limiting, benign events** related to anger or pain, and not the most common cause of syncope across all pediatric ages. - They are characterized by **cyanosis** or pallor followed by a brief loss of consciousness, but differ from true syncope in their underlying mechanism. *Hypoglycemia* - Although it can cause **lightheadedness, confusion, and sometimes loss of consciousness**, it is not the most frequent cause of syncope in generally healthy children without underlying metabolic disorders or diabetes. - Diagnosis requires demonstrating **low blood sugar levels** at the time of the event. *Hypovolemia* - This can cause syncope due to **decreased circulating blood volume** and reduced cerebral perfusion, often seen in cases of severe dehydration or hemorrhage. - However, in the general pediatric population, it is a **less common cause of syncope** compared to neurocardiogenic mechanisms.
Question 7: 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 8: A 38-year-old man presents with pain and shortness of breath. His pulse rate is 85 per minute, blood pressure is 180/80 mmHg, and the cardiac examination reveals an ejection systolic murmur. The ECG shows a LVH pattern and ST depression in the anterior leads. His Troponin T test is positive. Based on these findings, the echocardiogram is likely to reveal which of the following conditions?
- A. Aortic regurgitation
- B. Aortic stenosis (Correct Answer)
- C. Mitral regurgitation
- D. Mitral valve prolapse
Explanation: Aortic stenosis - The presence of an **ejection systolic murmur** [2], **left ventricular hypertrophy** on ECG [1], and a history of **pain and shortness of breath** are classic signs of aortic stenosis. The **wide pulse pressure** (180/80 mmHg) despite a normal pulse rate suggests increased peripheral resistance, common in advanced aortic stenosis. - **Elevated troponin T** suggests myocardial injury, which can occur due to increased myocardial oxygen demand in the context of severe aortic stenosis and LVH. *Aortic regurgitation* - This condition typically presents with a **diastolic murmur**, not an ejection systolic one [3]. - While it can cause LVH, the hallmark symptom of an **ejection systolic murmur** points away from regurgitation. *Mitral regurgitation* - This condition is characterized by a **holosystolic murmur** best heard at the apex and radiating to the axilla, different from the ejection systolic murmur described [1]. - While it can lead to LVH over time, the clinical presentation and specific murmur type are not consistent with mitral regurgitation. *Mitral valve prolapse* - This condition is often associated with a **mid-systolic click** followed by a late systolic murmur, rather than a clear ejection systolic murmur [4]. - Although it can sometimes cause chest pain, it rarely leads to the degrees of LVH and **troponin elevation** described in this scenario without other contributing factors.
Question 9: What is the Lovibond angle?
- A. The angle between the iris and cornea
- B. The angle between the long axis of the forearm and the long axis of the upper arm
- C. The angle between the nail bed and the proximal nail fold (Correct Answer)
- D. The angle between the manubrium sternum and the body of the sternum
Explanation: **Explanation:** The **Lovibond angle** (also known as the profile angle) is a critical clinical landmark used to identify **clubbing** (hypertrophic osteoarthropathy). In a normal individual, the angle formed between the proximal nail fold and the nail bed is approximately **160°**. When clubbing occurs, there is proliferation of soft tissue at the nail base, causing this angle to increase and eventually exceed **180°** (obliteration of the angle). **Analysis of Options:** * **Option A:** The angle between the iris and cornea is the **iridocorneal angle**, which is evaluated via gonioscopy to differentiate between open-angle and closed-angle glaucoma. * **Option B:** The angle between the long axis of the forearm and upper arm is the **carrying angle** (normal: 5–15°). An increase is called cubitus valgus; a decrease is cubitus varus. * **Option D:** The angle between the manubrium and the body of the sternum is the **Angle of Louis** (Sternal angle), a key anatomical landmark for the 2nd rib and the T4-T5 vertebral level. **Clinical Pearls for NEET-PG:** 1. **Schamroth’s Sign:** The loss of the diamond-shaped window when the dorsal surfaces of terminal phalanges of corresponding fingers are opposed. 2. **Curth’s Modified Profile Angle:** Measured between the distal and proximal phalanges; an angle >190° is indicative of clubbing. 3. **Grades of Clubbing:** * Grade 1: Softening of the nail bed (fluctuancy). * Grade 2: Obliteration of Lovibond angle. * Grade 3: Increased curvature of the nail (Parrot-beak appearance). * Grade 4: Drumstick appearance. * Grade 5: Hypertrophic Osteoarthropathy (HOA) with bone involvement.
Question 10: Which of the following statements is true regarding digital clubbing?
- A. Clubbing always indicates heart disease
- B. Clubbing is seen in pulmonary arteriovenous fistula (Correct Answer)
- C. Clubbing is common in cirrhosis of the liver
- D. Presence of clubbing warrants a search for sickle cell disease
Explanation: **Explanation:** Digital clubbing is a clinical sign characterized by the focal bulbous enlargement of the distal segments of fingers and toes due to proliferation of connective tissue between the nail matrix and the distal phalanx [1]. **Why Option B is Correct:** **Pulmonary arteriovenous fistulas (AVFs)** are a classic cause of clubbing. They create a right-to-left shunt, allowing deoxygenated blood to bypass the pulmonary capillary bed. This leads to systemic hypoxemia and allows large platelets/megakaryocytes to enter the systemic circulation. These cells lodge in the distal capillaries of the digits and release **Platelet-Derived Growth Factor (PDGF)** and **Vascular Endothelial Growth Factor (VEGF)**, which promote the soft tissue and vascular proliferation characteristic of clubbing. **Analysis of Incorrect Options:** * **Option A:** Clubbing does **not** always indicate heart disease. While it occurs in cyanotic congenital heart diseases (e.g., Tetralogy of Fallot), it is more frequently associated with pulmonary conditions (e.g., Bronchogenic carcinoma, Bronchiectasis, Lung abscess) [1], [2]. * **Option C:** While clubbing can occur in cirrhosis (specifically primary biliary cholangitis), it is **not "common"** in general cirrhosis [1]. It is more frequently associated with Hepatopulmonary Syndrome. * **Option D:** Sickle cell disease is **not** a recognized cause of clubbing. In fact, if a patient with sickle cell disease develops clubbing, it usually suggests a secondary complication like chronic lung disease. **High-Yield NEET-PG Pearls:** * **Earliest sign of clubbing:** Obliteration of the **Lovibond angle** (the angle between the nail base and the adjacent skin fold). * **Schamroth’s Sign:** Loss of the diamond-shaped window when the dorsal surfaces of terminal phalanges are opposed. * **Most common cause of unilateral clubbing:** Axillary artery aneurysm or Pancoast tumor. * **Most common cause of clubbing in adults:** Bronchogenic carcinoma (specifically non-small cell) [1], [2]. Note: Clubbing is **rare** in COPD; its presence in a COPD patient should trigger a search for underlying malignancy.
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