CONGENITAL HEART DISEASE – 20 MCQs | Kenya MBChB

20 Year 3: Cardiovascular System Pathology exam questions on CONGENITAL HEART DISEASE for medical students. Includes MCQs, answers, explanations and written que

This MCQ set contains 20 questions on CONGENITAL HEART DISEASE in the Year 3: Cardiovascular System Pathology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.

Q1: At what stage of gestation does the heart and vasculature become the first fully functional organ system?

  1. A. 4 weeks
  2. B. 8 weeks
  3. C. 12 weeks
  4. D. 20 weeks

Correct answer: A – 4 weeks

The heart and vasculature become the first fully functional organ system at approximately 4 weeks of gestation.

Q2: Which of the following is the most common genetic cause of congenital heart disease?

  1. A. Trisomy 18
  2. B. DiGeorge syndrome
  3. C. Turner syndrome
  4. D. Trisomy 21 (Down syndrome)

Correct answer: D – Trisomy 21 (Down syndrome)

Trisomy 21, or Down syndrome, is the most common genetic cause associated with congenital heart disease.

Q3: What percentage of patients with Down syndrome have one or more heart defects?

  1. A. 25%
  2. B. 10%
  3. C. 40%
  4. D. 60%

Correct answer: C – 40%

Approximately 40% of patients with Down syndrome have one or more heart defects.

Q4: A "shunt" in congenital heart disease is best defined as:

  1. A. A thickening of the ventricular wall
  2. B. A complete obstruction of a valve
  3. C. An abnormal communication between chambers or vessels
  4. D. A failure of the heart to beat

Correct answer: C – An abnormal communication between chambers or vessels

A shunt refers to an abnormal communication allowing blood to flow between chambers or vessels, bypassing normal circulation.

Q5: Which condition is characterized by a "machinery-like" murmur?

  1. A. Ventricular septal defect (VSD)
  2. B. Tetralogy of Fallot
  3. C. Atrial septal defect (ASD)
  4. D. Patent ductus arteriosus (PDA)

Correct answer: D – Patent ductus arteriosus (PDA)

Patent ductus arteriosus (PDA) is classically associated with a continuous, 'machinery-like' murmur.

Q6: Cyanosis is a primary clinical feature of which group of disorders?

  1. A. Primary hypertension
  2. B. Right-to-left shunts
  3. C. Left-to-right shunts
  4. D. Isolated obstructive lesions

Correct answer: B – Right-to-left shunts

Cyanosis, a bluish discoloration of the skin, results from deoxygenated blood bypassing the lungs, which occurs in right-to-left shunts.

Q7: Eisenmenger syndrome occurs when:

  1. A. The aorta is completely obstructed
  2. B. The tricuspid valve is absent
  3. C. A right-to-left shunt becomes left-to-right
  4. D. A left-to-right shunt reverses to right-to-left due to pulmonary hypertension

Correct answer: D – A left-to-right shunt reverses to right-to-left due to pulmonary hypertension

Eisenmenger syndrome is characterized by the reversal of a left-to-right shunt to a right-to-left shunt, caused by severe pulmonary hypertension.

Q8: Which of the following is NOT one of the four cardinal features of Tetralogy of Fallot?

  1. A. Overriding aorta
  2. B. Left atrial dilation
  3. C. Ventricular septal defect
  4. D. Right ventricular hypertrophy

Correct answer: B – Left atrial dilation

The four cardinal features of Tetralogy of Fallot are overriding aorta, ventricular septal defect, right ventricular hypertrophy, and pulmonary stenosis (subpulmonic stenosis). Left atrial dilation is not a primary feature.

Q9: What is the most common form of congenital heart disease (excluding bicuspid aortic valve)?

  1. A. Patent ductus arteriosus
  2. B. Ventricular septal defect
  3. C. Atrial septal defect
  4. D. Coarctation of the aorta

Correct answer: B – Ventricular septal defect

Ventricular septal defect (VSD) is the most common form of congenital heart disease, excluding bicuspid aortic valve.

Q10: The "second heart field" in fetal development primarily populates which structures?

  1. A. The pulmonary veins
  2. B. The mitral valve
  3. C. Left ventricle only
  4. D. Outflow tract, right ventricle, and most of the atria

Correct answer: D – Outflow tract, right ventricle, and most of the atria

The second heart field contributes significantly to the formation of the outflow tract, right ventricle, and much of the atria.

Q11: Which transcription factor mutation is specifically linked to DiGeorge syndrome and neural crest migration?

  1. A. NKX2.5
  2. B. TBX1
  3. C. GATA4
  4. D. NOTCH1

Correct answer: B – TBX1

TBX1 mutation is specifically linked to DiGeorge syndrome, which involves defective neural crest migration.

Q12: Paradoxical embolism is a potential complication of:

  1. A. Mitral valve prolapse
  2. B. Left ventricular hypertrophy
  3. C. Right-to-left shunts (or transient reversal of left-to-right shunts)
  4. D. Purely obstructive lesions

Correct answer: C – Right-to-left shunts (or transient reversal of left-to-right shunts)

Paradoxical embolism occurs when an embolus from the venous system crosses to the arterial system through a right-to-left shunt, such as a patent foramen ovale or an ASD/VSD with reversed flow.

Q13: Which of these is a typical "obstructive" congenital lesion?

  1. A. Persistent truncus arteriosus
  2. B. Atrial septal defect
  3. C. Coarctation of the aorta
  4. D. Transposition of the great arteries

Correct answer: C – Coarctation of the aorta

Coarctation of the aorta is an obstructive lesion characterized by a narrowing of the aorta.

Q14: Secundum ASDs (90% of all ASDs) result from a deficiency in the:

  1. A. Endocardial cushions
  2. B. Septum secundum
  3. C. Infundibular septum
  4. D. Septum primum

Correct answer: B – Septum secundum

Secundum atrial septal defects, the most common type, are due to a deficiency in the septum secundum.

Q15: At birth, the closure of the foramen ovale is triggered by:

  1. A. A surge in prostaglandin E2
  2. B. Contraction of the ductus arteriosus
  3. C. Increased right atrial pressure
  4. D. Decreased pulmonary vascular pressure and increased left atrial pressure

Correct answer: D – Decreased pulmonary vascular pressure and increased left atrial pressure

At birth, lung expansion leads to decreased pulmonary vascular resistance, increasing pulmonary blood flow and left atrial pressure, which functionally closes the foramen ovale.

Q16: "Clubbing" of the fingers is a clinical sign associated with:

  1. A. Simple ASDs in infancy
  2. B. Chronic severe hypoxia/cyanosis
  3. C. Mild aortic stenosis
  4. D. Acute hypertension

Correct answer: B – Chronic severe hypoxia/cyanosis

Clubbing of the fingers is a sign of chronic severe hypoxia or cyanosis, often seen in cyanotic congenital heart diseases.

Q17: Most ventricular septal defects (VSDs) occur in which part of the septum?

  1. A. Lower septum
  2. B. Muscular part
  3. C. Membranous part
  4. D. Infundibular part

Correct answer: C – Membranous part

The membranous part of the ventricular septum is the most common site for VSDs.

Q18: In Tetralogy of Fallot, "subpulmonic stenosis" refers to:

  1. A. Atresia of the tricuspid valve
  2. B. Closure of the mitral valve
  3. C. Narrowing of the aortic valve
  4. D. Obstruction of the right ventricular outflow tract

Correct answer: D – Obstruction of the right ventricular outflow tract

Subpulmonic stenosis in Tetralogy of Fallot refers to the obstruction of the right ventricular outflow tract, leading to reduced pulmonary blood flow.

Q19: Which medication is used to maintain ductal patency in certain life-threatening CHDs?

  1. A. Beta-blockers
  2. B. Aspirin
  3. C. Prostaglandin E1
  4. D. Prostaglandin synthesis inhibitors

Correct answer: C – Prostaglandin E1

Prostaglandin E1 is administered to maintain the patency of the ductus arteriosus in infants with ductal-dependent congenital heart defects.

Q20: Which syndrome involves a deletion on chromosome 22q11.2?

  1. A. Noonan syndrome
  2. B. Marfan syndrome
  3. C. Down syndrome
  4. D. DiGeorge syndrome

Correct answer: D – DiGeorge syndrome

DiGeorge syndrome is characterized by a microdeletion on chromosome 22q11.2, leading to various developmental abnormalities including heart defects.

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