Congenital Anomalies — MCQs
A newborn male is noted to have difficulty feeding and "turns blue and chokes when drinking formula." The prenatal records reveal that the amniotic fluid appeared normal on ultrasound. A pediatric feeding tube is passed orally to 20 cm without difficulty, with gastric secretions aspirated. Which of the following is the most likely diagnosis?
Which of the following causes teratogenicity?
The commonest type of congenital heart disease is –
Which one of the following life-threatening congenital anomalies in the newborn presents with polyhydramnios, aspiration pneumonia, excessive salivation and difficulty in passing a nasogastric tube?
Which of the following anti-epileptic drugs has the highest teratogenic potential?
A child presented at 10 weeks with recurrent episode of pneumonia and failure to thrive. X-ray shows cardiomegaly & pulmonary plethora. What is the diagnosis?
In pregnancy, neural tube defects arise in the fetus due to a deficiency of which specific vitamin in the mother?
Which of the following drugs taken by the mother during pregnancy can cause the congenital defect shown in the image?
18 weeks pregnant female presents with no high risk of NTD and low risk of trisomy 21 on quad test. What is the most appropriate next step in management?
USG of 28 weeks gestation showing oligohydramnios is likely to be due to?
Congenital Anomalies Indian Medical PG Practice Questions and MCQs
Question 1: A newborn male is noted to have difficulty feeding and "turns blue and chokes when drinking formula." The prenatal records reveal that the amniotic fluid appeared normal on ultrasound. A pediatric feeding tube is passed orally to 20 cm without difficulty, with gastric secretions aspirated. Which of the following is the most likely diagnosis?
- A. Floppy epiglottis
- B. Tracheoesophageal fistula (Correct Answer)
- C. Zenker diverticulum
- D. Congenital heart disease
Explanation: ***Tracheoesophageal fistula*** - The combination of **feeding difficulties**, **cyanosis** ("turns blue"), and **choking** in a newborn, along with the ability to pass a feeding tube to 20 cm, strongly suggests a tracheoesophageal fistula (TEF), specifically a type where the **proximal esophagus ends in a blind pouch and the distal esophagus connects to the trachea**. - The **normal amniotic fluid** on prenatal ultrasound suggests that the fetus was able to swallow amniotic fluid, ruling out esophageal atresia without a fistula as the primary cause of polyhydramnios. Passage of the feeding tube to 20 cm and aspiration of gastric secretions indicates that the stomach is connected to the esophagus, but the reflux of gastric contents during feeding leads to aspiration into the trachea via the fistula. *Floppy epiglottis* - **Laryngomalacia**, or "floppy epiglottis," typically causes **stridor** (a high-pitched inspiratory sound), especially when crying or feeding, which is not the primary symptom described here. - While it can cause some feeding difficulties, **severe cyanosis and recurrent choking** during feeding are more characteristic of aspiration due to a different anatomical defect like TEF. *Zenker diverticulum* - A **Zenker diverticulum is a pharyngoesophageal pouch** that typically causes dysphagia, regurgitation of undigested food, and halitosis, primarily in **older adults**. - It is an acquired condition and **extremely rare in newborns**, making it an unlikely diagnosis for these symptoms in an infant. *Congenital heart disease* - While congenital heart disease can cause **cyanosis and feeding difficulties** due to increased metabolic demand or heart failure, it would not typically present with the specific description of **choking during feeding and successful passing of a feeding tube to the stomach with aspirated gastric secretions**. - The symptoms in this case point more directly to a **problem with the swallowing mechanism or the connection between the esophagus and the trachea**.
Question 2: Which of the following causes teratogenicity?
- A. Vitamin E
- B. Vitamin D
- C. Vitamin A (Correct Answer)
- D. Vitamin C
Explanation: ***Vitamin A*** - Excessive intake of **Vitamin A (retinoids)**, particularly during early pregnancy, is a known cause of **teratogenicity**. - It can lead to various birth defects, including **craniofacial abnormalities**, **cardiac defects**, and **central nervous system malformations**. *Vitamin E* - **Vitamin E** is generally considered safe during pregnancy and has no known teratogenic effects at recommended dosages. - It functions as an **antioxidant** and is important for cell protection. *Vitamin D* - While **Vitamin D** is essential for proper fetal development, excessive intake is not typically associated with teratogenicity but can cause **hypercalcemia** in the mother and fetus. - Mild to moderate supplementation is often recommended during pregnancy for bone health. *Vitamin C* - **Vitamin C** is a water-soluble vitamin and is not considered teratogenic, even at higher doses, as excess amounts are readily excreted. - It plays a crucial role in **collagen synthesis** and immune function during pregnancy.
Question 3: The commonest type of congenital heart disease is –
- A. ASD
- B. PDA
- C. TOF
- D. VSD (Correct Answer)
Explanation: ***VSD*** - **Ventricular Septal Defect (VSD)** is the most common type of **congenital heart disease**, accounting for approximately 25-30% of all congenital heart defects. - It involves a hole in the septum separating the **ventricles**, leading to a **left-to-right shunt** of blood. *ASD* - **Atrial Septal Defects (ASDs)** are common but less frequent than VSDs, typically accounting for about 10% of congenital heart defects. - ASDs involve a hole in the septum separating the **atria**, also causing a **left-to-right shunt**. *PDA* - **Patent Ductus Arteriosus (PDA)** is another common congenital heart defect, but it is less prevalent than VSD, accounting for around 5-10% of cases. - PDA is the persistence of the fetal **ductus arteriosus**, allowing blood to flow from the **aorta to the pulmonary artery**. *TOF* - **Tetralogy of Fallot (TOF)** is a complex cyanotic congenital heart defect, representing about 5-7% of all congenital heart diseases. - It is characterized by four distinct anomalies: **pulmonary stenosis**, **ventricular septal defect**, **overriding aorta**, and **right ventricular hypertrophy**.
Question 4: Which one of the following life-threatening congenital anomalies in the newborn presents with polyhydramnios, aspiration pneumonia, excessive salivation and difficulty in passing a nasogastric tube?
- A. Choanal atresia
- B. Gastroschisis
- C. Diaphragmatic hernia
- D. Tracheo-esophageal fistula (Correct Answer)
Explanation: ***Tracheo-esophageal fistula*** - This condition presents with **polyhydramnios** due to the fetus being unable to swallow amniotic fluid, **excessive salivation** from accumulated secretions in the blind-ending esophageal pouch, and difficulty passing a **nasogastric tube** because of the esophageal obstruction. - **Aspiration pneumonia** is a common complication as saliva and gastric contents can be aspirated into the lungs through the fistula. *Choanal atresia* - Characterized by **blocked nasal passages**, leading to **cyclical cyanosis** relieved by crying, but not typically associated with polyhydramnios or excessive salivation in this manner. - While it can cause respiratory distress, it does not involve esophageal obstruction or directly cause aspiration pneumonia from swallowed fluids. *Gastroschisis* - This is an **abdominal wall defect** where intestines protrude outside the body, unrelated to swallowing difficulties, polyhydramnios caused by inability to swallow, or excessive salivation. - It does not involve difficulty in passing a nasogastric tube or directly cause aspiration pneumonia. *Diaphragmatic hernia* - Involves **abdominal contents herniating into the chest cavity**, leading to **pulmonary hypoplasia** and respiratory distress. - It does not explain polyhydramnios due to impaired swallowing, excessive salivation, or the characteristic inability to pass a nasogastric tube.
Question 5: Which of the following anti-epileptic drugs has the highest teratogenic potential?
- A. Carbamazepine
- B. Phenytoin
- C. Valproate (Correct Answer)
- D. Lamotrigine
Explanation: ***Correct: Valproate*** - **Valproate has the highest teratogenic potential** among all anti-epileptic drugs, with a **10-20% risk of major congenital malformations** - **Neural tube defects** (spina bifida) occur in **1-2% of exposed pregnancies**, which is 10-20 times higher than the general population - Other significant risks include **cardiac malformations, craniofacial abnormalities**, and **neurodevelopmental disorders** (autism spectrum disorder, reduced IQ) - **Fetal valproate syndrome** is a recognized clinical entity - Current guidelines strongly recommend **avoiding valproate in women of childbearing potential** unless no alternatives exist *Incorrect: Carbamazepine* - Has teratogenic risks but significantly **lower than valproate** (2-5% risk of major malformations) - Associated with **neural tube defects** (0.5-1% risk, lower than valproate) - Considered a safer alternative when valproate must be avoided *Incorrect: Phenytoin* - Causes **fetal hydantoin syndrome** with characteristic features: craniofacial anomalies, nail/digital hypoplasia, growth restriction, and developmental delay - Teratogenic risk is **moderate** (approximately 5-10% risk of major malformations) - Risk is significant but **lower than valproate** *Incorrect: Lamotrigine* - Considered **one of the safest anti-epileptic drugs** during pregnancy - Low teratogenic risk with **major malformation rate of 2-3%** (close to baseline population risk) - Slight increased risk of **oral clefts** at higher doses - **Preferred choice** for women of childbearing potential requiring anti-epileptic therapy
Question 6: A child presented at 10 weeks with recurrent episode of pneumonia and failure to thrive. X-ray shows cardiomegaly & pulmonary plethora. What is the diagnosis?
- A. VSD (Correct Answer)
- B. TOF
- C. Patent foramen ovale
- D. ASD
Explanation: ***VSD*** - **Ventricular septal defect (VSD)** is the most common cause of this presentation in early infancy (symptoms typically appear at **6-10 weeks** of age). - Large VSDs cause significant **left-to-right shunt** leading to pulmonary overcirculation, resulting in **recurrent pneumonia** and **failure to thrive**. - **Cardiomegaly** (due to volume overload of left atrium and ventricle) and **pulmonary plethora** (increased pulmonary vascular markings) on X-ray are classic findings. - The infant may also present with tachypnea, feeding difficulties, and poor weight gain. *TOF* - **Tetralogy of Fallot (TOF)** is a **cyanotic heart defect** with right-to-left shunt, presenting with cyanosis and hypoxic spells, not recurrent pneumonia. - X-ray shows **boot-shaped heart** and **pulmonary oligemia** (decreased pulmonary vascular markings), not pulmonary plethora. - Does not typically cause failure to thrive in the same manner as acyanotic left-to-right shunt lesions. *Patent foramen ovale* - A **patent foramen ovale (PFO)** is a normal variant in infants and typically remains **asymptomatic**. - Does not cause significant hemodynamic shunting in the absence of elevated right atrial pressure. - Does not cause **cardiomegaly**, **pulmonary plethora**, recurrent pneumonia, or failure to thrive. *ASD* - An **atrial septal defect (ASD)** also causes left-to-right shunt with pulmonary plethora, but the shunt develops **gradually** over time. - ASD typically presents **later in childhood or adulthood** with milder symptoms (fatigue, exercise intolerance) due to lower pressure gradient across atria. - **Recurrent pneumonia and failure to thrive at 10 weeks** are uncommon with isolated ASD, as the hemodynamic changes are less pronounced in early infancy compared to VSD. - When symptomatic in infancy, large ASDs present later (around 6 months to 1 year) rather than at 10 weeks.
Question 7: In pregnancy, neural tube defects arise in the fetus due to a deficiency of which specific vitamin in the mother?
- A. Folic Acid (Correct Answer)
- B. Vitamin A
- C. Vitamin C
- D. Vitamin D
Explanation: ***Folic Acid*** - Deficiency of **folic acid (Vitamin B9)** during early pregnancy is a well-established cause of **neural tube defects (NTDs)** in the fetus. - Adequate folate intake is crucial for proper **neural tube closure**, which occurs at 3-4 weeks gestation. *Vitamin D* - **Vitamin D deficiency** is linked to bone health issues, such as **rickets** in children and **osteomalacia** in adults, and can impact immune function. - It is not directly associated with the development of **neural tube defects**. *Vitamin A* - **Vitamin A** is essential for vision, immune function, and cell growth, but both its **deficiency** and **excess** can cause birth defects. - Excessive intake of preformed Vitamin A (retinol) is **teratogenic** (e.g., causing craniofacial, cardiac, and central nervous system anomalies), but deficiency does not typically cause neural tube defects. *Vitamin C* - **Vitamin C** is vital for collagen synthesis, wound healing, and acts as an antioxidant. - Its deficiency causes **scurvy**, characterized by weakened connective tissue, but is not implicated in neural tube defects.
Question 8: Which of the following drugs taken by the mother during pregnancy can cause the congenital defect shown in the image?
- A. Folic acid
- B. Niacin
- C. Retinoic acid (Correct Answer)
- D. Thiamine
Explanation: ***Retinoic acid*** - The image depicts a severe **cleft lip and palate**, a common and well-documented teratogenic effect of **retinoids**, especially **isotretinoin (13-cis-retinoic acid)**, when taken during pregnancy. - Retinoic acid is an active metabolite of **vitamin A** and has critical roles in **embryonic development**; however, its excess can disrupt normal craniofacial development. *Folic acid* - **Folic acid** supplementation during pregnancy is protective and prevents **neural tube defects** (e.g., spina bifida, anencephaly), not associated with causing cleft lip or palate. - Adequate folic acid intake is recommended before and during early pregnancy to prevent neural tube defects. *Niacin* - **Niacin (vitamin B3)** supplementation in standard doses has not been directly implicated in causing cleft lip and palate. - Severe niacin deficiency can lead to **pellagra**, but this is not related to the craniofacial malformation shown. *Thiamine* - **Thiamine (vitamin B1)** supplementation is safe during pregnancy and not associated with teratogenic effects. - Thiamine deficiency can lead to **beriberi**, affecting the cardiovascular or nervous systems, but there is no established link between thiamine and cleft lip and palate.
Question 9: 18 weeks pregnant female presents with no high risk of NTD and low risk of trisomy 21 on quad test. What is the most appropriate next step in management?
- A. Repeat non-invasive screening test.
- B. Perform invasive diagnostic testing.
- C. Perform amniotic fluid analysis.
- D. Perform a detailed fetal ultrasound. (Correct Answer)
Explanation: ***Perform a detailed fetal ultrasound.*** - A **detailed fetal ultrasound** (often referred to as an **anatomy scan**) at around 18-22 weeks is a standard component of prenatal care for all pregnant women, regardless of screening test results. - This ultrasound evaluates fetal anatomy for structural anomalies, assesses fetal growth, and confirms gestational age, providing crucial information even with low-risk screening. *Repeat non-invasive screening test.* - Repeating a non-invasive screening test (like another quad screen or NIPT) is generally **not indicated** when initial results show a low risk and there are no other clinical concerns. - Such tests are primarily for screening purposes, and a second low-risk result would offer little additional actionable information, as their positive predictive value is low. *Perform invasive diagnostic testing.* - **Invasive diagnostic testing**, such as **amniocentesis** or **chorionic villus sampling (CVS)**, carries a risk of miscarriage and is reserved for situations with a high risk of chromosomal abnormalities or genetic conditions. - Given the low-risk quad screen results for trisomy 21 and no high risk for NTDs, invasive testing is **not warranted** at this stage. *Perform amniotic fluid analysis.* - **Amniotic fluid analysis** is part of an amniocentesis, an **invasive diagnostic procedure** designed to detect chromosomal abnormalities or genetic disorders. - This procedure is typically reserved for cases where screening tests indicate a high risk or there is a clinical suspicion of a genetic condition; it's **not a routine step** after a low-risk quad screen.
Question 10: USG of 28 weeks gestation showing oligohydramnios is likely to be due to?
- A. Renal pathway obstruction (Correct Answer)
- B. Neuromuscular disorder
- C. Gastrointestinal obstruction
- D. Anencephaly
Explanation: ***Renal pathway obstruction*** - **Oligohydramnios** (low amniotic fluid) in the late second or third trimester is often caused by conditions that impair fetal urine production or outflow. - **Renal pathway obstruction** (e.g., posterior urethral valves, bilateral renal agenesis) prevents the fetus from producing or excreting sufficient urine, a primary source of amniotic fluid. *Gastrointestinal obstruction* - **Gastrointestinal obstruction** is more commonly associated with **polyhydramnios** because it impairs the fetal swallowing of amniotic fluid. - Inability to swallow leads to an *accumulation* of amniotic fluid, not a reduction. *Anencephaly* - **Anencephaly** is typically associated with **polyhydramnios** due to impaired swallowing of amniotic fluid. - The exposed brain tissue can also lead to increased fluid transudation. *Neuromuscular disorder* - **Neuromuscular disorders** can cause **polyhydramnios** if they lead to impaired fetal swallowing due to muscle weakness. - If a neuromuscular disorder affects the renal system, it could potentially cause oligohydramnios, but it is not the primary cause of oligohydramnios itself.
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