Congenital defects Practice Questions

Q: A 2600-g (5-lb 8-oz) male newborn is delivered at 34 weeks' gestation to a 22-year-old woman. The mother did not have prenatal care. Upon examination in the delivery room, the newborn's skin appears blue. He is gasping and breathing irregularly. The ears are low-set with broad auricles, and the nasal tip is flattened. The lower jaw is small and displaced backward. The right foot is clubbed. Which of the following is the most likely underlying cause of this patient's condition?

Posterior urethral valves. ***Posterior urethral valves*** - The combination of **respiratory distress** and distinctive craniofacial and limb abnormalities (low-set ears, broad auricles, flattened nasal tip, micrognathia, club foot) in a premature infant suggests **Potter sequence**, which is usually caused by **severe oligohydramnios**. - **Posterior urethral valves** are the most common cause of lower urinary tract obstruction in male infants, leading to **oligohydramnios** and subsequent Potter sequence. *Pulmonary hypoplasia* - While present in this case due to Potter sequence, **pulmonary hypoplasia** is a consequence, not the underlying cause. - It results from the lung compression due to **oligohydramnios**, preventing normal lung development. *Fetal anemia* - Fetal anemia typically manifests as **hydrops fetalis**, characterized by severe edema, ascites, and pleural effusions, which are not described here. - It does not directly lead to the specific constellation of craniofacial and limb anomalies seen in this patient. *Anencephaly* - **Anencephaly** is a severe form of neural tube defect involving absence of a major portion of the brain and skull. - While associated with **polyhydramnios** (due to impaired fetal swallowing), it does not cause the specific features of Potter sequence. *Esophageal atresia* - **Esophageal atresia** often presents with **polyhydramnios** due to the inability of the fetus to swallow amniotic fluid. - The primary clinical sign after birth is excessive salivation and inability to pass a feeding tube, not the craniofacial and limb anomalies described.

Q: A newborn male is evaluated 30 minutes after birth. He was born at 38 weeks gestation to a 39-year-old gravida 3 via vaginal delivery. The pregnancy was complicated by gestational diabetes, and the patient’s mother received routine prenatal care. The family declined all prenatal testing, including an anatomy ultrasound. The patient’s two older siblings are both healthy. Upon delivery, the patient appeared well and had good respiratory effort. He was noted to have acrocyanosis, and his Apgar scores were 8 and 9 at one and five minutes of life, respectively. The patient’s birth weight is 3840 g (8 lb 7 oz). His temperature is 98.7°F (37.1°C), blood pressure is 66/37 mmHg, pulse is 142/min, and respirations are 34/min. On physical exam, the patient has low-set ears, upslanting palpebral fissures, and a hypoplastic fifth finger. Which of the following is most likely to be found in this patient?

Complete atrioventricular septal defect. **Complete atrioventricular septal defect** - The patient's presentation with **low-set ears**, **upslanting palpebral fissures**, and a **hypoplastic fifth finger**, combined with the mother's advanced maternal age, are classic features suggestive of **Down syndrome (Trisomy 21)**. - **Complete atrioventricular septal defect (AVSD)** is the most common cardiac anomaly seen in individuals with Down syndrome, occurring in approximately 40-50% of cases. *Bicuspid aortic valve* - A **bicuspid aortic valve** is a common congenital heart defect but is not specifically associated with Down syndrome. - It is more commonly seen in familial cases or associated with conditions like **Turner syndrome**, which presents differently. *Aortic root dilation* - **Aortic root dilation** is characteristic of connective tissue disorders such as **Marfan syndrome** or **Ehlers-Danlos syndrome**. - These conditions have distinct phenotypic features not described in this patient. *Coarctation of the aorta* - **Coarctation of the aorta** is often associated with Turner syndrome, which affects females, or isolated cases. - It presents with differences in blood pressure between the upper and lower extremities, a finding not noted here. *Truncus arteriosus* - **Truncus arteriosus** is a severe congenital heart defect typically associated with **DiGeorge syndrome (22q11.2 deletion syndrome)**. - Patients with DiGeorge syndrome often present with specific facial dysmorphisms, hypocalcemia, and immunodeficiency, none of which are described.

Q: A 3175-g (7-lb) female newborn is delivered at 37 weeks to a 26-year-old primigravid woman. Apgar scores are 8 and 9 at 1 and 5 minutes, respectively. The pregnancy had been uncomplicated. The mother had no prenatal care. She immigrated to the US from Brazil 2 years ago. Immunization records are not available. One day after delivery, the newborn's temperature is 37.5°C (99.5°F), pulse is 182/min, respirations are 60/min, and blood pressure is 82/60 mm Hg. The lungs are clear to auscultation. Cardiac examination shows a continuous heart murmur. The abdomen is soft and nontender. There are several discolored areas on the skin that are non-blanchable upon pressure application. Slit lamp examination shows cloudy lenses in both eyes. The newborn does not pass her auditory screening tests. Which of the following is the most likely diagnosis?

Congenital rubella infection. ***Congenital rubella infection*** - The constellation of **congenital cataracts** (cloudy lenses), **patent ductus arteriosus** (continuous murmur), **sensorineural hearing loss** (failed auditory screening), and **blueberry muffin rash** (discolored, non-blanchable skin areas) is highly characteristic of congenital rubella syndrome. - The mother's lack of prenatal care and unknown immunization status, coupled with immigration from Brazil where rubella might be more prevalent, increases the likelihood of an unvaccinated mother acquiring the infection during pregnancy. *Congenital CMV infection* - While CMV can cause **sensorineural hearing loss**, it typically presents with **periventricular calcifications** on neuroimaging, **microcephaly**, and often **hepatosplenomegaly** and **thrombocytopenia**, which are not mentioned here. - Although CMV can cause chorioretinitis and cataracts, the classic cardiac and skin findings of rubella are absent. *Congenital syphilis* - Congenital syphilis can present with a wide range of manifestations, including **hepatosplenomegaly**, **snuffles**, **bone lesions** (e.g., periostitis), and a **rash**, but the specific combination of cataracts, patent ductus arteriosus, and blueberry muffin rash is not typical. - Eye involvement in syphilis is usually interstitial keratitis, not cataracts, and cardiac defects are less common or different. *Congenital parvovirus B19 infection* - Parvovirus B19 is primarily associated with **hydrops fetalis**, severe **anemia**, and sometimes myocarditis. - It does not typically cause **cataracts**, **patent ductus arteriosus**, or the characteristic rash seen in this case. *Congenital toxoplasmosis* - Congenital toxoplasmosis classically presents as a triad of **hydrocephalus**, **intracranial calcifications**, and **chorioretinitis**. - It does not typically cause **congenital cataracts**, **patent ductus arteriosus**, or the "blueberry muffin" rash.

Q: A female infant is born with a mutation in PKD1 on chromosome 16. An abdominal ultrasound performed shortly after birth would most likely reveal which of the following?

Normal kidneys. ***Normal kidneys*** - Autosomal dominant polycystic kidney disease (ADPKD), caused by a mutation in **PKD1 or PKD2**, typically presents with **cysts that develop later in life**, usually in adulthood. - At birth, the kidneys of an infant with the ADPKD mutation are usually **structurally normal** and do not yet show macroscopic cyst formation on ultrasound. *Microscopic cysts* - While the genetic mutation is present, significant **macroscopic cyst formation** detectable by standard abdominal ultrasound does not typically occur at birth in ADPKD. - The cysts develop and enlarge over decades, leading to symptoms later in adulthood. *Adrenal atrophy* - **Adrenal atrophy** is not a feature of polycystic kidney disease and is caused by other conditions like autoimmune diseases or prolonged corticosteroid use. - The adrenal glands are distinct from the kidneys and are not directly affected by PKD1 mutations. *Horseshoe kidney* - **Horseshoe kidney** is a congenital anomaly where the kidneys are fused, usually at the lower poles, and is not associated with PKD1 mutations. - This condition is a **developmental fusion defect** during embryogenesis. *Bilateral kidney enlargement* - Bilateral kidney enlargement due to multiple cysts is characteristic of **ADPKD in adulthood**, not at birth. - Though ADPKD is a genetic condition, the **phenotypic expression (cyst growth)** progresses over time.

Q: A previously healthy 2-year-old girl is brought to the physician because of a 1-week history of yellow discoloration of her skin, loss of appetite, and 3 episodes of vomiting. Her parents also report darkening of her urine and light stools. During the last 2 days, the girl has been scratching her abdomen and arms and has been crying excessively. She was born at 38 weeks' gestation after an uncomplicated pregnancy and delivery. Her family emigrated from Japan 8 years ago. Immunizations are up-to-date. Her vital signs are within normal limits. Examination shows jaundice of her skin and sclerae. Abdominal examination shows a mass in the right upper abdomen. Serum studies show: Bilirubin (total) 5 mg/dL Direct 4.2 mg/dL Aspartate aminotransferase (AST) 20 U/L Alanine aminotransferase (ALT) 40 U/L γ-Glutamyltransferase (GGT) 110 U/L Abdominal ultrasonography shows dilation of the gall bladder and a fusiform dilation of the extrahepatic bile duct. Which of the following is the most likely diagnosis?

Biliary cyst. ***Biliary cyst*** - The combination of **jaundice**, **pruritus**, **light stools**, **dark urine**, an **RUQ mass**, and **fusiform dilation of the extrahepatic bile duct** on ultrasound is highly suggestive of a biliary cyst (specifically a choledochal cyst). - The **elevated direct bilirubin** and **GGT** are consistent with **biliary obstruction**, while normal AST/ALT suggest minimal hepatocellular injury. *Biliary atresia* - Characterized by **progressive obliteration of the extrahepatic bile ducts**, typically presenting with persistent jaundice in the **first few weeks of life**, not at 2 years old. - Ultrasound in biliary atresia often shows a **nondilated, atretic or absent common bile duct** and a **small or absent gallbladder**, which contradicts the findings of gallbladder dilation and a fusiform mass. *Mirizzi syndrome* - This syndrome involves **common hepatic duct obstruction** due to external compression by an impacted **gallstone in the cystic duct or gallbladder neck**. - It is typically seen in **adults** and would not explain a congenital fusiform dilation of the extrahepatic bile duct. *Pancreatic pseudocyst* - A pancreatic pseudocyst is a **collection of pancreatic fluid** usually resulting from **pancreatitis or pancreatic trauma**. - While it can cause an abdominal mass and obstructive symptoms, it would typically be located near the pancreas, not specifically presenting as a fusiform dilation of the bile duct, and pancreatic enzyme elevations would be more prominent. *Hepatic abscess* - A hepatic abscess is a **localized collection of pus in the liver**, often presenting with **fever, RUQ pain**, and elevated inflammatory markers. - It would show as a **fluid collection within the liver parenchyma** on ultrasound, not a fusiform dilation of the bile duct.

Q: A 28-year-old woman gives birth to a male infant. During her third-trimester antenatal sonogram, the radiologist noted a suspected congenital heart defect, but the exact nature of the defect was not clear. The pediatrician orders an echocardiogram after making sure that the baby’s vital signs are stable. This reveals the following findings: atresia of the muscular tricuspid valve, pulmonary outflow tract obstruction, open patent ductus arteriosus, a small ventricular septal defect, and normally related great arteries. The pediatrician explains the nature of the congenital heart defect to the infant's parents. He also informs them about the probable clinical features that are likely to develop in the infant, the proposed management plan, and the prognosis. Which of the following signs is most likely to manifest first in this infant?

Bluish discoloration of lips. **Bluish discoloration of lips** - The presence of **tricuspid atresia** and **pulmonary outflow tract obstruction** means that deoxygenated blood cannot effectively reach the lungs for oxygenation. - This leads to a right-to-left shunt of deoxygenated blood through the **patent ductus arteriosus (PDA)** and **ventricular septal defect (VSD)** into the systemic circulation, causing **cyanosis** which would visibly manifest as bluish discoloration of the lips. *Hepatomegaly* - **Hepatomegaly** is typically observed in states of **right-sided heart failure** due to congestion of the liver. While structural heart defects can lead to heart failure, cyanosis due to shunting is a more immediate and direct consequence of the described anatomy. - It would develop later as the heart struggles over time, not as the first sign. *Peripheral edema* - **Peripheral edema** is also a sign of **heart failure**, usually **right-sided heart failure**, and would indicate significant fluid retention. - Like hepatomegaly, this symptom is not expected to be the very first manifestation, as the immediate problem is the lack of oxygenated blood. *Clubbing of finger nails* - **Clubbing of fingernails** is a **chronic sign of hypoxemia**, developing over weeks to months in response to persistent low oxygen levels. - This condition requires sustained cyanosis over a longer period and would not be an initial finding in a newborn. *Diaphoresis while sucking* - **Diaphoresis while sucking** is a classic sign of **congestive heart failure** in infants, indicating increased metabolic demand and effort for feeding. - While the infant may eventually develop heart failure symptoms, the immediate issue of inadequate pulmonary blood flow leads to central cyanosis as the earliest and most direct manifestation.

Q: A 3-week-old boy has non-bilious projectile vomiting that occurred after feeding. After vomiting, the infant is still hungry. The infant appears dehydrated and malnourished. A firm, “olive-like” mass of about 1.5 cm in diameter is palpated in the right upper quadrant, by the lateral edge of the rectus abdominus muscle. On laboratory testing, the infant is found to have a hypochloremic, hypokalemic metabolic alkalosis. Which of the following is most likely the cause of this patient’s symptoms?

Hypertrophy of the pylorus muscle. ***Hypertrophy of the pylorus muscle*** - The classic presentation of **pyloric stenosis** includes **non-bilious projectile vomiting** in an infant, followed by continued hunger, a palpable **"olive-like" mass** in the right upper quadrant, and findings of **hypochloremic, hypokalemic metabolic alkalosis** due to fluid and acid loss from vomiting. - The hypertrophy of the pylorus obstructs gastric emptying, leading to the characteristic vomiting pattern and subsequent electrolyte imbalances. *Intussusception* - This condition presents with sudden onset of intermittent, **severe abdominal pain**, often drawing the legs up to the chest, and produces **"currant jelly" stools** (blood and mucus). - A palpable **sausage-shaped mass** may be felt, but projectile vomiting and the classic electrolyte abnormalities described are not typical features. *Achalasia* - Achalasia is a motility disorder of the **esophagus** characterized by impaired relaxation of the lower esophageal sphincter and absence of esophageal peristalsis. - While it causes **dysphagia** and regurgitation, it does not typically present in a **3-week-old infant** with projectile vomiting or an "olive-like" mass. *Duodenal atresia* - This is a congenital obstruction of the duodenum, often presenting with **bilious vomiting** within the first 24-48 hours of life, and a characteristic **"double bubble" sign** on abdominal X-ray. - It does not involve a palpable "olive-like" mass or the specific electrolyte imbalance seen in pyloric stenosis. *Aganglionic colon segment* - This describes **Hirschsprung disease**, which is characterized by the absence of ganglion cells in the distal colon, leading to **functional obstruction**. - Symptoms typically involve **delayed passage of meconium** and chronic constipation, abdominal distension, and sometimes bilious vomiting, not the projectile non-bilious vomiting or palpable mass of pyloric stenosis.

Question 1

A 2600-g (5-lb 8-oz) male newborn is delivered at 34 weeks' gestation to a 22-year-old woman. The mother did not have prenatal care. Upon examination in the delivery room, the newborn's skin appears blue. He is gasping and breathing irregularly. The ears are low-set with broad auricles, and the nasal tip is flattened. The lower jaw is small and displaced backward. The right foot is clubbed. Which of the following is the most likely underlying cause of this patient's condition?

Accepted Answer

Posterior urethral valves

Answer

Pulmonary hypoplasia

Answer

Fetal anemia

Answer

Anencephaly

Answer

Esophageal atresia

Question 2

A newborn male is evaluated 30 minutes after birth. He was born at 38 weeks gestation to a 39-year-old gravida 3 via vaginal delivery. The pregnancy was complicated by gestational diabetes, and the patient’s mother received routine prenatal care. The family declined all prenatal testing, including an anatomy ultrasound. The patient’s two older siblings are both healthy. Upon delivery, the patient appeared well and had good respiratory effort. He was noted to have acrocyanosis, and his Apgar scores were 8 and 9 at one and five minutes of life, respectively. The patient’s birth weight is 3840 g (8 lb 7 oz). His temperature is 98.7°F (37.1°C), blood pressure is 66/37 mmHg, pulse is 142/min, and respirations are 34/min. On physical exam, the patient has low-set ears, upslanting palpebral fissures, and a hypoplastic fifth finger.

Which of the following is most likely to be found in this patient?

Accepted Answer

Complete atrioventricular septal defect

Answer

Bicuspid aortic valve

Answer

Aortic root dilation

Answer

Coarctation of the aorta

Answer

Truncus arteriosus

Question 3

A 3175-g (7-lb) female newborn is delivered at 37 weeks to a 26-year-old primigravid woman. Apgar scores are 8 and 9 at 1 and 5 minutes, respectively. The pregnancy had been uncomplicated. The mother had no prenatal care. She immigrated to the US from Brazil 2 years ago. Immunization records are not available. One day after delivery, the newborn's temperature is 37.5°C (99.5°F), pulse is 182/min, respirations are 60/min, and blood pressure is 82/60 mm Hg. The lungs are clear to auscultation. Cardiac examination shows a continuous heart murmur. The abdomen is soft and nontender. There are several discolored areas on the skin that are non-blanchable upon pressure application. Slit lamp examination shows cloudy lenses in both eyes. The newborn does not pass her auditory screening tests. Which of the following is the most likely diagnosis?

Accepted Answer

Congenital rubella infection

Answer

Congenital CMV infection

Answer

Congenital syphilis

Answer

Congenital parvovirus B19 infection

Answer

Congenital toxoplasmosis

Question 4

A female infant is born with a mutation in PKD1 on chromosome 16. An abdominal ultrasound performed shortly after birth would most likely reveal which of the following?

Accepted Answer

Normal kidneys

Answer

Microscopic cysts

Answer

Adrenal atrophy

Answer

Horseshoe kidney

Answer

Bilateral kidney enlargement

Question 5

A previously healthy 2-year-old girl is brought to the physician because of a 1-week history of yellow discoloration of her skin, loss of appetite, and 3 episodes of vomiting. Her parents also report darkening of her urine and light stools. During the last 2 days, the girl has been scratching her abdomen and arms and has been crying excessively. She was born at 38 weeks' gestation after an uncomplicated pregnancy and delivery. Her family emigrated from Japan 8 years ago. Immunizations are up-to-date. Her vital signs are within normal limits. Examination shows jaundice of her skin and sclerae. Abdominal examination shows a mass in the right upper abdomen. Serum studies show:
Bilirubin (total) 5 mg/dL
Direct 4.2 mg/dL
Aspartate aminotransferase (AST) 20 U/L
Alanine aminotransferase (ALT) 40 U/L
γ-Glutamyltransferase (GGT) 110 U/L
Abdominal ultrasonography shows dilation of the gall bladder and a fusiform dilation of the extrahepatic bile duct. Which of the following is the most likely diagnosis?

Accepted Answer

Biliary cyst

Answer

Biliary atresia

Answer

Mirizzi syndrome

Answer

Pancreatic pseudocyst

Answer

Hepatic abscess

Question 6

An 8-year-old boy presents with a skin lesion on his back as shown in the picture. On physical examination, there are synchronous spasmodic movements of the neck, trunk, and extremities. The physician explains that this is likely due to a genetic condition, and further testing would be necessary to confirm the diagnosis. Which of the following genes is involved in the development of this patient’s condition?

Accepted Answer

TSC1

Answer

NF2

Answer

GNAQ

Answer

VHL

Answer

NF1

Question 7

Cardiac surgery is consulted on a newborn with a large ventricular septal defect. The child has poor weight gain and feeding difficulties. He requires furosemide and captopril to avoid dyspnea. On physical examination his temperature is 36.9°C (98.4°F), pulse rate is 158/min, respiratory rate is 30/min, and blood pressure is 94/62 mm Hg. Chest auscultation reveals a holosystolic murmur along the left lower sternal border and a mid-diastolic low-pitched rumble at the apex. Abdominal examination reveals the presence of hepatomegaly. An echocardiogram confirms a diagnosis of a membranous VSD while hemodynamic studies show a Qp:Qs ratio of 2.8:1. Which of the following is the best management option?

Accepted Answer

Surgical closure of the defect

Answer

Continue medical treatment and provide reassurance about spontaneous closure of the defect

Answer

Hybrid surgery using both transcatheter device and surgical repair

Answer

Transcatheter occlusion of the defect

Answer

Addition of digoxin to the current medical regimen with regular follow-up until spontaneous closure occurs

Question 8

A 3-week-old firstborn baby girl is brought to the pediatric emergency room with projectile vomiting. She started vomiting while feeding 12 hours ago and has been unable to keep anything down since then. After vomiting, she appears well and hungry, attempting to feed again. The vomitus has been non-bloody and non-bilious. The last wet diaper was 10 hours ago. The child was born at 40 weeks gestation to a healthy mother. On examination, the child appears sleepy but has a healthy cry during the exam. The child has dry mucous membranes and delayed capillary refill. There is a palpable olive-shaped epigastric mass on palpation. Which of the following is the most likely cause of this patient's condition?

Accepted Answer

Hypertrophic muscularis externa

Answer

Failure of neural crest cell migration into the rectum

Answer

Telescoping of the small bowel into the large bowel

Answer

Patent tract between the trachea and esophagus

Answer

Failure of duodenal lumen recanalization

Question 9

A 28-year-old woman gives birth to a male infant. During her third-trimester antenatal sonogram, the radiologist noted a suspected congenital heart defect, but the exact nature of the defect was not clear. The pediatrician orders an echocardiogram after making sure that the baby’s vital signs are stable. This reveals the following findings: atresia of the muscular tricuspid valve, pulmonary outflow tract obstruction, open patent ductus arteriosus, a small ventricular septal defect, and normally related great arteries. The pediatrician explains the nature of the congenital heart defect to the infant's parents. He also informs them about the probable clinical features that are likely to develop in the infant, the proposed management plan, and the prognosis. Which of the following signs is most likely to manifest first in this infant?

Accepted Answer

Bluish discoloration of lips

Answer

Hepatomegaly

Answer

Peripheral edema

Answer

Clubbing of finger nails

Answer

Diaphoresis while sucking

Question 10

A 3-week-old boy has non-bilious projectile vomiting that occurred after feeding. After vomiting, the infant is still hungry. The infant appears dehydrated and malnourished. A firm, “olive-like” mass of about 1.5 cm in diameter is palpated in the right upper quadrant, by the lateral edge of the rectus abdominus muscle. On laboratory testing, the infant is found to have a hypochloremic, hypokalemic metabolic alkalosis. Which of the following is most likely the cause of this patient’s symptoms?

Accepted Answer

Hypertrophy of the pylorus muscle

Answer

Intussusception

Answer

Achalasia

Answer

Duodenal atresia

Answer

Aganglionic colon segment

Congenital defects — MCQs

Congenital defects — MCQs

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