A pregnant woman gives birth to her 1st child at the family farm. After delivery, the assisting midwife notices a triangular defect in the lower anterior abdominal wall of the baby. She clamps the umbilical cord with a cloth and urges the family to seek immediate medical care at the nearest hospital. Upon admission, the attending pediatrician further notices an open bladder plate with an exposed urethra, a low set umbilicus, an anteriorly displaced anus, and an inguinal hernia. No omphalocele is noted. The external genitalia is also affected. On physical exam, a shortened penis with a pronounced upward curvature and the urethral opening along the dorsal surface are also noted. What is the most likely diagnosis?
Q92
A 2-week-old boy has developed bilious vomiting. He was born via cesarean section at term. On physical exam, his pulse is 140, blood pressure is 80/50 mmHg, and respirations are 40/min. His abdomen appears distended and appears diffusely tender to palpation. Abdominal imaging is obtained (Figures A). Which of the following describes the mechanism that caused this child's disorder?
Q93
A 4-month-old girl is brought to the office by her parents because they noticed a mass protruding from her rectum and, she has been producing green colored emesis for the past 24 hours. Her parents noticed the mass when she had a bowel movement while changing her diaper. She strained to have this bowel movement 24 hours ago, shortly afterwards she had 3 episodes of greenish vomiting. She has a past medical history of failure to pass meconium for 2 days after birth. Her vital signs include: heart rate 190/min, respiratory rate 44/min, temperature 37.2°C (99.0°F), and blood pressure 80/50 mm Hg. On physical examination, the abdomen is distended. Examination of the anus reveals extrusion of the rectal mucosa through the external anal sphincter, and digital rectal examination produces an explosive expulsion of gas and stool. The abdominal radiograph shows bowel distention and absence of distal gas. What is the most likely cause?
Q94
A 3200-g (7.1-lb) female newborn is delivered at 38 weeks' gestation to a 24-year-old woman. The mother had regular prenatal visits throughout the pregnancy. The newborn's blood pressure is 53/35 mm Hg. Examination in the delivery room shows clitoromegaly and posterior labial fusion. One day later, serum studies show:
Na+ 131 mEq/L
K+ 5.4 mEq/L
Cl− 102 mEq/L
Urea nitrogen 15 mg/dL
Creatinine 0.8 mg/dL
Ultrasound of the abdomen and pelvis shows a normal uterus and ovaries. Further evaluation of the newborn is most likely to show which of the following findings?
Q95
A 4-year-old Caucasian male suffers from cyanosis and dyspnea relieved by squatting. Which of the following abnormalities is most likely present?
Q96
A 4-day-old male infant is brought to the physician because of respiratory distress and bluish discoloration of his lips and tongue. He was born at term and the antenatal period was uncomplicated. His temperature is 37.3°C (99.1°F), pulse is 170/min, respirations are 65/min, and blood pressure is 70/46 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 82%. A grade 3/6 holosystolic murmur is heard over the left lower sternal border. A single S2 that does not split with respiration is present. Echocardiography shows defects in the interatrial and interventricular septae, as well as an imperforate muscular septum between the right atrium and right ventricle. Further evaluation of this patient is most likely to show which of the following?
Q97
A 7-month-old boy is brought to the physician for a well-child examination. He was born at 36 weeks' gestation and has been healthy since. He is at the 60th percentile for length and weight. Vital signs are within normal limits. The abdomen is soft and nontender. The external genitalia appear normal. Examination shows a single palpable testicle in the right hemiscrotum. The scrotum is nontender and not enlarged. There is a palpable mass in the left inguinal canal. Which of the following is the most appropriate next best step in management?
Q98
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?
Q99
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?
Q100
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 defects US Medical PG Practice Questions and MCQs
Question 91: A pregnant woman gives birth to her 1st child at the family farm. After delivery, the assisting midwife notices a triangular defect in the lower anterior abdominal wall of the baby. She clamps the umbilical cord with a cloth and urges the family to seek immediate medical care at the nearest hospital. Upon admission, the attending pediatrician further notices an open bladder plate with an exposed urethra, a low set umbilicus, an anteriorly displaced anus, and an inguinal hernia. No omphalocele is noted. The external genitalia is also affected. On physical exam, a shortened penis with a pronounced upward curvature and the urethral opening along the dorsal surface are also noted. What is the most likely diagnosis?
A. Posterior urethral valves
B. Bladder exstrophy (Correct Answer)
C. Body stalk anomaly
D. Cloacal exstrophy
E. Urachal cyst
Explanation: ***Bladder exstrophy***
- The findings of a **triangular defect in the lower anterior abdominal wall**, an **open bladder plate with an exposed urethra**, a **low set umbilicus**, an **anteriorly displaced anus**, and affected external genitalia including a **shortened penis with pronounced upward curvature** (epispadias) are pathognomonic for **bladder exstrophy**.
- This condition results from a developmental failure of the infraumbilical abdominal wall and anterior bladder wall to close, leading to the bladder being open to the outside and often associated with epispadias due to abnormal tubercle development.
*Posterior urethral valves*
- This condition is characterized by **obstructive membranes within the posterior urethra of male infants**, leading to urinary obstruction and hydronephrosis.
- It does not involve an open bladder plate or abdominal wall defect, and the external genitalia are typically normal save for potential complications of urinary outflow obstruction.
*Body stalk anomaly*
- This is a severe congenital malformation characterized by **defects of the abdominal wall, thorax, and limbs**, with the fetus usually attached to the placenta by a short, thick umbilical cord.
- While it involves abdominal wall defects, it does not typically present with an exposed bladder plate and exposed urethra as the primary defect, nor is it specifically associated with epispadias.
*Cloacal exstrophy*
- Cloacal exstrophy is a more severe and complex defect than bladder exstrophy, involving the **exstrophy of both the bladder and a portion of the hindgut (intestine)**, often with omphalocele.
- The absence of an **omphalocele** and the specific description of an **open bladder plate** without obvious intestinal exposure make bladder exstrophy a more likely diagnosis.
*Urachal cyst*
- An urachal cyst is a **remnant of the allantois** that persists as a cystic structure between the bladder and the umbilicus, often presenting as a palpable mass or a discharge from the umbilicus.
- It does not involve an open abdominal wall defect, exposed bladder, or epispadias, which are central to the patient's presentation.
Question 92: A 2-week-old boy has developed bilious vomiting. He was born via cesarean section at term. On physical exam, his pulse is 140, blood pressure is 80/50 mmHg, and respirations are 40/min. His abdomen appears distended and appears diffusely tender to palpation. Abdominal imaging is obtained (Figures A). Which of the following describes the mechanism that caused this child's disorder?
A. Hypertrophy of the pylorus
B. Abnormal rotation of the midgut (Correct Answer)
C. Ischemia-reperfusion injury in premature neonate
D. Partial absence of ganglion cells in large intestine
E. Telescoping segment of bowel
Explanation: ***Abnormal rotation of the midgut***
- The presentation of **bilious vomiting** in a neonate, along with abdominal distension and tenderness, is highly suggestive of a **malrotation with midgut volvulus**. This condition results from an incomplete or abnormal rotation of the fetal midgut during development, leading to an improperly fixed mesentery.
- The narrow mesenteric base, characteristic of malrotation, predisposes to twisting of the bowel around the superior mesenteric artery, causing **bowel obstruction and ischemia**. The provided image would likely show findings consistent with obstruction, such as dilated loops of bowel and possibly signs of compromised blood flow (e.g., pneumatosis intestinalis in severe cases, though not explicitly mentioned for this image).
*Hypertrophy of the pylorus*
- This condition is known as **pyloric stenosis** and typically presents with **non-bilious projectile vomiting** around 3-6 weeks of age, not bilious vomiting.
- While it causes gastric outlet obstruction, the vomiting is non-bilious because the obstruction is proximal to the entry of bile ducts into the duodenum.
*Ischemia-reperfusion injury in premature neonate*
- This mechanism is associated with **necrotizing enterocolitis (NEC)**, which primarily affects **premature neonates** and presents with abdominal distension, feeding intolerance, and bloody stools.
- The patient in the question is a **term neonate**, making NEC less likely, and the primary symptom is bilious vomiting rather than bloody stools.
*Partial absence of ganglion cells in large intestine*
- This describes **Hirschsprung disease**, which typically presents with **constipation**, abdominal distension, and failure to pass meconium, rather than acute bilious vomiting as the primary symptom in an infant.
- While it can cause bowel obstruction, the pathology involves the large intestine and often has a more chronic presentation of obstructive symptoms.
*Telescoping segment of bowel*
- This describes **intussusception**, which is characterized by sudden onset of **intermittent, crampy abdominal pain**, **vomiting (often bilious)**, and "currant jelly" stools.
- While intussusception can cause bilious vomiting and bowel obstruction, it typically occurs in infants aged 6 months to 3 years and is less common in a 2-week-old neonate where malrotation/volvulus is more prominent for acute obstructive symptoms.
Question 93: A 4-month-old girl is brought to the office by her parents because they noticed a mass protruding from her rectum and, she has been producing green colored emesis for the past 24 hours. Her parents noticed the mass when she had a bowel movement while changing her diaper. She strained to have this bowel movement 24 hours ago, shortly afterwards she had 3 episodes of greenish vomiting. She has a past medical history of failure to pass meconium for 2 days after birth. Her vital signs include: heart rate 190/min, respiratory rate 44/min, temperature 37.2°C (99.0°F), and blood pressure 80/50 mm Hg. On physical examination, the abdomen is distended. Examination of the anus reveals extrusion of the rectal mucosa through the external anal sphincter, and digital rectal examination produces an explosive expulsion of gas and stool. The abdominal radiograph shows bowel distention and absence of distal gas. What is the most likely cause?
A. Enterobiasis
B. Cystic fibrosis
C. Hirschsprung disease (Correct Answer)
D. Malnutrition
E. Myelomeningocele
Explanation: ***Hirschsprung disease***
- The combination of **failure to pass meconium** at birth, **abdominal distention**, **green emesis**, and **rectal prolapse** with an **explosive expulsion of gas and stool** on digital rectal examination is highly suggestive of Hirschsprung disease.
- This condition is caused by the **absence of ganglion cells** in the distal colon, leading to a functional obstruction.
*Enterobiasis*
- **Enterobiasis**, or pinworm infection, commonly causes **perianal itching**, especially at night.
- It does not typically present with **rectal prolapse**, **abdominal distention**, or **vomiting** in infants.
*Cystic fibrosis*
- While cystic fibrosis can cause **meconium ileus** (failure to pass meconium), other symptoms like **malabsorption**, **respiratory issues**, and specific laboratory findings (e.g., sweat chloride test) would be expected.
- Rectal prolapse in cystic fibrosis is mainly due to chronic **straining from constipation** or **malabsorption**, not a primary motility disorder causing obstruction.
*Malnutrition*
- **Malnutrition** can lead to various symptoms, but it does not directly cause an acute presentation of **rectal prolapse**, **bowel obstruction**, and **explosive stool** on digital rectal examination.
- This patient's symptoms point to a specific congenital anatomical or functional issue.
*Myelomeningocele*
- A **myelomeningocele** is a severe form of spina bifida and involves a sac protruding from the back containing spinal cord and nerves, leading to neurological deficits.
- While it can cause **neurogenic bowel dysfunction** and chronic constipation, it does not typically present with acute **rectal prolapse** and other signs of immediate functional obstruction as observed here.
Question 94: A 3200-g (7.1-lb) female newborn is delivered at 38 weeks' gestation to a 24-year-old woman. The mother had regular prenatal visits throughout the pregnancy. The newborn's blood pressure is 53/35 mm Hg. Examination in the delivery room shows clitoromegaly and posterior labial fusion. One day later, serum studies show:
Na+ 131 mEq/L
K+ 5.4 mEq/L
Cl− 102 mEq/L
Urea nitrogen 15 mg/dL
Creatinine 0.8 mg/dL
Ultrasound of the abdomen and pelvis shows a normal uterus and ovaries. Further evaluation of the newborn is most likely to show which of the following findings?
A. Increased 11-deoxycorticosterone
B. Increased 17-hydroxyprogesterone (Correct Answer)
C. Increased corticosterone
D. Decreased renin activity
E. Decreased dehydroepiandrosterone
Explanation: ***Increased 17-hydroxyprogesterone***
- The combination of **ambiguous genitalia** (clitoromegaly, posterior labial fusion) in a female newborn, followed by signs of **salt-wasting crisis** (hyponatremia, hyperkalemia, hypotension), is highly suggestive of **congenital adrenal hyperplasia (CAH)**.
- The most common cause of CAH (>90%) is **21-hydroxylase deficiency**, which leads to an accumulation of steroid precursors, primarily **17-hydroxyprogesterone (17-OHP)**, proximal to the enzymatic block.
*Increased 11-deoxycorticosterone*
- An increase in **11-deoxycorticosterone** would typically be seen in **11β-hydroxylase deficiency**, another form of CAH.
- While 11β-hydroxylase deficiency also causes virilization in females, it is associated with **hypertension** due to the accumulation of mineralocorticoid precursors, rather than the hypotension seen in this patient.
*Increased corticosterone*
- **Corticosterone** is an intermediate product in the cortisol synthesis pathway, but its independent increase without other specific markers is not characteristic of the described presentation.
- A deficiency in 17α-hydroxylase can lead to increased corticosterone, but this condition typically presents with **female pseudohermaphroditism** in XY individuals and **primary amenorrhea** in XX individuals, along with hypertension and hypokalemia.
*Decreased renin activity*
- In salt-wasting CAH, the lack of aldosterone production leads to renal salt loss, **volume depletion**, and **hyponatremia**, which in turn stimulates the **renin-angiotensin-aldosterone system**.
- Therefore, **renin activity** would be **increased**, not decreased, in an attempt to compensate for the hypovolemia and electrolyte imbalances.
*Decreased dehydroepiandrosterone*
- **Dehydroepiandrosterone (DHEA)** is an androgen precursor produced in the adrenal cortex. In 21-hydroxylase deficiency, the shunting of steroid precursors towards the **androgen pathway** results in **increased DHEA** and other androgens, leading to virilization.
- Therefore, DHEA levels would be **increased**, not decreased, in this condition.
Question 95: A 4-year-old Caucasian male suffers from cyanosis and dyspnea relieved by squatting. Which of the following abnormalities is most likely present?
A. Atrial septal defect
B. Coarctation of the aorta
C. Bicuspid aortic valve
D. Ventricular septal defect
E. Tetralogy of Fallot (Correct Answer)
Explanation: ***Tetralogy of Fallot***
- **Cyanosis** and **dyspnea relieved by squatting** are the hallmark clinical features of **Tetralogy of Fallot**, making this the correct diagnosis.
- The condition consists of four anatomic abnormalities: **ventricular septal defect (VSD)**, **right ventricular outflow tract obstruction**, **right ventricular hypertrophy**, and **overriding aorta**.
- The right-to-left shunt across the VSD causes **deoxygenated blood** to enter systemic circulation, producing **cyanosis**.
- **Squatting increases systemic vascular resistance (SVR)**, which decreases the right-to-left shunt, improves pulmonary blood flow, and relieves cyanosis and dyspnea during **"tet spells"**.
*Atrial septal defect*
- ASDs typically cause **left-to-right shunts** and are **acyanotic lesions**.
- Patients may be asymptomatic or present with **exertional dyspnea** and **fatigue** in later childhood or adulthood.
- Cyanosis would only occur if **Eisenmenger syndrome** develops (reversal to right-to-left shunt due to pulmonary hypertension), which is rare at age 4 and does not improve with squatting.
*Coarctation of the aorta*
- This is an **acyanotic** lesion characterized by **narrowing of the descending aorta**.
- Classic findings include **upper extremity hypertension**, **diminished or delayed femoral pulses**, and **lower extremity hypotension**.
- Does not cause cyanosis or squatting relief.
*Bicuspid aortic valve*
- A common **acyanotic** congenital abnormality that may lead to **aortic stenosis** or **regurgitation** over time.
- Usually asymptomatic in childhood; may present with **murmur**, chest pain, or syncope in adulthood.
- Does not cause cyanosis or relief with squatting.
*Ventricular septal defect*
- Isolated VSDs typically cause **left-to-right shunts** and are **acyanotic**.
- May present with **heart failure symptoms** (tachypnea, poor feeding, failure to thrive) in infancy if the defect is large.
- Cyanosis occurs only if **Eisenmenger syndrome** develops (usually takes years to decades), and symptoms are not relieved by squatting.
Question 96: A 4-day-old male infant is brought to the physician because of respiratory distress and bluish discoloration of his lips and tongue. He was born at term and the antenatal period was uncomplicated. His temperature is 37.3°C (99.1°F), pulse is 170/min, respirations are 65/min, and blood pressure is 70/46 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 82%. A grade 3/6 holosystolic murmur is heard over the left lower sternal border. A single S2 that does not split with respiration is present. Echocardiography shows defects in the interatrial and interventricular septae, as well as an imperforate muscular septum between the right atrium and right ventricle. Further evaluation of this patient is most likely to show which of the following?
A. Elfin facies
B. Tracheal bowing on chest x-ray
C. Increased pulmonary vascular markings on chest x-ray
D. Delta wave on electrocardiogram
E. Left-axis deviation on electrocardiogram (Correct Answer)
Explanation: ***Left-axis deviation on electrocardiogram***
- The combination of **cyanosis**, a **holosystolic murmur**, and defects in the **interatrial and interventricular septa** along with an **imperforate tricuspid valve** (muscular septum between the right atrium and right ventricle) is highly suggestive of **tricuspid atresia** with a **ventricular septal defect (VSD)** and an **atrial septal defect (ASD)**.
- In tricuspid atresia, the **right ventricle is hypoplastic**, leading to LV dominance and a characteristic **left-axis deviation** on the ECG due to an enlarged left ventricle taking over the pumping action for the systemic and pulmonary circulation.
*Elfin facies*
- **Elfin facies** is a characteristic feature of **Williams syndrome**, which is associated with **supravalvular aortic stenosis** and not typically with cyanotic heart defects like tricuspid atresia.
- There is no clinical information in the vignette that suggests features of Williams syndrome.
*Tracheal bowing on chest x-ray*
- **Tracheal bowing or compression** is commonly seen in conditions like a **vascular ring** or **large mediastinal masses**, which can cause respiratory distress but generally do not present with the specific cardiac findings described.
- This finding is not characteristic of tricuspid atresia.
*Increased pulmonary vascular markings on chest x-ray*
- In tricuspid atresia, **pulmonary blood flow is often decreased** due to reduced flow to the right ventricle and pulmonary artery, especially if the VSD is restrictive or there's pulmonary stenosis. This would lead to **decreased, not increased, pulmonary vascular markings**.
- Increased pulmonary vascular markings suggest conditions with **left-to-right shunting** or **pulmonary venous congestion**, which is contradictory to the physiology of complicated tricuspid atresia.
*Delta wave on electrocardiogram*
- A **delta wave** on an ECG is characteristic of **Wolff-Parkinson-White (WPW) syndrome**, indicating a pre-excitation pathway.
- While WPW can occur with congenital heart disease, it is not a direct or expected consequence of tricuspid atresia and does not explain the cyanosis or specific cardiac defects mentioned.
Question 97: A 7-month-old boy is brought to the physician for a well-child examination. He was born at 36 weeks' gestation and has been healthy since. He is at the 60th percentile for length and weight. Vital signs are within normal limits. The abdomen is soft and nontender. The external genitalia appear normal. Examination shows a single palpable testicle in the right hemiscrotum. The scrotum is nontender and not enlarged. There is a palpable mass in the left inguinal canal. Which of the following is the most appropriate next best step in management?
A. Orchidopexy (Correct Answer)
B. Gonadotropin therapy
C. Exploration under anesthesia
D. Reassurance
E. Serum testosterone level
Explanation: ***Orchidopexy***
- Since the testicle is **palpable in the inguinal canal** at 7 months, it is unlikely to spontaneously descend, making **orchidopexy** the definitive surgical treatment.
- Recommended by 6-12 months of age to prevent complications such as **infertility** and increased risk of **testicular cancer**.
*Gonadotropin therapy*
- **Gonadotropin therapy** is rarely used and has limited efficacy for **cryptorchidism**, especially for palpable undescended testes.
- It's typically reserved for specific cases and has a lower success rate compared to surgery.
*Exploration under anesthesia*
- While exploration is part of any surgical correction for an undescended testicle, **orchidopexy** specifically describes the complete procedure of bringing the testicle into the scrotum and fixing it there.
- **Exploration under anesthesia** alone is not a complete management step; it precedes the definitive repair.
*Reassurance*
- An undescended testicle at 7 months of age is unlikely to descend spontaneously and carries risks if left untreated, so **reassurance** is inappropriate.
- Intervention is necessary to prevent potential long-term complications.
*Serum testosterone level*
- **Serum testosterone level** evaluation is typically reserved for cases of **bilateral non-palpable testes** to assess for anorchia or other endocrine disorders.
- In a case with a palpable inguinal testicle and a normal contralateral testicle, it is not the next best step.
Question 98: 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?
A. Pulmonary hypoplasia
B. Posterior urethral valves (Correct Answer)
C. Fetal anemia
D. Anencephaly
E. Esophageal atresia
Explanation: ***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.
Question 99: 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?
A. Complete atrioventricular septal defect (Correct Answer)
B. Bicuspid aortic valve
C. Aortic root dilation
D. Coarctation of the aorta
E. Truncus arteriosus
Explanation: **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.
Question 100: 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?
A. Congenital CMV infection
B. Congenital syphilis
C. Congenital parvovirus B19 infection
D. Congenital toxoplasmosis
E. Congenital rubella infection (Correct Answer)
Explanation: ***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.
