A 35-year-old woman has been trying to conceive with her 37-year-old husband for the past 4 years. After repeated visits to a fertility clinic, she finally gets pregnant. Although she missed most of her antenatal visits, her pregnancy was uneventful. A baby girl is born at the 38th week of gestation with some abnormalities. She has a flat face with upward-slanting eyes and a short neck. The tongue seems to be protruding from a small mouth. She has poor muscle tone and excessive joint laxity. The pediatrician orders an analysis of the infant’s chromosomes, also known as a karyotype (see image). The infant is most likely to suffer from which of the following conditions in the future?
Q202
A full-term and healthy infant girl presents to the office for a newborn visit. The baby was born at 40 weeks to a 35-year-old G2P1 mother via cesarean section for breech presentation. She had an unremarkable delivery and hospital course, but family history is significant for a sister with developmental dysplasia of the hip (DDH). A physical exam is normal. During a discussion with the mother about the possibility of screening imaging for DDH she becomes very anxious and would like something done as soon as possible. What would be the imaging of choice in this scenario?
Q203
A 2500-g (5.5-lb) male newborn is delivered at 35 weeks' gestation to a 25-year-old woman, gravida 2, para 1. The pregnancy was complicated by oligohydramnios. Pulse oximetry on room air shows an oxygen saturation of 78%. Examination in the delivery room shows that the newborn's skin appears blue with weak cry and irregular breathing and gasping. The nose is flat with bilateral epicanthal folds. The ears are low-set with broad auricles. The lower jaw is abnormally displaced backwards. The right lower limb appears shorter than the left lower limb with displaced right great toe. Breath sounds are decreased bilaterally. Renal ultrasound shows bilateral dilatation of the renal pelvis and ureters. Which of the following is most likely to confirm the underlying cause of this patient's condition?
Q204
A 4-year-old girl is brought to the clinic by her parents, who are concerned about an abdominal swelling that they noticed 2 days ago. The family immigrated from Bangladesh to the United States recently. The mother mentions that the girl has never been as active as other children of the same age but has no medical conditions either. Her appetite has declined, and she vomited a few times last week. On physical examination, slight prominence of frontal bosses at the forehead is noticeable with malar prominence and massive splenomegaly. Slight beading at the end of her ribs is evident. She has a dusky complexion, sclerae are anicteric, and oral mucosa is pale. Laboratory results are pending. Which of the following is the most likely explanation for the findings seen in this patient?
Q205
A 4-year-old boy presents with involuntary jerks seen in his upper extremities. The patient’s mother says that “his eyes move in different directions every now and then”. Last winter, the patient had chickenpox but otherwise has always been healthy. His vital signs are a blood pressure of 100/90 mm Hg, temperature of 36.8°C (98.2°F), and respiratory rate of 17/min. On physical examination, the patient’s eyes move chaotically in all directions. Laboratory tests are unremarkable, except for a random urinary vanillylmandelic acid (VMA) level of 18 mg/g creatinine (reference range for children aged 2–4 years: < 13 mg/g creatinine). An abdominal ultrasound shows a 2 cm x 3 cm x 5 cm mass in the left adrenal gland. A biopsy of the mass reveals neuroblasts arranged in a rosette pattern. Which of the following oncogenes is most commonly associated with this condition?
Q206
A 7-month-old boy is brought to the ED by his mother because of abdominal pain. Two weeks ago, she noticed he had a fever and looser stools, but both resolved after a few days. One week ago, he began to experience periodic episodes during which he would curl up into a ball, scream, and cry. The episodes lasted a few minutes, and were occasionally followed by vomiting. Between events, he was completely normal. She says the episodes have become more frequent over time, and this morning, she noticed blood in his diaper. In the ED, his vitals are within normal ranges, and his physical exam is normal. After confirming the diagnosis with an abdominal ultrasound, what is the next step in management?
Q207
A 5-year-old girl is brought to a medical office for evaluation of persistent abdominal pain that has worsened over the past 24 hours. The mother states that the girl often has constipation which has worsened over the last 3 days. The mother denies that the girl has had bloody stools. The girl has not had a bowel movement or passed flatulence in 72 hours. She has vomited 3 times since last night and refuses to eat. She has no significant medical history, including no history of surgeries. On exam, there are no abdominal masses; however, the upper abdomen is distended and tympanic. What is the most likely underlying cause of the girl’s symptoms?
Q208
A 4-day-old newborn is brought to the physician because of a generalized rash for 1 day. He was born at term. The mother had no prenatal care and has a history of gonorrhea, which was treated 4 years ago. The newborn is at the 50th percentile for head circumference, 60th percentile for length, and 55th percentile for weight. His temperature is 36.8°C (98.2°F), pulse is 152/min, and respirations are 51/min. Examination shows an erythematous maculopapular rash and pustules with an erythematous base over the trunk and extremities, sparing the palms and soles. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?
Q209
A 2-week-old newborn is brought to the physician for a follow-up examination. He was born at term and the pregnancy was uncomplicated. His mother says he has been feeding well and passing adequate amounts of urine. He appears healthy. He is at the 60th percentile for length and 40th percentile for weight. His temperature is 37.3°C (99.1°F), pulse is 130/min, respirations are 49/min and blood pressure is 62/40 mm Hg. A thrill is present over the third left intercostal space. A 5/6 holosystolic murmur is heard over the left lower sternal border. An echocardiography shows a 3-mm membranous ventricular septal defect. Which of the following is the most appropriate next step in management?
Q210
A 4-week-old male presents with his parents to the pediatrician for a well-child visit. The patient’s mother reports that the patient was eating well until about one week ago, when he began vomiting after breastfeeding. His mother has tried increasing the frequency of feeds and decreasing the amount of each feed, but the vomiting seems to be getting worse. The patient now vomits after every feed. His mother states the vomitus looks like breastmilk. The patient’s mother is exclusively breastfeeding and would prefer not to switch to formula but worries that the patient is not getting the nutrition he needs. Two weeks ago, the patient was in the 75th percentile for weight and 70th for height. He is now in the 60th percentile for weight and 68th percentile for height. On physical exam, the patient has dry mucous membranes. His abdomen is soft and non-distended.
Which of the following is the best next step in management?
Congenital defects US Medical PG Practice Questions and MCQs
Question 201: A 35-year-old woman has been trying to conceive with her 37-year-old husband for the past 4 years. After repeated visits to a fertility clinic, she finally gets pregnant. Although she missed most of her antenatal visits, her pregnancy was uneventful. A baby girl is born at the 38th week of gestation with some abnormalities. She has a flat face with upward-slanting eyes and a short neck. The tongue seems to be protruding from a small mouth. She has poor muscle tone and excessive joint laxity. The pediatrician orders an analysis of the infant’s chromosomes, also known as a karyotype (see image). The infant is most likely to suffer from which of the following conditions in the future?
A. Red blood cell sickling
B. Chronic myelogenous leukemia
C. Macroorchidism
D. Acute lymphoblastic leukemia (Correct Answer)
E. Immotile cilia syndrome
Explanation: ***Acute lymphoblastic leukemia***
- The description of the baby suggests **Down syndrome (Trisomy 21)**, characterized by **upward-slanting eyes**, a **flat face**, **short neck**, **protruding tongue**, **poor muscle tone**, and **excessive joint laxity**.
- Individuals with Down syndrome have a significantly increased risk of developing **acute lymphoblastic leukemia (ALL)**, particularly during childhood, with a 10-20 fold increased risk compared to the general population.
*Red blood cell sickling*
- **Red blood cell sickling** is characteristic of **sickle cell anemia**, an autosomal recessive genetic disorder.
- Sickle cell anemia is caused by a **point mutation** in the beta-globin gene, not a chromosomal abnormality like trisomy 21.
*Chronic myelogenous leukemia*
- **Chronic myelogenous leukemia (CML)** is typically associated with the **Philadelphia chromosome (t(9;22))**, a reciprocal translocation.
- CML is **not associated with Down syndrome**. While Down syndrome increases risk of **acute lymphoblastic leukemia (ALL)** and **acute myeloid leukemia (AML)**, it does not increase the risk of chronic myelogenous leukemia.
*Macroorchidism*
- **Macroorchidism**, or abnormally large testes, is a characteristic feature of **Fragile X syndrome**.
- Fragile X syndrome is caused by a **CGG trinucleotide repeat expansion** on the FMR1 gene on the X chromosome, not trisomy 21.
*Immotile cilia syndrome*
- **Immotile cilia syndrome** (also known as **primary ciliary dyskinesia** or PCD) is a genetic disorder affecting ciliary function.
- It leads to recurrent respiratory infections, situs inversus, and infertility and is not associated with Down syndrome.
Question 202: A full-term and healthy infant girl presents to the office for a newborn visit. The baby was born at 40 weeks to a 35-year-old G2P1 mother via cesarean section for breech presentation. She had an unremarkable delivery and hospital course, but family history is significant for a sister with developmental dysplasia of the hip (DDH). A physical exam is normal. During a discussion with the mother about the possibility of screening imaging for DDH she becomes very anxious and would like something done as soon as possible. What would be the imaging of choice in this scenario?
A. Hip radiograph at 5 months of age
B. Hip ultrasound at 6 weeks of age
C. Hip ultrasound within the next week (Correct Answer)
D. Hip MRI at 6 weeks of age
E. Hip radiograph at 6 weeks of age
Explanation: ***Hip ultrasound within the next week***
- This infant has **risk factors for DDH** (breech presentation, female sex, family history of DDH in a first-degree relative), warranting screening.
- An ultrasound is the preferred imaging modality for newborns as their **bones are cartilaginous** and not well-ossified, making X-rays less informative. Given the mother's anxiety, performing the ultrasound sooner rather than later is appropriate.
*Hip ultrasound at 6 weeks of age*
- While ultrasound is the correct modality, waiting until 6 weeks for a high-risk infant with an anxious mother is **not ideal when an earlier evaluation can be done**.
- Delaying imaging could lead to increased maternal anxiety and potentially a missed opportunity for early intervention in a high-risk infant.
*Hip radiograph at 5 months of age*
- **Radiographs are not effective** for detecting DDH in infants younger than 4-6 months because their femoral heads and acetabular roofs are primarily cartilage.
- Delaying imaging until 5 months would be a significant delay for early detection and intervention, which is crucial for successful DDH treatment.
*Hip MRI at 6 weeks of age*
- **MRI is not routinely used** for DDH screening due to its **high cost**, need for **sedation** in infants, and **limited availability** compared to ultrasound.
- It offers no significant advantage over ultrasound for initial screening in this age group.
*Hip radiograph at 6 weeks of age*
- At 6 weeks of age, the infant's hip structures are still **predominantly cartilaginous**, making a radiograph **unreliable** for assessing the bony development of the hip joint.
- **Ultrasound is the imaging of choice** for evaluating DDH in newborns and young infants due to its ability to visualize cartilaginous structures.
Question 203: A 2500-g (5.5-lb) male newborn is delivered at 35 weeks' gestation to a 25-year-old woman, gravida 2, para 1. The pregnancy was complicated by oligohydramnios. Pulse oximetry on room air shows an oxygen saturation of 78%. Examination in the delivery room shows that the newborn's skin appears blue with weak cry and irregular breathing and gasping. The nose is flat with bilateral epicanthal folds. The ears are low-set with broad auricles. The lower jaw is abnormally displaced backwards. The right lower limb appears shorter than the left lower limb with displaced right great toe. Breath sounds are decreased bilaterally. Renal ultrasound shows bilateral dilatation of the renal pelvis and ureters. Which of the following is most likely to confirm the underlying cause of this patient's condition?
A. Echocardiography
B. Voiding cystourethrogram (Correct Answer)
C. Blood cultures
D. X-ray of the chest
E. Karyotyping
Explanation: ***Voiding cystourethrogram***
- This male newborn presents with **Potter sequence** (Potter facies, pulmonary hypoplasia, limb deformities) secondary to severe **oligohydramnios**.
- The key finding of **bilateral hydronephrosis** (dilated renal pelvis and ureters) in a male newborn strongly suggests **obstructive uropathy**, most commonly due to **posterior urethral valves (PUV)**.
- **Voiding cystourethrogram (VCUG)** is the diagnostic test of choice to visualize the urethra during voiding and identify posterior urethral valves or other lower urinary tract obstruction causing the bilateral hydronephrosis and subsequent oligohydramnios.
- The oligohydramnios from urinary obstruction leads to pulmonary hypoplasia (explaining respiratory distress) and compression deformities (Potter facies and limb abnormalities).
*Karyotyping*
- While chromosomal abnormalities (trisomy 13, 18, 21) can cause multiple congenital anomalies, the specific pattern here points to **Potter sequence from obstructive uropathy** rather than a primary genetic syndrome.
- The presence of **bilateral hydronephrosis** indicates the kidneys are present but obstructed, not absent or severely dysplastic as might occur with chromosomal syndromes.
- Karyotyping would be indicated if there were additional features suggestive of specific aneuploidies, but the clinical picture is most consistent with anatomical urinary obstruction.
*Echocardiography*
- While cardiac defects can occur with genetic syndromes, echocardiography would not identify the **underlying urinary tract obstruction** causing the oligohydramnios and Potter sequence.
- The primary pathology is in the **urinary system**, not the cardiovascular system.
*Blood cultures*
- Blood cultures are indicated for sepsis evaluation, but this presentation reflects **chronic intrauterine pathology** from oligohydramnios, not acute postnatal infection.
- The constellation of Potter facies, limb deformities, and bilateral hydronephrosis indicates a developmental/structural problem, not infection.
*X-ray of the chest*
- Chest X-ray would show **pulmonary hypoplasia** (small lung volumes, bell-shaped chest) as a consequence of oligohydramnios but would not identify the **underlying cause** of the urinary obstruction.
- While helpful for assessing the degree of pulmonary hypoplasia, it does not establish the diagnosis of posterior urethral valves or other obstructive uropathy.
Question 204: A 4-year-old girl is brought to the clinic by her parents, who are concerned about an abdominal swelling that they noticed 2 days ago. The family immigrated from Bangladesh to the United States recently. The mother mentions that the girl has never been as active as other children of the same age but has no medical conditions either. Her appetite has declined, and she vomited a few times last week. On physical examination, slight prominence of frontal bosses at the forehead is noticeable with malar prominence and massive splenomegaly. Slight beading at the end of her ribs is evident. She has a dusky complexion, sclerae are anicteric, and oral mucosa is pale. Laboratory results are pending. Which of the following is the most likely explanation for the findings seen in this patient?
A. Glycogen storage disease
B. Graves disease
C. Renal failure
D. Extramedullary hematopoiesis due to thalassemia (Correct Answer)
E. Lymphoma
Explanation: ***Extramedullary hematopoiesis due to thalassemia***
- The constellation of **massive splenomegaly**, **frontal bossing**, and **malar prominence** in a child from Bangladesh strongly suggests **beta-thalassemia major**, with expansion of bone marrow leading to characteristic facial features and extramedullary hematopoiesis causing splenomegaly.
- The history of **reduced activity**, **declined appetite**, **vomiting**, **dusky complexion**, and **pale oral mucosa** are consistent with **chronic anemia**, a hallmark of thalassemia.
*Glycogen storage disease*
- While some types can cause **hepatomegaly**, **splenomegaly** is less common, and the characteristic skeletal changes like **frontal bossing** and **malar prominence** are not typically seen.
- Patients usually present with **hypoglycemia** and muscle weakness, which are not clearly described here as the primary concern.
*Graves disease*
- This is an **autoimmune hyperthyroid condition** that primarily presents with **goiter**, **exophthalmos**, and symptoms of hypermetabolism like weight loss, tachycardia, and irritability, which are inconsistent with this patient's presentation.
- It does not cause **splenomegaly** or the specific skeletal changes observed.
*Renal failure*
- **Chronic renal failure** in children can cause growth retardation, anemia, and bone deformities (renal osteodystrophy), but the specific facial features (**frontal bossing**, **malar prominence**) and **massive splenomegaly** described are not typical primary manifestations.
- The patient's symptoms are more indicative of a hematologic disorder.
*Lymphoma*
- While lymphoma can cause **splenomegaly** and systemic symptoms like fatigue and weight loss, it typically does not lead to the specific skeletal changes such as **frontal bossing** and **malar prominence** seen in this patient.
- The chronic nature of the symptoms and the specific physical findings point away from lymphoma as the primary diagnosis.
Question 205: A 4-year-old boy presents with involuntary jerks seen in his upper extremities. The patient’s mother says that “his eyes move in different directions every now and then”. Last winter, the patient had chickenpox but otherwise has always been healthy. His vital signs are a blood pressure of 100/90 mm Hg, temperature of 36.8°C (98.2°F), and respiratory rate of 17/min. On physical examination, the patient’s eyes move chaotically in all directions. Laboratory tests are unremarkable, except for a random urinary vanillylmandelic acid (VMA) level of 18 mg/g creatinine (reference range for children aged 2–4 years: < 13 mg/g creatinine). An abdominal ultrasound shows a 2 cm x 3 cm x 5 cm mass in the left adrenal gland. A biopsy of the mass reveals neuroblasts arranged in a rosette pattern. Which of the following oncogenes is most commonly associated with this condition?
A. MYCN (Correct Answer)
B. JAK2
C. RET
D. ALK
E. KRAS
Explanation: ***MYCN***
- The clinical presentation with **opsoclonus-myoclonus syndrome**, elevated **urinary VMA**, an adrenal mass with a biopsy showing **neuroblasts arranged in a rosette pattern**, is classic for neuroblastoma.
- **MYCN amplification** is the most commonly associated oncogene with neuroblastoma, found in ~20-25% of cases, and is the single most important prognostic indicator of aggressive disease.
*JAK2*
- **JAK2 mutations** are primarily associated with **myeloproliferative neoplasms** (e.g., polycythemia vera, essential thrombocythemia, primary myelofibrosis), which are hematologic malignancies and do not present as an adrenal mass.
- There is no clinical or pathological evidence to suggest a myeloproliferative disorder in this patient.
*RET*
- **RET proto-oncogene mutations** are linked to **Multiple Endocrine Neoplasia type 2 (MEN2)** syndromes and **medullary thyroid carcinoma**.
- These conditions typically involve endocrine tumors and do not present with opsoclonus-myoclonus syndrome or neuroblastoma histology.
*ALK*
- **ALK gene alterations** occur in ~10-15% of neuroblastomas and can be a therapeutic target, but are **less frequently amplified than MYCN** (20-25%).
- While clinically important (especially for targeted therapy with ALK inhibitors), **MYCN amplification** remains the most common oncogenic driver and primary prognostic marker in neuroblastoma.
*KRAS*
- **KRAS mutations** are common in many adult solid tumors, such as **pancreatic adenocarcinoma**, **colorectal cancer**, and **non-small cell lung cancer**.
- They are not typically associated with neuroblastoma.
Question 206: A 7-month-old boy is brought to the ED by his mother because of abdominal pain. Two weeks ago, she noticed he had a fever and looser stools, but both resolved after a few days. One week ago, he began to experience periodic episodes during which he would curl up into a ball, scream, and cry. The episodes lasted a few minutes, and were occasionally followed by vomiting. Between events, he was completely normal. She says the episodes have become more frequent over time, and this morning, she noticed blood in his diaper. In the ED, his vitals are within normal ranges, and his physical exam is normal. After confirming the diagnosis with an abdominal ultrasound, what is the next step in management?
A. Supportive care
B. Broad-spectrum antibiotics
C. Air contrast enema (Correct Answer)
D. Abdominal laparotomy
E. Abdominal CT scan
Explanation: ***Air contrast enema***
- An **air contrast enema** is both diagnostic and therapeutic for **intussusception**, which is strongly suggested by the patient's symptoms (colicky abdominal pain, drawing legs to chest, currant jelly stools).
- It uses air pressure to **reduce the intussusception**, avoiding surgery if successful and the bowel is not compromised.
*Supportive care*
- While supportive care (IV fluids, pain control) is important, it does not address the underlying mechanical issue of **intussusception** and would not resolve the condition.
- Delaying definitive treatment for intussusception can lead to **bowel ischemia, necrosis, and perforation**, which are life-threatening.
*Broad-spectrum antibiotics*
- Antibiotics are not the primary treatment for **intussusception**, as it is a mechanical obstruction, not typically a primary infection.
- They might be considered if there are signs of **perforation or peritonitis**, but the immediate goal is reduction.
*Abdominal laparotomy*
- An **abdominal laparotomy** is a surgical intervention reserved for cases where **non-operative reduction** (like an air enema) fails or if there are signs of **bowel perforation or gangrene**.
- It is not the *first-line* next step after diagnosis, especially if non-invasive options remain viable.
*Abdominal CT scan*
- An **abdominal CT scan** can diagnose intussusception but is typically not the preferred initial imaging because it involves **radiation exposure** and **does not offer therapeutic benefit**, unlike an air contrast enema.
- Abdominal ultrasound is usually sufficient for diagnosis and safer for pediatric patients.
Question 207: A 5-year-old girl is brought to a medical office for evaluation of persistent abdominal pain that has worsened over the past 24 hours. The mother states that the girl often has constipation which has worsened over the last 3 days. The mother denies that the girl has had bloody stools. The girl has not had a bowel movement or passed flatulence in 72 hours. She has vomited 3 times since last night and refuses to eat. She has no significant medical history, including no history of surgeries. On exam, there are no abdominal masses; however, the upper abdomen is distended and tympanic. What is the most likely underlying cause of the girl’s symptoms?
A. Duodenal atresia
B. Malrotation of the gut (Correct Answer)
C. Pyloric stenosis
D. Meckel’s diverticulum
E. Volvulus
Explanation: ***Malrotation of the gut***
- The question asks for the **underlying cause** of symptoms in a 5-year-old presenting with her **first episode** of acute bowel obstruction and **no prior surgical history**. **Malrotation** is the congenital anatomical abnormality that predisposes to **midgut volvulus**.
- **Malrotation** occurs when the bowel fails to rotate properly during fetal development, leaving the mesentery on a narrow pedicle. This anatomical defect is the underlying cause that makes volvulus possible.
- While volvulus (twisting) is the acute mechanical event causing obstruction, **malrotation is the underlying anatomical defect** being asked for in the question.
- The presentation of **abdominal pain**, **vomiting**, **abdominal distension**, inability to pass **flatus or stool** for 72 hours, and **tympanic upper abdomen** indicates acute bowel obstruction from midgut volvulus occurring on the background of malrotation.
*Volvulus*
- **Volvulus** (twisting of the bowel) is the **acute complication** that occurs, not the underlying cause.
- Volvulus is the mechanism of obstruction, but it occurs because of the underlying anatomical defect (malrotation).
- The question specifically asks for "underlying cause" - volvulus is the acute event, while malrotation is the predisposing anatomical abnormality.
*Duodenal atresia*
- **Duodenal atresia** is a congenital complete obstruction that presents in the **neonatal period** with vomiting (bilious), the classic "double bubble" sign, and feeding intolerance.
- This would have been diagnosed much earlier than 5 years of age and is not compatible with this presentation.
*Pyloric stenosis*
- **Pyloric stenosis** presents with **non-bilious projectile vomiting** in infants between **2 to 6 weeks of age**, not in a 5-year-old child.
- Physical exam classically reveals an **olive-shaped mass** in the epigastrium and visible gastric peristaltic waves.
*Meckel's diverticulum*
- **Meckel's diverticulum** most commonly presents with **painless rectal bleeding** (from ectopic gastric mucosa causing ulceration) following the "rule of 2s."
- While it can cause obstruction via intussusception or serve as a lead point, it is not the most likely underlying cause of this presentation in a 5-year-old with acute complete bowel obstruction and no prior symptoms.
Question 208: A 4-day-old newborn is brought to the physician because of a generalized rash for 1 day. He was born at term. The mother had no prenatal care and has a history of gonorrhea, which was treated 4 years ago. The newborn is at the 50th percentile for head circumference, 60th percentile for length, and 55th percentile for weight. His temperature is 36.8°C (98.2°F), pulse is 152/min, and respirations are 51/min. Examination shows an erythematous maculopapular rash and pustules with an erythematous base over the trunk and extremities, sparing the palms and soles. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?
A. Congenital syphilis
B. Acropustulosis
C. Milia
D. Erythema toxicum (Correct Answer)
E. Pustular melanosis
Explanation: **Erythema toxicum**
- Erythema toxicum is a **benign, self-limited rash** commonly seen in newborns, characterized by an **erythematous maculopapular rash** with pustules on an erythematous base.
- The rash typically appears on the **trunk and extremities**, sparing the palms and soles, and is generally asymptomatic, matching the presentation in this 4-day-old infant.
*Congenital syphilis*
- Congenital syphilis would typically present with a rash that can involve the **palms and soles**, and is often accompanied by other systemic signs like **hepatosplenomegaly**, rhinitis, or skeletal abnormalities, which are absent here.
- Although the mother had no prenatal care and a history of gonorrhea, no specific risk factors or clinical signs of congenital syphilis are present in the newborn's history or examination.
*Acropustulosis*
- Infantile acropustulosis is characterized by **recurrent crops of pruritic vesicles and pustules** predominantly on the **palms and soles**, which is contrary to the described sparing of these areas.
- This condition typically presents with significant **itching**, which is not mentioned in the newborn's presentation.
*Milia*
- Milia consists of **tiny, pearly white or yellow papules** that are typically found on the face, especially the nose and cheeks, and are essentially clogged pores.
- They are **not erythematous** and do not present as a generalized maculopapular rash with pustules on an erythematous base.
*Pustular melanosis*
- Transient neonatal pustular melanosis is characterized by pustules that rupture to leave a **collarette of scale** and then hyperpigmented macules, without an erythematous base.
- The lesions are usually present at birth, and the characteristic residual hyperpigmented macules are a key diagnostic feature, which is not described.
Question 209: A 2-week-old newborn is brought to the physician for a follow-up examination. He was born at term and the pregnancy was uncomplicated. His mother says he has been feeding well and passing adequate amounts of urine. He appears healthy. He is at the 60th percentile for length and 40th percentile for weight. His temperature is 37.3°C (99.1°F), pulse is 130/min, respirations are 49/min and blood pressure is 62/40 mm Hg. A thrill is present over the third left intercostal space. A 5/6 holosystolic murmur is heard over the left lower sternal border. An echocardiography shows a 3-mm membranous ventricular septal defect. Which of the following is the most appropriate next step in management?
A. Indomethacin therapy
B. Cardiac catheterization
C. Amoxicillin therapy
D. Prostaglandin E1 therapy
E. Outpatient follow-up (Correct Answer)
Explanation: ***Outpatient follow-up***
- The patient has a **small ventricular septal defect (VSD)** (3 mm) and is **asymptomatic**, feeding well, and growing appropriately. Many small VSDs close spontaneously, so watchful waiting with outpatient follow-up is the most appropriate initial management.
- The presence of a thrill and a loud holosystolic murmur with a small VSD is often due to the **high-velocity jet** of blood across a small opening, rather than indicative of severe hemodynamic instability.
*Indomethacin therapy*
- **Indomethacin** is used to close a **patent ductus arteriosus (PDA)**, not a VSD.
- VSDs do not respond to indomethacin.
*Cardiac catheterization*
- **Cardiac catheterization** or surgical repair is typically reserved for **large, symptomatic VSDs** that cause heart failure, pulmonary hypertension, or significant growth failure, none of which are present in this case.
- Performing an invasive procedure on an asymptomatic infant with a small VSD is unnecessary and carries risks.
*Amoxicillin therapy*
- **Amoxicillin** is an antibiotic and is not indicated for the management of a VSD.
- While it can be used for endocarditis prophylaxis in some high-risk cardiac conditions, a small VSD is typically not considered a high-risk lesion requiring routine prophylaxis.
*Prostaglandin E1 therapy*
- **Prostaglandin E1 (PGE1)** is used to maintain the **patency of the ductus arteriosus** in ductal-dependent cardiac lesions (e.g., critical coarctation, hypoplastic left heart syndrome) to ensure systemic or pulmonary blood flow.
- In this case, the VSD does not require the PDA to remain open; in fact, maintaining PDA patency would worsen a VSD by increasing pulmonary blood flow.
Question 210: A 4-week-old male presents with his parents to the pediatrician for a well-child visit. The patient’s mother reports that the patient was eating well until about one week ago, when he began vomiting after breastfeeding. His mother has tried increasing the frequency of feeds and decreasing the amount of each feed, but the vomiting seems to be getting worse. The patient now vomits after every feed. His mother states the vomitus looks like breastmilk. The patient’s mother is exclusively breastfeeding and would prefer not to switch to formula but worries that the patient is not getting the nutrition he needs. Two weeks ago, the patient was in the 75th percentile for weight and 70th for height. He is now in the 60th percentile for weight and 68th percentile for height. On physical exam, the patient has dry mucous membranes. His abdomen is soft and non-distended.
Which of the following is the best next step in management?
A. Abdominal radiograph
B. Trial of empiric proton pump inhibitor
C. Supplement breastfeeding with formula
D. Abdominal ultrasound (Correct Answer)
E. Trial of cow's milk-free diet
Explanation: ***Abdominal ultrasound***
- The history of **progressive non-bilious vomiting** after every feed, worsening over time, and **weight percentile drop** in a 4-week-old infant strongly suggests **pyloric stenosis**. The best next step for diagnosis is an abdominal ultrasound which can visualize the thickened pylorus (>3-4 mm muscle thickness, >14-16 mm channel length).
- The physical exam finding of **dry mucous membranes** indicates dehydration, a common complication of recurrent vomiting.
*Abdominal radiograph*
- An abdominal radiograph is generally not the initial imaging of choice for diagnosing pyloric stenosis, as it is less sensitive and specific than ultrasound for visualizing soft tissue structures like the pylorus.
- While it may show a **dilated stomach** or **absent gas in the distal bowel**, these findings are not diagnostic of pyloric stenosis and do not pinpoint the obstruction.
*Trial of empiric proton pump inhibitor*
- A proton pump inhibitor would be considered for **gastroesophageal reflux disease (GERD)**, but the **worsening pattern of vomiting after every feed** and **rapid weight loss** are atypical for simple GERD and point to a more serious mechanical obstruction.
- Treating with a PPI would delay the proper diagnosis and treatment of pyloric stenosis, which requires surgical intervention (pyloromyotomy).
*Supplement breastfeeding with formula*
- While ensuring adequate nutrition is important, simply supplementing with formula will not resolve the underlying issue of **pyloric obstruction**, and the infant will likely continue to vomit and experience dehydration.
- This approach would delay definitive diagnosis and treatment, potentially leading to further compromise of the infant's health.
*Trial of cow's milk-free diet*
- A cow's milk-free diet is indicated for suspected **cow's milk protein allergy (CMPA)**, which can present with vomiting, but typically also includes symptoms like **bloody stools**, **eczema**, or **colic**, which are not reported here.
- The **progressive non-bilious vomiting after every feed** and rapid weight loss are more characteristic of a mechanical obstruction like pyloric stenosis than a dietary allergy.