A two-year-old female presents to the pediatrician with her mother for a routine well-child visit. Her mother is concerned that the patient is a picky eater and refuses to eat vegetables. She drinks milk with meals and has juice sparingly. She goes to sleep easily at night and usually sleeps for 11-12 hours. The patient has trouble falling asleep for naps but does nap for 1-2 hours a few times per week. She is doing well in daycare and enjoys parallel play with the other children. Her mother reports that she can walk down stairs with both feet on each step. She has a vocabulary of 10-25 words that she uses in the form of one-word commands. She is in the 42nd percentile for height and 48th percentile for weight, which is consistent with her growth curves. On physical exam, she appears well nourished. She can copy a line and throw a ball. She can follow the command to “give me the ball and then close the door.”
This child is meeting her developmental milestones in all but which of the following categories?
Q2
A 30-year-old gravida 1 woman comes to the office for a prenatal visit. She is at 20 weeks gestation with no complaints. She is taking her prenatal vitamins but stopped the prescribed ferrous sulfate because it was making her constipated. Urinalysis shows trace protein. Uterine fundus is the expected size for a 20-week gestation. Just before leaving the examination room, she stops the physician and admits to eating laundry detergent. She is embarrassed and fears she is going crazy. Which of the following is the most likely diagnosis?
Q3
A 7-year-old boy is brought in to clinic by his parents with a chief concern of poor performance in school. The parents were told by the teacher that the student often does not turn in assignments, and when he does they are partially complete. The child also often shouts out answers to questions and has trouble participating in class sports as he does not follow the rules. The parents of this child also note similar behaviors at home and have trouble getting their child to focus on any task such as reading. The child is even unable to watch full episodes of his favorite television show without getting distracted by other activities. The child begins a trial of behavioral therapy that fails. The physician then tries pharmacological therapy. Which of the following is most likely the mechanism of action of an appropriate treatment for this child's condition?
Q4
A 4-month-old girl is brought to the physician because she has been regurgitating and vomiting 10–15 minutes after feeding for the past 3 weeks. She is breastfed and formula-fed. She was born at 38 weeks' gestation and weighed 2966 g (6 lb 9 oz). She currently weighs 5878 g (12 lb 15 oz). She appears healthy. Vital signs are within normal limits. Examination shows a soft and nontender abdomen and no organomegaly. Which of the following is the most appropriate next best step in management?
Q5
A previously healthy 21-year-old woman is brought to the physician because of weight loss and fatigue. Over the past 12 months she has lost 10.5 kg (23.1 lb). She feels tired almost every day and says that she has to go running for 2 hours every morning to wake up. She had been a vegetarian for 2 years but decided to become a vegan 6 months ago. She lives with her mother, who has obsessive-compulsive disorder. The mother reports that her daughter refuses to eat with the family and only eats food that she has prepared herself. When asked about her weight, the patient says that despite her weight loss, she still feels “chubby”. She is 160 cm (5 ft 3 in) tall and weighs 42 kg (92.6 lb); BMI is 16.4 kg/m2. Her temperature is 35.7°C (96.3°F), pulse is 39/min, and blood pressure is 100/50 mm Hg. Physical examination shows emaciation. There is dry skin, covered by fine, soft hair all over the body. On mental status examination, she is oriented to person, place, and time. Serum studies show:
Na+ 142 mEq/L
Cl 103 mEq/L
K+ 4.0 mEq/L
Urea nitrogen 10 mg/dL
Creatinine 1.0 mg/dL
Glucose 65 mg/dL
Which of the following is the most appropriate next step in management?
Q6
A 2-month-old girl is brought to the physician for a well-child examination. She was born at 32 weeks' gestation and weighed 1616 g (3 lb 9 oz); she currently weighs 2466 g (5 lb 7 oz). She is exclusively breastfed and receives vitamin D supplementation. Physical examination shows no abnormalities apart from low height and weight. This patient is at increased risk for which of the following complications?
Q7
A 2-year-old boy is brought to a pediatrician because his parents have noticed that he seems to be getting tired very easily at home. Specifically, they have noticed that he is often panting for breath after walking around the house for a few minutes and that he needs to take naps fairly often throughout the day. He has otherwise been well, and his parents do not recall any recent infections. He was born at home, and his mom did not receive any prenatal care prior to birth. Physical exam reveals a high-pitched, harsh, holosystolic murmur that is best heard at the lower left sternal border. No cyanosis is observed. Which of the following oxygen tension profiles would most likely be seen in this patient? (LV = left ventricle, RV = right ventricle, and SC = systemic circulation).
Q8
A 4-week-old infant is brought to the physician by his mother because of blood-tinged stools for 3 days. He has also been passing whitish mucoid strings with the stools during this period. He was delivered at 38 weeks' gestation by lower segment transverse cesarean section because of a nonreassuring fetal heart rate. He was monitored in the intensive care unit for a day prior to being discharged. His 6-year-old brother was treated for viral gastroenteritis one week ago. The patient is exclusively breastfed. He is at the 50th percentile for height and 60th percentile for weight. He appears healthy and active. His vital signs are within normal limits. Examination shows a soft and nontender abdomen. The liver is palpated just below the right costal margin. The remainder of the examination shows no abnormalities. Test of the stool for occult blood is positive. A complete blood count and serum concentrations of electrolytes and creatinine are within the reference range. Which of the following is the most appropriate next step in management?
Q9
A 1-day-old infant in the general care nursery, born at full term by uncomplicated cesarean section delivery, is noted to have a murmur, but otherwise appears well. On examination, respiratory rate is 40/min and pulse oximetry is 96%. Precordium is normoactive. With auscultation, S1 is normal, S2 is single, and a 2/6 systolic ejection murmur is heard at the left upper sternal border. Echocardiography shows infundibular pulmonary stenosis, overriding aorta, ventricular septal defect and concentric right ventricular hypertrophy. Which of the following correlate with the presence or absence of cyanosis in this baby?
Q10
A 5-month-old boy is brought to the emergency department by his mother because his lips turned blue for several minutes while playing earlier that evening. She reports that he has had similar episodes during feeding that resolved quickly. He was born at term following an uncomplicated pregnancy and delivery. He is at the 25th percentile for length and below the 5th percentile for weight. His temperature is 37°C (98.6°F), pulse is 130/min, blood pressure is 83/55 mm Hg, and respirations are 42/min. Pulse oximetry on room air shows an oxygen saturation of 90%. During the examination, he sits calmly in his mother's lap. He appears well. The patient begins to cry when examination of his throat is attempted; his lips and fingers begin to turn blue. Further evaluation of this patient is most likely to show which of the following?
Feeding disorders in children US Medical PG Practice Questions and MCQs
Question 1: A two-year-old female presents to the pediatrician with her mother for a routine well-child visit. Her mother is concerned that the patient is a picky eater and refuses to eat vegetables. She drinks milk with meals and has juice sparingly. She goes to sleep easily at night and usually sleeps for 11-12 hours. The patient has trouble falling asleep for naps but does nap for 1-2 hours a few times per week. She is doing well in daycare and enjoys parallel play with the other children. Her mother reports that she can walk down stairs with both feet on each step. She has a vocabulary of 10-25 words that she uses in the form of one-word commands. She is in the 42nd percentile for height and 48th percentile for weight, which is consistent with her growth curves. On physical exam, she appears well nourished. She can copy a line and throw a ball. She can follow the command to “give me the ball and then close the door.”
This child is meeting her developmental milestones in all but which of the following categories?
A. Social and receptive language skills
B. Fine motor skills
C. This child is developmentally normal
D. Gross motor skills
E. Expressive language skills (Correct Answer)
Explanation: ***Expressive language skills***
- At two years old, a child should typically have an **expressive vocabulary of 50-200 words** and be putting **two-word sentences** together.
- This child's vocabulary of 10-25 words, used primarily as one-word commands, is significantly below the expected range for her age.
*Social and receptive language skills*
- The child is reported to be doing well in daycare and enjoys **parallel play**, which reflects appropriate **social development** for her age.
- Her ability to follow the two-step command "give me the ball and then close the door" demonstrates intact **receptive language skills**.
*This child is developmentally normal*
- While many areas of her development appear normal, her **expressive language skills** are clearly delayed, indicating that she is not entirely developmentally normal.
- Identifying specific areas of delay is crucial for early intervention.
*Gross motor skills*
- The child's ability to **walk down stairs with both feet on each step** is a normal gross motor milestone for a two-year-old.
- Other gross motor skills like running and kicking a ball are typically present, and there is no information to suggest a deficit.
*Fine motor skills*
- The ability to **copy a line** is an expected fine motor skill for a two-year-old.
- Throwing a ball also involves fine motor coordination and is within the expected range for this age.
Question 2: A 30-year-old gravida 1 woman comes to the office for a prenatal visit. She is at 20 weeks gestation with no complaints. She is taking her prenatal vitamins but stopped the prescribed ferrous sulfate because it was making her constipated. Urinalysis shows trace protein. Uterine fundus is the expected size for a 20-week gestation. Just before leaving the examination room, she stops the physician and admits to eating laundry detergent. She is embarrassed and fears she is going crazy. Which of the following is the most likely diagnosis?
A. Normal pregnancy
B. Iron deficiency anemia (Correct Answer)
C. Plummer-Vinson syndrome
D. Brief psychotic disorder
E. Pre-eclampsia
Explanation: ***Iron deficiency anemia***
- The patient exhibits **pica** (craving and eating non-food substances such as laundry detergent), which is a common manifestation of **iron deficiency anemia** in pregnant women.
- She also stopped taking **ferrous sulfate** due to constipation, indicating a potential ongoing iron deficiency that is now symptomatic.
- Pica in pregnancy is strongly associated with iron deficiency and typically resolves with iron supplementation.
*Normal pregnancy*
- While trace protein in urine can be normal in pregnancy, **pica** (eating non-food items) is not a normal physiological finding and suggests an underlying nutritional deficiency.
- The patient's admission of shame and fear of "going crazy" further indicates this is a pathological behavior requiring evaluation.
*Plummer-Vinson syndrome*
- This syndrome is characterized by **iron deficiency anemia**, **dysphagia** (due to esophageal webs), and **glossitis**.
- Although the patient likely has iron deficiency, dysphagia and glossitis are not mentioned, making this specific syndrome diagnosis less likely without the classic triad.
*Brief psychotic disorder*
- This disorder involves a sudden onset of **psychotic symptoms** such as delusions, hallucinations, or disorganized speech, lasting less than a month.
- Pica, while unusual behavior, is not a primary psychotic symptom and is specifically linked to nutritional deficiencies (particularly iron) rather than a thought disorder.
*Pre-eclampsia*
- Pre-eclampsia is characterized by **new-onset hypertension** (blood pressure ≥140/90 mmHg) and **proteinuria** after 20 weeks of gestation.
- The patient's blood pressure is not mentioned, and while she has trace proteinuria, there is no indication of hypertension or other classic symptoms like severe headaches, visual disturbances, or right upper quadrant pain.
Question 3: A 7-year-old boy is brought in to clinic by his parents with a chief concern of poor performance in school. The parents were told by the teacher that the student often does not turn in assignments, and when he does they are partially complete. The child also often shouts out answers to questions and has trouble participating in class sports as he does not follow the rules. The parents of this child also note similar behaviors at home and have trouble getting their child to focus on any task such as reading. The child is even unable to watch full episodes of his favorite television show without getting distracted by other activities. The child begins a trial of behavioral therapy that fails. The physician then tries pharmacological therapy. Which of the following is most likely the mechanism of action of an appropriate treatment for this child's condition?
A. Increases the frequency of GABAa channel opening
B. Increases the duration of GABAa channel opening
C. Decreases synaptic reuptake of norepinephrine and dopamine (Correct Answer)
D. Blockade of D2 receptors
E. Antagonizes NMDA receptors
Explanation: ***Decreases synaptic reuptake of norepinephrine and dopamine***
- The presented symptoms (inattention, impulsivity, hyperactivity) are characteristic of **Attention-Deficit/Hyperactivity Disorder (ADHD)**.
- The most common pharmacological treatments for ADHD are **stimulants** (e.g., methylphenidate, amphetamines) which work by **inhibiting the reuptake of norepinephrine and dopamine**, thereby increasing their synaptic concentrations.
*Increases the frequency of GABAa channel opening*
- This is the mechanism of action for **benzodiazepines**, which are primarily used for anxiety, seizures, and insomnia.
- Benzodiazepines are not indicated for ADHD and would likely worsen symptoms due to their sedative effects.
*Increases the duration of GABAa channel opening*
- This describes the mechanism of action of **barbiturates**, which are potent central nervous system depressants.
- Like benzodiazepines, barbiturates are not used for ADHD and would have inappropriate sedative side effects.
*Blockade of D2 receptors*
- This is the primary mechanism of action for **antipsychotic medications**, used to treat conditions like schizophrenia or bipolar disorder.
- Blocking D2 receptors would likely cause side effects such as drowsiness and extrapyramidal symptoms, and would not address the core symptoms of ADHD.
*Antagonizes NMDA receptors*
- NMDA receptor antagonists (e.g., memantine, ketamine) are used in conditions like **Alzheimer's disease** or for anesthetic purposes.
- This mechanism is not relevant to the treatment of ADHD; enhancing NMDA receptor activity might actually be beneficial in some cognitive disorders.
Question 4: A 4-month-old girl is brought to the physician because she has been regurgitating and vomiting 10–15 minutes after feeding for the past 3 weeks. She is breastfed and formula-fed. She was born at 38 weeks' gestation and weighed 2966 g (6 lb 9 oz). She currently weighs 5878 g (12 lb 15 oz). She appears healthy. Vital signs are within normal limits. Examination shows a soft and nontender abdomen and no organomegaly. Which of the following is the most appropriate next best step in management?
A. Upper endoscopy
B. Ultrasound of the abdomen
C. Esophageal pH monitoring
D. Positioning therapy (Correct Answer)
E. Pantoprazole therapy
Explanation: ***Positioning therapy***
- This infant is thriving, as evidenced by her significant weight gain, despite her regurgitation and vomiting. Her examination is also benign. These features make **gastroesophageal reflux (GER)**, a physiological process, the most likely diagnosis.
- **Positioning therapy** (e.g., keeping the infant upright during and after feeds) is a first-line, conservative management strategy for GER in infants who are otherwise healthy and gaining weight well.
*Upper endoscopy*
- **Upper endoscopy** is an invasive procedure and is typically reserved for evaluating patients with suspected complicated gastroesophageal reflux disease (GERD), such as those with **poor weight gain**, **hematemesis**, or **esophagitis**, none of which are seen here.
- It would not be the initial step in a thriving infant with symptoms consistent with uncomplicated GER.
*Ultrasound of the abdomen*
- An **abdominal ultrasound** is primarily used to diagnose **pyloric stenosis** in infants, which typically presents with **projectile, non-bilious vomiting** and **poor weight gain** or weight loss, usually between 3 and 6 weeks of age.
- This infant's symptoms are different in character (regurgitation/vomiting 10-15 minutes after feeding, not projectile) and she is gaining weight well, making pyloric stenosis less likely.
*Esophageal pH monitoring*
- **Esophageal pH monitoring** is used to quantify acid reflux episodes and is typically reserved for infants with atypical symptoms, suspected **complicated GERD**, or those who have failed empirical therapy.
- It is not indicated as a primary diagnostic or management step in a healthy, thriving infant with typical GER symptoms.
*Pantoprazole therapy*
- **Proton pump inhibitors (PPIs)** like pantoprazole are used to treat **GERD** by reducing stomach acid production, especially in cases with evidence of **esophagitis** or significant symptoms impacting growth or comfort.
- Given this infant is thriving and has no signs of complications, acid-suppressing medication is not appropriate as the initial management step; conservative measures should be tried first.
Question 5: A previously healthy 21-year-old woman is brought to the physician because of weight loss and fatigue. Over the past 12 months she has lost 10.5 kg (23.1 lb). She feels tired almost every day and says that she has to go running for 2 hours every morning to wake up. She had been a vegetarian for 2 years but decided to become a vegan 6 months ago. She lives with her mother, who has obsessive-compulsive disorder. The mother reports that her daughter refuses to eat with the family and only eats food that she has prepared herself. When asked about her weight, the patient says that despite her weight loss, she still feels “chubby”. She is 160 cm (5 ft 3 in) tall and weighs 42 kg (92.6 lb); BMI is 16.4 kg/m2. Her temperature is 35.7°C (96.3°F), pulse is 39/min, and blood pressure is 100/50 mm Hg. Physical examination shows emaciation. There is dry skin, covered by fine, soft hair all over the body. On mental status examination, she is oriented to person, place, and time. Serum studies show:
Na+ 142 mEq/L
Cl 103 mEq/L
K+ 4.0 mEq/L
Urea nitrogen 10 mg/dL
Creatinine 1.0 mg/dL
Glucose 65 mg/dL
Which of the following is the most appropriate next step in management?
A. Hospitalization and topiramate therapy
B. Hospitalization and fluoxetine therapy
C. Food diary and outpatient follow-up
D. Inpatient nutritional rehabilitation (Correct Answer)
E. Outpatient psychodynamic psychotherapy
Explanation: ***Inpatient nutritional rehabilitation***
- This patient exhibits severe **anorexia nervosa** with a **BMI of 16.4 kg/m²**, **bradycardia (39/min)**, **hypothermia (35.7°C)**, **hypotension (100/50 mm Hg)**, and **emaciation with lanugo hair**. These symptoms indicate an urgent need for medical stabilization.
- Inpatient nutritional rehabilitation is crucial for safe **weight restoration**, correction of electrolyte imbalances, and medical monitoring to prevent serious complications like **refeeding syndrome**.
*Hospitalization and topiramate therapy*
- While hospitalization is indicated, **topiramate** is an anticonvulsant sometimes used for binge-eating disorder or bulimia nervosa, but it is **contraindicated** in anorexia nervosa due to its potential to cause **further weight loss**.
- **Hospitalization** alone without a clear plan for nutritional rehabilitation and weight restoration is insufficient for a patient with severe anorexia nervosa.
*Hospitalization and fluoxetine therapy*
- **Fluoxetine** (an SSRI) is generally **not effective** for weight restoration in the acute phase of anorexia nervosa and is typically reserved for comorbid depression or anxiety **after significant weight restoration** has occurred.
- Starting fluoxetine during severe malnutrition can be ineffective and may even carry risks without addressing the primary need for nutritional rehabilitation.
*Food diary and outpatient follow-up*
- This option is **inappropriate** given the patient's critically low BMI, significant bradycardia, hypothermia, and hypotension, which are all signs of medical instability requiring **immediate inpatient care**.
- **Outpatient management** would be insufficient and potentially dangerous for a patient with such severe signs of malnutrition and organ compromise.
*Outpatient psychodynamic psychotherapy*
- While **psychotherapy** is a cornerstone of long-term treatment for anorexia nervosa, **outpatient psychodynamic psychotherapy** is not the appropriate first step for a patient with significant medical instability.
- Medical stabilization and weight restoration through **inpatient nutritional rehabilitation** must precede or occur concurrently with intensive psychotherapy for optimal and safe recovery.
Question 6: A 2-month-old girl is brought to the physician for a well-child examination. She was born at 32 weeks' gestation and weighed 1616 g (3 lb 9 oz); she currently weighs 2466 g (5 lb 7 oz). She is exclusively breastfed and receives vitamin D supplementation. Physical examination shows no abnormalities apart from low height and weight. This patient is at increased risk for which of the following complications?
A. Iron deficiency anemia (Correct Answer)
B. Hemorrhage
C. Scurvy
D. Subacute combined degeneration
E. Intussusception
Explanation: ***Iron deficiency anemia***
- Preterm infants have **lower iron stores** at birth due to reduced placental transfer in the third trimester.
- Their rapid growth rate and exclusive breastfeeding (breast milk has low iron content) further increase their risk of **iron deficiency anemia**.
*Hemorrhage*
- While preterm infants are at higher risk for certain hemorrhages (e.g., intraventricular hemorrhage), this typically occurs in the **immediate neonatal period** and risk significantly decreases by 2 months of age.
- Hemorrhage is not a common long-term complication unique to a 2-month-old preterm infant without additional risk factors.
*Scurvy*
- Scurvy is caused by **vitamin C deficiency**, which is typically not a concern in breastfed infants as breast milk provides adequate vitamin C.
- The primary deficiency risk addressed by supplementation in breastfed infants is vitamin D, not vitamin C.
*Subacute combined degeneration*
- This condition is caused by **vitamin B12 deficiency**, leading to demyelination of the spinal cord.
- While possible in infants of vegan mothers, it is unlikely in a breastfed infant without specific dietary restrictions in the mother.
*Intussusception*
- Intussusception is a condition where one segment of the intestine telescopes into another, usually occurring between **3 months and 3 years of age**.
- It is not specifically linked to prematurity or low birth weight as an increased long-term risk.
Question 7: A 2-year-old boy is brought to a pediatrician because his parents have noticed that he seems to be getting tired very easily at home. Specifically, they have noticed that he is often panting for breath after walking around the house for a few minutes and that he needs to take naps fairly often throughout the day. He has otherwise been well, and his parents do not recall any recent infections. He was born at home, and his mom did not receive any prenatal care prior to birth. Physical exam reveals a high-pitched, harsh, holosystolic murmur that is best heard at the lower left sternal border. No cyanosis is observed. Which of the following oxygen tension profiles would most likely be seen in this patient? (LV = left ventricle, RV = right ventricle, and SC = systemic circulation).
A. LV: normal, RV: normal, SC: normal
B. LV: normal, RV: increased, SC: normal (Correct Answer)
C. LV: decreased, RV: increased, SC: decreased
D. LV: decreased, RV: normal, SC: decreased
E. LV: normal, RV: normal, SC: decreased
Explanation: ***LV: normal, RV: increased, SC: normal***
- The patient's presentation with easy fatigability, dyspnea on exertion, and a **holosystolic murmur** at the **lower left sternal border** strongly suggests a **ventricular septal defect (VSD)**. These symptoms result from a **left-to-right shunt**, leading to increased blood flow and pressure in the **right ventricle (RV)** and pulmonary circulation.
- In a VSD, highly oxygenated blood from the **left ventricle (LV)** shunts into the RV. This increases the **oxygen tension** in the RV, while the LV and systemic circulation (SC) typically maintain normal oxygen tension if the shunt is not so large that it causes **pulmonary hypertension** with **Eisenmenger syndrome**.
*LV: normal, RV: normal, SC: normal*
- This profile would indicate a **normal cardiovascular system** without any significant shunting or cardiac anomaly.
- It does not align with the patient's symptoms of easy fatigability, dyspnea, and the presence of a pathological murmur.
*LV: decreased, RV: increased, SC: decreased*
- A **decreased oxygen tension in the left ventricle** and **systemic circulation** typically indicates a **right-to-left shunt** or severe **pulmonary disease**, often associated with **cyanosis**, which is noted as absent in this patient.
- While RV oxygen tension *could* be increased in some complex congenital heart diseases with right-to-left shunting (e.g., mixing lesions), the overall profile does not fit the characteristic presentation of a VSD without cyanosis.
*LV: decreased, RV: normal, SC: decreased*
- This profile with **decreased oxygen tension in the left ventricle** and **systemic circulation** suggests a condition where oxygenated blood supply to the systemic circulation is compromised, such as severe **left ventricular dysfunction** or a **right-to-left shunt**.
- A **normal RV oxygen tension** without **cyanosis** makes this unlikely in the context of the patient's symptoms.
*LV: normal, RV: normal, SC: decreased*
- A **decreased oxygen tension in the systemic circulation** with **normal LV and RV oxygen tension** is inconsistent with a **VSD**.
- This profile might be observed in conditions like severe **anemia** or **hypoxia** without a primary cardiac shunt.
Question 8: A 4-week-old infant is brought to the physician by his mother because of blood-tinged stools for 3 days. He has also been passing whitish mucoid strings with the stools during this period. He was delivered at 38 weeks' gestation by lower segment transverse cesarean section because of a nonreassuring fetal heart rate. He was monitored in the intensive care unit for a day prior to being discharged. His 6-year-old brother was treated for viral gastroenteritis one week ago. The patient is exclusively breastfed. He is at the 50th percentile for height and 60th percentile for weight. He appears healthy and active. His vital signs are within normal limits. Examination shows a soft and nontender abdomen. The liver is palpated just below the right costal margin. The remainder of the examination shows no abnormalities. Test of the stool for occult blood is positive. A complete blood count and serum concentrations of electrolytes and creatinine are within the reference range. Which of the following is the most appropriate next step in management?
A. Perform stool antigen immunoassay
B. Perform an air enema on the infant
C. Assess for IgA (anti‑)tissue transglutaminase antibodies (tTG)
D. Stop breastfeeding and switch to soy-based formula
E. Continue breastfeeding and advise mother to avoid dairy and soy products (Correct Answer)
Explanation: ***Continue breastfeeding and advise mother to avoid dairy and soy products***
- The infant's symptoms of **blood-tinged stools** and **mucoid strings**, along with a positive occult blood test, in an otherwise healthy, exclusively breastfed infant point towards **food protein-induced proctocolitis (FPIAP)**.
- The most common triggers for FPIAP are **cow's milk protein** and **soy protein** from the maternal diet transmitted through breast milk. The initial management involves the mother eliminating these proteins from her diet.
*Perform stool antigen immunoassay*
- This test is used to detect specific viral, bacterial, or parasitic antigens in stool, often for conditions like **rotavirus, giardiasis, or C. difficile**.
- The infant's clinical presentation with **no fever, vomiting, or diarrhea**, and an otherwise healthy appearance, makes an infectious cause less likely compared to FPIAP.
*Perform an air enema on the infant*
- An air enema is primarily a diagnostic and therapeutic intervention for **intussusception**, a condition where one segment of the intestine telescopes into another.
- Intussusception typically presents with sudden onset of severe, colicky abdominal pain, **"currant jelly" stools**, and often a palpable abdominal mass, none of which are described in this infant.
*Assess for IgA (anti‑)tissue transglutaminase antibodies (tTG)*
- This test is used to screen for **celiac disease**, an autoimmune disorder triggered by gluten consumption.
- Celiac disease typically presents after the introduction of **gluten-containing foods** into the diet, usually around 6-12 months of age, and is characterized by malabsorption symptoms like diarrhea, weight loss, and failure to thrive, which are absent here.
*Stop breastfeeding and switch to soy-based formula*
- Stopping breastfeeding is generally **not recommended** as breast milk provides numerous benefits.
- Switching to a **soy-based formula** may not resolve the issue, as many infants with cow's milk protein allergy also have a **soy protein allergy**. The preferred approach is to eliminate allergens from the maternal diet while continuing breastfeeding.
Question 9: A 1-day-old infant in the general care nursery, born at full term by uncomplicated cesarean section delivery, is noted to have a murmur, but otherwise appears well. On examination, respiratory rate is 40/min and pulse oximetry is 96%. Precordium is normoactive. With auscultation, S1 is normal, S2 is single, and a 2/6 systolic ejection murmur is heard at the left upper sternal border. Echocardiography shows infundibular pulmonary stenosis, overriding aorta, ventricular septal defect and concentric right ventricular hypertrophy. Which of the following correlate with the presence or absence of cyanosis in this baby?
A. The degree of right ventricular outflow tract obstruction (Correct Answer)
B. The ratio of reduced hemoglobin to oxyhemoglobin
C. The concentration of hemoglobin
D. The size of ventricular septal defect
E. The concentration of pulmonary surfactant
Explanation: ***The degree of right ventricular outflow tract obstruction***
- The severity of **pulmonary stenosis** in **tetralogy of Fallot** dictates the amount of blood shunted from the right ventricle to the aorta via the **ventricular septal defect (VSD)**.
- A **less severe obstruction** allows more blood to flow to the lungs, leading to less right-to-left shunting and consequently **less cyanosis**.
*The ratio of reduced hemoglobin to oxyhemoglobin*
- While this ratio directly reflects the presence of cyanosis, it does not explain its *cause* in the context of the given congenital heart defect.
- The question asks what *correlates* with the presence or absence of cyanosis, implying a causal or pathophysiological link rather than a descriptive measure.
*The concentration of hemoglobin*
- **Hemoglobin concentration** affects the *visibility* of cyanosis (e.g., polycythemia can make mild desaturation appear more cyanotic), but it doesn't primarily determine the *presence* or *absence* of shunt-related cyanosis itself.
- A patient can be significantly desaturated with a normal hemoglobin concentration, and the degree of desaturation is largely driven by the shunt.
*The size of ventricular septal defect*
- In tetralogy of Fallot, the **VSD is typically large and non-restrictive**, meaning its size itself doesn't limit blood flow between the ventricles.
- The **pulmonary stenosis** is the primary determinant of the shunt direction and magnitude, not the size of the VSD.
*The concentration of pulmonary surfactant*
- **Pulmonary surfactant** is crucial for maintaining alveolar stability and preventing atelectasis, thereby ensuring efficient gas exchange in the lungs.
- While important for overall respiratory function, it does not directly correlate with the degree of shunting and cyanosis in **tetralogy of Fallot**.
Question 10: A 5-month-old boy is brought to the emergency department by his mother because his lips turned blue for several minutes while playing earlier that evening. She reports that he has had similar episodes during feeding that resolved quickly. He was born at term following an uncomplicated pregnancy and delivery. He is at the 25th percentile for length and below the 5th percentile for weight. His temperature is 37°C (98.6°F), pulse is 130/min, blood pressure is 83/55 mm Hg, and respirations are 42/min. Pulse oximetry on room air shows an oxygen saturation of 90%. During the examination, he sits calmly in his mother's lap. He appears well. The patient begins to cry when examination of his throat is attempted; his lips and fingers begin to turn blue. Further evaluation of this patient is most likely to show which of the following?
A. Pulmonary vascular congestion on x-ray of the chest
B. Right axis deviation on ECG (Correct Answer)
C. Anomalous pulmonary venous return on MR angiography
D. Diminutive left ventricle on echocardiogram
E. Machine-like hum on auscultation
Explanation: ***Right axis deviation on ECG***
- The presentation of **cyanotic spells** ("blue lips for several minutes", "lips and fingers begin to turn blue" with crying), **poor weight gain**, and **hypoxemia** (SpO2 90%) in an infant strongly suggests a **cyanotic congenital heart defect** like **Tetralogy of Fallot** (TOF).
- TOF is characterized by **right ventricular outflow tract obstruction**, leading to **right ventricular hypertrophy** and subsequently **right axis deviation** on ECG.
*Pulmonary vascular congestion on x-ray of the chest*
- **Pulmonary vascular congestion** is typically seen in conditions with **increased pulmonary blood flow** or **left-sided heart failure**, such as a large ventricular septal defect or patent ductus arteriosus.
- In Tetralogy of Fallot, there is often **decreased pulmonary blood flow** due to right ventricular outflow tract obstruction, leading to a **clear lung fields** on chest x-ray.
*Anomalous pulmonary venous return on MR angiography*
- **Total anomalous pulmonary venous return (TAPVR)** is a cyanotic heart defect where all pulmonary veins drain into the systemic circulation.
- While it causes cyanosis, it typically presents with **pulmonary congestion** and signs of **right heart strain**, which is less consistent with the spells described.
*Diminutive left ventricle on echocardiogram*
- A **diminutive left ventricle** is characteristic of **hypoplastic left heart syndrome**, which is a severe cyanotic defect.
- However, patients with hypoplastic left heart syndrome usually present with **severe heart failure** and shock much earlier in infancy, often in the neonatal period, which is not described here.
*Machine-like hum on auscultation*
- A **machine-like hum** is the classic auscultatory finding for a **patent ductus arteriosus (PDA)**.
- While a PDA can cause cyanosis if pulmonary hypertension is severe (Eisenmenger syndrome), isolated PDA typically presents with **left-to-right shunting** and **pulmonary overcirculation**, not the classic cyanotic spells seen with activities like crying, characteristic of TOF.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.