Pediatrics

A $3$-year-old unimmunized boy is brought to the pediatric emergency department with a $6$-hour history of high fever, severe sore throat, and progressive difficulty breathing. On presentation, he is sitting on his mother's lap, leaning forward with his neck extended. He is drooling continuously and appears highly anxious. Inspiratory stridor and moderate suprasternal retractions are visible. His temperature is $39.5^{\circ}\text{C}$ ($103.1^{\circ}\text{F}$), heart rate is $145\text{/min}$, and respiratory rate is $38\text{/min}$. Arrange the following management steps in the most appropriate sequential order for this patient.

Match each neonatal clinical presentation (left) with the most likely causative pathogen and its appropriate diagnostic and management strategy (right).

A medical genetics team is evaluating several pediatric patients with suspected inborn errors of amino acid metabolism. Based on the findings provided, match each patient's clinical presentation with the specific enzyme defect most likely responsible for their condition.

A $48$-hour-old term male newborn is evaluated in the nursery for a new skin eruption. The infant was delivered via uncomplicated spontaneous vaginal delivery at $39$ weeks gestation to a $28$-year-old primigravida. Maternal prenatal laboratory studies were unremarkable, and maternal Group B Streptococcus screening was negative. The newborn has been breastfeeding vigorously and has had normal bowel and bladder output. Vital signs show a temperature of $37.0$ °C ($98.6$ °F), a heart rate of $135$/min, and a respiratory rate of $42$/min. Physical examination reveals a well-appearing, alert infant. His skin exhibits a scattered rash on the chest, abdomen, and proximal extremities consisting of $1$- to $3$-cm erythematous macules, many of which contain a central $1$- to $2$-mm yellow-white pustule. The palms, soles, and mucous membranes are entirely clear. Which of the following is the most appropriate next step in management?

A 28-year-old primigravida presents to the labor and delivery ward in active labor following spontaneous rupture of membranes $22\text{ hours}$ prior. Her prenatal care was limited, and her maternal Group B Streptococcus (GBS) colonization status is unconfirmed. She delivers a female neonate at $36\text{ weeks}$ gestation. The infant's birth weight is $2600\text{ g}$ ($5\text{ lb } 12\text{ oz}$). APGAR scores are $7$ and $8$ at $1$ and $5\text{ minutes}$, respectively.

At $30\text{ hours}$ of life, the newborn develops profound lethargy and poor feeding. Vital signs are:

Physical examination reveals an ill-appearing infant with audible grunting, intercostal retractions, and a capillary refill time of $4\text{ seconds}$.

Laboratory evaluation shows:

Cerebrospinal fluid, blood, and urine specimens are obtained for culture.

Which of the following represents the most appropriate initial empiric pharmacotherapy for this patient?

An infant, currently $7$ months of age, presents to the emergency room with severe lethargy and tachypnea that began yesterday. The patient's diet was recently transitioned from exclusive breastfeeding to include high-protein solid foods such as meat purees. The mother notes the child can no longer sit up independently, a milestone he had successfully mastered two weeks ago.

Vital signs show a heart rate of $165/\text{min}$ and a respiratory rate of $60/\text{min}$. He is afebrile. Physical examination demonstrates an encephalopathic infant with diffuse muscle weakness, significant head lag, and absent deep tendon reflexes.

Laboratory analysis reveals:
Serum sodium: $139 \text{ mEq/L}$
Serum chloride: $103 \text{ mEq/L}$
Serum bicarbonate: $11 \text{ mEq/L}$
Blood glucose: $48 \text{ mg/dL}$
Serum ammonia: $340 \ \mu\text{mol/L}$ (normal: $15$-$50 \ \mu\text{mol/L}$)
Arterial pH: $7.23$
Arterial pCO2: $24 \text{ mmHg}$

Blood cultures collected two days prior at an urgent care clinic during a mild febrile illness are positive for *Streptococcus pneumoniae*; the preliminary susceptibility report confirms the organism is highly sensitive to penicillin.

Which of the following is the most appropriate next step in the management of this patient?

A $3$-year-old boy is brought to the pediatrician's office during the winter with a $4$-day history of high fever, worsening cough, and rapid breathing. The mother reports that he has been less active than usual but continues to drink fluids well. He has no significant past medical history and is up to date on all immunizations. His temperature is $39.2^{\circ}\text{C}$ ($102.6^{\circ}\text{F}$), pulse is $135\text{/min}$, respirations are $42\text{/min}$, and blood pressure is $94/60\text{ mm Hg}$. Oxygen saturation is $96\%$ on room air. He is alert and interactive. Physical examination reveals focal crackles and decreased breath sounds over the left lower lung field. There are no retractions, diffuse wheezing, or stridor. Which of the following is the most appropriate next step in management?

Emergency medical services bring a somnolent 4-year-old girl to the resuscitation bay due to progressive respiratory distress and a high fever lasting 48 hours. Her parents report a severe, harsh cough leading up to her rapid clinical deterioration. She is barely arousable upon arrival. Vital signs reveal a temperature of 39.6°C (103.3°F), a heart rate of 175/min, a respiratory rate of 45/min, and a blood pressure of 70/40 mm Hg. Pulse oximetry shows an oxygen saturation of 88% on ambient air. Physical examination demonstrates cold extremities, mottled skin, and a prolonged capillary refill time of 5 seconds. Lung auscultation reveals dense crackles over the right lower lung field. Arrange the following initial management steps in the most appropriate sequential order according to pediatric resuscitation and sepsis guidelines.

A 10-day-old female infant is brought to the pediatrician's clinic for a follow-up visit. Her state newborn screening test, collected at 48 hours of life, returned positive for an isolated, markedly elevated phenylalanine level. The infant was born at term following an uncomplicated pregnancy and is currently exclusively breastfed. She appears active and healthy, and her physical examination is unremarkable. Arrange the following diagnostic and management steps in the most appropriate chronological order.

Pediatric head and neck infections and localized lymphadenopathy have distinct clinical presentations that guide specific management. Match each clinical vignette (left) describing a pediatric patient to the most appropriate management strategy (right).

Match each pediatric clinical presentation with the most likely causative pathogen.

Match each clinical description of a benign neonatal skin finding to its most accurate diagnosis. Recognizing these normal variants is critical to prevent unnecessary diagnostic interventions and parental anxiety.

An 8-year-old boy is evaluated in the hospital on hospital day 4. He was originally admitted for acute, severe right thigh pain, limp, and high fever. Magnetic resonance imaging (MRI) of the right lower extremity at admission demonstrated marrow edema and a subperiosteal fluid collection in the distal femur. He was diagnosed with acute hematogenous osteomyelitis and empirically started on intravenous vancomycin and ceftriaxone. Over the last 48 hours, his temperature has normalized, and his thigh pain has significantly decreased.

Blood cultures drawn prior to the administration of antibiotics have grown *Staphylococcus aureus*. The susceptibility report is as follows:

The patient has no known drug allergies. Which of the following is the most appropriate next step in the pharmacologic management of this patient?

A 10-week-old boy is brought to the emergency department in mid-January by his parents due to a 3-day history of nasal congestion and a worsening cough. Over the past 12 hours, he has been feeding poorly and breathing rapidly. The family recently immigrated to the United States, and the infant has not received any immunizations. His temperature is 37.9°C (100.2°F), heart rate is 156/min, respiratory rate is 68/min, and oxygen saturation is 89% on room air. On physical examination, the infant appears mildly lethargic and is using accessory respiratory muscles. Copious clear rhinorrhea is present. Lung auscultation reveals diffuse polyphonic wheezing and crackles bilaterally. Skin examination shows multiple scattered erythematous papules and pustules on his cheeks, which the parents state have been present since he was 3 weeks old. Which of the following is the most appropriate next step in the management of this patient?

A 5-year-old boy recently immigrated to the United States and has an unknown immunization history. He is brought to the emergency department by his parents due to the sudden onset of high fever, severe sore throat, and difficulty breathing over the past 4 hours. The patient appears highly anxious, toxic, and is sitting leaning forward with his neck extended. He is drooling profusely and has a muffled voice, but no cough is noted. Vital signs reveal a temperature of 39.8°C (103.6°F), heart rate of 145/min, respiratory rate of 42/min, and oxygen saturation of 91% on room air. Marked inspiratory stridor and suprasternal retractions are present. Arrange the following management steps in the most appropriate and safest sequence for this patient.

The parents of a $22$-day-old female neonate bring her to the urgent care clinic during the winter due to worsening breathing difficulties. Over the past three days, the infant has had clear nasal discharge and a mild cough, but today she is breathing much faster than usual and tiring quickly while breastfeeding. The mother also expresses concern regarding a facial rash that appeared a week ago. The infant was born full-term with no perinatal complications. Her temperature is $37.3^\circ\text{C}$ ($99.1^\circ\text{F}$), pulse is $165/\text{min}$, respiratory rate is $72/\text{min}$, and oxygen saturation is $94\%$ on room air. Physical examination reveals an alert but tachypneic infant with moderate subcostal retractions and diffuse bilateral expiratory wheezing. Examination of the face reveals multiple erythematous papules and pustules localized to the cheeks and forehead, with an absence of open or closed comedones. Which of the following is the most appropriate next step in the management of this patient?

Match each clinical presentation of a neonatal gastrointestinal emergency to the most appropriate next step in diagnosis or management.

Match each pediatric clinical vignette describing a severe infection with the most likely causative pathogen based on the specific diagnostic or microbiological clues provided.

A $48$-hour-old male neonate is evaluated in the nursery for worsening jaundice. He was born at $39$ weeks of gestation via spontaneous vaginal delivery to a $26$-year-old primigravid mother. His birth weight was $3400\text{ g}$. APGAR scores were $8$ and $9$ at $1$ and $5$ minutes, respectively. The mother's blood type is O, Rh-positive, and the infant's blood type is A, Rh-positive. The direct antiglobulin test (Coombs test) is positive. The infant is exclusively breastfed and latching well.

Vital signs are:
Temperature: $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$)
Heart rate: $138\text{/min}$
Respiratory rate: $38\text{/min}$
Blood pressure: $68/42\text{ mmHg}$
Oxygen saturation: $99\%$ on room air

Physical examination reveals marked scleral icterus and jaundice extending to the lower abdomen. The infant is alert and active with normal tone. Additionally, there is a prominent, blotchy erythematous rash with scattered $1\text{-to-}2\text{ mm}$ pale-yellow pustules over the trunk and proximal extremities.

Which of the following is the most appropriate next step in the management of this patient?

A $2$-year-old girl is evaluated in the emergency department at 11:00 PM for a worsening cough and noisy breathing. Two days ago, she developed a mild fever, nasal congestion, and clear rhinorrhea. This evening, her cough became harsh and sounds similar to a barking seal. Her temperature is $38.1^\circ\text{C}$ ($100.6^\circ\text{F}$), heart rate is $130/\text{min}$, respiratory rate is $40/\text{min}$, and oxygen saturation is $96\%$ on room air. The patient is sitting in her mother's lap and appears anxious. There is noticeable inspiratory stridor even when the child is resting quietly. Chest auscultation reveals transmitted upper airway sounds but no lower airway wheezing or crackles. Which of the following is the most appropriate next step in management?