Pediatry USMLE

You are seeing a 14-year-old boy in your office who complains of fever, facial pain, and cough at night. His mother states that he has had problems with sinusitis for the past few months and has required repeated antimicrobial therapy during this period. Physical examination reveals a temperature of 101 °F (38.3° C), yellow-green nasal discharge, and tenderness to palpation of the maxillary and frontal sinus regions. Of the following, the MOST likely pathogen associated with chronic sinusitis is

You are evaluating a 7-year-old boy who has sickle cell disease for a 5-day history of fever, rhinorrhea, headache, and worsening fatigue. Physical examination reveals a tired-appearing, pale boy who has a temperature of 101.5°F (38.6°C); heart rate of 150 beats/min; very pale conjunctivae and mucous membranes; and a faint diffuse, erythematous, lacy rash that is most prominent on his cheeks and trunk. Laboratory tests show a white blood cell count of 12x103/mcL (12x109/L), with SOo/o neutrophils, 45% lymphocytes, and So/o monocytes; hemoglobin of 4 g/dL (40 g/L); hematocrit of 16% (0.16); and reticulocyte count of less than 1 % (0.01). Of the following, the MOST likely cause for this patient's present illness is infection with

An 11-day-old infant presents to the clinic with a history of a temperature of l00.8° F (38.2° C) and a 1-day history of poor feeding. Findings on physical examination are normal. You initiate a sepsis evaluation that includes a lumbar puncture. The cerebrospinal fluid results demonstrate a white blood cell count of 6x103/mcL (6x109/L), with 68o/o neutrophils, 2% bands, and 30%
lymphocytes. The protein concentration is 200 mg/dL (2 g/L), and the glucose value is 36 mg/dL
(2.0 mmol/L). The abnormal findings prompt you to order magnetic resonance imaging, which
demonstrates abnormal frontal lobes bilaterally that includes some degree of infarction but also
abscesses and cerebritis. Of the following, the MOST likely pathogen is

A 4-month-old boy presents to the clinic with a 2-day history of a temperature of 100.6°F (38.1 °C) and vomiting. The infant was born at 26 weeks' gestation, and his birthweight was 960g. He remained I n the hospital for 3 months after birth because of multiple complications, including bilateral grade 4 intraventricular hemorrhages necessitating the placement of a ventriculoperitoneal shunt 6 weeks ago. Physical examination reveals an afebrile infant who has a shunt bubble on the right temporo-occipital region and a gastrostomy button. You explain that his shunt bubble requires aspiration to evaluate the cerebrospinal fluid for infection. Of the following, the organism that is MOST likely to be isolated in the aspirate is

A 16-year-old previously healthy boy presents with a 2-week history of intermittent elevated temperatures to 102°F (39° C), headache, malaise, fatigue, myalgias, and a progressively worsening nonproductive cough. During history-taking, be reports that recently he explored several caves while hiking in a forest preserve in Ohio. Physical examination reveals a tiredappearing adolescent who has a temperature of 102.4°F (39.1 ° C), a dry cough, and diffuse intermittent rhonchi on chest auscultation. Laboratory findings include a white blood cell count of 12x103/mcL (12x109/L), with 60% neutrophils, 2% band forms, and 38% lymphocytes. Chest radiograph (Item Q190A) shows patchy left upper and left lower lobe opacities and hilar adenopathy. Of the following, the MOST likely pathogen causing this patient's condition is

You are asked to review a case for morbidity and mortality conference. The infant was born at term to a 19-year-old gravida 1, para 1 woman by normal spontaneous vaginal delivery. The mother was known to be group B Streptococcus-negative, but she did have genital warts. The Apgar scores were 9 at 1 minute and 10 at 5 minutes. On the seventh postnatal day, the infant developed a temperature of 103°F (39.4°C) and was brought to the emergency department. At this time, the infant was in shock and required mechanical ventilation. Physical examination revealed scleral icterus and hepatosplenomegaly but no skin lesions. A lumbar puncture could not be performed. Laboratory results include: White blood cell count of 2.34x103/mcL (2.34x109/L), with 32% lymphocytes, 41 % neutrophils, 8% bands, 15% monocytes, 3% eosinophils, and 1 % basophils, Hemoglobin of 7.1 g/dL (71 g/L), Hematocrit of 21 % (0.21), Platelet count of 40x103/mcL (40x109/L), Prothrombin time of 41.2 seconds, Activated partial thromboplastin time of> 106 seconds, Aspartate aminotransferase concentration of 3,086 U/L, Alanine aminotransferase concentration of 456 U/L, Total bilirubin of 4.4 mg/dL (75.2 mcmol/L). The chest radiograph demonstrated diffuse interstitial initltrates bilaterally (Item Q204A). The patient did poorly over the next 3 days and died despite aggressive management in a pediatric intensive care unit. Of the following, the MOST likely cause of this patient's death is

A 5-month-old female infant presents with a 1-day history of fever to 102°F (38.9°C), emesis, and multiple episodes of greenish diarrhea with streaks of blood. Her mother states that the infant is less active, sleepier, and has no interest in feeding. Physical examination reveals a listless infant who has a sunken anterior fontanelle, dry mucous membranes with decreased skin turgor, and skin irritation in the diaper area. Of the following, the MOST likely cause of this patient's gastroenteritis is

A 5-year-old girl presents after having a brief generalized seizure. Her mother reports that the child has had a 3-day history of fever, tenesmus, and bloody diarrhea. On physical examination, you find a mildly toxic-appearing child who has a temperature of 104° F (40°C) and diffuse abdominal tenderness. The rectal examination produces significant pain. Stool from her rectum is guaiac-positive. You tell her mother that you believe the diarrhea has an infectious cause. Of the following, the MOST likely pathogen is

A 4-year-old boy with severe ezcema is brought to accident and emergency by his mother. His skin has been worse recently since the weather ha.s become colder. He is scratching a lot more and now is very miserable and has a temperature of 38.6°C today. On examination of his skin he has multiple areas of erythematous, excoriated lesions on his elbow and knee flexures as well as his trunk and back. In addition they are hot, tender and slightly swollen with areas of broken skin. There are also some yellow fluid-filled vesicles on some of these lesions. You send some blood tests and commence him on IV flucloxacillin and aciclovir. Which are the two most likely organisms that can complicate eczema?

You are in immunology clinic and the first patient is a 2-year-old boy who has a complement deficiency. You know this involves a cascade of proteins involved with innate immunity but are unsure about the manifestations in children. The professor of immunology asks you which organism is this child at risk of being infected with. He gives you a clue by telling you the child has a late complement deficiency, meaning C5-C9. What is the most likely causative organism
that infects these children?

A 15-year-old boy attends his GP with a week of cough productive of yellow sputum, fever to 39° C and chest pain on the right side of the chest on coughing. There is no history of foreign travel or unwell contacts. On examination there is reduced air entry in the right lower zone with crepitations and bronchial breathing. You diagnose a right-sided chest infection. What is the most likely causative organism?

An 8 year old known asthmatic is brought into accident and emergency by ambulance as a 'blue call'. He has been unwell with an upper respiratory tract infection for the past 2 days. For the past 24 hours his parents have given him 10 puffs of salbutamol every 4 hours, his last dose being 90 minutes ago. The ambulance staff have given him a nebulizer but he remains agitated with a heart rate of 155, respiratory rate of 44 and sub/intercostal recessions and on auscultation there is little air movement heard bilaterally. Saturations in air are 85 per cent. He is started on 'back to back' nebulizers with high flow oxygen. How severe is his asthma exacerbation and
what other bedside test would support this?

A 3-month-old boy is admitted to the hospital for evaluation of failure to thrive. His birthweight was at the 50th percentile and length at the 75th percentile. Currently, his weight is below the 5th percentile and length is at the 25th percentile. His vital signs and physical examination results are otherwise normal. He appears well hydrated. Measurement of serum electrolytes reveals: sodium, 139 mEq/L (139 mmol/L); potassium, 4.7 mEq/L (4.7 mmol/L); chloride, 114 mEq/L (114 mmol/L); bicarbonate 12 mEq/L (12 mmol/L); blood urea nitrogen, 8 mg/dL (2.9 mmol/L); and creatinine, 0.3 mg/dL (26.5 mcmol/L). A consulting nephrologist recommends measurement of urine pH (which is 7.5) and urine ammonium (which is 12,000 mcM/L) (normal, >60,000 mcM/L). Of the following, the MOST likely cause of this child's acidosis is

You are called to see a hospitalized 9-year-old girl who suddenly has become dystonic, with her neck hyperextended, and is unable to move her eyes, now superiorly deviated. The nurses relate that this girl has non-Hodgkin lymphoma and has been receiving highly emetogenic chemotherapy. Of the following, the drug MOST likely to have caused this girl's symptoms and • • signs 1s

A 13-month-old boy presents to your office after his mother called for an urgent appointment because he had a bad cough and noisy breathing. He has been previously healthy and is fully immunized. On physical examination, his temperature is 100.9° F (38.3° C), pulse rate is 142 beats/min, respiratory rate is 36 breaths/min ( crying), and pulse oximetry reading is 98 o/o on room air. The mother states that he went to sleep normally with only mild symptoms of an upper respiratory tract infection and awakened at 4 am with noisy breathing. He tolerated sips of juice this morning and has had no vomiting, diarrhea, or high fever. After the boy settles down from having his vital signs measured, he has a ''barking cough,'' and on auscultation, you notice stridor with every breath. Mild suprasternal retractions are visible on examination of the chest. He prefers to sit up and looks slightly anxious. Of the following, the treatment MOST likely to provide improvement is

A 9-year-old girl is stung on the left leg by a hornet while playing outside. Within 10 minutes, she experiences diffuse pruritusevident during examination, and her symptoms gradually resolve over 4 hours. Of the following,
the NEXT recommended step in her management is to, and a large area of erythema develops at the sting site. Five minutes later, extensive raised welts appear on her trunk and extremities. Her parents rush her to the emergency department, where intravenous antihistamines and steroids are administered. During this episode, she denies difficulty breathing or swallowing. No tongue or uvula edema is 

A 6-month-old infant has been receiving high-dose amoxicillin therapy for bilateral otitis media. After 48 hours of therapy, she continues to be febrile, with a temperature of 102°F (38.9°C), and is irritable. Physical examination reveals erythematous, dull, and bulging tympanic membranes, with no movement on insufflation. Of the following, the MOST appropriate antibiotic to change this patient to is

A 3-year-old boy who has myelomeningocele and a history of recurrent urinary tract infections presents with a 1-day history of a temperature to 102°F (38.9°C) and cloudy urine. Laboratory test results include a peripheral white blood cell count of 15x103/mcL (15x109/L), with 60% neutrophils, 30% lymphocytes, and 10% monocytes. Urine obtained by catheterization is cloudy; has a strong odor; and is positive for nitrites, leukocyte esterase, and blood. Microscopic analysis shows too numerous- to-count white blood cells and 50 to 100 red blood cells, and gramnegative bacilli are seen on Gram stain. One day later, the urine culture is positive for Pseudomonas aeruginosa. Of the following, the MOST appropriate antibiotic for treatment of this patient is

An 18-year-old boy presents to the emergency department 30 minutes after eating at a seafood restaurant. He states that approximately 10 minutes into his meal he developed generalized hives, pruritus, and difficulty breathing. He has a history of shellfish food allergy, although he had ordered steak and denies eating any crab, lobster, or shrimp. On physical examination, the patient appears to have labored breathing, audible wheezing, and diffuse raised erythematous lesions (Item QlSA) on his trunk and extremities. His vital signs include a temperature of 98.5°F
(37° C), heart rate of 100 beats/min, respiratory rate of 22 breaths/min, blood pressure of 110/60
mm Hg, and pulse oximetry of 92 % on room air. Of the following, the MOST appropriate
immediate action is: