A 3-week-old infant is brought to the clinic for poor feeding and irritability. On examination, the infant has hepatosplenomegaly and a mucopurulent, hemorrhagic nasal discharge. A maculopapular rash is noted on the palms and soles. Which of the following is the most specific clinical sign for early congenital syphilis in this patient?
A 6-year-old boy with hereditary spherocytosis presents to the emergency department with profound anemia, pallor, and lethargy. His reticulocyte count is 0.1%. A diagnosis of transient aplastic crisis due to parvovirus B19 is made. This clinical crisis occurs coincident with which phase of the infection?
A 17-year-old adolescent female with HIV presents with a copious, malodorous, frothy gray vaginal discharge. A wet mount shows motile, pear-shaped protozoa. Which of the following treatment regimens is considered superior for trichomoniasis in this specific patient population?
A 14-year-old with cystic fibrosis and a history of methicillin-resistant Staphylococcus aureus (MRSA) colonization develops hospital-acquired pneumonia with a fever of 39.2°C (102.6°F) and new infiltrates. Blood cultures grow MRSA. Why is daptomycin an unsuitable choice for treating the pneumonia component of this child’s illness?
A 17-year-old college student develops explosive, non-bloody, watery diarrhea and abdominal cramps two days after returning from a spring break trip to Mexico. He has no fever. The illness resolves within four days with only supportive care. Which Escherichia coli pathotype is the most likely cause of his illness?
A 12-year-old girl from a rural area in Maine presents in July with a unilateral right-sided facial droop that began two days ago. She denies headache or fever but recalls removing a tick from her scalp last month. Examination confirms isolated peripheral facial nerve palsy. What is the most appropriate oral antibiotic for treating her likely condition?
A 4-week-old, non-breastfed infant was born to a mother with HIV. The infant had a negative HIV RNA PCR test at 14 days of life and another negative HIV RNA PCR test at 4 weeks of life. Based on these results, what is the HIV infection status of this infant?
A 5-year-old child is diagnosed with an amebic liver abscess. Ultrasonography is performed to localize the lesion. What is the most common finding on imaging for this condition?
A 12-year-old boy who recently immigrated from Southeast Asia presents with a single, 4-cm, well-demarcated, hypopigmented plaque on his forearm. The lesion has raised borders and a flattened center. Sensation to light touch and pinprick is markedly reduced over the plaque. Based on the Ridley-Jopling classification, which form of Hansen disease does this most likely represent?
A 2-month-old infant presents with a 3-week history of tachypnea and a distinctive “staccato” cough. The infant is afebrile and does not have wheezing on auscultation, but chest radiography shows hyperinflation with minimal interstitial infiltrates. A complete blood count reveals peripheral eosinophilia. What is the most likely causative agent of this infant’s pneumonia?
