A 16-year-old with inflammatory bowel disease is hospitalized for an exacerbation and develops diarrhea. A stool sample is positive by nucleic acid amplification test (NAAT) for a Clostridioides difficile toxin gene, but the enzyme immunoassay (EIA) for toxin A/B is negative. What is the most accurate interpretation of these results?
A 7-year-old with acute myelogenous leukemia and prolonged neutropenia develops fever, nasal discharge, and a black necrotic lesion on his palate. Rhinocerebral mucormycosis is suspected. What is the recommended first-line medical therapy for this life-threatening condition?
A 5-year-old boy develops a raised, erythematous, serpiginous track on his foot after playing barefoot in a sandbox contaminated by cat feces in the southeastern United States. The lesion is intensely pruritic. What is the most common causative agent of this “creeping eruption”?
An 8-month-old unimmunized infant has a significant household exposure to a sibling with a confirmed case of measles. The mother brings the infant for evaluation 5 days after the sibling’s rash first appeared. What is the most appropriate management to prevent or modify the disease in this infant?
An asymptomatic 8-year-old is identified as a household contact of a patient with confirmed respiratory diphtheria. His immunization status is uncertain. After obtaining appropriate cultures, what is the correct management for this child?
A 16-year-old adolescent presents with a 2-month history of night sweats, weight loss, and a productive cough, occasionally streaked with blood. She acquired a tuberculosis infection at age 8 years that was untreated. Which of the following radiographic findings is most characteristic of reactivation tuberculosis in this patient?
A 6-year-old girl with a severe, documented allergy to tetracyclines presents with a mild case of acute Q fever diagnosed on day 2 of her symptoms. What is the most appropriate alternative treatment for this child?
A 3-year-old child recently immigrated from a resource-limited setting presents with gradual onset of colicky abdominal pain and 6-8 heme-positive stools per day for the last week. A stool antigen test is positive for Entamoeba histolytica. After an initial course of tinidazole for invasive disease, which follow-up treatment is necessary?
A 6-year-old girl is evaluated for a fever of 39.5°C (103.1°F). Her heart rate is noted to be 95 beats/minute, which is unexpectedly low for her degree of fever. This finding of temperature-pulse dissociation is a recognized clinical sign associated with which of the following infectious diseases?
A 10-year-old child presents with a slowly growing, firm submandibular mass. A biopsy confirms cervicofacial actinomycosis. In addition to prolonged antibiotic therapy, what is a hallmark pathologic feature of this infection?
