A 14-year-old boy presents with two well-demarcated, erythematous plaques on his trunk that are anesthetic to light touch. To confirm a diagnosis of Hansen disease and determine the type of immunologic response, which diagnostic procedure is most critical?
An adolescent with perinatally acquired HIV, who has been off therapy for several years due to non-adherence, presents with a rapidly declining CD4+ T-lymphocyte count and a high viral load. A change in viral tropism is suspected to be contributing to this accelerated disease progression. This phenotypic switch most likely involves the virus changing from using which co-receptors for cellular entry?
A 15-year-old boy with Crohn’s disease, who is about to start high-dose corticosteroid therapy, is found to have asymptomatic Strongyloides stercoralis infection on screening. What is the primary reason for treating this latent infection before initiating immunosuppression?
A 19-day-old neonate presents with irritability and a rectal temperature of 38.6°C (101.5°F). A lumbar puncture is performed. The cerebrospinal fluid shows 25 white blood cells/mm³, a protein of 140 mg/dL, and glucose of 28 mg/dL. Which interpretation of these findings is most accurate?
An 18-year-old college freshman presents to the emergency department with fever, headache, nuchal rigidity, and a petechial rash. Invasive meningococcal disease is suspected. The causative organism, Neisseria meningitidis, is classified into serogroups based on antigenic differences in which structure?
A 16-year-old adolescent with a history of untreated latent tuberculosis infection presents with a one-month history of night sweats, anorexia, and a productive cough. A chest radiograph reveals a cavitary lesion in the right upper lobe. Which clinical feature is most consistent with this presentation of reactivation tuberculosis?
A 6-year-old unimmunized child presents with a biphasic illness. After an initial flu-like syndrome that resolved, he now has a severe headache, fever, and nuchal rigidity. Lumbar puncture is performed. Which of the following cerebrospinal fluid profiles is most characteristic of nonparalytic poliomyelitis?
A 5-year-old boy with a history of pica presents with persistent fever, wheezing, and marked hepatomegaly. Laboratory tests show significant eosinophilia, leukocytosis, and an elevated IgE level. Serology is positive for Toxocara canis with a high titer. This clinical picture is most consistent with which syndrome?
A 16-year-old adolescent presents with acute pharyngitis indistinguishable from that caused by Streptococcus pyogenes. Culture grows Streptococcus dysgalactiae subspecies equisimilis (SDSE). Although reactive arthritis can occur following an SDSE infection, which non-suppurative complication has NOT been clearly associated with this organism?
An antimicrobial stewardship program launches an initiative to have clinicians and pharmacists perform a structured history on patients with a reported penicillin allergy. The goal is to re-classify those with low-risk reactions like a rash in childhood. What is the primary rationale for this penicillin allergy assessment intervention?
