Match each pediatric clinical vignette to the microbiologic description of its most likely causative pathogen.
- A 15-month-old child presents with an insidious onset of limp and refusal to walk. Vital signs are normal. Labs show a mildly elevated C-reactive protein but a normal white blood cell count. Blood cultures remain sterile after 5 days, but synovial fluid polymerase chain reaction is positive.Fastidious, facultatively anaerobic Gram-negative coccobacillus that frequently colonizes the pediatric oropharynx and is a leading cause of occult skeletal infections in toddlers.
- A 14-year-old adolescent develops high fever, severe sore throat, and unilateral neck swelling. Two days later, he presents with progressive respiratory distress; a computed tomography scan of the chest reveals multiple cavitating pulmonary nodules.Anaerobic, non-spore-forming Gram-negative bacillus known for causing septic thrombophlebitis of the internal jugular vein and metastatic abscesses.
- A 3-week-old infant, born at term following an uncomplicated pregnancy, presents with sudden-onset focal seizures. Examination reveals a cluster of erythematous vesicular lesions on the scalp. Cerebrospinal fluid analysis shows mononuclear pleocytosis and elevated protein.Enveloped, double-stranded DNA virus that typically infects the neonate via vertical transmission during passage through an infected birth canal, presenting with neurotropic spread.
- A 6-week-old infant is evaluated for poor weight gain, persistent rhinitis with blood-tinged discharge, and a desquamating maculopapular rash on the palms and soles. Radiographs reveal diaphyseal periostitis and metaphyseal lucencies.Highly motile spirochete that crosses the placenta, producing widespread fetal infection characterized by hepatosplenomegaly, mucocutaneous lesions, and osteochondritis.
Answer
The correct pairings precisely match the specific pediatric infectious disease syndromes (Kingella kingae osteoarthritis, Fusobacterium necrophorum Lemierre syndrome, neonatal Herpes simplex virus, and early congenital Treponema pallidum) to their respective microbiologic profiles.
Each vignette provides highly specific clinical clues that point to a single diagnosis, which uniquely corresponds to the provided microbiologic descriptions. The toddler's culture-negative, PCR-positive arthritis aligns with the fastidious Kingella coccobacillus. The adolescent's post-pharyngitis cavitary lung lesions align with the anaerobic Fusobacterium. The neonate's delayed-onset seizures and scalp vesicles align with the intrapartum-acquired HSV DNA virus. The young infant's snuffles and periostitis align with the transplacental Treponema spirochete.
Step-by-Step Solution
Key Concept
Clinical and microbiologic correlation of complex pediatric infectious syndromes, relying on atypical presentations, chronological onset, and specialized pathogen characteristics.