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Difficulty: MediumPediatric Infectious Diseases

Match each of the following pediatric clinical vignettes describing an acute osteoarticular presentation with the most likely responsible infectious agent.

  • An adolescent female with a recent history of unprotected intercourse presenting with fever, migratory asymmetric oligoarthritis, inflammation of the tendon sheaths, and scattered painless pustular skin lesions.Neisseria gonorrhoeae
  • A young child homozygous for a hemoglobin structural variant who develops acute, severe focal bone pain, localized warmth, and tenderness over the diaphysis of the humerus.Salmonella species
  • An unimmunized toddler who acutely refuses to bear weight on his right leg; arthrocentesis of the swollen knee yields purulent synovial fluid demonstrating pleomorphic Gram-negative coccobacilli on Gram stain.Haemophilus influenzae type b
  • A previously healthy elementary school student with a recent history of a superficial skin abrasion who develops high fever, localized bone pain, and significant elevation of acute phase reactants.Staphylococcus aureus

Answer

The correct pairings align the adolescent triad of tenosynovitis/dermatitis/arthritis with Neisseria gonorrhoeae, the sickle cell patient's bone infection with Salmonella species, the unimmunized toddler's Gram-negative joint aspirate with Haemophilus influenzae type b, and the healthy child's osteomyelitis with Staphylococcus aureus.
Each vignette contains distinct clues pointing to a specific pathogen: the gonococcal triad (N. gonorrhoeae), sickle cell disease increasing risk for encapsulated organisms (Salmonella), lack of immunizations with characteristic Gram-negative morphology (H. influenzae type b), and the healthy pediatric baseline (S. aureus).

Step-by-Step Solution

1
Evaluate the adolescent vignette focusing on the classic physical examination triad.
The combination of tenosynovitis, dermatitis, and migratory polyarthralgia in a sexually active patient specifically directs the diagnosis toward a disseminated gonococcal infection.
Recognizing this triad is essential to differentiate gonococcal arthritis from other causes of acute joint inflammation in young adults.
2
Identify the underlying hemoglobinopathy in the second vignette to determine specific infectious susceptibilities.
The patient with a hemoglobin structural variant (sickle cell disease) has a uniquely elevated risk for non-typhoidal Salmonella bone infections.
Functional asplenia and microinfarctions in the bone marrow create an environment highly susceptible to Salmonella bacteremia and subsequent osteomyelitis.
3
Utilize the vaccination status and microbiological findings in the third vignette.
The presence of pleomorphic Gram-negative coccobacilli in an unimmunized child strongly points to Haemophilus influenzae type b.
Routine Hib vaccination has made this presentation rare, but it remains a primary diagnostic consideration in the unimmunized population.
4
Assess the risk factors in the final vignette featuring an otherwise healthy child.
In the absence of underlying disease, Staphylococcus aureus is the overwhelmingly most frequent culprit of acute hematogenous osteomyelitis.
S. aureus commonly colonizes the skin and can easily cause transient bacteremia and bone seeding following minor superficial trauma.

Key Concept

Etiologic agents of pediatric osteoarticular infections are strongly correlated with patient age, underlying hematologic conditions, vaccination status, and sexual activity.
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Topics

Pediatric Infectious Diseases

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