Pediatric head and neck infections and localized lymphadenopathy have distinct clinical pr… — USMLE Step 2 CK

Pediatric head and neck infections and localized lymphadenopathy have distinct clinical presentations that guide specific management. Match each clinical vignette (left) describing a pediatric patient to the most appropriate management strategy (right).

A $3$ -year-old child with a $4$ -cm, rapidly enlarging, tender, and erythematous unilateral anterior cervical lymph node. Temperature is $39.0^\circ\text{C}$ ( $102.2^\circ\text{F}$ ). There is no fluctuance on palpation.Empiric oral clindamycin or amoxicillin-clavulanate
A $4$ -year-old child with a slowly enlarging, painless, unilateral submandibular mass present for $4$ weeks. The overlying skin is thinned and has a violaceous discoloration. The child is afebrile.Complete surgical excision; avoid incision and drainage
A $7$ -year-old child with a tender axillary lymph node and low-grade fever for $2$ weeks. Examination reveals a $3$ -mm crusted papule on the ipsilateral hand. The family recently adopted a stray kitten.Oral azithromycin therapy
A $15$ -year-old adolescent with a $10$ -day history of severe fatigue, exudative pharyngitis, and diffuse bilateral cervical lymphadenopathy. Palpation of the abdomen reveals mild splenomegaly.Supportive care and avoidance of contact sports for at least 3-4 weeks

Answer

The correct matches are: 1) Acute unilateral lymphadenitis pairs with oral clindamycin/amoxicillin-clavulanate. 2) Nontuberculous mycobacterial lymphadenitis pairs with complete surgical excision. 3) Cat-scratch disease pairs with oral azithromycin. 4) Infectious mononucleosis pairs with supportive care and avoidance of contact sports.

Each correct pair directly maps a classic pediatric infectious disease syndrome to its definitive, guideline-concordant therapy or critical management step.

Step-by-Step Solution

Analyze the first vignette to identify the etiology of the acute, unilateral, tender cervical mass with fever.

Diagnosis is acute bacterial cervical lymphadenitis (commonly S. aureus or S. pyogenes).

Guides selection of clindamycin or amoxicillin-clavulanate to cover common gram-positive organisms including MRSA.

Evaluate the second vignette focusing on the subacute timeline, lack of systemic symptoms, and violaceous skin overlying a submandibular node.

Diagnosis is nontuberculous mycobacterial (NTM) lymphadenitis.

Recognizing NTM is critical to select surgical excision and strictly avoid incision and drainage, which causes chronic fistulas.

Assess the third vignette noting the regional (axillary) lymphadenopathy, inoculation papule, and kitten exposure.

Diagnosis is cat-scratch disease (Bartonella henselae).

Directs management to azithromycin, which is indicated for reducing lymph node size in this specific infection.

Examine the fourth vignette for classic infectious mononucleosis symptoms (fatigue, exudative pharyngitis, bilateral adenopathy, splenomegaly).

Diagnosis is Epstein-Barr virus (EBV) infection.

Confirms management is purely supportive but necessitates strict restriction from contact sports to prevent splenic rupture.

Key Concept

Identifying characteristic clinical patterns of pediatric lymphadenopathy (acute bacterial, NTM, Bartonella, EBV) is essential to determine specific, etiology-driven management and avoid contraindicated interventions.

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