Exam takeaway: For uncomplicated pediatric mastoiditis without otorrhea, tubes, or MRSA risk, start IV beta‑lactam (eg, ceftriaxone); reserve vancomycin when MRSA risk is present. Quick boards rationale: match empiric regimen to clinical context.
A 20 mo boy presents with fever and ear pain. The patient began with fever 5 days ago and was seen by his pediatrician and diagnosed with acute otitis media (AOM). He was started on amoxicillin and has been taking it as prescribed. Since that time his fever has continued, and he has complained of increasing pain. He has no prior history of AOM and has been otherwise healthy. His exam reveals a non-toxic appearing child with tenderness posterior to his ear along with the finding below.
What is the appropriate intravenous antibiotic choice for this patient?
Answer Options:
A. Ampicillin/sulbactam
The keyed answer (vancomycin) was incorrect. Validated correct answer: Ampicillin/sulbactam.
Why: The clinical picture and image show acute mastoiditis (pinna protrusion, postauricular erythema/tenderness/swelling) complicating AOM in a previously healthy toddler without recurrent AOM or chronic ear disease. Current guidance favors empiric IV beta-lactam therapy (ampicillin/sulbactam or ceftriaxone) to cover S. pneumoniae, S. pyogenes, H. influenzae, and MSSA. Vancomycin is added only when MRSA risk exists; antipseudomonal agents (e.g., cefepime) are reserved for chronic suppurative disease, tympanostomy-tube otorrhea, or recurrent AOM. Sources: AAP Red Book 2021–2024; CHOP Clinical Pathway 2024; UCSF IDMP 2021–2024; RCH Melbourne CPG 2022.
Many examinees over-escalate to vancomycin monotherapy or vancomycin plus antipseudomonal therapy. However, vancomycin alone lacks Gram-negative coverage (e.g., non-typeable H. influenzae) and is not first-line in uncomplicated cases. Broad antipseudomonal combinations are reserved for children with recurrent/chronic ear disease or tubes with otorrhea.
Boards expect you to map the empiric regimen to the clinical context: uncomplicated mastoiditis → beta-lactam (ampicillin/sulbactam or ceftriaxone) ± vancomycin only for MRSA risk; chronic/recurrent disease or tubes/otorrhea → add antipseudomonal coverage.
Pattern-recognition bias: mastoiditis prompts knee-jerk “vancomycin” even when MRSA or chronic ear disease isn’t present.
Failure to recall that vancomycin lacks coverage for common Gram-negative AOM pathogens.
Overgeneralization of antipseudomonal therapy to all mastoiditis rather than limiting to chronic/recurrent disease or tympanostomy-tube otorrhea.
| Option | What It Tests / Implies | Why It’s Wrong Here |
| Ampicillin/sulbactam | First-line beta-lactam coverage for uncomplicated mastoiditis | This is actually correct per current guidance (AAP Red Book; CHOP; UCSF). |
|---|---|---|
| Cefepime and vancomycin | Regimen for chronic ear disease/tubes or pseudomonal risk | Overly broad; no history of recurrent AOM, tubes, or otorrhea to suggest Pseudomonas. |
| Clindamycin | MRSA/MSSA and anaerobe coverage | Poor S. pneumoniae coverage and no Gram-negative coverage; inadequate empiric choice. |
| Vancomycin | MRSA-focused therapy | Lacks Gram-negative coverage (e.g., H. influenzae); not first-line in uncomplicated mastoiditis. |
Uncomplicated pediatric mastoiditis: start IV ampicillin/sulbactam or ceftriaxone; add vancomycin only with MRSA risk; add antipseudomonal coverage only for chronic/recurrent disease or tubes with otorrhea.
The stem omits MRSA and pseudomonal risk factors; the image drives a reflex toward “big guns.” Resist escalation unless the history includes MRSA risk or chronic ear disease/tube-related otorrhea.
A 3-year-old with 3 days of worsening postauricular swelling after AOM; no tubes, no MRSA history, immunizations up to date, nontoxic.
A. Vancomycin
B. Ampicillin/sulbactam
C. Cefepime + vancomycin
D. Clindamycin
E. Linezolid
A 2-year-old with tympanostomy tubes and purulent otorrhea develops mastoid tenderness, pinna protrusion, and fever.
A. Cefepime + vancomycin
B. Ampicillin/sulbactam
C. Vancomycin
D. Ceftriaxone
A 4-year-old with prior MRSA skin abscess now has uncomplicated mastoiditis; no tubes or otorrhea.
A. Ceftriaxone alone
B. Ampicillin/sulbactam + vancomycin
C. Cefepime alone
D. Clindamycin
A 6-year-old with months of otorrhea and conductive hearing loss presents with mastoiditis; afebrile but toxic-appearing.
A. Ampicillin/sulbactam
B. Piperacillin–tazobactam + vancomycin
C. Vancomycin alone
D. Ceftriaxone alone
A 2-year-old started on ampicillin/sulbactam for uncomplicated mastoiditis improves; middle ear culture grows pan-susceptible S. pneumoniae.
A. Continue IV ampicillin/sulbactam indefinitely
B. Narrow to high-dose IV ampicillin or ceftriaxone and transition to oral when stable
C. Add vancomycin
D. Switch to cefepime
Compare empiric therapy choices for mastoiditis in: (a) unimmunized toddler without tubes; (b) child with tympanostomy tubes and active otorrhea; and (c) child with prior MRSA infection but no chronic ear disease. Discuss how each scenario modifies the need for MRSA and/or antipseudomonal coverage and the role of early ENT consultation.
- Q: Do all children with mastoiditis need vancomycin?
A: No. Add vancomycin only when MRSA risk exists; beta-lactam monotherapy is first-line in uncomplicated cases.
- Q: When is antipseudomonal coverage indicated?
A: In chronic suppurative otitis media, recurrent AOM, or tympanostomy-tube otorrhea—situations associated with Pseudomonas.
- Q: What if imaging shows a subperiosteal abscess?
A: Continue appropriate empiric antibiotics and obtain urgent ENT consultation; many require surgical drainage in addition to antibiotics.
- Q: Which beta-lactam is preferred initially?
A: Ampicillin/sulbactam or ceftriaxone are both acceptable per AAP Red Book and pediatric institutional pathways; choose based on local susceptibility, allergy, and severity.
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