What is the recommended treatment for acute mastoiditis in adults and children, including empiric intravenous antibiotics, therapy duration, outpatient management criteria, and indications for surgical intervention?

Treatment of Mastoiditis

Immediate Management: Start IV Antibiotics Without Delay

Initiate intravenous broad-spectrum antibiotics immediately upon diagnosis of acute mastoiditis, as this is the cornerstone of treatment for all patients. 1, 2

First-Line Antibiotic Regimens

For empiric therapy, use one of the following IV regimens:

• Cloxacillin/flucloxacillin: 50 mg/kg every 6 hours (pediatric) or 2g every 6 hours (adult) for 10 days 2
• Ceftriaxone: 50-80 mg/kg/day (pediatric) or 2g daily (adult) as second-line option 2, 3
• Amoxicillin-clavulanate IV: 80-90 mg/kg/day of amoxicillin component divided every 8-12 hours (maximum 4000 mg/day) 1

The rationale for these choices is that Streptococcus pneumoniae remains the most common pathogen (28-39% of culture-positive cases), followed by Streptococcus pyogenes, Staphylococcus aureus (16%), Haemophilus influenzae, and Pseudomonas aeruginosa (6-8%). 1, 4, 5, 6

Broader Coverage for Complicated Cases

If complications are present or suspected (subperiosteal abscess, intracranial extension, toxic appearance), use broader empiric coverage: 1

• Vancomycin PLUS one of: piperacillin-tazobactam, carbapenem, OR ceftriaxone plus metronidazole 1
• For confirmed Streptococcus pyogenes, add clindamycin to penicillin therapy 1

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Adjunctive Surgical Drainage: Myringotomy

Consider myringotomy with or without tympanostomy tube insertion at initial presentation to facilitate drainage and obtain cultures. 1, 2, 7 This combined approach (antibiotics plus myringotomy) achieves 68% success rates compared to only 10% with antibiotics alone. 1, 2

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Critical 48-Hour Reassessment Point

Reassess all patients after 48 hours of IV antibiotic therapy to determine if escalation is needed. 1, 2

Indications for CT Imaging at 48 Hours:

• Failure to improve clinically 1, 2
• Clinical deterioration at any point 1
• Persistent fever or worsening pain 1
• Development of neurological signs (altered consciousness, seizures, focal deficits, nuchal rigidity) 1

Order CT temporal bone with IV contrast to assess for bony erosion, subperiosteal abscess, and intratemporal complications. 1 If intracranial complications are suspected, obtain MRI brain with and without contrast as it has superior sensitivity for detecting brain abscess, subdural empyema, meningitis, or venous sinus thrombosis. 1

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Indications for Mastoidectomy

Proceed to mastoidectomy if any of the following are present: 1, 2, 8

• No clinical improvement after 48 hours of IV antibiotics 1, 2
• Presence of subperiosteal abscess 2, 8
• Development of intracranial complications 1
• Intratemporal complications (facial nerve palsy, labyrinthitis) 3

Mastoidectomy is required in 22-77% of cases depending on severity and timing of intervention. 1, 5, 8 Early mastoidectomy may prevent serious complications and reduce recurrence risk. 8

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Transition to Oral Antibiotics

Once clinical improvement is documented (typically after 48-72 hours of IV therapy), transition to oral antibiotics to complete a total 10-day course. 1, 2

Preferred Oral Step-Down Regimens:

• High-dose amoxicillin-clavulanate: 80-90 mg/kg/day divided twice daily (pediatric, maximum 4000 mg/day) or 2000 mg twice daily (adult) 1
• For non-immediate β-lactam allergy: Cefdinir, cefpodoxime, or cefuroxime 1
• For immediate Type I β-lactam allergy: Clindamycin PLUS an agent covering H. influenzae and M. catarrhalis (cefixime or cefdinir if tolerated) 1

Critical Pitfall to Avoid:

Do NOT use macrolides (azithromycin, clarithromycin) or trimethoprim-sulfamethoxazole as step-down therapy due to 20-25% failure rates from pneumococcal resistance. 1

Reassess patients within 48-72 hours after switching to oral therapy to ensure continued improvement. 1

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Follow-Up and Monitoring

Persistent middle ear effusion is expected and normal: 60-70% of children have effusion at 2 weeks, decreasing to 10-25% at 3 months. 1 This does not require continued antibiotics unless symptomatic. 1

Perform hearing assessment if effusion persists ≥3 months. 1

Monitor for complications throughout treatment:

• Sigmoid sinus thrombosis (consider anticoagulation if confirmed) 1
• Intracranial extension (brain abscess, subdural empyema, meningitis) 1, 3
• Facial nerve palsy 3
• Recurrence (occurs in 8% of cases) 8

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Important Clinical Caveats

Prior antibiotic treatment does NOT prevent mastoiditis development - 33-81% of patients with acute mastoiditis had received antibiotics before admission. 1, 4, 2 This emphasizes the importance of clinical vigilance even in treated patients. 5, 6

Cultures may be negative in 33-53% of cases, so empiric therapy must be broad and clinical diagnosis remains paramount. 2, 5, 6

Pain management is a critical component of care and should be addressed aggressively throughout treatment. 1