What is the incidence and treatment of mastoiditis in newborns?

Mastoiditis in Newborns: Incidence and Management

Incidence

Acute mastoiditis is extremely rare in infants under 6 months of age, with only isolated case series reported in the literature. A Swedish nationwide study over 15 years (1993-2007) identified only 17 infants aged 0-5 months with acute mastoiditis 1. Similarly, an Israeli series found 24 infants (median age 6 months) among 113 total mastoiditis cases over 12 years, though a significant increase in incidence was noted during that period 2.

Key Epidemiological Features:

• Most cases occur after the first episode of acute otitis media (AOM) - approximately 70% of infants develop mastoiditis following their initial middle ear infection 1, 3
• Male predominance is observed (approximately 62% male) 3
• No predisposing diseases are typically present in affected infants 1

Clinical Presentation

Diagnostic Challenges:

Mastoiditis in newborns and young infants presents atypically and is frequently missed on initial evaluation. The classic triad is often incomplete 4.

Common Presenting Features:

• Fever >38°C (present in 57-77% of cases) 2, 3
• Post-auricular swelling and redness (77% of cases) 2
• Protruding ear with retroauricular signs (nearly universal when present) 1
• Blurred or red tympanic membrane (100% and 36% respectively) 3

Systemic Manifestations (More Common in Infants):

• Weight loss (76% of cases) 3
• Vomiting and diarrhea (51% each) 3
• Severe anemia requiring transfusion (16%) 3

Timeline:

• Upper respiratory infection precedes mastoiditis by mean of 7 days (median 3 days) 1
• Ear symptoms present for mean of 3 days (median 2 days) before hospitalization 1
• Rapid progression - time from first ear symptoms to hospitalization is very short 1

Microbiology

Streptococcus pneumoniae remains the most common pathogen (32-58% of culture-positive cases) 1, 2, 3. Other significant pathogens include:

• Streptococcus pyogenes (23% - higher than typical AOM) 2
• Staphylococcus aureus (21.5%) 3
• Non-typable Haemophilus influenzae (5.5-12%) 2, 3
• Culture-negative cases occur in 35-40% 2, 3

Diagnostic Workup

Essential Investigations:

• Tympanocentesis with culture should be performed in all cases prior to surgery 2, 3
• Temporal bone CT scan is the diagnostic modality of choice, showing bone destruction in approximately 54% of cases 2
• Complications identified on imaging include subperiosteal abscess (12-47% of cases) and lateral sinus thrombosis (12%) 1, 2

Clinical Pitfall:

Plain radiographs are usually not diagnostic early in the disease course 4. CT scanning is necessary for definitive diagnosis when clinical suspicion exists 4.

Treatment Algorithm

Initial Management:

All infants with suspected mastoiditis require immediate hospitalization and intravenous antibiotics 1, 3. Mean hospitalization duration is 6 days 1.

Antibiotic Coverage:

Empirical antibiotics must cover S. pneumoniae (including intermediately resistant strains), S. pyogenes, H. influenzae, and M. catarrhalis 4. Treatment should be administered both before and after surgical intervention 3.

Surgical Intervention:

The combination of antibiotic and surgical treatment is optimal 3. Surgical approaches include:

• Myringotomy (performed in 76% of Swedish cases) 1
• Mastoid incision or puncture (29% of cases) 1
• Cortical mastoidectomy (18-42% of cases, reserved for non-resolution with conservative measures) 1, 2
• Ventilation tube insertion (30% of cases with prior AOM history) 3

Indications for Surgery:

Surgery is indicated when symptoms and signs do not resolve with antibiotic therapy alone 2. In the Swedish series, 94% of infants underwent some form of surgical intervention 1.

Conservative Management:

A minority of carefully selected cases (approximately 10-15%) may heal with antibiotics alone, but this requires close monitoring 2.

Outcomes and Complications

With timely administration of IV antibiotics and appropriate surgical intervention, severe complications can be prevented 1. In reported series:

• No intracranial complications occurred in the Swedish cohort 1
• No deaths were recorded 1
• Subperiosteal abscesses were the most common complication (12-47%) 1, 2

Critical Warning:

Mastoiditis should always be considered in the differential diagnosis of prolonged AOM with no improvement after 10 days of antibiotic treatment, especially when accompanied by weight loss and worsening general condition 3. The disease is potentially life-threatening but often overlooked because specific symptoms may be absent 4, 3.