What is an infected eardrum?

Characteristics of an Infected Eardrum

An infected eardrum is characterized by inflammation, fluid accumulation, and distinctive visual changes that indicate middle ear infection (otitis media). An infected eardrum typically appears reddened, bulging, and may show impaired mobility on pneumatic otoscopy, often accompanied by middle ear effusion and symptoms such as pain, fever, and hearing difficulties. 1

Visual Appearance

• Redness (erythema): The tympanic membrane appears reddened due to inflammation and increased vascularity 1
• Bulging: The eardrum may bulge outward due to pressure from fluid accumulation behind it 1
• Opacity: Loss of normal translucency of the tympanic membrane 1
• Fluid level/bubbles: Visible fluid or air bubbles may be seen behind the eardrum 1
• Discharge: In cases of perforation, purulent or serous discharge may be present 2

Structural Changes

• Decreased mobility: The infected eardrum shows reduced or absent mobility when tested with pneumatic otoscopy 1
• Perforation: In severe cases or chronic infections, the eardrum may develop a hole or perforation 1
• Retraction: In some cases, especially with otitis media with effusion, the eardrum may appear retracted rather than bulging 3

Associated Findings

• Middle ear effusion: Fluid accumulation behind the tympanic membrane is a hallmark finding 1
• Tympanosclerosis: White patches on the eardrum may develop in chronic or recurrent infections 3
• Landmarks obscured: Normal anatomical landmarks of the eardrum (such as the light reflex, malleus) may be difficult to visualize 1

Types of Infected Eardrums

1. Acute Otitis Media (AOM):

   • Reddened, bulging eardrum
   • Signs of acute inflammation
   • Often accompanied by fever, pain, and irritability 1, 4

2. Otitis Media with Effusion (OME):

   • Fluid behind an intact tympanic membrane
   • Minimal redness
   • No acute symptoms of infection 1, 3

3. Chronic Suppurative Otitis Media:

   • Persistent perforation
   • Ongoing discharge
   • Thickened, inflamed tympanic membrane 1, 5

Clinical Significance

• Hearing impact: Infected eardrums often cause conductive hearing loss due to fluid interference with sound transmission 3
• Pain mechanism: Bulging of the eardrum due to pressure causes the characteristic pain of acute otitis media 4
• Diagnostic importance: Visual examination of the eardrum is crucial for distinguishing between different types of ear infections 1

Common Pitfalls in Examination

• Cerumen impaction: Earwax can obstruct proper visualization of the tympanic membrane
• Uncooperative patients: Especially in children, obtaining a clear view can be challenging
• Misinterpretation: Normal variations in eardrum color can be mistaken for infection, particularly in crying children (who may have temporarily reddened eardrums) 4
• Incomplete examination: Failure to assess mobility with pneumatic otoscopy can lead to missed diagnoses 1

Proper identification of an infected eardrum requires adequate visualization, appropriate lighting, and sometimes specialized equipment like pneumatic otoscopy to assess membrane mobility, which is essential for accurate diagnosis and appropriate treatment planning.