A 6-year-old child presents with acute onset otalgia, fever (38.5°C), and conductive hearing loss. Otoscopy reveals a bulging, hyperemic tympanic membrane with loss of landmarks. The child has no history of ear discharge. Which investigation is most appropriate to confirm the diagnosis of acute suppurative otitis media and guide management?

Explanation

## Diagnosis of Acute Suppurative Otitis Media **Key Point:** Tympanometry is the gold-standard non-invasive investigation for confirming acute suppurative otitis media (ASOM) by objectively documenting middle ear effusion and reduced compliance. ### Why Tympanometry Type B? In acute suppurative otitis media: - The middle ear is filled with pus/fluid, reducing the compliance (stiffness) of the tympanic membrane–ossicular system - Tympanometry Type B shows **absent or severely reduced compliance** with a **flat baseline** (no peak at any pressure) - This indicates fluid/effusion in the middle ear space, which is pathognomonic for ASOM ### Tympanometry Curves at a Glance | Curve Type | Compliance | Peak Pressure | Middle Ear Status | Clinical Significance | |---|---|---|---|---| | **Type A** | Normal (0.3–0.85 mL) | 0 daPa | Normal | Excludes middle ear effusion | | **Type B** | Reduced/absent (<0.3 mL) | Flat baseline | Effusion/fluid present | **Diagnostic of ASOM** | | **Type C** | Normal | Negative (–100 to –200 daPa) | Eustachian tube dysfunction | Early serous otitis media | | **Type Ad** | Increased (>0.85 mL) | 0 daPa | Ossicular discontinuity | Congenital or traumatic | | **Type As** | Increased | 0 daPa | Flaccid TM | Myringitis or TM perforation | **High-Yield:** Type B tympanogram is the **objective confirmation** of middle ear effusion in ASOM, even before perforation occurs. ### Clinical Pearl In this case, the child has clinical signs of ASOM (fever, otalgia, bulging hyperemic TM, conductive hearing loss) but no perforation or discharge. Tympanometry Type B would objectively confirm the presence of middle ear fluid and exclude other causes of conductive hearing loss (e.g., ossicular fixation). ### Why Not Type A? Type A curve indicates normal middle ear compliance and normal pressure—this would **exclude** ASOM and suggest a normal ear or ossicular problem, which contradicts the clinical presentation.