## Stages of Acute Suppurative Otitis Media **Key Point:** The stage of suppuration is characterized by accumulation of pus under tension in the middle ear cavity, causing the tympanic membrane to bulge outward. This is the critical stage where spontaneous perforation may occur if untreated. ### Five Stages of ASOM | Stage | Duration | Pathology | Clinical Features | | --- | --- | --- | --- | | **Hyperaemia** | 24 hrs | Congestion, hyperemia of mucosa | Ear pain, fever; TM appears dull and injected | | **Pre-suppuration** | 24–48 hrs | Exudation, edema, early pus formation | Severe pain, fever; TM bulges slightly | | **Suppuration** | 48–72 hrs | Pus accumulation under tension | **Maximum pain and fever; TM markedly bulged** | | **Perforation** | Variable | Rupture of TM | Pain suddenly relieved; purulent discharge from ear | | **Resolution** | 7–14 days | Healing if perforation occurs; resorption if no perforation | Gradual improvement; TM heals | **High-Yield:** The stage of suppuration is the most critical stage clinically — it carries the highest risk of spontaneous perforation and intracranial complications if untreated. **Clinical Pearl:** A bulging, under-tension tympanic membrane in a febrile child with severe otalgia is a classic presentation of the suppuration stage and may warrant myringotomy to prevent spontaneous perforation and allow drainage. **Mnemonic:** **HPSR** — *Hyperaemia*, *Pre-suppuration*, *Suppuration*, *Resolution* (note: Perforation can occur during suppuration stage). 
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