Acute Otitis Media (AOM) ในผู้ใหญ่
1) Overview & Clinical relevance
- AOM ในผู้ใหญ่พบ น้อยกว่าเด็กมาก
- Incidence
โดยประมาณ:
- อายุ 15–24 ปี: ~3–3.5%
- อายุ 25–85 ปี: ~1.5–2.3%
- ต่างจากเด็ก:
👉 ผู้ใหญ่มีโอกาสเกิด complication สูงกว่า → ควรให้ antibiotics เป็นมาตรฐาน
2) Definition (Key concept)
Acute otitis media (AOM) =
- Infected
middle ear effusion
- Acute
inflammation ของ middle ear mucosa
- มักเกิดจาก Eustachian tube dysfunction → fluid retention → bacterial infection
อาจมี:
- Purulent
otorrhea (ถ้า TM rupture)
3) Microbiology (Adult AOM)
ลักษณะคล้าย pediatric AOM แต่บางเชื้อพบมากขึ้นในผู้ใหญ่
Common pathogens
- Streptococcus
pneumoniae
- Nontypeable
Haemophilus influenzae
- Moraxella
catarrhalis
Pathogens ที่ควรนึกถึงในผู้ใหญ่เพิ่ม
- Staphylococcus
aureus (รวม MRSA)
- Group
A Streptococcus (อาจ fulminant)
- Pseudomonas
(บางราย โดยเฉพาะ perforation/severe)
Viral role
- URI เป็น trigger สำคัญ
- Coinfection
virus + bacteria พบได้ (rhinovirus, RSV, coronavirus)
4) Predisposing factors (ผู้ใหญ่)
4.1 Eustachian tube dysfunction (สำคัญที่สุด)
- URI
- Allergic
rhinitis
- Barotrauma
- Smoking
/ mucociliary dysfunction
4.2 Mechanical obstruction (ต้องระวัง unilateral)
- Nasopharyngeal
carcinoma
- Lymphoma
- Post-radiation
fibrosis
4.3 Host factors
- Immunocompromised
- Malignancy
- Immunosuppressive
drugs
- Primary
ciliary dyskinesia
5) Clinical presentation (Adults)
Typical symptoms
- Otalgia
(unilateral)
- Muffled
hearing / conductive hearing loss
- Aural
fullness
- Recent
URI or allergic rhinitis (common preceding)
Clue sign
- Sudden
pain relief + otorrhea →
TM rupture
Less common
- Dysequilibrium
- Mild
vertigo (rare)
Alarm symptoms (คิดถึง complication)
- High
fever
- Severe
retroauricular pain
- Facial
weakness
- Severe
vertigo
- Persistent
severe headache
6) Diagnosis (Key for avoiding overtreatment)
6.1 Essential: Otoscopic diagnosis
Hallmark finding
- 🔴
Bulging tympanic membrane (most specific)
Supporting findings
- Decreased
TM mobility (pneumatic otoscopy)
- Opaque
/ cloudy / yellow TM
- Erythema
(nonspecific)
- Air-fluid
level
- Purulent
otorrhea (ถ้า perforation)
Red TM alone ≠ AOM
6.2 Practical exam tips
- Remove
cerumen under direct visualization
- ❗
หลีกเลี่ยง irrigation ถ้าสงสัย AOM
(risk TM rupture)
7) Differentiating AOM vs OME (สำคัญมากในผู้ใหญ่)
|
Feature |
AOM |
OME |
|
Pain |
+++ |
Minimal/none |
|
Fever |
Possible |
No |
|
TM |
Bulging |
Neutral/retracted |
|
Effusion |
Infected |
Non-infected |
|
Mobility |
↓ |
↓ |
|
Treatment |
Antibiotics |
Usually observe |
Clinical pitfall
- ผู้ใหญ่ที่ถูกวินิจฉัย AOM ผิด → จริงๆ
คือ OME (พบบ่อย)
8) Treatment of AOM in Adults (Core Clinical Protocol)
8.1 General principle
- ผู้ใหญ่ → ให้ antibiotics เป็นมาตรฐาน
- ต่างจากเด็ก (บางราย observe ได้)
8.2 Symptomatic treatment (ทุกเคส)
- NSAIDs
หรือ acetaminophen (pain control)
- Nasal
decongestant (adjunct ใน URI)
- Hydration
9) First-line Antibiotic (No allergy)
Preferred: Amoxicillin-clavulanate
Standard dose
- Amoxicillin-clavulanate
875/125 mg PO BID
Severe infection / resistant risk
- Amoxicillin-clavulanate
ER 2000/125 mg PO BID
Risk group:
- Age
>65
- Recent
antibiotics (<1 month)
- Immunocompromised
- High
local resistance
10) Alternative regimens
10.1 If cannot use amox-clav (no severe allergy)
- Cefdinir
300 mg BID
- Cefpodoxime
200 mg BID
- Cefuroxime
500 mg BID
- Ceftriaxone
1–2 g IV/IM daily × 3 days
10.2 Penicillin allergy
Non-severe allergy
- Cephalosporin
(preferred)
- Doxycycline
100 mg BID
Severe beta-lactam allergy (anaphylaxis/SJS)
- Doxycycline
100 mg BID
- Levofloxacin
500–750 mg daily
- Moxifloxacin
400 mg daily
Less preferred
- Azithromycin
/ Clarithromycin (high S. pneumo resistance)
Avoid
- TMP-SMX
(resistance high)
- Clindamycin
(no H. influenzae coverage)
11) Duration of therapy
- Mild–moderate
AOM: 5–7 days
- Severe
AOM (severe pain, marked erythema, HL): 10 days
- Severe/systemic:
IV antibiotics + culture + admit
12) Lack of response (Key timeline)
Reassess at 48–72 hours
If no improvement:
1.
Re-examine TM (misdiagnosis? OME?)
2.
Consider resistant organism
3.
Escalate therapy:
o High-dose
amox-clav (if not used)
o Ceftriaxone
IV
o Respiratory
fluoroquinolone
Persistent failure (2nd line)
→ ENT
referral + tympanocentesis for culture
13) Special situations
13.1 AOM with tympanic membrane rupture
- ส่วนใหญ่ หายเอง
- Treat:
- Oral
antibiotics ± topical non-ototoxic drops
- Water
precautions:
- No
swimming
- Avoid
water entry (petroleum jelly cotton)
14) When to refer ENT (Important board-level points)
14.1 Urgent referral
- Severe
AOM not improving 48–72 hr
- Severe
hearing loss
- Facial
nerve palsy
- Vertigo
/ SNHL
- Suspected
mastoiditis
14.2 Routine referral
- Recurrent
unilateral AOM (>2 episodes/6 months)
→ Rule out nasopharyngeal tumor - Persistent
hearing loss >1–2 weeks post-resolution
- TM
perforation >12 weeks
- Suspected
cholesteatoma
15) Major complications (Rare but high-risk)
Overall <0.5% แต่สำคัญมากในผู้ใหญ่
Extracranial
- Acute
mastoiditis (most common)
- Labyrinthitis
- Facial
nerve palsy
- Petrositis
(Gradenigo syndrome)
Intracranial
- Otitic
meningitis
- Brain
abscess (temporal/cerebellar)
- Epidural/subdural
abscess
- Septic
lateral sinus thrombosis
- Otitic
hydrocephalus
Red flags:
- Postauricular
swelling
- Pinna
displacement
- Severe
headache + otorrhea
- Neurologic
deficit
16) Mastoiditis: Clinical pearls (Emergency relevance)
Signs:
- Postauricular
erythema/swelling
- Fever
+ severe otalgia
- Auricle
displaced outward/downward
Management:
- Admit
- IV
antibiotics (cover S. pneumo + H. influenzae)
- CT
temporal bone
- ENT
surgical consult ± mastoidectomy
17) Key clinical pearls (High-yield)
- Adult
AOM = antibiotics indicated (unlike selective pediatric approach)
- Bulging
TM > redness for diagnosis
- Most
common misdiagnosis = OME
- Unilateral
recurrent OME/AOM in adults →
rule out nasopharyngeal carcinoma (especially Southeast Asia risk)
- Reassess
at 48–72 hr = critical decision point
- Persistent
HL >1–2 weeks after AOM →
audiogram + ENT referral
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