Acute Otitis Media Overview

Acute Otitis Media (AOM)

• AOM is a rapid onset inflammatory process in the middle ear space, specifically the mucous membrane lining the middle ear cleft.
• It's the second most common illness in childhood after upper respiratory tract infections (URTI).
• An infection lasting less than three weeks is considered acute.

Outline

• Introduction
• Epidemiology
• Etiology
• Risk factors
• Clinical features
• Investigations
• Management
• Complications
• Prevention

Case Studies

• Case 1: A 3-year-old girl presenting with fever and ear pain, hyperemic bulging tympanic membranes.
• Case 2: A 7-year-old girl presenting with aural fullness, reduced hearing, and ear pain, no fever, air bubbles behind tympanic membrane.

Introduction

• AOM is the rapid onset of inflammation within the middle ear, without necessarily specifying the cause.

Epidemiology

• AOM is more common in children than adults.
• Boys are slightly more affected than girls.
• Peak incidence is in the first 6-12 months of life.
• Approximately 80% of children experience at least one episode of AOM.
• Incidence significantly declines after age 7.

Etiology

• Common bacterial causes:
  • Streptococcus pneumoniae (30-35%)
  • Haemophilus influenzae (20-25%)
  • Moraxella catarrhalis (10-15%)
  • Streptococcus pyogenes (3%)
  • Staphylococcus aureus (1%)
  • Gram-negative bacilli (higher in infants).

Routes of Infection

• Eustachian tube
• External auditory canal
• Blood borne

Eustachian Tube

• Shorter, wider, and more horizontal in infants, which makes it easier for pathogens to travel directly to the middle ear.
• Large adenoids can interfere with the eustachian tube opening, hindering proper ventilation and creating an ideal environment for infection.
• Immature immune systems in infants contribute.

External Acoustic Meatus

• Infection, trauma to the tympanic membrane, and procedures like myringotomy or tympanostomy tubes are possible routes.

Pathogenesis

• Stages of AOM:
  • Tubal occlusion
  • Pre-suppuration
  • Suppuration
  • Resolution and Complications

Stage of Tubal Occlusion

• Edema and hyperemia of the nasopharynx and eustachian tube occlude the Eustachian tube.
• Negative middle ear pressure causes symptoms like ear fullness, tinnitus, hearing loss, and earache.
• Signs include retraction of the tympanic membrane, loss of cone reflex, and conductive hearing loss in tuning fork tests.

Stage of Pre-Suppuration

• Prolonged tubal occlusion allows pyogenic organism invasion resulting in middle ear mucosal hyperemia.
• Inflammation results and exudates appear in the middle ear.
• Symptoms (throbbing ear pain, bubbling sound in ear, tinnitus.)
• Signs (High fever and cartwheel appearance of tympanic membrane, conductive hearing loss).

Stage of Suppuration

• Pus formation in the middle ear and mastoid air cells.
• Symptoms: high-grade fever, severe ear pain, deafness.
• Signs: bulging tympanic membrane.
• X-ray may show clouding of air cells due to exudate.

Stage of Resolution

• TM rupture (due to necrosis) and otorrhea occur.
• Subsidence of other symptoms; ear pain and fever.
• Inflammatory process resolves.
• Complications like:
  1. Intratemporal,
  2. Intracranial

Clinical Presentation

• Neonates: irritability, feeding difficulties (possible septic focus).
• Older children: fever, otalgia (ear pain), ear tugging.
• Other signs: hearing loss, conjunctivitis (tearing, itchiness of eyes).
• Ear stuffiness may be observed before detection of middle ear fluid in older children/adults.

Diagnosis

• Key: TM examination and pneumatic otoscopy.
• Signs of inflammation noted:
  1. Color – Red TM
  2. Position – Displaced bulging TM
  3. Transluency – Opaque TM
  4. Mobility – Immobile TM

Investigations

• Testing in acute phase is generally unhelpful due to conductive hearing loss in most cases.
• Tympanometry may assist with middle ear effusion diagnosis but isn't always necessary.
• Tympanocentesis (culture and sensitivity) may be helpful for specimens from fresh perforations or tympanic punctures.

Imaging

• Radiological procedures (X-ray, CT scan, MRI) may be unnecessary for uncomplicated AOM.
• CT scan helps rule out complications (e.g., intracranial).
• MRI is useful if intracranial complications are suspected.

Differential Diagnosis

• Otitis media with effusion (OME): middle ear fluid without acute bacterial signs
• Chronic suppurative otitis media: Purulent drainage through perforated TM

Treatments of AOM

• Primarily medical (antibiotics), with surgical therapies available as well.
• Medications: antibiotics, decongestants, antihistamines, steroids

Pharmacological Therapy

• Commonly utilized antibiotics for AOM:
  • Penicillins (amoxicillin, augmentin)
  • Cephalosporins (cefixime)
  • Macrolides (azithromycin)

Surgical Therapies

• Tympanocentesis
• Myringotomy (+/- grommet)
• Adenoidectomy (+/- tonsillectomy)

Prevention

• Vaccination: PCV7 (Prevnar) against pneumococcal bacteria.
• Managing environmental risk factors:
  • Breastfeeding (first 6 months)
  • Avoid supine bottle feeding/pacifiers
  • Eliminating passive smoking exposure
• Control of nasal inflammation, addressing allergies or recurrent infections.
• Adenoidectomy can help with recurrent AOM.