Otitis Media

Anatomy of Ear
3. Vestibular system
Physiology of hearing
1. External Ear
  1. Localization and amplification of sounds and transmission to tympanic membrane.
2. Middle Ear
  1. Vibration of tympanic membrane
  2. Impedance matching
3. Inner Ear
  1. Excitation of Hair Receptors.
    1. Stereocilia of the hair receptors are tightly fixed in a rigid structure ➝ reticular lamina + triangular rods of the Corti + basilar fiber.
      1. In response to sound waves, basilar membrane vibrate and move up and down ➝ inward and outward movement of the reticular lamina.
    2. Hair cells to bend toward the longer ones ➝ Excitation
The Auditory Pathway
Differential Diagnosis
1. Vertigo
  1. FALSE SENSE OF MOTION, usually rotational.
2. Tinnitus
  2. The perception of sound in the absence of external stimuli.
  3. May be perceived as unilateral or bilateral originating in the ears or around the head
3. Otorrhea
  2. Mucoid discharge indicates a perforation of the tympanic membrane.
  3. Clear, watery fluid, especially when associated with a history of trauma or skull base surgery, is likely to be CSF.
  4. Purulent discharge indicates the presence of infection: Onset of an acute infections (white), persistent (yellow or brown).
  5. Bloody discharge may follow trauma or occur with granulation tissue associated with chronic infection.
  6. A foul-smelling discharge is usually associated with cholesteatoma or a neoplasm.
4. Otalgia
Types of Hearing Loss
1. Conductive Hearing Loss
  1. Impairment of the physical structures of the ear that conduct sound to the cochlea: ear canal, tympanic membrane, or middle ear and the 3 auditory ossicles.
  2. Malformation of outer ear, ear canal, or middle ear structures\ Otitis Media\ Poor Eustachian tube function\ Perforated eardrum\ Benign tumors\ Impacted earwax\ Infection in the ear canal\ Foreign body in the ear\ Otosclerosis
2. Sensorineural Hearing Loss
  1. Impairment of the cochlea or the auditory nerve.
  2. Exposure to loud noise\ Head trauma\ Ototoxic drugs\ Autoimmune inner ear disease\ Aging (presbycusis)\ Malformation of the inner ear\ Meniere’s Disease\ Tumors
3. Mixed Hearing Loss
  1. Conductive hearing loss occurs in combination with Sensorineural hearing loss.
  2. Sensorineural component is permanent, while the conductive component can either be permanent or temporary.
Microbiology of Ear Infections
1. Otitis Externa
  1. Acute localized otitis externa
    1. Infection of the hair follicle “ Furuncle”
    2. Staphylococcus aureus
    3. S&S: Sever pain, discharge, hearing loss, and aural fullness.
    4. On examination: Local tenderness, EAC edematous, tender preauricular lymph node, furuncle in the posterior meatal, and obliterations of the retroauricular groove.
  2. Acute diffuse otitis externa
    1. Commonest, called swimmer’s
    2. Pseudomonas aeruginosa, staphylococcus aureus, proteus mirabilis
    3. S&S: Pain, itching, aural fullness, and hearing loss.
    4. On examination: tenderness, EAC narrow and congested, with edematous skin, and there will be clear or purulent exudates.
  3. Malignant otitis externa
    1. pseudomonas aeruginosa.
    2. Invasive infection
    3. Immune compromised people, malnourished, diabetes mellitus, leukemia
    4. S&S: Otalgia, otorrhea, pain that tend to be worse at night, radiating pain to temporomandibular joint “pain with chewing”.
  4. Fungal otitis externa (otomycosis)
    1. 90% aspergillus species, the rest candida species
    2. S&S: Malodorous discharge, inflammation, pruritus, scaling, and severe discomfort.
2. Otitis Media
  1. Acute otitis media
    1. Children after sore throat, cold, or upper respiratory
    2. Bacteria: Streptococcus pneumoniae (40%), haemophilus influenzae (25%), moraxella catarrhalis (15%).
    3. Viruses: Respiratory syncytial virus, rhinoviruses, influenza viruses, and adenoviruses.
    4. S&S: Fever, irritability, vomiting, anorexia, cough, pulling or rubbing of the “below 2 years”, otalgia, otorrhea, pain and hearing loss, upper respiratory symptoms.
  2. Chronic Otitis Media
    1. Otitis media with effusion
      1. S&S: Hearing loss, conductive hearing loss, tinnitus, and bulging or retraction of tympanic membrane.
      2. Self-limiting 80%, if it persists (tympanostomy tube insertion).
    2. Chronic suppurative otitis media
      1. S&S: Hearing loss, delayed intellectual development, limited employability, and disturbed social life, fatal if untreated.
Cholesteatoma
1. Primary acquired cholesteatomas
  1. It happens because of tympanic membrane retraction which forms a cyst or pouch.
2. Secondary Acquired cholesteatomas
  1. Happens secondary to the pathologic changes that happens to the tympanic membrane: recurrent infections, perforation of tympanic membrane or trauma to tympanic membrane.
3. Congenital cholesteatomas
  1. Caused by the remnants of epithelium that accumulate during the embryological development and get trapped in the middle ear behind the tympanic membrane
Aural polyps
1. An otic, or aural, polyp is a benign proliferation of chronic inflammatory cells and granulation tissue that is usually lined with benign reactive epithelium.
2. Solitary, Polypoid, Reddish mass
3. granulation tissue with edematous stroma and high density of capillaries
Investigations
1. Clinical Examination
  1. Otoscope
  2. Tuning fork tests
2. History
  1. External ear
    1. cleaning their ears with cotton swabs\ foreign body\ local trauma or recent instrumentation\ Recurrent ear infections\ Regular immersion in cold water
  2. Middle ear
    1. pain, fever, muffled hearing\(URTI)\ Recurrent ear drainage with a strong odour
  3. Inner ear
    1. Recurrent episodes of vertigo with fluctuating hearing loss\ Previous exposure to sustained high levels of noise\ Bilateral, gradual-onset hearing loss
3. Audiometer tests
  1. Pure tone audiometry
  2. Speech audiometry
  3. Oto-acoustic emissions
4. Radiology
5. Special tests
Management of Otitis Media
3. Mastoidectomy
  1. Types of mastoidectomy
    1. Simple mastoidectomy: removing the infected air cells, and draining middle ear
    2. Radical mastoidectomy: removing mastoid air cells, eardrum, most of middle ear structures, and ear canal. This procedure is reserved for complicated mastoid disease.
    3. Modified radical mastoidectomy: less severe form of radical mastoidectomy involves removing mastoid air cells along with some, but not all, middle ear structures
  2. Indications
    1. Complications of chronic otitis media\ Cholesteatoma\ Abnormal growths at the base of skull.
  3. complications
    1. Facial nerve paralysis\Sensorineural hearing loss \Vertigo (several days)\Titinus
Complications of Otitis Media
1. Extracranial
  1. Hearing loss\ Chronic suppurative otitis media\ Facial nerve paralysis\ Labyrinthitis\ Mastoiditis with subperiosteal abscess\ Petrositis
2. Intracranial
  1. Epidural abscess\Meningitis\ Sigmoid sinus thrombosis\ Otitic hydrocephalus

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Otitis Media

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