Ear

Ear

Normal
1. Structure
  3. Vestibular system
2. Physiology
  1. Hearing
    1. Conduction of Sound
      1. External Ear
        Localization and amplification of sounds
        Transmission to tympanic membrane
      2. Middle Ear
        Vibration of tympanic membrane
        Impedance matching
      3. Inner Ear
        3 Parts separated by membranes
        Organ of Corti
        Excitation of Hair Receptors
        Balance
  2. Auditory Pathway
Abnormal
1. Ear Infections
  1. Otitis Externa
    1. Acute localized otitis externa
      1. Infection of the hair follicle “ Furuncle” / Staphylococcus aureus / Cartilaginous meatus
      2. S&S: Sever pain, discharge, hearing loss, and aural fullness. 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 ear / Pseudomonas aeruginosa, staphylococcus aureus, proteus mirabilis
      2. S&S: Pain, itching, aural fullness, and hearing loss. On examination: tenderness, EAC narrow and congested, with edematous skin, and there will be clear or purulent exudates
    3. Malignant otitis externa
      1. Invasive infection / Pseudomonas aeruginosa / Extend into deeper tissues (bone, soft tissue, and vascular system) / Immune compromised people, malnourished, diabetes mellitus, leukemia
      2. 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. 10% presents with S&S of otitis externa / 90% aspergillus species, the rest candida species
      2. S&S: Malodorous discharge, inflammation, pruritus, scaling, and severe discomfort
  2. Otitis Media
    1. Acute
      1. Children after sore throat, cold, or upper respiratory / Bacteria: Streptococcus pneumoniae (40%), haemophilus influenzae (25%), moraxella catarrhalis (15%) / Viruses (20%): Respiratory syncytial virus, rhinoviruses, influenza viruses, and adenoviruses
      2. 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
      1. Otitis media with effusion
        S&S: Hearing loss, conductive hearing loss, tinnitus, and bulging or retraction of tympanic membrane. Self-limiting 80%, if it persists (tympanostomy tube insertion)
        Self-limiting 80%, if it persists (tympanostomy tube insertion)
      2. Chronic suppurative otitis media
        S&S: Hearing loss, delayed intellectual development, limited employability, and disturbed social life, fatal if untreated
    3. Complications
      1. Extracranial
        Hearing loss
        Types
        Conductive Hearing Loss
        Sensorineural Hearing Loss
        Mixed Hearing Loss
        Facial nerve paralysis
        Labyrinthitis
        Mastoiditis with subperiosteal abscess
        Mastoidectomy
        Types
        Simple mastoidectomy: removing the infected air cells, and draining middle ear
        Radical mastoidectomy: removing mastoid air cells, eardrum, most of middle ear structures, and ear canal. This procedure is reserved for complicated mastoid disease
        Modified radical mastoidectomy: less severe form of radical mastoidectomy involves removing mastoid air cells along with some, but not all, middle ear structures
        Petrositis
        Cholesteatoma
        Types
        Primary acquired
        It happens because of tympanic membrane retraction which forms a cyst or pouch
        Secondary Acquired
        Happens secondary to the pathologic changes that happens to the tympanic membrane: recurrent infections, perforation of tympanic membrane or trauma to tympanic membrane
        Congenital
        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
        An otic, or aural, polyp is a benign proliferation of chronic inflammatory cells and granulation tissue that is usually lined with benign reactive epithelium
        Solitary, Polypoid, Reddish mass
    4. Management
      1. First-line
        Amoxicillin
        Amoxicillin-clavulanate
        In case the bacteria produce beta-lactamase
      2. Second-line or nonsevere penicillin allergy
        Cefdinir / cefuroxime / cefpodoxime
        Ceftriaxone (i.m)
2. Vertigo
  1. Peripheral vestibular causes
    1. Acute labrynthitis / Vestibular neuritis / BPPV / Cholestotoma / Menier’s disease / Ostosclerosis / Perilymphatic fistula, SCDS / Impacted wax
  2. Central vestibular causes
    1. Cerebellopontine angle tumor / Cerebrovascular disease / Migraine / Multiple sclerosis
  3. False sense of motion, usually rotational
3. Tinnitus
  1. Objective
    1. Vascular (pulsatile)
      1. A/V malformations / Vascular tumors / Venous hum (cardiac murmurs, anemia, BIH, thyrotoxicosis, pregnancy, dehiscent jugular bulb) / Atherosclerosis / Ectopic carotid artery / Persistent stapedial artery / Vascular loops
    2. Neuromuscular
      1. Palatomyclonus / Stapedial muscle spasm
    3. Patulous eustachian tube
      1. Significant weight loss, radiation to the nasopharynx
  2. Subjective
    1. Otologic
      1. Hearing loss (presbycusis, noise exposure, otosclerosis, middle ear effusion) / Meniere’s disease / Acoustic neuroma
    2. Ototoxic drugs or substances
    3. Neurologic
      1. MS / Head trauma
    4. Metabolic
      1. Thyroid disorders / Hyperlipidemia / B12 deficiency
    5. Psychological
      1. Depression / anxiety
    6. Infectious
      1. Syphilis / Meningitis
  3. The perception of sound in the absence of external stimuli
4. Otorrhea
  1. Purulent discharge indicates the presence of infection: Onset of an acute infections (white), persistent (yellow or brown)
  2. Mucoid discharge indicates a perforation of the tympanic membrane
  3. Bloody discharge may follow trauma or occur with granulation tissue associated with chronic infection
  4. Clear, watery fluid, especially when associated with a history of trauma or skull base surgery, is likely to be CSF
  5. Foul-smelling discharge is usually associated with cholesteatoma or a neoplasm
5. Otalgia
  1. Primary
  2. Secondry

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	Created by Moza Almualla about 6 years ago