Relevant Ear Anatomy

Relevant Ear Anatomy

 

 

OTITIS EXTERNA and OTITIS MEDIA

BY DR BULUS N G
MAY HOSPITAL SHENDAM
28/03/2024

 

OUTLINE

  • INTRODUCTION
  • RELEVANT ANATOMY
  • PRIMARY FUNCTION OF THE EXTERNAL EAR
  • OTITIS EXTERNA
  • OTITIS MEDIA
  • PREVENTION
  • CONCLUSION

 

INTRODUCTION

  • The ear is the organ of the body used for hearing and balancing.
  • Divided into three; the outer or external ear, middle ear and inner ear.
  • The outer and middle ear are responsible for conduction of sound impulses to the inner ear
  • The outer and middle ear are prone to exposure to various injurious agents.
  • This can result to inflammation of the outer or inner ear
  • Otitis Externa is simply the inflammation of the outer opening of the ear and the ear canal.
  • Also referred to as the swimmers ear.
  • Otitis Media Is the inflammation of the mucous membranes of the middle ear cavity (Eustachian tube, mastoid antrum, mastoid air cells and tympanic cavity).
  • Some causative organisms includes;1.Acute Bacterial Infection

    2.Fungal Infection

    3.Acute Viral

    4.Associated with Allergy

Primary functions of Ext Ear

 

OTITIS EXTERNA  

CLINICAL FEATURES OF OTITIS EXTERNA

  • Pain
  1.      Aggravated at night
  2.      Worsened by contact with pinna
  • Swelling
  • Otorrhoea (non-mucoid)
  1.         Purulent
  2.         Watery
  3.        Desquamated tissues
  • Itching
  1.        Otomycosis
  2.        Allergy
  • Tinnitus
  • Hearing loss- otorrhoea, stenosis & canal plug
  • Trismus –when anterior canal wall /TMJ are involved
  • Tragal tenderness

 

BACTERIAL OTITIS EXTERNA

  • Common aetiology- Pseudomonas, Staph spp, Strep spp, gram negative rods spp
  • Localised e.g. Furunculosis
  1.            Hair root infections.
  2.            usually from staph. aureus
  • Generalised e.g. Erisipelas
  1.            Acute streptococcal lymphangitis and dermatitis with propensity for  rapid spread .
  2.            commonly  triggered by scratching.
  • +/- purulent discharge

Illustrations

 

FUNGAL OTITIS EXTERNA (OTOMYCOSIS)

  • Fungal infections of the ear(external)
  • Common agents
  1.             Aspergillius– nigra
  2.             Aspergillius fumigatus 
  3.               Aspergillius flavus
  4.            Candida albicans
  5.             Yeast spp

 

CLINICAL FEATURES OF OTOMYCOSIS

  • Invades the deeper layers of the skin unlike the bacterial OE.
  • Aggravated by moisture and humidity
  • Very itchy
  • Black, brown or dirty-white discharge
  • Cotton-like growth
  • Spores formation
  • Resistant and requires prolonged therapy
  • Tinnitus
  • Hearing loss
  • Exuberant and florid features in the immuno-compromised.

 

VIRAL OTITIS EXTERNA

  • This is not as prevalent as bacterial or fungal.
  • Herpes simplex (H. simplex virus 1)
  1.            characterised by inflammed mucosa
  2.             Assoc with clear fluid discharge.
  • Herpes zoster(Varicella varice)
  1. Assoc with vesicular eruption within EAC
  2. Paralysis of VII & other CNs may result (Ramsay –Hunt syndrome).
  • Bullous myringitis causative org,
  1. May be associated with influenza
  2. Haemorrhagic vesicles on external  surface of TM

Illustrations

 

ATOPIC (ECZEMATOUS) & SEBORRHOEIC OTITIS EXTERNA

  • OE associated with atopy or allergic conditions.
  • Basically an allergic dermatitis/irritation of the skin of the EAC.
  • May be similar to the seborrheic scalp infections .

 

Features of Atopic Otitis Externa

  • Irritation
  • Scaling
  • Swelling
  • Weeping of the EAC skin
  • Secondary infections

Illustrations

 

Investigations

I. Clinical findings key

II. Microscopy culture and sensitivity

III. Imaging

  1. X-ray mastoid
  2. CT scan

IV. Pure Tone Audiogram

Treatment

  • TOPICAL
  1. Aural toileting
  2. Keep ears dry
  3. Topical antibiotics
  4. Topical anti-inflammatory +/- steroid
  • SYSTEMIC
  1. Antibiotics
  2. Analgesic
  3. Antipruritic agents

Differentials

  • Otitis externa maligna
  • Myringitis
  • Wax
  • Foreign bodies
  • Keratosis Obturans
  • Exostosis
  • Otitis media
  • Neoplasm

 

 

OTITIS MEDIA

Definition

  • Otitis media is simply inflammation or infection of the middle ear.
  • The mucosa of the middle ear cleft is the point of infection.
  • It is a global ear disease with health-economic burden.
  • Most prevalent(up to 11%) in Africa and developing world.

CLINICAL FEATURES OF OTITIS MEDIA

  • Presents with varied clinical features depending on the duration, severity and progression of disease.
  • Due to the complex contiguous relationship between middle ear and essential intracranial structures , complications could be bizarre.
  • Intra cranial and extra cranial sequelae results from untreated or poorly treated OM
  • The acute phase can get resolved
  • May progress to chronicity with attendant complications
  • Good Knowledge of Anatomy of middle ear is necessary for attendant physicians.

Predisposing Factors

  • HOST-RELATED

1.Age-highest incidence 6-11 months

2.Sex –nil preponderance

3.Race –inconclusive

4.Prematurity – lowbirthweight(+ve)

5.Allergy- (+ve)controversy in pathogenesis

6.Immunocompetency

7.Cleftplate/craniofacial abromalities(+ve)

8.Genetic predispo-(+ve)

    • ENVIRONMENTAL FACTORS

    1.URTI/Seasonal

    2.Day care/Home care/sibs

    3.Tobacco smoke exposure

    4.Breastfeeding vs bottle feeding

    5.Socioeconomic status

    6.Pacifier use

    7.Obesity

Classifications of Otitis Media

  • DURATION OF INFECTION

1.ACUTE  OM (6 WEEKS)

2.CHRONIC OM (BEYOND 6WEEKS)

3.(NB: VARIATIONS 2WKS , 4WKS)

  • NATURE OF FLUID OR DISCHARGE

1.SUPPURATIVE OM

2.NON-SUPPURATIVE OM

3.OME

4.AERO-OM

    • CAUSATIVE ORGANISM

    1.Bacterial OM eg S. Pneumoniae, H. Influenza, Moraxella catarrhalis

    2.Specific  e.g. TB, SYPHILIS

    • MUCCOSAL CONDITION(BROWNINGS CLASSF)

    1.ACTIVE

    2.INACTIVE

    3.HEALED

ACUTE OTITS MEDIA (AOM)

  • Predominantly a childhood infection
  • No sex preponderance
  • About 75% of cases are young adults < 44 yrs.
  • Aetiology:

1.H. Influenza & S. Pneumonia globally predominates  though Staph. aureus and S. pyogenes                      predominate in African.

Clinical features of AOM

  • SYSTEMIC(GENERALIZED)

I.High grade fever (40-41 oC)

II.Refusal of feeds

III.Incessant cries & irritability

  • LOCAL(EAR)

I.Otalgia

II.Otorrhoea

III.Tinnius

IV.Conductive hearing loss

V. Hyperemic tympanic membrane

VI. Bulging TM or purulent discharge

Sequalae of AOM

  • FULL RESOLUTION
  • COMPLICATIONS
  1. EXTRACRANIAL

I. Acute mastoiditis

II. Subperiosteal abscess

III. Facial nerve paralysis

IV. Labyrinthitis

    • INTRACRANIAL

    I.Extradural abscesses

    II.Subdural abscesses

    III.Meningitis

    IV. Otitic brain abscess

    V. Otitic hydrocephaluus

    VI. Lateral sinus thrombosis

Otitis media with effusion (OME)

  • Predominantly a childhood illness like AOM
  • About 85% of cases in children
  • Commoner among Caucasians, especially Canadians, Australians and American aborigines.
  • Predispositions include adenoid enlargement, Eustachian tube dysfunctions, Anatomic congenital defects especially clefts.
  • NPC and rhinosinusitis in adults.

Clinical features of OME

  • Conductive Hearing loss(CHL)
  • Mild to moderate CHL (<40dB)
  • Prevalent in age <5years
  • Otalgia
  • Sometimes incidentally found in routine hearing screening.
  • Speech difficulties
  • Shows type B tympanometry
  • Bulgy and immobile tympanic membrane
  • Loss of light reflexes on tympanic membrane
  • Pneumatic otoscope useful for diagnosis
  • Tympanometry is gold standard for diagnosis
  • TM may show air bubbles
  • Effusion usually serous
  • Can organize into glue ear

Sequalae of OME

  • Mainly resolves spontaneously
  • Failure to resolve in 6wks can give rise to glue ear
  • Ossicular bone erosion

Chronic Otitis Media (COM)

  • Permanent abnormality on the tympanic membrane following a long standing middle ear infection emanating from previous AOM, OME or negative pressure of middle ear.
  • Duration suggested from 2weeks -3months.
  • Prevalence (6-11.1%) high in developing countries
  • Preponderant in adults

CSOM

  • Chronic suppurative & chronic non-suppurative OM.
  • Tubotympanic & Attico antral (so called Safe and unsafe OM) considering chances of cholesteatoma formation.
  • Most recent classification

A. Mucossal or squamous

  1.  Active,
  2. Inactive or
  3. healed.
    • AETIOLOGY
    • Common aerobes are:

    I.Pseudomonas aeuroginosa

    II.Proteus spp

    III.Esschericha coli

    IV.Staph aureus

    • Common Anaerobes

    A.Peptostreptococcus,

    1. Prevotel

    2.B. fragilis

Clinical features of OME

  • Mixed hearing loss
  • Sensorineural hearing loss
  • Otorrhoea (usually Scanty foul smelling)
  • Neo membrane formation
  • Aural polyp

Complications of CSOM

Extratemporal

1.Lucs abscess—temporalis region

2.Citelli——-subperiosteal abscess

3.Bezolds abscess———-Sternocleidomastoid.

Illustrations

 

Investigations

  • M/C/S
  • Imaging
  • X-ray mastoid
  • Cranial & Brain CT Scan
  • Audiogram-Pure Tone Audiogram Tympanometry
  • FBC

 

Treatment

1.Medical

2.Surgical

 

Prevention

  • Mainly Environmental Factor Mgt
  • Vaccines-

i.Bacterial S. Pneumoniae(Prevenar CV5, PCV7 & PCV-13).

ii.Maternal immunization-H. influenza, M cattarhalis Vaccines.

iii.VIRAL

iv.Inflenza

v.Resp. Cynct Virus vaccine

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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