Intratemporal complications of otitis media

INTRATEMPORAL COMPLICATIONS OF OTITIS

MEDIA

Dr. Mohammed Shafeeq

● Otitis media is an inflammation of part or all of the mucoperiosteal lining of the tympanomastoid compartment comprising of eustachian tube, tympanic cavity, mastoid antrum and all the pneumatized spaces of the temporal bone.

● Complications of otitis media have been defined as spread of infection beyond the confines of lining mucosa of the middle ear cleft

● Both acute and chronic otitis media can cause complications

● In preantibiotic era, 52% of complications were associated with virulent AOM

● Today, majority of complications result from COM

● Complications of otitis media can be classified into two main categories:● Intratemporal (those within the temporal bone)● Intracranial (those within the cranial cavity)

Intratemporal complications

● MASTOIDITIS● PETROSITIS● FACIAL NERVE PALSY● LABYRINTHITIS

Intracranial complications

● EXTRADURAL ABSCESS● SUBDURAL ABSCESS● MENINGITIS● BRAIN ABSCESS● LATERAL SINUS THROMBOPHLEBITIS● OTITIC HYDROCEPHALUS

Pathways of spread of infections

● Direct bone erosion● Acute infections – hyperaemic decalcification● Chronic infections – bone resorption by

cholesteatoma / granulation tissue / osteitis

● Venous thrombophlebitis● Infected clot within small veins – bone and dura –

venous sinuses● Intact bone may be transgressed by

thrombophlebitis within haversian canal system – dural veins – dural venous sinuses – superficial veins of brain

● Preformed pathways● Anatomic pathways

– Oval window / round window– Cochlear & vestibular ducts– Dehiscence of thin bony covering of jugular bulb– Dehiscence of tegmen tympani– Dehiscent suture lines

● Non anatomical defects– Trauma:

● Accidental – through fracture lines● Surgical - stapedectomy, fenestra

– Neoplastic erosions

● Into brain tissue along periarteriolar spaces of Virchow-Robin

Factors influencing development of complications

● Age● Poor socioeconomic group● Virulence of organisms● Immunocompromised hosts

Acute Mastoiditis

● It is the extension of middle ear inflammation of AOM into antrum and mastoid air cells

● This spread is because mastoid antrum and epitympanum communicate freely through aditus and antrum

● Common in children

● Pathogenesis:● Following otitis media – tympanomastoiditis● Blockade of aditus – loculation of mucopurulent

material within antrum and air cells● Persistent blockade of aditus – retrograde

thrombophlebitis – oedema and cellulitis of tissues overlying mastoid

● If pus not drained – necrosis and demineralization of bony trabeculae – 'Coalescent mastoiditis'

● Further disease depends on direction of erosive process● Mastoid cortex is eroded – Subperiosteal abscess● Medial progression – petrous pyramid● Anterior – fallopian canal / labyrinth● Mastoid tip – Bezold's abscess● Towards tegmen / trautmann's triangle – epidural

abscess● Invasion of perilymph / CSF - meningitis

● Clinical features

Symptoms● Pain behind the ear● Fever● Ear discharge

Signs● Mastoid tenderness● Ear discharge – 'light house sign'● Sagging of posterosuperior meatal wall● Perforation of pars tensa● Swelling over mastoid● Hearing loss

● Masked Mastoiditis - ● Complication of COM with granulation tissue

formation and bone erosion which can occur without ottorhoea

● Usually occurs in patients who have received numerous courses of antibiotics

● Epitympanum and aditus is blocked so that middle ear responds to antibiotics but mastoid does not

● Symptoms & Signs– Often occurs in children– Mild pain behind the ear– Persistent hearing loss– TM – appears thick, loss of translucency– Slight tenderness over mastoid– PTA – conductive hearing loss– X-ray mastoids – clouding of air cells

● Differential diagnosis● Furunculosis of meatus● Suppuration of mastoid lymph node● Infected sebaceous cyst

● Managment

Investigations● CBC / ESR● X-ray mastoids● Ear swab for C&S

Treatment● Antibiotics● Myringotomy● Cortical mastoidectomy

● Complications● Subperiosteal abscess● Labyrinthitis● Facial paralysis● Petrositis● Extradural abscess● Subdural abscess● Meningitis● Brain abscess● Lateral sinus thrombophlebitis● Otitic hydrocephalus

● Abscesses in relation to mastoiditis● Postauricular abscess

– Commonest abscess – forms over mastoid– Pinna displaced – outward & forward– Infection may spread from mastoid to subperiosteal

space– Treatment includes incision and drainage along with

mastoidectomy

● Bezold's abscess - – Occur following acute coalescent mastoiditis– Pus breaks through thin medial side of tip of mastoid– Swelling in upper neck– Abcess may

● Deep to SCM pushing the muscle outwards● Along posterior belly of digastric – swelling between tip of

mastoid and angle of jaw● Upper part of psterior triangle● Parapharyngeal space● Along the carotid vessels

● Clinical features – insidous onset, h/o of ottorhoea, sweeling in neck associated with pain, torticollis

● CT temporal bone & neck● Treatment

– Drainage of abscess– Cortical mastoidectomy

● Luc's abscess - – Meatal abscess– Pus breaks through bony wall between antrum and bony

external auditory meatus– It may burst into meatus

● Citelli's abscess - – Abscess formed behind the mastoid towards the occipital

bone

Petrositis

● It is the inflammation of pneumatized spaces of petrous portion of temporal bone

● Is pneumatised only in 30% of individuals● Air cells of petrous pyramid are classified into

two groups

● Anterior group – extends from mesotympanum, hypotympanum and protympanum and passes around cochlea to petrous apex

● Posterior group – continous with mastoid antrum and epitympanum that cluster around semicircular canals at base of pyramid and extend medially to petrous apex

● Acute Petrosistis - ● Middle ear inflammation – antrum and mastoid air

cells – medial progression involving petrous pyramid

● If inflammatory products are retained – osteitis of petrous apex – retro orbital pain, ipsilateral lateral rectus palsy

● Gradenigo's syndrome – lateral rectus palsy (Abducens N), deep seated ear / retroorbital pain (Trigeminal N), Ear discharge

● Chronic Petrositis - ● In addition to inflammatory changes – new bone

formation and resorption

● Management

Investigations● CT temporal bone

Treatment● Systemic Antibiotics● Radical Mastoidectomy with skeletinization of

semicircular canals to remove disease from middle ear and petrous apex

● Approaches to Petrous apex

● Eagleton's approach -

– This is the superior approach to the petrous apex involving removal of tegmen to base of zygoma together with removal of part of squamous temporal bone. Dura of MCF is now elevated to expose the petrous apex

● Thornwaldt's operation -

– This approach is along the supralabyrithine tracts. It merges with Eagleton's approach

● Almoor's approach - – It is an inferior approach to petrous apex through a space

bounded by cochlea, carotid artery and tegmen tympani

● Ramadier's operation - – This approach is slightly anterior to that of Almmor's

approach that pursues the peritubal cells to petrous apex between cochlea and carotid artery

● Frenckner's operation - – This approach is through arch of superior semicicular

canal. Blood supply to the labyrinth arises from this arch and some labyrinthine loss in inevitable in this approach.

This has to be combined with an inferior approach

Facial nerve palsy

● It can occur in acute and chronic otitis media● Pathophysiology – routes of spread

● natural dehiscences – fallopian canal● natural pathways – canal for stapedius,

neurovascular bundle, mastoid air cells● direct infection - osteitis

● Symptoms and Signs -

Insidious onset , gradually progressive

Unable to close the eyes

Facial asymmetry

Epiphora

Noise intolerance due to stapedial palsy

Loss of taste sensation

Bell's phenomenon

● In AOM – pus/osteitis around dehiscent facial N – inflammation / swelling around the nerve

● Management● Treat AOM with antibiotics● Myringotomy with/without tympanostomy tube

insertion● Intact canal wall mastoidectomy – coalescent

mastoiditis● Facial N decompression is not indicated as 95% of

casesnrecover completely secondary to AOM

● In COM – cholesteatoma – bony erosion – direect infection of nerve

● Management -● Antibiotics● Steroids● Definitive treatment – Canal wall down

mastoidectomy and decompression of fallopian canal

Labyrinthitis

● Inflammation of inner ear / labyrinth● Pathogenesis -

● AOM:

– Spread through round window– Round window : thinner , increased permeability– Inflammatory products pass into perilymph of scala

tympani by diapedesis from adjacent labyrinthine vessels

– Fibrilliary precipitate accumalates in perilymphatic and endolymphatic spaces – endolymphatic hydrops – destruction of membranous labyrinth

– Preformed fistula into labyrinth from middle ear after stapedectomy offer another route for infective spread

● If inflammatory changes induced in labyrinth by transgression are irreversible – Serous labyrinthitis

● If intralabyrinthine suppuration destroy cochlear and vestibular function in affected ear – Suppurative labyrinthitis

● COM :– Erode bony labyrinth by cholesteatoma or osteitis leading

to inner ear destruction– Fully developed intralabyrinthine inflammation is

preceded by thining of labyrinthine wall and development of fistula of labyrinth

– Labyrinthine damage from slowly eroding cholesteatoma is followed by new bone deposition – destruction of part of labyrinth with partitioning and preservation of rest

– Bony fistula are often closed by new bone deposition after eroding disease has been eliminated

● Suppurative labyrinthitis is a rare complication of OM – prompt use of antibiotics

● Development of labyrinthine fistula has remained common in COM – about 10%

● Rarely infection maay spread from meningitis to labyrinth through internal auditory meatus or through cochlear / vestibular aqueducts

● Most rarely infection may be blood borne

● Symptoms and signs - ● Vertigo ● Loss of balance● Tinnitus● Nausea / vomiting● Hearing loss – SNHL

● Treatment● Complete bed rest – with restriction of head movt● Vertigo/vomiting – parenteral chlorperazine /

cinnarizine● Dehydration – IV fluids● IV antibiotics● Acute infection – Myringotomy● Chronic infection – Mastoid exploration

– Premature surgical trauma – dissemination of infection● After recovery of acute symptoms

– Vestibular head exercises – Cawthrone-Cooksey regimen

● Labyrinthine fistula● Complication of COM● Results from erosion of endochondral bone of bony

labyrinth – movement of perilymph and structures of endolymphatic compartments when pressure in EAC changes

● Most commonly – dome of lateral SCC● Cholesteatoma is found in all cases● Incidence of fistula in cholesteatoma is 7-10%

● Symptoms / Signs -● Short periods of imbalance● Vertigo● Tullio's phenomenon – feeling of imbalance on

sudden exposure to loud noise● Fistula sign – positive● Investigations:

– CT – erosion of lateral SCC, cholesteatoma

● Treatment - ● Canal wall down mastoidectomy

– All cholesteatoma is removed except for small area around fistula site. After careful removal of cholesteatoma debri without disturbing matrix. Matrix is elevated. A small piece of tissue / thin cap of bone placed over site and secured with fibrin glue / packing after the cholesteatoma is removed

– Risk of removing cholesteatoma from fistula is total / partial loss of hearing

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