ROLE OF C.T.SCAN IN DIAGNOSIS &

MANAGEMENT OF OTOGENIC INTRA CRANIAL

ABSCESS

MODERATOR:Dr.C.P.DAS PRESENTER:RAVINDRA.D

COMPLICATIONS OF C.S.O.M.

DEFINiTION

Spreading of infection beyond muco-periosteal lining of middle ear cleft to involve bone & neighboring structures like facial nerve, inner ear, dural venous sinuses, meninges, brain tissue & extra-temporal soft tissue .

FEATURES Severe otalgia, painful swelling around

ear,

Vertigo, nausea, vomiting,

Headache + blurred vision + projectile

vomiting,

Fever + neck rigidity + irritability /

drowsiness,

Facial asymmetry ,

Otorrhoea + Retro-orbital pain +

diplopia,

Ataxia.

ROUTES OF ENTRY

Congenital bony defects: facial canal, tegmen plate.

Anatomical pathway: oval window, round window,

internal auditory canal, suture line, cochlear &

vestibular aqueduct

Bony erosion (cholesteatoma destruction, osteitis).

Retrograde Thrombophlebitis.

Acquired bony defects: fracture, neoplasm,

stapedectomy

Peri-arteriolar space of Virchow-Robin: spread into brain.

CLASSIFICATION

Intra-cranial complications

Extra-cranial complications

Intra-temporal

Extra-temporal

Systemic: septicemia, otogenic tetanus

INTRA CRANIAL COMPLICATIONS

1. Extra-dural abscess

2. Subdural abscess

3. Meningitis

4. Brain abscess

5. Lateral Sinus thrombophlebitis

6. Otitic hydrocephalus

EXTRA CRANIAL COMPLICATIONS

INTRA TEMPORAL

1. Acute mastoiditis

2. Coalescent

mastoiditis

3. Masked mastoiditis

4. Facial nerve palsy

5. Labyrinthitis

6. Labyrinthine fistula

7. Petrositis.

EXTRA TEMPORAL

1. Post-auricular abscess

2. Bezold abscess

3. Behind the

mastoid(Citelli’s)abscess

4. Meatal(Luc’s)abscess

5. Zygomatic abscess

FACTORS AFFECTING

PATHOGEN FACTORS PATIENT FACTORS

High virulence bacteria Young age

Antimicrobial resistance Poor immune status

Chronic disease (DM, TB)

PHYSICIAN FACTORS Poor socio-economiC

status

Non-availability Lack of health awareness

Injudicious antibiotic use

Error in recognizing dangerous symptoms & signs

OTOGENIC BRAIN ABSCESS

50-75 % adult brain abscess & 25% in child is otogenic.

Temporal abscess is twice as common as cerebellar

abscess

ROUTES OF INFECTION:

1. Direct spread:

via Tegmen plate: Temporal abscess

via Trautmann’s triangle: Cerebellar abscess

2. Retrograde spread: via thrombophlebitis

sometimes the infection could extend via the Virchow -Robin spaces in to the cerebral white matter.

Virchow–Robin spaces (VRS) are perivascular, fluid-filled canals that surround perforating arteries and veins in the parenchyma of the brain.

Cerebellar abscess is usually preceded by thrombosis of lateral sinus.

Abscess in the cerebellum may involve the lateral lobe of the cerebellum, and it may be adherent to the lateral sinus or to a patch of dura underneath the Trautmann's triangle.

TRAUTMANN’S TRIANGLESuperiorly: superior

petrosal sinus

Posteriorly: sigmoid sinus

Anteriorly: solid angle

(semi-circular canals)

It is Pathway to posterior

cranial fossa from mastoid

cavity

STAGES OF BRAIN ABSCESS

1. INVASION OR ENCEPHALITIS (1-10 days)

2. LOCALIZATION OR LATENT ABSCESS (10-14

days)

3. EXPANSION OR MANIFEST ABSCESS (> 14

days): leads to raised intracranial tension & focal

signs

4. TERMINATION OR ABSCESS RUPTURE: leads

to fatal meningitis

BACTERIOLOGY

Anaerobic streptococci

Streptococcus pneumoniae

Staphylococci

Proteus

E. coli

Pseudomonas

Bacteroidis fragilis

FOCAL CLINICAL FEATURES

TEMPORAL LOBE CEREBELLUM

Nominal aphasia I/L nystagmus

Quadrantic homonymous I/L weakness

hemianopia (C/L) I/L hypotonia

Epileptic seizures I/L ataxia

Pupillary dilatation Intention tremor

Hallucination (smell & taste) Past-pointing

C/L hemiplegia

Dysdiadochokinesia

CLINICAL FEATURES OF RAISED I.C.T.Seen more in cerebellar abscess

Severe persistent headache, worse in

morning,

Projectile vomiting,

Blurring of vision & Papilloedema,

Lethargy drowsiness confusion coma

Bradycardia,

Subnormal temperature.

INVESTIGATIONSCT SCAN OF BRAIN & TEMPORAL BONE WITH CONTRAST

It shows Ring enhancement with central necrosis, and surrounding edema.

It is used for:

Site, size & staging of abscess

Observe progression of brain abscess

Associated intra-cranial complications

MRI BRAIN

To differentiate pus, abscess ,capsule, edema & normal brain

Spread to ventricles & subarachnoid space

AVOID LUMBAR PUNCTURE TO PREVENT CONING

TEMPORAL ABSCESS CERBELLAR ABSCESS

C.T.FEATURES

TREATMENT

MEDICAL

High dose broad spectrum I.V. antibiotics:

Ceftriaxone + Metronidazole + Gentamicin

I.V. Dexamethasone 4mg Q6H: for decreasing

edema

I.V. 20% Mannitol (0.5 gm/kg):for decreasing I.C.T.

Anti-epileptics like Phenytoin sodium

Antibiotic ear drops and aural toilet.

SURGICAL

Repeated burr hole aspirations,

Excision of brain abscess with capsule (best

T/T)

Open incision & evacuation of pus,

Radical mastoidectomy after pt becomes

stable.

JOURNAL

ROLE OF C.T.SCAN INDIAGNOSIS AND MANAGEMENT OFOTOGENIC INTRACRANIAL ABSCESS

INTRODUCTION In the 5 yr. period preceding the introduction of

antibiotics, approximately 1 in 40 deaths in a large hospital is due to intra cranial complications of C.S.O.M.

The complications develop when middle ear infection spreads from its confined space to adjacent space and structures.

The symtomatology of these complications is slow in development and diagnosis is difficult.

C.T. scan has formed the main stay of diagnosis in recent years.

It offers a highly accurate and rapid means of establishing the diagnosis and following the course of disease.

MATERIALS &METHODS All cases with h/o C.S.O.M. and having

additional symptoms of fever, ear ache, vertigo, head ache, vomitings, altered sensorium were investigated.

Patients with otogenic brain abscess diagnosed with C.T.scan were included in study.

All pts were infused with triple antibiotics(gr.+,gr-ve,anaerobic),

Mannitol , dexamethasone, anti convulsants are used when needed.

Usually trans mastoid route was used to drain the abscess,

Then, cortical mastoidectomy was done.

Status of the dural/sinus plate was observed. Usually it found eroded…if it is intact,then it

was drilled. Burr hole,craniotomy approaches were used

when the abscess Is not approachable through trans mastoid route.

Repeat C.T.scans done after 10 to 14 days of antibiotics to confirm resolution of abscess.

If the size found greater than 1.5c.m.then re aspiration was done.

The canal wall down mastoidectomy was done once the C.T. showed resolution of abscess.

Suitable tympanoplasty, meatoplasty done depending upon middle ear disease.

RESULTS AND OBSERVATIONS

Symptoms and signs of cerebellar abscess were present in 4 out of 18 cases…but 8 out of 18 were diagnosed on C.T.scan.

Symptoms and signs of temporal lobe abscess were present in 5 out of 18 cases…but 7 out of 18 were diagnosed on C.T.scan.

12 pts.had other intra cranial complications which could be detected by C.T.scan.

This emphasizes the need of C.T.scan in diagnosis of multiple complications.

Repeat C.T.scan after clinical improvement and cessation of pus was done in 15 pts.

Resolution was observed in 10 pts.but 5 showed residual abscess and required re drianage procedure.

After final confirmation of resolution, all had underwent canal wall down mastoidectomy as all have extensive attico antral CSOM.

The pts were followed for an average period of 14 months.

No pt reported with recurrence of intra cranial complications.

C.T.SCAN FINDINGS IN Pts.

LEFT TEMPORAL LOBE ABSCESS PRE OP.

14 DAYS AFTER TRANS MASTOID DRIANAGE

26 DAYS AFTER 1ST DRAINAGE

LARGE CEREBELLAR ABSCESS PRE OP.

RESIDUAL ABSCESS ON 18TH DAY OF DRAINAGE

FULLY RESOLVED CEREBELLAR ABSCESS

DISCUSSION The procedure of C.T.is non invasive, easily

available, relatively cheap and can be repeated with out any hazards to the pts.

The uses of C.T. in a case of otogenic brain abscess are:

1. In coma pts,where history,signs,symptoms are unavailable, it helps in accurate diagnosis.

2. In case of bilateral disease, it helps in deciding which ear to operate first.

3. In case of brain abscess associated with other complications, it helps in deciding which complication to be given priority.

4. By knowing exact size and multiplicity of abscess, it avoids unnecessary surgery.

5. By knowing the stage of abscess, surrounding edema, it helps in deciding timing of surgery.

6. By knowing the size and position we can know the best approach for the drainage of abscess.

7. Follow up C.T. scans help in confirming the resolution of abscess.

8. We can detect residual abscess and treat them adequately thus reducing over all mortality and morbidity.

CONCLUSION All the complications of CSOM are

decreasing with increased use of antibiotics.

The treatment plan should be tailored according to pt’s condition.

It is recommended to confirm the brain abscess by follow up C.T. scan in all pts.

This will eliminate residual abscess and helps in reducing the mortality and morbidity.

BIBLIOGRAPHY SCOTT&BROWN 7TH EDITION LUDDMAN INDIAN JOURNAL OF OTOLARYNGOLOGY

AND HEAD&NECK SURGERY(july- sept 2011)