Acoustic neuroma

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1. Acoustic Neuroma

2. Objectives Acoustic Neuroma: definition, histopathology Etiopathogenesis Classification Clinical Features Management WHAT WILL I LEARN TODAY ?

3. FAQ’s in RGUHS Acoustic Neuroma Clinical features of acoustic neuroma Hitzelberger’s sign

4. Acoustic Neuroma Definition: Tumour of eighth cranial Nerve. Eponyms: Vestibular Schwannoma Neurilemmoma Incidence: 80% of Cerebellopontine angle tumours 10% of all brain tumours

5. Pathology Gross: Benign, Encapsulated, Slow-growing Microscopy: Elongated spindle cells Rod-shaped nuclei in rows or palisades.

6. Origin & Growth Origin: Schwann Cells of Vestibular Nerve, rarely from cochlear nerve Growth: (slow) Causes widening and erosion of the canal and appears in the CP angle Anterosuperior growth: 5 th Inferior: 9 th , 10 th & 11 th Later stages: displacement of brainstem, pressure on cerebellum and raised intracranial tension

7. Origin & Growth

8. Classification

9. Clinical Features Age : 40-60 years Sex: M=F Symptoms: Progressive unilateral SNHL Tinnitus Marked difficulty in understanding speech Imbalance/ Unsteadiness Vertigo Sudden Hearing loss Fullness in the ear

10. Cranial Nerve Involvement 1. 5 th nerve: EARLIEST Reduced cornea sensitivity, paraesthesia of face Involvement indicates : tumour size = 2.5cm & occupies CP angle 2. 9 th & 10 th : dysphagia & hoarseness due to palatal, pharyngeal, laryngeal paralysis 3. Other cranial nerves: affected only when tumour size is very large

11. Cranial Nerve Involvement Facial nerve: Sensory fibres are affected early. Hitzelberger’s sign : Hypoaesthesia of posterior meatal wall Loss of taste ( Electrogustometry ) Schirmer test : Reduced lacrimation Motor fibres: Affected late Delayed blink reflex

12. Brainstem Involvement Ataxia Weakness & Numbness of arms and legs Exaggerated tendon reflexes Raised Intra-cranial tension Headache, nausea, vomiting, diplopia(6 th ) & papillo-edema with blurring of vision.

13. Cerebellar involvement Pressure symptoms on cerebellum are seen in large tumors Revealed by Finger-nose test Knee-heel test Dysdiadochokinesia Ataxic gait Inability to walk along a straight line (tendency to fall on the affected side)

14. Investigations Audiological tests: PTA Speech Audiometry Recruitment phenomena: Absent Short Increment Sensitivity Index: 0-20% Threshold tone decay test : Retrocochlear type of lesion

15. Vestibular Tests Caloric test: Diminished or absent response in 96% of patients May be normal when tumour is small

16. Neurological Tests Complete examination of: Cranial nerves Cerebellar functions Brainstem signs of pyramidal & sensory tracts Fundus

17. Radiological tests 1. Plain X-ray: Positive in 80% of patients Different views: Transorbital Stenver’s Towne’s Submentovertical 2. Vertebral angiography: Helps in differentiating AN from other tumours

18. Radiological Test 3. CT scan: More sensitive than X-ray Can detect even intra-meatal and posterior fossa tumors 4. MRI with Gadolinium contrast: GOLD Standard Can detect even intracanalicular tumours of few mm

19. Stapedial reflex Decay Test

20. Other tests BERA: A delay of >0.2ms in wave V between 2 ears in case of 8 th nerve tumour CSF Examination: Protie level raised, Lumbar puncture should be avoided

21. Investigations Important tests for AN work-up: PTA Speech discrimination score Roll-over curve Stapedial reflex decay BERA MRI with gadolinium contrast

22. Differential Diagnosis Meniere’s Disease Tumours of CPangle : Meningioma Epidermoid Arachnoid Cyst Schwannoma of other cranial nerves Aneurysm Glomus tumour Metastasis

23. Treatment

24. Surgical Treatment of Choice

25. Radiotherapy Conventional Radiotherapy X-knife/ɣ-knife surgery Cyber knife

26. X-knife/ɣ-knife surgery Stereotactic radiotherapy Advantages: Minimal radiological effect Causes reduction in tumour size & growth. Can be used in patients where surgery is not feasible. Procedure : linear accelerator ɣ-knife through cobalt-60

27. Radiotherapy Conventional: Not prefered now due to low tolerance of CNS to radiation Cyber knife: Modified X-knife More accurate & frameless Method: real-time image guidance technology through computer controlled robotics.

28. Thank you