Recommendation of a Diagnostic Algorithm in Suspected Tumoursof the VIIIth Cranial Nerve

Overview

The authors try to find an optimal diagnostic algorithm in suspected tumours of theVIIIth cranial nerve. Incorrect or late diagnosis can cause not only severe damage to health or evendeath but may have also unpleasant forensic consequences for the attending physician.The authors prefer a quick, direct and if possible economical diagnostic procedure. Subjectivesuprathreshold audiometric tests are of limited diagnostic value. Objective audiometric tests. inparticular BERA and examination of stapedial reflex are more significant for the diagnosis ofa retrocochlear lesion. In case of sustantiated suspicion of a tumour of the VIIIth nerve or a tumourin the area of the pontocerebellar angle examination by magnetic resonance (MRI) is indicated.The authors recommend the following diagnostic algorithm:1. ORL examination incl. otomicroscopy2. Pure tone audiogram and in case of symmetrical hearing or a very small interaural differencea verbal audiogram into earphones separately for each ear.3. Tympanometry with examination of stapedial reflexes (ipsi and contra) incl. the reflex decay test.4. Examination of acustically evoked potentials of the brain stem (BERA).5. Vestibular examination (always in case of impaired equilibrium).6. MRI if according to results of BERA or vestibular examination a retrocochlear lesion is suspected.The authors assume that it be useful to define an uneqivocal and mandatory diagnostic procedurein suspected tumours of the VIIIth cranial nerve. This woud help to prevent late diagnosis andpossible unpleasant forensic sequelae.

Key words:
neurinoma of the acustic nerve, tumour of the VIIIth cranial nerve, diagnosticalgorithm.