SANS Neurootology Flashcards
Seorang wanita berusia 48 tahun dengan riwayat paresis fasialis progresif, nyeri telinga kanan yang berat, vertigo, hilang keseimbangan, dan hilangnya pendengaran. Riwayat penyakit dahulunya tidak ada yang aneh. Terdapat nistagmus sebelah kanan. Berdasarkan gambaran MRI yang terlampir, apakah diagnosis anda?
A. Zoster oticus
B. Hemangioma nervus fasialis
C. Schwannoma nervus fasialis
D. Bell Palsy
E. Schwannoma vestibuler
A. Zoster oticus
The correct answer is zoster oticus, also known as Ramsay-Hunt syndrome. The sudden onset of ear pain, facial paralysis, hearing loss and vertigo is classic for zoster oticus which is a form of polyneuritis. The MRI demonstrates a linear enhancement in the internal auditory canal with extension into the tympanic segment of the facial nerve.
There is no nodular mass seen on the facial or other nerves in the fundus on the FIESTA sequence. Facial nerve schwannoma would present with slow facial twitching and at times conductive hearing loss which is not reversible. It would not cause sudden vertigo attacks. Facial nerve hemangiomas (actually vascular malformation of the geniculate ganglion) present with longstanding facial twitches and spasms and needs to cause major boney destruction before hearing loss is encountered. This is not seen on the MRI scan. Bell’s palsy is facial nerve mononeuritis. Vestibular schwannomas are typically not associated with sudden hearing loss and facial nerve palsy. The enhancement pattern seen on the MRI is not consistent with a vestibular schwannoma.
Seorang bankir, pria, berusia 50 tahun datang dengan riwayat beberapa bulan lalu terdengar suara uap mendesis dari telinga kiri diikuti suara pendengaran yang teredam (muffled hearing). Pasien memiliki lima episode vertigo yang memiliki onset mendadak dan dua kali menyebabkan pasien hilang keseimbangan dan terjatuh selama 5 sampai 15 menit. Pasien juga mengalami mual dan muntah pada tiap episodenya dan harus beristirahat selama beberapa jam setiap serangan. Hasil MRI menunjukkan hasil yang normal. Audiogram mengidentifikasi adanya “low frequency hearing loss” dengan perbedaan nilai ambang batas dengar. Apakah diagnosis yang paling mungkin :
A. Neuronitis vestibular
B. Neuroma akustik
C. Penyakit Meniere
D. Vertigo postural berat
E. Insufisiensi vertebro-basilar
C. Penyakit Meniere
Labyrinthine disease is the most common cause of true vertigo. Meniere’s disease, which is thought to be caused by a derangement of endolymphatic fluid regulation, is the classic variety of labyrinthine dysfunction. The clinical triad of Meniere’s disease includes intermittent severe episodes of disabling vertigo, tinnitus (often described as resembling the sound of escaping steam), and fluctuating low frequency hearing loss. Attacks may last several minutes and often require several hours for full recovery. Nausea, vomiting, and diaphoresis often accompany the vertigo. A small portion of patients with Meniere’s disease experience sudden, violent falling attacks. Clinical onset is commonly in middle age, and the disorder affects up to 1 per 100,000 population. The fluctuating hearing loss mentioned is common and can progress to deafness in the affected ear (in contrast to benign positional vertigo and vestibular neuronitis in which there is no loss of hearing). Only one in five will develop bilateral symptoms. The disease frequently has periods of remission and may “burn out.” Electronystagmography (ENG) provides an objective assessment of the oculomotor and vestibular systems. This test consists of three parts: oculomotor evaluation, positioning/positional testing, and caloric stimulation of the vestibular system. ENG typically shows a reduced output from the vestibule of the involved side in Meniere’s disease.
Seorang akuntan berusia 55 tahun dengan perburukan pendengaran secara bertahap pada telinga kanannya selama 12 bulan terakhir. Pasien tidak dapat menggunakan telinga kanannya untuk menelpon selama 5 bulan terakhir. Hasil Speech Audiometry menunjukkan skor ambang batas dengar dari 85% di telinga kiri pada 60 dB dan 30% di telinga kanan pada 100 dB. Hasil MRI ditunjukkan pada gambar 1. Hasil yang didapatkan pada brainstem auditory evoked responses telinga kanan pasien adalah :
A. Prolongation of the I-V interpeak latency
B. Loss of wave VI-VII
C. Loss of wave I
D. High frequency loss of the interaural difference in wave V latency
A. Prolongation of the I-V interpeak latency
Brainstem auditory evoked responses (BAERs) are obtained by averaging a series of potentials thought to be generated from the major processing centers of the auditory system in response to a repetitive sound stimulus. The generally agreed on anatomical correlates are as follows: Wave I: cochlear nerve Wave II: cochlear nuclei (pons) (may also reflect auditory nerve activity) Wave III: superior olivary complex (pons) Wave IV: lateral lemniscus (pons) Wave V: inferior colliculus (midbrain) Wave VI: medial geniculate (thalamus) Wave VII: auditory radiations BAERs are highly reproducible in some participants and show little variation among normal persons. Patients with retro-cochlear lesions, such as acoustic neuromas typically have prolonged I-III and I-V interpeak latencies. Patients with cochlear lesions more typically are found to have a progressive disappearance at high intensity stimulation of the interaural difference in the latency of wave V.
Pada kasus Schwannoma vestibular intrakanalikuler, apa yang menjadi keuntungan dalam metode tindakan melalui fossa cranial medial dibandingkan melalui retrosigmoid?
A. Penurunan risiko perlukaan pada nervus petrosal superfisialis besar
B. Identifikasi dini pada nervus fasialis
C. Improved preservation of vestibular nerve function
D. Penurunan risiko kebocoran CSF
B. Identifikasi dini pada nervus fasialis
Small intracanalicular vestibular schwannomas in patients with preserved hearing can be approached via the suboccipital or middle fossa approach; the latter allows for early identification of CN VII because of the nerves supero-anterior location in the distal internal auditory canal. Importantly, however, early identification does not necessarily make preservation of the nerve easier, especially if the tumor arises from the inferior vestibular nerve. The greater superficial petrosal nerve (GSPN) may be stretched during elevation of the temporal lobe during the middle fossa approach and thus damaged. Preservation of vestibular nerve is not a distinguishing feature of the middle fossa over the retrosigmoid approach. The CSF leak rate is similar between the two.
