Download Key Topics in Otolaryngology, Second Edition by N. J. Roland, R. D. R. McRae, A. W. McCombe PDF

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Complications • • • • Otitis externa. Ossicular erosion, especially the long process of the incus. High tone sensorineural hearing loss. Vertigo. Typically mild and transient. Intermittent benign paroxysmal positional vertigo has been described. Episodes can also be secondary to acute labyrinthine failure which usually reverses spontaneously but if a permanent paresis occurs it may take several months before compensation is complete. • Tympanosclerosis. • Middle ear adhesions. Intracranial and severe cochleovestibular symptoms are unusual as is a lower motor neurone facial palsy.

Induced hypotension This can reduce blood loss during head and neck operations. It may result in cerebral or myocardial ischaemia and renal or hepatic hypoperfusion. It is contraindicated in patients with coexisting hypertension, ischaemic heart disease, previous cerebrovascular accident, pregnancy, anaemia, hypovolaemia or impaired renal or hepatic function. Techniques of inducing hypotension include: • • • • the prevention of anxiety-related tachycardia by good premedication; the avoidance of hypertension during laryngoscopy and intubation; volatile agent-induced vasodilatation; the use of head-up positioning to encourage venous drainage from the operative site.

Vagal paragangliomas arise from paraganglionic tissue within the perineurium of the vagus, the glomus vagale tumour, which, if it involves the ganglion nodosum just below the jugular foramen, is referred to as a glomus jugulare. The cells are not functionally active. Patients present with a slow-growing painless lump in the neck or a mass pushing the tonsil medially, although with the vagal nerve paragangliomas pulsating, tinnitus, syncope, and glossopharyngeal, vagal, accessory and hypoglossal nerve palsies may arise if the tumour expands at the skull base.