TEST YOUR KNOWLEDGE: ENT quiz

Increasing loss

Paul Fagan, MBBS, FRACS, FRCS, is Consultant Otologist, St Vincent’s Hospital, Sydney, New South Wales.

A 40 year old man has been aware of an increasing in the right ear. He is no longer able to use the phone on that side. There is a low grade, persistent, high pitched and he has recently noticed a tendency to bump into doors or walls when walking. There is no past history of ear disease. There is very little to note clinically. The tympanic membranes are normal and air conduction right is clearly less than air conduction left but the (Figure 1a, 1b) is positive for both sides, ie. air conduction is better than . The (Figure 2) is heard centrally. When the patient stands with his feet in line and the eyes closed (tandem Romberg’s test) (Figure 3) he tends to fall over.

Question 1 Question 3 Question 5 Is the hearing loss sensori-neural or Are this patient’s problems with the Do all patients with this condition conductive? phone significant? require treatment?

Question 2 Question 4 Question 6 What is the most likely diagnosis? What is the significance of the tandem Does unilateral tinnitus have the same Romberg’s test? significance as a unilateral sensori-neural hearing loss?

Figure 1a). The fork is held next to the ear Figure 2. The Weber test to test air conduction

Figure 3a). Figure 3b). The Romberg The tandem test Romberg test

Figure 1b). The fork is applied to the mastoid Figure 4. Aluminium tuning fork. Is best to test bone conduction struck lightly as shown. Aluminium will hold a tune for much longer than the Figures 1-4 reprinted with permission: equivalent steel fork Modern Medicine August 1992. Reprinted from Australian Family Physician Vol. 31, No. 8, August 2002 • 1 n ENT quiz

Answers

to be excluded, preferably by magnetic (acoustic neuroma or schwannoma, resonance imaging (MRI) (Figure 5). meningioma, epidermoid cyst) many can In approximately 80% of patients with be followed, having serial imaging at yearly asymmetrical hearing loss no cause is intervals. This is especially so in the elderly found. Meniere’s disease is one of the or infirm. In younger patients, especially recognisable causes, as is an acoustic when contact with the brainstem is tumour. Head trauma will occasionally beginning, surgical treatment is required.1,2 produce the same effect as will oto-toxic Answer 6 drugs applied locally. Unilateral tinnitus, which is steady and This patient is unlikely to have Meniere’s persistent, should be assessed in the disease as he does not have the same way as a unilateral hearing fluctuating hearing loss that characterises loss. this condition. Also in Meniere’s disease Tinnitus which is pulsatile (ie. the is of the rotatory type, synchronous) has different implications. If associated with nausea, vomiting and a stethoscope on the scalp reveals a bruit, Figure 5. There is a large tumour in the left often prostration. an arterio-venous malformation has to be cerebello-pontine angle with a small Magnetic resonance imaging is the gold excluded. A mass in the in extension into the internal auditory canal. standard investigation in cases such as There is significant brain stem compression these circumstances would suggest a these. CT scan can also be used, however, glomus tumour. smaller tumours - those that project less Answer 1 than 1 cm into the cerebello-pontine angle References The patient’s hearing loss is sensori- - may be missed. Caloric tests, ENG or 1. Al-Abdulwahed S, Fagan P A. Acoustic neural. The Weber test gives the best other audiological tests no longer have neuroma: the use of radiotherapy and a much of a role in the diagnosis of guide to the nature of an asymmetrical comparison with the results of surgery. hearing loss. It is best carried out with a cerebello-pontine angle tumours as MRI is Aust J Otolaryng 1999; 3:211-218. tuning fork at 512 cycles per second. so accurate. 2. Glasscock M E, Pappas D G, Manolidis S, Lower frequencies transmit vibration Vondoersten P G, Jackson C G, Storper I S. Answer 3 rather than sound. If the vibrating tuning Management of acoustic neuroma in the fork is placed on the forehead or the top of Problems with using the phone are elderly population. Am J Otol 1997; the , it will be heard in the ear with significant as tumours of this type result in 18:236-242. the conductive loss, even when this is very a loss of ability to understand amplified minor. This can be simulated in the speech, referred to as the speech observer by repeating the manoeuvre on discrimination score (SDS). An inability to oneself, firmly occluding the external ear understand speech on the phone, out of with a finger. proportion to the degree of hearing loss, is a pointer toward an underlying tumour. If the hearing loss is sensori-neural, the central tuning fork will be heard in the Answer 4 ‘good’ ear or in the middle of the head. Romberg’s and its more severe variant When the middle ear is woking as it tandem Romberg’s, is a nonspecific test should, air conduction will be heard better which, by narrowing the proprioceptive than bone conduction, so hearing loss in base (feet together or in line) and closing the test ear in these circumstances is the eyes, throws the greater part of the probably in the inner ear (sensori-neural). responsibility for keeping upright on the However, because the middle ear labyrinths. It does not tell us which mechanism amplifies sound to a labyrinth is at fault so the direction in significant degree, a conductive loss has which the patient falls has no significance. to be marked before bone conduction The test is invalid if there are problems becomes greater than air conduction. with proprioception, eg. knee or hip disease or if cerebellar function is not Answer 2 normal. In this patient, there is strong suspicion of an asymmetrical inner ear hearing loss. If Answer 5 this is confirmed by an audiogram, a As tumours in the cerebello-pontine angle tumour of the cerebello-pontine angle has are nearly all benign histologically

2 • Reprinted from Australian Family Physician Vol. 31, No. 8, August 2002