Download CASE REPORT 13-1E

CASE REPORT 13-1E.
History
A 56-year-old drama lecturer was on holiday m Europe, having travelled by rail, when he
noticed a sudden deterioration in hearing in his left ear. There was no tinnitus or
disequilibrium but he did complain of extreme discomfort when exposed to loud sounds.
There was no relevant past otological history. He visited a doctor in France who
confirmed, by pure-tone audiometry, a profound left-sided sensorineural hearing
impairment and prescribed a course of oral steroids.
There had been no improvement in his symptoms by the time of his return to Scotland 2
weeks later. Otoscopic examination at that time was normal. Clinical voice tests of hearing
were normal in the right ear, but he could only hear a conversational voice 6 inches (15cm)
from the left ear. Tuning fork tests suggested the left-sided hearing impairment to be
sensorineural in origin. Further pure-tone audiometry showed normal thresholds in his
right ear, with a 60 dB HL flat sensorineural hearing loss in the left ear. Serial audiometry
performed over the next 2 weeks failed to show any improvement in the hearing
thresholds.
Questions
1. Discuss the evaluation of the above patient.
2. What are the management options for a patient with a sudden onset sensorineural
hearing impairment?
PF: Conductive and sensorineural hearing loss
PA atherosclerosis
Discussion
1 Evaluation of a patient with a sudden onset hearing impairment is aimed at determining
the severity of the impairment and attempting to identify the site of the defect and any
possible etiological agent. A detailed history and examination should detect any obvious
relevant factors such as recent head injury, ototoxic drugs and aural surgery. Routine blood
investigations, including serological tests for syphilis, are commonly ordered. These are
unlikely to be helpful, but it is probably reasonable to measure the ESR and serum
immunoglobulins as investigation for autoimmune ear disease.
Audiometric investigations are essential. A pure-tone audiogram should be the first test
performed; others such as speech audiometry, otoadmittance studies and
electronystagmography with caloric testing may be carried out later but often fail to add
further worthwhile information. It is reported that sudden sensorineural hearing loss will be
the initial presentation in up to 13% of acoustic neuromas and, as in other cases of
asymmetric sensorineural hearing impairments, it is worthwhile performing brain-stem
evoked response audiometry, a reasonably sensitive method of screening for such a
tumor. It should be remembered, however, that acoustic neuromas probably account for
less than 1% of cases of sudden deafness. If the evoked response audiometry fails
satisfactorily to exclude a posterior fossa lesion (by analysis of the interval between
waves I and V and the mteraural latency difference for wave V), then scanning of the
•cerebellopontine angle by CT or MRI should be performed. Despite such investigation,
it is likely that the cause of the hearing impairment will remain unknown in the majority of
cases. It should also be borne in mind that a small percentage of patients will have a nonorganic hearing impairment.
2 Sudden onsets sensorineural hearing loss is an uncommon condition, the etiology is
often obscure and, therefore, treatment directed at the cause cannot often be prescribed.
The management options that are often advocated are by no means proven as
Most centers do not see a sufficient number of cases to permit randomized controlled trials
to be performed, and in assessing the potential benefit of treatment, the situation is further
complicated by the high spontaneous improvement rate.
Unless there is an obvious reason for surgical intervention (i.e. trauma), initial management
will be medical. Daily pure-tone audiograms are an important means of documenting the
patient's progress, as is clinical evaluation of the vestibular system. Systemic steroid therapy,
commenced early, is popular and often recommended if it is considered that the cause is
inflammatory. However, reports suggest that steroids may only be of benefit in patients
with a mild to moderate hearing loss, and that patients with a severe loss are unlikely to
respond.
Should an underlying vascular etiology be considered, anticoagulant/vasodilator therapy is
often commenced. Low molecular weight dextrans, intravenous histamine, oral nicotinic
acid, grosgrain and inhalation of carbon dioxide have all been administered. There is as yet
no substantial evidence that any of these agents will alter the natural history of the
condition.
Autoimmune ear disease has attracted some attention in the literature since first being
described in 1979, The presenting symptoms can be auditory, vestibular or a combination
and, although it can present as a sudden hearing loss, the majority of patients will typically
have bilateral disease progressing over a period of weeks or even months. Management with
a combination of steroids and immunosuppressive (cyclophosphamide) is advocated but
there are no controlled trials to support the use of these drugs.
Surgery (exploratory tympanotomy) should be considered if, despite conservative
measures, the patient's cochlear and/or vestibular function continues to deteriorate, the
purpose of the tympanotomy is to exclude a perilymph fistula, but both the indications for
such a procedure and the time at which it should be performed are matters for debate. It
would appear that surgical closure of the fistula is more likely to resolve vestibular symptoms
than have any significant effect on hearing.
Finally, management of residual hearing impairment should be considered. The patient may
obtain the greatest benefit from provision of an appropriate hearing aid system if there
is significant overall hearing disability. This was not the case in the patient described, as he
had a unilateral loss. Further investigations of this man failed to reveal any underlying
cause and no further management was offered.