Page 8 - Portuguese Journal - SPORL - Vol 61. Nº1
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corticosteroids, anticoagulants, diuretics, and
onset and HOT treatment has a significant effect
on hearing outcomes. antivirals. Currently, systemic or intratympanic
Keywords: Sudden deafness; tinnitus; hyperbaric corticosteroid therapy appears to be the most
oxygen therapy; sensorineural hearing loss recommended treatment 2,3,9 , as it reduces
inflammation and edema in the inner ear.
Introduction Hyperbaric oxygen therapy (HOT) is a
Sudden sensorineural hearing loss (SSNHL) is coadjuvant treatment that entails the
defined as a loss of hearing of at least 30 dB administration of 100% oxygen at a pressure
in three consecutive audiometric frequencies greater than 1 ATM. Despite its widespread use,
occurring within at least 72 hours . Its the results are controversial 14–16 , partly because
1,2
incidence is estimated between five and of the high variability of the clinical criteria
30 cases/100,000/year . Although it affects and protocols that are used. HOT increases
3
individuals of all ages, the peak incidence is the partial pressure and concentration of
between the fifth and sixth decades of life, oxygen in the inner ear, thereby improving
and it occurs with equal frequency in men and microvascularization and reducing the
9,17
women 2,4,5 . Between 2% and 5% of patients associated edema . HOT appears to improve
exhibit bilateral involvement, which is typically hypoacusis after ISSNHL, but there is very
sequential . The accompanying symptoms little evidence about its benefit regarding the
2
include tinnitus (80-90%), vertigo (29-56%) 2,4,6,7 , associated tinnitus . The reduced quality of
16
and ear fullness. When the symptoms are life of patients with SSNHL appears to be more
severe, they may be associated with anxiety, related to the intensity of tinnitus than to the
18
depression, and sleep disturbances 9,10 . hearing loss itself . Therefore, it is important
The etiology of SSNHL is only identified to determine the effect of HOT on SSNHL-
in 10% of patients , with the remaining associated tinnitus, in addition to its impact
11
cases being denominated as “idiopathic” on auditory acuity per se.
(ISSNHL) 2,4,12 . The differential diagnosis The objective of this study was to assess the
includes infectious, traumatic, vascular, effect of HOT on the progression of tinnitus and
neoplastic, autoimmune, metabolic, and auditory thresholds in patients with SSNHL-
neurological causes . In most cases in which associated tinnitus, in whom treatment with
2,3
it is possible to determine the etiology, systemic or transtympanic corticosteroid
hypoacusis results from irreversible damage therapy did not lead to a significant symptom
to the cilia . In response to an incongruent improvement.
2
auditory message, the cortical auditory
centers adapt and remodel the transmitted Methods
signal, and this neuroplasticity can lead to This was a prospective non-controlled study
the perception of unreal sounds (tinnitus) . conducted between May and December 2018
13
Most patients with ISSNHL spontaneously at the Center for Underwater and Hyperbaric
recover some degree of their hearing (32%- Medicine of the Portuguese Navy in patients
65%) in the first two weeks . When the diagnosed with sudden hearing loss
4
condition lasts longer than two to three refractory to treatment with systemic and/
months, the hearing loss will probably become or transtympanic corticosteroid therapy, who
permanent . Some prognostic factors were referred to the Center. All patients were
2,4
include age, degree of hypoacusis, affected over 18 years old at the time of the study and
frequencies, presence of vertigo, and time signed an informed consent form.
window between the onset of symptoms and The criterion for treatment (and, therefore,
the start of treatment . Several treatments inclusion in the study) has been defined as the
2,3
have been proposed and used for this disease, presence of hypoacusis of 30 dB or more in at
including vasodilators, plasma expanders, least three contiguous frequencies occurring
8 Portuguese Journal of Otorhinolaryngology - Head and Neck Surgery
