|Year : 2016 | Volume
| Issue : 1 | Page : 56-58
Sudden sensorineural hearing loss posthypothyroidism: A case study
Priya Karimuddanahally Premkumar, Varsha Vijayan, Rajith Begur Nataraj, Chandni Jain
Department of Audiology, All India Institute of Speech and Hearing, Mysore, Karnataka, India
|Date of Web Publication||16-Feb-2016|
Department of Audiology, All India Institute of Speech and Hearing, Manasagangothri, Mysore - 570 006, Karnataka
Source of Support: None, Conflict of Interest: None
Sudden sensorineural hearing loss is defined as a loss of at least 30 dB in three contiguous frequencies over a period of three days or less. In the present study a client with sudden hearing loss post hypothyroidism is discussed. A 56 year old client reported of awakening from sleep due to ear fullness along with severe tinnitus and experienced reduced hearing sensitivity in the right ear. The client had a history of hypothyroidism and was under medication for the same. The successive audiological investigations revealed that there was no improvement from prescribed medications, even with early identification and intervention. For better treatment outcomes correct identification of the cause as well as application of cause based treatment procedure is essential. Endocrine disorder is said to be one of the causes for sudden sensorineural hearing loss and one among this disorder is hypothyroidism. The present study aimed to throw a light on this aspect by giving a detailed case report of the client who suffered sudden sensorineural hearing loss which is suspected to be a long term effect of hypothyroidism.
Keywords: Endocrine disorders, Hypothyroidism, Sudden hearing loss
|How to cite this article:|
Premkumar PK, Vijayan V, Nataraj RB, Jain C. Sudden sensorineural hearing loss posthypothyroidism: A case study. Indian J Otol 2016;22:56-8
| Introduction|| |
Sudden sensorineural hearing loss (SSHL), or sudden deafness, is a rapid loss of hearing. SSHL can happen to a person all at once or over a period of up to 3 days. It should be considered as a medical emergency as there are chances for retrieval of the hearing. People who experience SSHL should see a physician immediately as it is believed that finding medical help increases the chances for recovery in the early stages of onset.
The incidence of SSHL is around 5–20 per 100,000 persons per year  with around 4000 new cases being reported in the United States every year as reported by the National Institute of Deafness and Other Communication Disorders. The prevalence of unilateral SSHL (96–99%) is more than bilateral cases (1–4%). SSHL can occur at any age with a greater incidence between ages of 50 and 60 years.
Cases with SSHL show spontaneous recovery without any treatment and may not report to audiologic or otologic clinic. Studies have shown that spontaneous improvement is seen in approximately 45–60% of subjects. Furthermore, spontaneous recovery is worse in older patients and those associated with vestibular symptoms. Singleton, 1971 reported that 25% of clients with SSHL in his study recovered completely, 25% of clients showed some improvement in hearing and whereas for the rest 50% of clients there was no change in hearing.
The exact cause of SSHL is still unknown. Approximately, 1% of cases of SSHL are due to neural pathologies such as vestibular schwannoma, demyelinating disease, or stroke. Another 10–15% are due to some identifiable causes such as Meniere's disease, trauma, autoimmune disease, and syphilis. The endocrine disorders are also said to be the cause for SSHL which can include hypothyroidism and diabetes. Hypothyroidism is a common disorder and can be under-diagnosed in patients with less severe symptoms. The prevalence of hypothyroidism in Indians is approximately 1 in 10 adults. Females and older age individuals are found to have a significant association with hypothyroidism. Typical symptoms of hypothyroidism include a decline in metabolic functions and symptoms ranging from fatigueness to changes in thinking and memory, lethargy, weight gain, cold intolerance, constipation, and goiters enlargement of the thyroid gland. It can be associated with other conditions such as hearing impairment and tinnitus, especially with the elderly population. The present case highlights SSHL caused due to hypothyroidism in an elderly woman.
| Case Report|| |
A 56-year-old female reported to the Department of Audiology, All India Institute of Speech and Hearing with the complaint of sudden reduced hearing sensitivity in the right ear. The client was interviewed for a detailed case history, and it revealed that she had a history of tinnitus from 1½ years, which was continuous and intermittent along with ear fullness. The client had undergone surgery for tonsillitis 15 years ago and was under medication for hypothyroidism from past 20 years. The client reported of awakening from sleep one night, due to ear fullness along with severe tinnitus, and experienced reduced hearing sensitivity in the right ear. Within 24 h of these symptoms, client visited a private clinic (otolaryngologist) and was diagnosed as having a severe mixed hearing loss in the right ear and normal hearing sensitivity in the left ear and was prescribed with medication Neuromet capsule 1OD for tinnitus. Neurobion Forte and Predmet 16 mg were also prescribed for the next 30 days and 5 days, respectively. The doctor also recommended the client for an intratympanic injection of steroids for a faster recovery from hearing loss. Hence, the client underwent intratympanic injection (Dexone) within 48 h of the sudden hearing loss. An intratympanic injection of steroid was given through the ear drum of the client, by way of a small needle.
The client reported to the audiology clinic after 2 days of undertaking the intratympanic injection. The routine audiological diagnostic evaluations which included pure tone audiometry, speech audiometry, and immittance evaluations were performed on the client. An audiometric measurement using a Grason-Stadler 61 (GSI-61) dual channel diagnostic audiometer was carried out. Results showed a severe degree of hearing loss (80 dB) for the right ear and normal hearing sensitivity (18.75 dB) for the left ear with speech identification scores of 92% and 100% for right and left ear, respectively [Figure 1]. Further immittance evaluation was carried out using a GSI Tympstar instrument, and the results indicated “B” type tympanogram for the right ear and “As” type for the left ear, respectively, with absent reflexes in both ears. Hence, a provisional diagnosis of severe mixed hearing loss in the right ear and hearing sensitivity within normal limits for the left ear was made.
|Figure 1: (a) Right ear: Severe mixed hearing loss. (b) Left ear: Normal hearing sensitivity|
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Further auditory brainstem responses audiometry was carried using Biologic Navigation Pro system (version 7.0.0, Natus Hearing Diagnostics) for site of lesion testing. Double channel, click-evoked recording was done with two repetition rates of 90.1 and 11.1/s at 80 dB nHL. Site of lesion testing indicated indication of no retrocochlear pathology in the left ear. However, recording could not be done for the right ear because of the greater degree of loss.
The client later continued with the same drugs prescribed by the otolaryngologist for 3 months. Audiological evaluation was repeated on her second visit, 3 months after the consumption of prescribed drugs. The pure tone evaluation revealed severe degree hearing loss (82.5 dB) for the right ear and normal hearing sensitivity (11.25 dB) for the left ear [Figure 2] with speech identification scores of 92% and 100% for right and left ear, respectively. Immittance evaluation showed A type tympanogram for both ears with right contralateral and left ipsilateral reflexes present, revealing no indication of middle ear pathology in both ears. The results thus show that there was no improvement in the hearing thresholds in the present client with the drugs and the intratympanic injection.
|Figure 2: (a) Right ear: Severe mixed hearing loss. (b) Left ear: Normal hearing sensitivity after drug intake|
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| Discussion|| |
Hypothyroidism is a condition in which the body lacks sufficient thyroid hormone. Since the main purpose of thyroid hormone is to “run the body's metabolism,” it is understandable that people with this condition will have symptoms associated with a slow metabolism. Several studies have shown that there is a clear association between congenital hypothyroidism and hearing loss. The possible cause may be because of immature development of the organ of Corti, including hair cells and tectorial membrane. Furthermore, an important function of thyroid hormone in human body cells is to control the rate of metabolism, altering thermogenesis and oxygen consumption. If cellular metabolism drops too low, the result is widespread dysfunction that can manifest in a variety of ways and hearing loss and tinnitus is one among that. In a study by Schroeder, it was inferred that persons with hypothyroidism are possibly more susceptible to noise-induced hearing loss because hypothyroidism can alter the state of reactive oxygen species in the cochlea. Anand et al., 1989 assessed auditory perception in thyroprivic hypothyroidism patients, and they reported that any type of hearing loss can result due to hypothyroidism, and there is a causal relation between hypothyroidism and hearing loss.
The client in this study had tinnitus for 1½ year and was under medication for hypothyroidism from past 20 years and at the first visit the audiological reports revealed mixed hearing loss. Literature has also supported that hearing loss can be a long-term effect of hypothyroidism, and the loss can be sudden too. Hence, it is important to get detailed case history information and to become more sensitized for medical conditions such as hypothyroidism, which can be the cause of SSHL. However, it is not possible to conclude that hypothyroidism is the definite cause for the SSHL in this study because of lack of significance due to the single case study and as there was no baseline audiological report. Since this study is preliminary study, it is recommended for additional research in this area with more sample size. It is important to continue research in this area to determine hypothyroidism as the cause of SSHL.
The authors would like to express gratitude to the Director, AIISH, and HOD - audiology for permitting us to carry out this research.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]