Cochlear hydrops

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Cochlear hydrops (or cochlear Meniere's or cochlear endolymphatic hydrops) is a condition of the inner ear involving a pathological increase of fluid affecting the cochlea. This results in swelling that can lead to hearing loss or changes in hearing perception. It is a form of endolymphatic hydrops and related to Meniere's disease. Cochlear hydrops refers to a case of inner-ear hydrops that only involves auditory symptoms and does not cause vestibular issues. [1]

Contents

Cause and behavior

Cochlear hydrops refers to an increase in endolymphatic fluid in the inner ear. This build-up is either due to an overproduction or insufficient drainage of endolymph in the constant regulation of fluid in the inner ear. Usually, only one ear is affected. The root cause of the process is unclear and may vary from patient to patient, but can have auto-immune, viral, and/or allergic triggers, among others. [2]

The build-up of endolymph creates pressure in the scala media. This causes its diameter to increase, and the vestibular membrane to curve outwards in the direction of the vestibule. The changes to the membrane can result in changes to either the hearing perception or hearing threshold of a patient. [3]

Episodes are usually cyclical and symptoms fluctuate through time. Patients may be symptom-free between episodes, which themselves may progressively worsen, improve, or remain constant in severity or duration. For some, permanent damage occurs, and they may be left with long-term hearing loss, hearing distortion, tinnitus, and/or a feeling of fullness in the affected ear(s). [4]

A study looking at spiral ganglion cell counts compared to hair cell counts in the inner ear of patients who had Meniere's disease found that they maintained more hair cells than spinal ganglion cells. [5] Thus, it could be possible that hydrops affects auditory nerves more than hair cells. [6] In contrast, a 2021 article by Richard Gacek posits that the hearing loss is actually caused by toxic nucleic acids that are released to the outer hair cells: "Since the outer hair cells (OHC) are freely surrounded by perilymph, their walls and nerve terminals are also bathed in this fluid. The few type-II spiral ganglion cells in contact with the OHC are unlikely to play a significant role in hearing loss because of their low numbers and the lack of a known connection to the central auditory pathway." [7]

Symptoms

Cochlear hydrops preferentially affects the apex of the cochlea where low-frequency sounds are interpreted. Due to the fluid imbalance in this area, parts of the cochlea are stretched or under more tension than usual, which can lead to distortions of sound, changes in pitch perception, or hearing loss, all usually in the low frequencies.

Common symptoms include:

As with Meniere's disease, atypical, early, or mild cases may only present some symptoms.

Diagnosis

Diagnosis is based on symptoms and a hearing test that documents a loss in the low and mid frequencies, usually only in one ear. For patients with mild or atypical hydrops, the hearing thresholds may be normal, but they may experience a subjective, unilateral distortion of sounds in lower frequencies, such as diplacusis or that voices are sounding "robotic". Patients may also mention a feeling of pressure or fullness in the ear. [8]

To objectively test for the presence of hydrops, an electrocochleography (or ECOG) procedure can be done to detect elevated inner ear pressure. [9] It is also possible to reveal the presence of hydrops with an MRI. [10]

If vertigo is experienced, the diagnosis progresses to Meniere's disease. This occurs if the fluid increase leads to a leak or rupture of the membranes in the inner ear, causing a mixture of perilymph and endolymph. [11]

Treatment

Treatment for cochlear hydrops is the same as for Meniere's disease. Currently, no cure exists for either. [12]

If a patient has undergone sudden sensorineural hearing loss, a course of steroids is often prescribed in an attempt to recover the hearing. Steroids may be injected directly through the eardrum. [13]

Like Meniere's Disease, a low salt diet is recommended as a preventative measure. A diuretic may be prescribed to help lower salt content. [14]

Betahistine is the most widely prescribed medication for the treatment of Meniere's disease. The drug is thought to increase blood flow to the inner ear and to prevent the frequency and intensity of episodes. While Betahistine is considered safe, there is insufficient evidence that it is an effective treatment. [15] It is not FDA approved in the United States, yet has still been clinically observed to benefit patients, and is considered safer and more effective than diuretics. [16] Betahistine at high doses (such as 144 mg/day) can yield similar vertigo control as intratympanic dexamethasone. [17] [18]

Antivirals have been proven effective for those who suspect a viral cause for their cochlear Hydrops. [19]

For some, surgery may be effective, such as an endolymphatic sac decompression. Surgery is often reserved for cases where other measures have proven ineffective and/or when vestibular issues are the main complaint, as it runs the risk of causing hearing or other nerve damage. [20]

Prognosis

The symptoms of cochlear hydrops fluctuate, and the condition tends to stabilize or go away on its own after several years. However, because the organ of Corti undergoes stress during the hydrops episodes, long-term hearing loss, tinnitus, or hyperacusis is possible.

It is considered by some that cochlear hydrops is an early form of Meniere's disease. However, while all people with Meniere's disease have some form of hydrops, the majority of cochlear hydrops patients do not go on to develop Meniere's disease. [3] It takes an average of one year from the onset of symptoms for someone to develop full Meniere's disease, if at all.

Relationship to Meniere's Disease

The data on how often progression to Meniere's disease occurs is mixed, but the majority of recent studies suggest a low likelihood.

A 1984 study from Japan looked at patients with Meniere's disease and classified them into subcategories based on their first symptoms. The study found that the majority of patients with Meniere's disease (104 out of 163, or 63.80%) presented vertigo with their first symptoms, and only 59 out of 163 (36.19%) of patients presented with cochlear symptoms first, such as "tinnitus or deafness." However, the study found that 59 out of 74 (79.72%) patients who started out with a cochlear hydrops diagnosis progressed to Meniere's disease, and concluded that "cochlear Meniere's disease frequently develops into Meniere's disease." [21]

Conversely, A 2006 study from doctors at the House Ear Institute found that “conversion from cochlear hydrops to Meniere's disease occurred in 33%” of diagnosed patients in a study including 46 subjects. [22] A 2009 study from Japan found that only about 10% of their diagnosed patients with sudden low-frequency hearing loss (SLFHL) went on to develop full Meniere's disease, and about 18% with recurring SLFHL developed Meniere's disease. [23] [24] From this study, about 70% of patients who did not develop Meniere's Disease maintained their hearing in the end. 30% went on to have lasting hearing difficulty, reported from a ten-year follow-up. [25] [26]

A 2018 study from Korea found the chance of progression to Meniere's disease of all participants with SLFHL to be 9.38% with an average progression time of 1.7±1.4 years, but when limited to patients with recurring symptoms "it was confirmed that about half (46.88%) of them progressed to Meniere's disease." However, the study was said to have limitations as "hearing fluctuations and the possibility of transitioning to Meniere's disease in the non-relapse group could not be completely ruled out." [27]

Related Research Articles

Ménières disease Disorder of the inner ear

Ménière's disease (MD) is a disease of the inner ear that is characterized by potentially severe and incapacitating episodes of vertigo, tinnitus, hearing loss, and a fullness in the ear. Typically, only one ear is affected initially, but over time, both ears may become involved. Episodes generally last from 20 minutes to a few hours. The time between episodes varies. The hearing loss and ringing in the ears can become constant over time.

Tinnitus is the perception of sound when no corresponding external sound is present. Nearly everyone will experience a faint "normal tinnitus" in a completely quiet room but it is only of concern if it is bothersome or interferes with normal hearing or correlated with other problems. While often described as a ringing, it may also sound like a clicking, buzzing, hiss, or roaring. The sound may be soft or loud, low or high pitched, and often appears to be coming from one or both ears or from the head itself. In some people, the sound may interfere with concentration and in some cases it is associated with anxiety and depression. Tinnitus is usually associated with a degree of hearing loss and with decreased comprehension of speech in noisy environments. It is common, affecting about 10–15% of people. Most, however, tolerate it well, and it is a significant problem in only 1–2% of all people. It can trigger a fight-or-flight response, as the brain may perceive it as dangerous and important. The word tinnitus comes from the Latin tinnire which means "to ring".

Vestibulocochlear nerve Cranial nerve VIII, for hearing and balance

The vestibulocochlear nerve or auditory vestibular nerve, also known as the eighth cranial nerve, cranial nerve VIII, or simply CN VIII, is a cranial nerve that transmits sound and equilibrium (balance) information from the inner ear to the brain. Through olivocochlear fibers, it also transmits motor and modulatory information from the superior olivary complex in the brainstem to the cochlea.

Otosclerosis Condition characterized by an abnormal bone growth in the middle ear

Otosclerosis is a condition of the middle ear where one or more foci of irregularly laid spongy bone replace part of normally dense enchondral layer of bony otic capsule in the bony labyrinth. This condition affects one of the ossicles resulting in hearing loss, tinnitus, vertigo or a combination of symptoms. The term otosclerosis is something of a misnomer. Much of the clinical course is characterized by lucent rather than sclerotic bony changes, so the disease is also known as otospongiosis.

Ototoxicity is the property of being toxic to the ear (oto-), specifically the cochlea or auditory nerve and sometimes the vestibular system, for example, as a side effect of a drug. The effects of ototoxicity can be reversible and temporary, or irreversible and permanent. It has been recognized since the 19th century. There are many well-known ototoxic drugs used in clinical situations, and they are prescribed, despite the risk of hearing disorders, for very serious health conditions. Ototoxic drugs include antibiotics, loop diuretics, and platinum-based chemotherapy agents. A number of nonsteroidal anti-inflammatory drugs (NSAIDS) have also been shown to be ototoxic. This can result in sensorineural hearing loss, dysequilibrium, or both. Some environmental and occupational chemicals have also been shown to affect the auditory system and interact with noise.

Endolymph

Endolymph is the fluid contained in the membranous labyrinth of the inner ear. The major cation in endolymph is potassium, with the values of sodium and potassium concentration in the endolymph being 0.91 mM and 154 mM, respectively. It is also called Scarpa's fluid, after Antonio Scarpa.

Sensorineural hearing loss Hearing loss caused by an inner ear or vestibulocochlear nerve defect

Sensorineural hearing loss (SNHL) is a type of hearing loss in which the root cause lies in the inner ear or sensory organ or the vestibulocochlear nerve. SNHL accounts for about 90% of reported hearing loss. SNHL is usually permanent and can be mild, moderate, severe, profound, or total. Various other descriptors can be used depending on the shape of the audiogram, such as high frequency, low frequency, U-shaped, notched, peaked, or flat.

<span class="mw-page-title-main">Hyperacusis</span> Medical condition

Hyperacusis is the increased sensitivity to sound and a low tolerance for environmental noise. Definitions of hyperacusis can vary significantly; it can refer to normal noises being perceived as: loud, annoying, painful, fear-inducing, or a combination of those, and is often categorized into four subtypes: loudness, pain, annoyance, and fear.

Unilateral hearing loss (UHL) is a type of hearing impairment where there is normal hearing in one ear and impaired hearing in the other ear.

Presbycusis, or age-related hearing loss, is the cumulative effect of aging on hearing. It is a progressive and irreversible bilateral symmetrical age-related sensorineural hearing loss resulting from degeneration of the cochlea or associated structures of the inner ear or auditory nerves. The hearing loss is most marked at higher frequencies. Hearing loss that accumulates with age but is caused by factors other than normal aging is not presbycusis, although differentiating the individual effects of distinct causes of hearing loss can be difficult.

Otology Branch of medicine for the ear

Otology is a branch of medicine which studies normal and pathological anatomy and physiology of the ear as well as their diseases, diagnosis and treatment. Otologic surgery generally refers to surgery of the middle ear and mastoid related to chronic otitis media, such as tympanoplasty, or ear drum surgery, ossiculoplasty, or surgery of the hearing bones, and mastoidectomy. Otology also includes surgical treatment of conductive hearing loss, such as stapedectomy surgery for otosclerosis.

Betahistine Chemical compound

Betahistine, sold under the brand name Serc among others, is an anti-vertigo medication. It is commonly prescribed for balance disorders or to alleviate vertigo symptoms. It was first registered in Europe in 1970 for the treatment of Ménière's disease but current evidence does not support its efficacy in treating it.

Perilymph Extracellular fluid located within the inner ear

Perilymph is an extracellular fluid located within the inner ear. It is found within the scala tympani and scala vestibuli of the cochlea. The ionic composition of perilymph is comparable to that of plasma and cerebrospinal fluid. The major cation in perilymph is sodium, with the values of sodium and potassium concentration in the perilymph being 138 mM and 6.9 mM, respectively. It is also named Cotunnius' liquid and liquor cotunnii for Domenico Cotugno.

Endolymphatic hydrops is a disorder of the inner ear. It consists of an excessive build-up of the endolymph fluid, which fills the hearing and balance structures of the inner ear. Endolymph fluid, which is partly regulated by the endolymph sac, flows through the inner ear and is critical to the function of all sensory cells in the inner ear. In addition to water, endolymph fluid contains salts such as sodium, potassium, chloride and other electrolytes. If the inner ear is damaged by disease or injury, the volume and composition of the endolymph fluid can change, causing the symptoms of endolymphatic hydrops.

Superior semicircular canal dehiscence syndrome is a set of hearing and balance symptoms, related to a rare medical condition of the inner ear, known as superior canal dehiscence. The symptoms are caused by a thinning or complete absence of the part of the temporal bone overlying the superior semicircular canal of the vestibular system. There is evidence that this rare defect, or susceptibility, is congenital. There are also numerous cases of symptoms arising after physical trauma to the head. It was first described in 1998 by Lloyd B. Minor of Johns Hopkins University in Baltimore.

Autoimmune inner ear disease Medical condition

Autoimmune inner ear disease (AIED) was first defined by Dr. Brian McCabe in a landmark paper describing an autoimmune loss of hearing. The disease results in progressive sensorineural hearing loss (SNHL) that acts bilaterally and asymmetrically, and sometimes affects an individual's vestibular system. AIED is used to describe any disorder in which the inner ear is damaged as a result of an autoimmune response. Some examples of autoimmune disorders that have presented with AIED are Cogan's syndrome, relapsing polychondritis, systemic lupus erythematosus, granulomatosis with polyangiitis, polyarteritis nodosa, Sjogren's syndrome, and Lyme disease.

Enlarged vestibular aqueduct Human disease

Large vestibular aqueduct is a structural deformity of the inner ear. Enlargement of this duct is one of the most common inner ear deformities and is commonly associated with hearing loss during childhood. The term was first discovered in 1791 by Mondini when he was completing a temporal bone dissection. It was then defined by Valvassori and Clemis as a vestibular aqueduct that is greater than or equal to 2.0 mm at the operculum and/or greater than or equal to 1.0 mm at the midpoint. Some use the term enlarged vestibular aqueduct syndrome but this is felt by others to be erroneous as it is a clinical finding which can occur in several syndromes.

Electrocochleography is a technique of recording electrical potentials generated in the inner ear and auditory nerve in response to sound stimulation, using an electrode placed in the ear canal or tympanic membrane. The test is performed by an otologist or audiologist with specialized training, and is used for detection of elevated inner ear pressure or for the testing and monitoring of inner ear and auditory nerve function during surgery.

Endolymphatic sac tumor

An endolymphatic sac tumor (ELST) is a very uncommon papillary epithelial neoplasm arising within the endolymphatic sac or endolymphatic duct. This tumor shows a very high association with von Hippel-Lindau syndrome (VHL).

Ototoxic medication

Ototoxicity is defined as the toxic effect on the functioning of the inner ear, which may lead to temporary or permanent hearing loss (cochleotoxic) and balancing problems (vestibulotoxic). Drugs or pharmaceutical agents inducing ototoxicity are regarded as ototoxic medications.

References

  1. ↑ Glasscock III and Miller, M.E and G.W (1977). "Diagnosis and management of cochlear hydrops". The Laryngoscope. 87 (2): 198–206. doi:10.1288/00005537-197702000-00007. PMID   839917. S2CID   22900734.
  2. ↑ “Allergic and Inflammatory Inner Ear Disease | House Online Neurotology Education.” YouTube, YouTube, 20 May 2021, https://www.youtube.com/watch?v=vqEm7wPfZzM.
  3. 1 2 Salt AN, Plontke SK (2010). "Endolymphatic hydrops: pathophysiology and experimental models". Otolaryngologic Clinics of North America. 43 (5): 971–83. doi:10.1016/j.otc.2010.05.007. PMC 2923478. PMID 20713237.
  4. ↑ Zenner HP, Hören. Physiologie, Biochemie, Zell- und Neurobiologie. Thieme, Stuttgart 1994, S. 113–117.
  5. ↑ Nadol JB Jr, Thornton AR. Ultrastructural findings in a case of Menière's disease. Ann Otol Rhinol Laryngol. 1987 Jul-Aug;96(4):449-54. doi: 10.1177/000348948709600420. PMID 3619291.
  6. ↑ Archived at Ghostarchive and the Wayback Machine : Endolymphatic Hydrops and Sensorineural Hearing Loss | House Online Neurotology Education Program. YouTube .
  7. ↑ Gacek R, R: On the Nature of Hearing Loss in Méniere’s Disease. ORL 2021;83:144-150. doi: 10.1159/000511113
  8. ↑ WILLIAMS HL, HORTON BT, DAY LA. ENDOLYMPHATIC HYDROPS WITHOUT VERTIGO: Its Differential Diagnosis and Treatment. Arch Otolaryngol. 1950;51(4):557–581. doi:10.1001/archotol.1950.00700020580008
  9. ↑ Ferraro, John A. (November 15, 2000). "Clinical Electrocochleography: Overview of Theories, Techniques and Applications". Audiology Online. Retrieved 15 September 2014.
  10. ↑ Attyé, A., Dumas, G., Troprès, I. et al. Recurrent peripheral vestibulopathy: Is MRI useful for the diagnosis of endolymphatic hydrops in clinical practice?. Eur Radiol 25, 3043–3049 (2015). https://doi.org/10.1007/s00330-015-3712-5
  11. ↑ Michael M. Paparella (1983) Pathogenesis of Meniere's Disease and Meniere's Syndrome, Acta Oto-Laryngologica, 96:sup406, 10-25, DOI: 10.3109/00016488309122996
  12. ↑ "Ménière's Disease". NIDCD. 1 June 2016. Archived from the original on 27 July 2016. Retrieved 18 July 2016.
  13. ↑ Hillman, T.M., Arriaga, M.A. and Chen, D.A. (2003), Intratympanic steroids: Do they acutely improve hearing in cases of cochlear hydrops?. The Laryngoscope, 113: 1903-1907. https://doi.org/10.1097/00005537-200311000-00008
  14. ↑ "Endolymphatic hydrops". Ménière’s Society. Retrieved 3 November 2020.
  15. ↑ Adrion, C; Fischer, C. S.; Wagner, J; et al. (2016). "Efficacy and safety of betahistine treatment in patients with Meniere's disease: Primary results of a long term, multicentre, double blind, randomised, placebo controlled, dose defining trial (BEMED trial)". BMJ. 352: h6816. doi:10.1136/bmj.h6816. PMC 4721211. PMID 26797774.
  16. ↑ Basura GJ, Adams ME, Monfared A, Schwartz SR, Antonelli PJ, Burkard R, Bush ML, Bykowski J, Colandrea M, Derebery J, Kelly EA, Kerber KA, Koopman CF, Kuch AA, Marcolini E, McKinnon BJ, Ruckenstein MJ, Valenzuela CV, Vosooney A, Walsh SA, Nnacheta LC, Dhepyasuwan N, Buchanan EM. Clinical Practice Guideline: Ménière's Disease Executive Summary. Otolaryngol Head Neck Surg. 2020 Apr;162(4):415-434. doi: 10.1177/0194599820909439. PMID 32267820.
  17. ↑ Albu S, Nagy A, Doros C, Marceanu L, Cozma S, Musat G, Trabalzini F. Treatment of Meniere's disease with intratympanic dexamethazone plus high dosage of betahistine. Am J Otolaryngol. 2016 May-Jun;37(3):225-30. doi: 10.1016/j.amjoto.2015.12.007. Epub 2015 Dec 30. PMID 27178513.
  18. ↑ “Histamine: Friend or Foe? | House Online Neurotology Education Program.” YouTube, YouTube, 19 May 2021, www.youtube.com/watch?v=SybFDV3HDZk.
  19. ↑ Derebery MJ, Fisher LM, Iqbal Z. Randomized double-blinded, placebo-controlled clinical trial of famciclovir for reduction of Ménière's disease symptoms. Otolaryngol Head Neck Surg. 2004 Dec;131(6):877-84. doi: 10.1016/j.otohns.2004.08.012. PMID 15577784.
  20. ↑ Lim, Ming Yann; Zhang, Margaret; Yuen, Heng Wai; et al. (November 2015). "Current evidence for endolymphatic sac surgery in the treatment of Meniere's disease: a systematic review". Singapore Medical Journal. 56 (11): 593–98. doi:10.11622/smedj.2015166. ISSN 0037-5675. PMC 4656865. PMID 26668402.
  21. ↑ Masaaki Kitahara, Taizo Takeda, Yoshiro Yazawa, Hideharu Matsubara & Hitoshi Kitano (1983) Pathophysiology of Meniere's Disease and Its Subvarieties, Acta Oto-Laryngologica, 96:sup406, 52-55, DOI: 10.3109/00016488309123002
  22. ↑ House, John W.; Doherty, Joni K.; Fisher, Laurel M.; Derebery, M. Jennifer; Berliner, Karen I. Meniere's Disease: Prevalence of Contralateral Ear Involvement, Otology & Neurotology: April 2006 - Volume 27 - Issue 3 - p 355-361.
  23. ↑ Makiko Junicho, Shin Aso, Michiro Fujisaka & Yukio Watanabe (2008) Prognosis of low-tone sudden deafness – does it inevitably progress to Meniere's disease?, Acta Oto-Laryngologica, 128:3, 304-308, DOI: 10.1080/00016480601002096
  24. ↑ Olaf Michel: Morbus Menière und verwandte Gleichgewichtsstörungen. Georg Thieme Verlag, Stuttgart 1998, ISBN 3-13-104091-2, S. 34 ff.
  25. ↑ Helmut Schaaf (2007), Morbus Menière, Springer, Heidelberg, S. 58ff, ISBN 3-540-36960-0
  26. ↑ Imamura, S, Nozawa, I, Imamura, M, et al. Clinical observations on acute low-tone sensorineural hearing loss. Survey and analysis of 137 patients. Ann Otol Rhinol Laryngol 1997;106:746–50.
  27. ↑ Kim Ji Hyung,Kwak Sang Hyun,Bae Seong Hoon,Kim Sung Hunh,Nam Gi-Sung. Prognosis of Sudden Low Frequency Hearing Loss During Long-Term Follow-Up, res Vestib Sci
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