Tinnitus: Difference between revisions

Jump to navigation Jump to search
Line 28: Line 28:
==Pathophysiology==
==Pathophysiology==


In the normal functioning auditory pathway, there is ordered tonotopic frequency mapping from the cochlea to the auditory cortex via midbrain.  Conditions associated with cochlear damage result in altered tonotopic organization and ultimately tinnitus. The pathophysiology of tinnitus can be explained by the tinnitus model.
In the normal functioning auditory pathway, there is ordered tonotopic frequency mapping from the [[cochlea]] to the [[auditory cortex]] via [[midbrain]].  Conditions associated with [[Cochlear nucleus|cochlear]] damage result in altered tonotopic organization and ultimately tinnitus. The pathophysiology of tinnitus can be explained by the tinnitus model.


====Lesion projection zone (LPZ):====
====Lesion projection zone (LPZ):====
This zone is defined as the area in the auditory cortex that represents the damaged cochlear input.  The neurons in the LPZ zone show 2 main changes:
This zone is defined as the area in the [[auditory cortex]] that represents the damaged [[Cochlear nerve|cochlear]] input.  The [[neurons]] in the LPZ zone show 2 main changes:


*Accelerated spontaneous firing rate
*Accelerated spontaneous firing rate
*Increased representation of neurons that represent the damaged cochlear region also known as lesion edge frequencies in the LPZ
*Increased representation of [[neurons]] that represent the damaged [[Cochlear nerve|cochlear]] region also known as lesion edge frequencies in the LPZ


===Tinnitus model:===
===Tinnitus model:===
This model explains 2 major phenomena in the auditory cortex caused by lack of sensory peripheral auditory input (cochlea)
This model explains 2 major phenomena in the [[auditory cortex]] caused by lack of [[sensory]] [[Peripheral Nervous System|peripheral]] auditory input ([[cochlea]])


*Hyperactivity in the lesion projections zone (LPZ)
*Hyperactivity in the lesion projections zone (LPZ)
*Increased cortical representation of the lesion-edge frequencies in the LPZ
*Increased [[Cortical area|cortical]] representation of the lesion-edge frequencies in the LPZ


==Causes of subjective tinnitus==
==Causes of subjective tinnitus==
Line 47: Line 47:
====Sensorineural hearing loss:====
====Sensorineural hearing loss:====


*Ototoxicity
*[[Ototoxicity]]
*Presbycusis
*[[Presbycusis]]
*Noise induced hearing loss
*Noise induced [[hearing loss]]
*Late onset congenital hearing loss
*Late onset congenital [[hearing loss]]
*Idiopathic
*[[Idiopathic]]


====Cochlear injury:====
====Cochlear injury:====


*Ménière disease
*[[Ménière's disease|Meniere's disease]]
*Loop diuretics
*[[Loop diuretics]]
*Platinum based chemotherapy
*Platinum based [[chemotherapy]]
*Antibiotics
*[[Antibiotics]]
*Salicylate
*[[Salicylate]]
*Trauma
*[[Trauma]]


====Vascular causes:====
====Vascular causes:====


*Systemic hypertension
*[[Systemic hypertension]]
*Sickle cell anemia
*[[Sickle cell anemia]]
*Small vessel disease
*[[Small-sized vessel vasculitis|Small vessel disease]]
*Hypercholesterolemia
*[[Hypercholesterolemia]]
*Hypercoagulable state
*[[Hypercoagulable state]]
*Diabetic vasculopathy
*[[Diabetic vascular disease|Diabetic vasculopathy]]


====CNS causes:====
====CNS causes:====


*Pseudotumor cerebri
*[[Pseudotumor cerebri]]
*Stroke
*[[Stroke]]
*Vascular malformations
*[[Vascular malformations]]
*Tumor
*[[Tumor]]
*Sarcoid
*[[Sarcoid]]
*Multiple sclerosis
*[[Multiple sclerosis]]


====Infections:====
====Infections:====


*Rubella
*[[Rubella]]
*Cytomegalovirus
*[[Cytomegalovirus]]
*Chronic otitis media
*[[Chronic otitis media]]
*Neurosyphilis
*[[Neurosyphilis]]
*Measles
*[[Measles]]
*Lyme disease
*[[Lyme disease]]
*Meningitis
*[[Meningitis]]


====Bone disease:====
====Bone disease:====


*Otosclerosis
*[[Otosclerosis]]
*Fibrous dysplasia
*[[Fibrous dysplasia]]
*Osteogenesis imperfecta
*[[Osteogenesis imperfecta]]
*Paget disease
*[[Paget's disease]]


====Metabolic disorders:====
====Metabolic disorders:====


*Hyperparathyroidism
*[[Hyperparathyroidism]]
*Chronic renal failure
*[[Chronic renal failure]]
*Diabetes mellitus
*[[Diabetes mellitus]]
*Thyroid disease
*[[Thyroid diseases|Thyroid disease]]


====Autoimmune diseases:====
====Autoimmune diseases:====


*Autoimmune inner ear disease
*[[Autoimmune disease|Autoimmune]] inner ear disease
*SLE
*[[SLE]]
*Rheumatoid arthritis
*[[Rheumatoid arthritis]]


====Medications:====
====Medications:====


*ACE inhibitors
*[[ACE inhibitor|ACE inhibitors]]
*Antimalarial medications
*[[Antimalarial medication|Antimalarial]] medications
*Aminoglycosides
*[[Aminoglycosides]]
*Dapsone
*[[Dapsone]]
*Doxazosin
*[[Doxazosin]]
*Calcium channel blockers
*[[Calcium channel blockers]]
*Benzodiazepines
*[[Benzodiazepines]]
*Cisplatin
*[[Cisplatin]]
*Clarithromycin
*[[Clarithromycin]]
*COX-2 inhibitors
*[[COX-2 inhibitor|COX-2 inhibitors]]
*Loop diuretics
*[[Loop diuretics]]
*Tricyclic antidepressant<br />
*[[Tricyclic antidepressant]]<br />


==Differential Diagnosis of Tinnitus==
==Differential Diagnosis of Tinnitus==

Revision as of 05:00, 1 September 2020

WikiDoc Resources for Tinnitus

Articles

Most recent articles on Tinnitus

Most cited articles on Tinnitus

Review articles on Tinnitus

Articles on Tinnitus in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Tinnitus

Images of Tinnitus

Photos of Tinnitus

Podcasts & MP3s on Tinnitus

Videos on Tinnitus

Evidence Based Medicine

Cochrane Collaboration on Tinnitus

Bandolier on Tinnitus

TRIP on Tinnitus

Clinical Trials

Ongoing Trials on Tinnitus at Clinical Trials.gov

Trial results on Tinnitus

Clinical Trials on Tinnitus at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Tinnitus

NICE Guidance on Tinnitus

NHS PRODIGY Guidance

FDA on Tinnitus

CDC on Tinnitus

Books

Books on Tinnitus

News

Tinnitus in the news

Be alerted to news on Tinnitus

News trends on Tinnitus

Commentary

Blogs on Tinnitus

Definitions

Definitions of Tinnitus

Patient Resources / Community

Patient resources on Tinnitus

Discussion groups on Tinnitus

Patient Handouts on Tinnitus

Directions to Hospitals Treating Tinnitus

Risk calculators and risk factors for Tinnitus

Healthcare Provider Resources

Symptoms of Tinnitus

Causes & Risk Factors for Tinnitus

Diagnostic studies for Tinnitus

Treatment of Tinnitus

Continuing Medical Education (CME)

CME Programs on Tinnitus

International

Tinnitus en Espanol

Tinnitus en Francais

Business

Tinnitus in the Marketplace

Patents on Tinnitus

Experimental / Informatics

List of terms related to Tinnitus

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Kiran Singh, M.D. [2] Sabeeh Islam, MBBS[3]

Overview


Historical Perspective

  • In the early 19th century, Frenchman and Jean Marie Gaspard Itard introduced the concept of masking.  They were the first ones to differentiate between subjective and objective tinnitus.
  • Later in the 19th Century, with the introduction of germ theory and anesthesia, surgical therapy such as incudectomy was established.
  • Tinnitus is derived from the Latin word tinnire, meaning to ring.

Classification

Tinnitus can be classified as subjective and objective.  This classification not only explains the underlying etiology but also directs the management of tinnitus.

Subjective tinnitus:

  • It is only experienced by the affected individual in the absence of any auditory stimulation
  • More common, usually described as continuous ringing, high pitch sound

Objective tinnitus:

Pathophysiology

In the normal functioning auditory pathway, there is ordered tonotopic frequency mapping from the cochlea to the auditory cortex via midbrain.  Conditions associated with cochlear damage result in altered tonotopic organization and ultimately tinnitus. The pathophysiology of tinnitus can be explained by the tinnitus model.

Lesion projection zone (LPZ):

This zone is defined as the area in the auditory cortex that represents the damaged cochlear input.  The neurons in the LPZ zone show 2 main changes:

  • Accelerated spontaneous firing rate
  • Increased representation of neurons that represent the damaged cochlear region also known as lesion edge frequencies in the LPZ

Tinnitus model:

This model explains 2 major phenomena in the auditory cortex caused by lack of sensory peripheral auditory input (cochlea)

  • Hyperactivity in the lesion projections zone (LPZ)
  • Increased cortical representation of the lesion-edge frequencies in the LPZ

Causes of subjective tinnitus

Common Causes

Sensorineural hearing loss:

Cochlear injury:

Vascular causes:

CNS causes:

Infections:

Bone disease:

Metabolic disorders:

Autoimmune diseases:

Medications:

Differential Diagnosis of Tinnitus

Diseases Clinical manifestations Para-clinical findings Gold standard Additional findings
Symptoms Physical examination
Lab Findings Imaging
Acute onset Recurrency Nystagmus Hearing problems, tinnitus
Peripheral
HSV oticus
+ +/− +/− + VZV antibody titres
Meniere disease
+/− + +/− + (Progressive)
Labyrinthine concussion
+ +
Perilymphatic fistula
+/− + +
  • CT scan may show fluid around the round window recess
Semicircular canal

dehiscence syndrome

+/− + +

(air-bone gaps on audiometry)

Cogan syndrome
+ +/− + Increased ESR and cryoglobulins
  • CT scan may show calcification or soft tissue attenuation obliterating the intralabyrinthine fluid spaces
Vestibular schwannoma
+ +/− +
Otitis media
+ +/− Increased acute phase reactants
Aminoglycoside toxicity
+ +
Central
Vestibular migraine
+ +/− +/−
  • ICHD-3 criteria
Multiple sclerosis
+ +/− +/− Elevated concentration of CSF oligoclonal bands
  • CT scan shows brain atrophy and contrast enhanced demyelinating plaques
  • MRI showing cerebral plaques disseminating in time and space.
  • MS is twice as prevalent in women as compared to men
  • The onset of symptoms is mostly between the age of fifteen to forty years and rarely before the age of fifteen or after the age of sixty years
Brain tumors
+/− + + + Cerebral spinal fluid (CSF) may show cancerous cells
  • On CT scan most of the brain tumors appears as a hypodense mass lesions
  • On T1- weighted MRI most of the brain tumors appears as a hypointense or Isointense whereas on T2-weighted MRI they appear as hyperintense lesions
Cerebellar infarction/hemorrhage + ++/− +/−
  • Based on the time interval lapsed between the onset of stroke and imaging performed there may be different presentations
Brain stem ischemia + +/− +/−
  • Based on the time interval lapsed between the onset of stroke and imaging performed there may be different presentations
  • For more information click here

ABBREVIATIONS

VZV= Varicella zoster virus, MRI= Magnetic resonance imaging, ESR= Erythrocyte sedimentation rate, EEG= Electroencephalogram, CSF= Cerebrospinal fluid, GPe= Globus pallidus externa, ICHD= International Classification of Headache Disorders

Epidemiology and Demographics

  • Tinnitus affects 10 to 15% of the population.
  • 85% of the population presenting with ear symptoms/disorders report tinnitus as an associated symptom.
  • The incidence rate of tinnitus increases with age and is more prevalent in older people.

Risk Factors

  • Age
  • Sensorineural hearing loss
  • Loud noise exposure
  • Vestibular schwannoma
  • Ototoxic medication
  • History of anxiety and depression
  • History of head trauma
  • History of multiple sclerosis

Natural History, Complications and Prognosis

  • Early clinical features may include ear fullness, huming or ringing sensations in the ear
  • If left untreated, patients may progress to functional impairment, insomnia, anxiety, and depression.

Diagnosis

Diagnostic criteria:

Tinnitus severity index (TSI)

  • TSI is used to rank the patient's based upon their severity
  • The score ranges from 0-45

Tinnitus handicap questionnaire:

  • This questionnaire includes 27 questions and is used to estimate the social, physical and emotional handicap severity

Tinnitus handicap inventory:

  • This questionnaire has 4 categories to classify severity
  • None, mild,  moderate, and severe.

History and Symptoms:

  • Sounds such as ringing, buzzing, pulsatile, roaring and humming
  • Progressive hearing loss
  • Recent exposure to excessive or loud noise or head trauma
  • Poor hygiene leading to cerumen impaction
  • Ear pain
  • History of certain medication exposure

Physical Examination:

  • The ear examination may show signs of cerumen impaction, underlying infection or tympanic membrane perforation.
  • Auscultation of neck, orbits and periauricular areas as helpful in establishing the diagnosis of vascular causes
  • An extensive neurological examination may rule out underlying brainstem damage or hearing loss
  • The Weber and Rinne test are done to establish sensorineural or conductive hearing loss

Laboratory Findings:

  • There are no specific lab findings associated with tinnitis.

Imaging:

  • MRA and CTA are the gold standard diagnostic tests for arteriovenous fistula related tinnitus.
  • MRI with contrast is the initial preferred diagnostic test of choice for suspected vascular tinnitus.
  • MRI with contrast is followed by CT/CTA and ultimately interventional angiography, if needed.

Other Diagnostic Testing:

  • Initial audiometric tests are done to identify asymmetries between the ears and to locate the site of abnormality such as middle ear, cochlea, and brainstem.  These tests include:
    • Pure-tone audiogram
    • Tympanometry
    • Auditory reflex testing
    • Determination of speech discrimination abilities
    • Otoacoustic emissions testing
    • Auditory brainstem response testing (ABR)

Treatment

  • Tinnitus is a symptom and not a disease itself.  It is a chronic condition that can be managed by treating the underlying etiology.
  • The treatment of tinnitus is usually directed towards improvement in the quality of life by decreasing awareness or desensitizing towards tinnitus.  It is usually achieved by identifying the underlying pathology or the associated disease.
  • It is recommended to treat underlying insomnia and depression. (Grade 1B)

Medical Therapy

Following medications have minimal to modest role in relieving tinnitus.

  • Misoprostol
  • Lidocaine (intratympanic or intravenous)
  • Benzodiazepine (alprazolam)
  • Steroids such as dexamethasone (intratympanic)
  • Carbamazepine

Following medications have been studied for tinnitus but are not found to be effective and have no role in the treatment of tinnitus

  • Anticonvulsants
  • Melatonin
  • Ginkgo biloba
  • Niacin

Surgery

  • Cochlear implants may be considered for tinnitus associated with severe sensorineural hearing loss.

Other therapies:

  • Tinnitus retraining therapy (TRT) (Grade 1C)
  • Biofeedback (Grade 2C)
  • Cognitive behavioral therapy (CBT) as an adjunct to TRT (Grade 2C)
  • Acupuncture and electrical stimulation are considered equally effective as placebo, no significant role established so far.

Prevention

  • Tinnitus may be been prevented by limiting the exposure to loud noise.

References

Template:Diseases of the ear and mastoid process

Template:WikiDoc Sources