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Diagnosis is based on clinical findings.
'Clinical findings'
- Profound congenital sensorineural deafness is present
- CT scan or MRI of the inner ear shows no recognizable structure in the inner ear.
- As michel's aplasia is associated with LAMM syndrome there will be Microtia and microdontia present(small sized teeth).
Molecular genetic Testing
1. "FGF3" is the only gene, whose mutation can cause congenital deafness with Michel's aplasia, microdontia and microtia
Carrier testing for at-risk relatives requires identification of mutations which are responsible for occurrence of disease in the family.
Imaging is usually not pursued in those with uncomplicated conductive hearing loss and characteristic clinical findings. Those with only conductive hearing loss are often treated medically or with surgery without imaging. The diagnosis may be unclear clinically in cases of sensorineural or mixed hearing loss and may become apparent only on imaging. Therefore, imaging is often performed when the hearing loss is sensorineural or mixed.
A high-resolution CT shows very subtle bone findings. However, CT is usually not needed prior to surgery.
Otosclerosis on CT can be graded using the grading system suggested by Symons and Fanning.
- Grade 1, solely fenestral;
- Grade 2, patchy localized cochlear disease (with or without fenestral involvement) to either the basal cochlear turn (grade 2A), or the middle/apical turns (grade 2B), or both the basal turn and the middle/apical turns (grade 2C); and
- Grade 3, diffuse confluent cochlear involvement (with or without fenestral involvement).
Treatment of otosclerosis can be understood basically under three heads : medical, surgical and amplification.
Enlarged vestibular aqueducts are commonly picked up after newborn hearing screen when a child is identified as having a hearing loss. The hearing loss is commonly mixed and can be of any degree when first identified. The conductive component is due to a third window effect caused by the widened vestibular aqueduct.
Identification of the enlarged vestibular aqueduct in a child is usually by MRI scan which identifies the fluid within the endolymphatic duct and sac. CT scan may be needed to see the vestibular aqueduct clearly. In adults CT scan may be the first investigation.
In order to diagnose the cause of the enlarged vestibular aqueduct the physician will need a detailed family history, full examination to include vestibular examination and, if a bilateral finding, molecular genetic testing as appropriate. With unilateral enlarged vestibular aqueducts molecular genetic testing is currently not recommended.
Audiometry (measuring ability to hear sounds of a particular pitch) is usually abnormal, but the findings are not particularly specific and an audiogram is not sufficient to diagnose Pendred syndrome. A thyroid goitre may be present in the first decade and is usual towards the end of the second decade. MRI scanning of the inner ear usually shows widened or large vestibular aqueducts with enlarged endolymphatic sacs and may show abnormalities of the cochleae that is known as Mondini dysplasia. Genetic testing to identify the pendrin gene usually establishes the diagnosis. If the condition is suspected, a "perchlorate discharge test" is sometimes performed. This test is highly sensitive, but may also be abnormal in other thyroid conditions. If a goitre is present, thyroid function tests are performed to identify mild cases of thyroid dysfunction even if they are not yet causing symptoms.
Most causes of conductive hearing loss can be identified by examination but if it is important to image the bones of the middle ear or inner ear then a CT scan is required. CT scan is useful in cases of congenital conductive hearing loss, chronic suppurative otitis media or cholesteatoma, ossicular damage or discontinuity, otosclerosis and third window dehiscence. Specific MRI scans can be used to identify cholesteatoma.
This may include a blood or other sera test for inflammatory markers such as those for autoinflammatory diseases.
Once diagnosed, the gap in the temporal bone can be repaired by surgical resurfacing of the affected bone or plugging of the superior semicircular canal. These techniques are performed by accessing the site of the dehiscence either via a middle fossa craniotomy or via a canal drilled through the transmastoid bone behind the affected ear. Bone cement has been the material most often used, in spite of its tendency to slippage and resorption, and a consequent high failure rate; recently, soft tissue grafts have been substituted.
Tympanometry, or acoustic immitance testing, is a simple objective test of the ability of the middle ear to transmit sound waves across it. This test is usually abnormal with conductive hearing loss.
The presence of dehiscence can be detected by a high definition (0.6 mm or less) coronal CT scan of the temporal bone, currently the most reliable way to distinguish between superior canal dehiscence syndrome (SCDS) and other conditions of the inner ear involving similar symptoms such as Ménière's disease and perilymphatic fistula. Other diagnostic tools include the vestibular evoked myogenic potential or VEMP test, videonystagmography (VNG), electrocochleography (ECOG) and the rotational chair test. An accurate diagnosis is of great significance as unnecessary exploratory middle ear surgery may thus be avoided. Several of the symptoms typical to SCDS (e.g. vertigo and Tullio) may also be present singly or as part of Ménière's disease, sometimes causing the one illness to be confused with the other. There are reported cases of patients being affected by both Ménière's disease and SCDS concurrently.
As SCDS is a very rare and still a relatively unknown condition, obtaining an accurate diagnosis of this distressing (and even disabling) disease may take some time as many health care professionals are not yet aware of its existence.
Presence of inner ear abnormalities lead to Delayed gross development of child because of balance impairment and profound deafness which increases the risk of trauma and accidents.
- Incidence of accidents can be decreased by using visual or vibrotactile alarm systems in homes as well as in schools.
- Anticipatory education of parents, health providers and educational programs about hazards can help.
As part of differential diagnosis, an MRI scan may be done to check for vascular anomalies, tumors, and structural problems like enlarged mastoids. MRI and other types of scan cannot directly detect or measure age-related hearing loss.
There is no treatment to correct an enlarged vestibular aqueduct. Any hearing loss will need management with amplification and support in education and at work. If the hearing loss becomes severe to profound cochlear implants can be of significant value. Vestibular disturbance is usually short-lived and associated with head trauma but significant vestibular hypofunction may require rehabilitation.
People with enlarged vestibular aqueducts are advised to avoid head trauma where possible. This usually means avoiding contact sports such as boxing and rugby, but also horse riding, trampolining and other sports where head injury may occur. Some have symptoms when flying and should limit these activities if affected.
A temporal-bone CT using thin slices makes it possible to diagnose the degree of stenosis and atresia of the external auditory canal, the status of the middle ear cavity, the absent or dysplastic and rudimentary ossicles, or inner ear abnormalities such as a deficient cochlea. Two- and three-dimensional CT reconstructions with VRT and bone and skin-surfacing are helpful for more accurate staging and the three-dimensional planning of mandibular and external ear reconstructive surgery.
Treatment is supportive and consists of management of manifestations. User of hearing aids and/or cochlear implant, suitable educational programs can be offered. Periodic surveillance is also important.
A few techniques are used to confirm the diagnosis in TCS.
An orthopantomogram (OPG) is a panoramic dental X-ray of the upper and lower jaw. It shows a two-dimensional image from ear to ear. Particularly, OPG facilitates an accurate postoperative follow-up and monitoring of bone growth under a mono- or double-distractor treatment. Thereby, some TCS features could be seen on OPG, but better techniques are used to include the whole spectrum of TCS abnormalities instead of showing only the jaw abnormalities.
Another method of radiographic evaluation is taking an X-ray image of the whole head. The lateral cephalometric radiograph in TCS shows hypoplasia of the facial bones, like the malar bone, mandible, and the mastoid.
Finally, occipitomental radiographs are used to detect hypoplasia or discontinuity of the zygomatic arch.
Genetic testing for CHARGE syndrome involves specific genetic testing for the CHD7 gene. The test is available at most major genetic testing laboratories. Insurance companies sometimes do not pay for such genetic tests, though this is changing rapidly as genetic testing is becoming standard across all aspects of medicine. CHARGE syndrome is a clinical diagnosis, which means genetic testing is not required in order to make the diagnosis. Rather, the diagnosis can be made based on clinical features alone.
Differential testing is most useful when there is unilateral hearing loss, and distinguishes conductive from sensorineural loss. These are conducted with a low frequency tuning fork, usually 512 Hz, and contrast measures of air and bone conducted sound transmission.
- Weber test, in which a tuning fork is touched to the midline of the forehead, localizes to the normal ear in people with unilateral sensorineural hearing loss.
- Rinne test, which tests air conduction "vs." bone conduction is positive, because both bone and air conduction are reduced equally.
- less common Bing and Schwabach variants of the Rinne test.
- absolute bone conduction (ABC) test.
"Table 1". A table comparing sensorineural to conductive hearing loss
Other, more complex, tests of auditory function are required to distinguish the different types of hearing loss. Bone conduction thresholds can differentiate sensorineural hearing loss from conductive hearing loss. Other tests, such as oto-acoustic emissions, acoustic stapedial reflexes, speech audiometry and evoked response audiometry are needed to distinguish sensory, neural and auditory processing hearing impairments.
About half of people with SSNHL will recover some or all of their hearing spontaneously, usually within one to two weeks from onset. Eighty-five percent of those who receive treatment from an otolaryngologist (sometimes called an ENT) will recover some of their hearing.
- vitamins and antioxidants
- vasodilators
- betahistine (Betaserc), an anti-vertigo drug
- hyperbaric oxygen
- anti-inflammatory agents, primarily oral corticosteroids such as prednisone, methylprednisone
- Intratympanic administration - Gel formulations are under investigation to provide more consistent drug delivery to the inner ear. Local drug delivery can be accomplished through intratympanic administration, a minimally invasive procedure where the ear drum is anesthetized and a drug is administered into the middle ear. From the middle ear, a drug can diffuse across the round window membrane into the inner ear. Intratympanic administration of steroids may be effective for sudden sensorineural hearing loss for some patients, but high quality clinical data has not been generated. Intratympanic administration of an anti-apoptotic peptide (JNK inhibitor) is currently being evaluated in late-stage clinical development.
About 1 in 1,000 children in the United States is born with profound deafness. By age 9, about 3 in 1,000 children have hearing loss that affects the activities of daily living. More than half of these cases are caused by genetic factors. Most cases of genetic deafness (70% to 80%) are nonsyndromic; the remaining cases are caused by specific genetic syndromes. In adults, the chance of developing hearing loss increases with age; hearing loss affects half of all people older than 80 years.
Individuals with Nager syndrome typically have the malformations of the auricle, external auditory canal, and middle ear, including the ossicles. These malformations were found in 80% of individuals with Nager syndrome. Inner ear malformations, however, are not typically seen in this population. Middle ear disease is common among individuals with Nager syndrome. Chronic otitis media and Eustachian tube deformity can result in conductive hearing loss. For this reason, early detection and treatment for middle ear disease is crucial in this population. Sensorineural hearing loss is not a typical characteristic of Nager syndrome; however, a subset of individuals present with a mixed hearing loss, due to a progressive sensorineural component combined with the typical conductive hearing loss (Herrman "et al.", 2005).
The treatment will vary with the different grades, but the most common is a surgical repair. The surgical option is cosmetic reconstruction of the external ear's normal shape and repair of the ear canal. In less severe cases the reconstruction will be sufficient to restore hearing. In grades of anotia/microtia that affect the middle ear the surgery with the use of a Bone Anchored Hearing Aid (BAHA) will likely restore the hearing. The BAHA may be surgically implanted onto the skull which would allow for some hearing repair by conduction through the skull bone. "This allows sound vibrations to travel through bones in the head to the inner ear."
BAHA: An implantable hearing device. It is the only hearing aid device that works via direct bone conduction.
The constellation of anomalies seen with Nasodigitoacoustic syndrome result in a distinct diagnosis. The diagnostic criteria for the disorder are broad distal phalanges of the thumbs and big toes, accompanied by a broad and shortened nose, sensorineural hearing loss and developmental delay, with predominant occurrence in males.
Nasodigitoacoustic syndrome is similar to several syndromes that share its features. Brachydactyly of the distal phalanges, sensorineural deafness and pulmonary stenosis are common with Keutel syndrome. In Muenke syndrome, developmental delay, distal brachydactyly and sensorineural hearing loss are reported; features of Teunissen-Cremers syndrome include nasal aberrations and broadness of the thumbs and big toes, also with brachydactyly. Broad thumbs and big toes are primary characteristics of Rubinstein syndrome.
Once the diagnosis is made based on clinical signs, it is important to investigate other body systems that may be involved. For example, if the diagnosis is made based on the abnormal appearance of the ears and developmental delay, it is important to check the child's hearing, vision, heart, nose, and urogenital system. Ideally, every child newly diagnosed with CHARGE syndrome should have a complete evaluation by an ENT specialist, audiologist, ophthalmologist, pediatric cardiologist, developmental therapist, and pediatric urologist.