Violencia de género entre la población adolescente

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Prenatal causes

„ _{Genetic defects: They may affect inner ear alone or several}

organs (Table 1: syndromic deafness). The inner ear patholo- gies include:

 Michel aplasia: The inner ear does not develop at all.  Mondini aplasia: Cochlea has only 1.5 turns.

 Scheibe aplasia: In this commonest type of inner ear

pathology, the membranous cochlea and saccule are abnormal, but rest of the inner ear is normal.

 Alexander aplasia: This pathology, which affects only

basal turn of cochlea, causes high-frequency sensori- neural hearing loss (SNHL).

„ _{Maternal infections: They include toxoplasmosis, rubella,}

cytomegalovirus and herpes, type 1 and 2 (TORCH) and syphilis.

„ _{Drugs: They include streptomycin, gentamicin, tobramycin,}

amikacin, quinine and chloroquin. They cross the placental barrier and damage the cochlea. Thalidomide causes abnor- malities of ears, limbs, heart, face, lip and palate.

„ _{Birth injuries: Forceps delivery can result in intracranial}

hemorrhage with extravasation of blood in the inner ear.

„ _{Neonatal jaundice: Bilirubin level more than 20 mg %}

damages the cochlear nuclei.

„ _{Ototoxic drugs: They are used for neonatal meningitis or}

septicemia.

„ _{Neonatal meningitis.}

Postnatal causes

„ _{Genetic: Though genetic, it can manifest later in childhood}

or adult life (Table 1). The child may have hearing loss alone (as in familial progressive sensorineural deafness) or with anomalies of other systems (such as Alport, Klippel-Feil and Hurler syndromes).

„ _{Nongenetic: They are similar to adults and include following:}

 Infections: Measles, mumps, varicella, influenza, menin-

gitis, encephalitis and otitis media.

 Ototoxic drugs: Chapter “Sensorineural Hearing Loss.”  _{Trauma: Fractures of temporal bone, middle ear surgery}

or perilymph leak.

 _{Noise trauma: Chapter “Sensorineural Hearing Loss.”}

Syndrome System Features

Congenital autosomal recessive

Onchodystrophy Nail Dystrophy of finger and toe nails, defects of teeth, hair, sebaceous glands Jervell and Lange-Nielson Heart Syncopal attacks, prolonged QT interval in ECG

Pendred’s Thyroid Goiter, hypothyroidism

Klippel-Feil Short neck (fusion of one or more cervical vertebrae) spina bifida, canal atresia, mixed loss

Congenital autosomal dominant

Waardenburg’s Skin White forelock, depigmentation of skin, heterochromia iridis, increased intercanthal distance and antimongoloid slant of eyes

Teacher-Collins (mandibulofacial dysostosis)

Craniofacial and cervical

Hypoplasia of malar bones and mandible, coloboma of lower lids, malformed external and middle ear and conductive loss

Crouzon’s Craniofacial dysostosis (frog eyes), parrot nose, ear malformation, mixed loss Delayed onset autosomal recessive

Usher’s Eyes Progressive retinitis pigmentosa Delayed onset autosomal dominant

Alport’s Kidney Glomerulonephritis and corneal dystrophy

van der Hoeve’s Skeletal Fragile bones, blue sclera and deafness (conductive, sensorineural or mixed) Congenital chromosomal abnormalities

Trisomy 21(Down’s syndrome) Stenosis of ear canal, high incidence of serous otitis media

Trisomy 13–15 Low-set ears with malformation, cleft lip and palate, congenital heart disease Trisomy 16–18 Cardiac abnormalities, low-set pinna, atresia of canal

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clInIcal FEaturES

Hearing loss should be suspected in the following events:

„ _{Sudden loud sounds/noises fail to disturb the sleep and}

startle the child.

„ _{Failure to develop speech in 1–2 years.}

„ _{Defective speech and poor school performance can be due}

to hearing loss. These children may be wrongly labeled as mentally retarded.

meningitis

„ _{About 33% of all acquired SNHL are caused by meningitis.}

Hearing loss varies by causative organisms: Streptococcus

pneumoniae, 20%; Haemophilus influenzae, 12%; and Neisseria meningitidis, 5%.

„ _{Bacteria, fungi or inflammatory cells reach the basal turn}

of scala tympani from the subarachnoid space by way of a patent cochlear aqueduct (often patent in small children and closes as the skull grows) or up the internal auditory canal reaching the cochlear modiolus passing through perineural and perivascular spaces.

„ _{Otological findings: Deafness (usually profound and perma-}

nent involving all frequencies) may be either unilateral or bilateral. It usually occurs early.

 _{Vertigo, nausea, vomiting and ataxia often develop}

regardless of hearing loss.

„ _{Treatment: Immediate broad-spectrum antibiotic and then}

modified as per the report of culture and sensitivity of CSF.

 _{Corticosteroids at the earliest for 2 days reduces inci-}

dence of hearing losses, which once occur is permanent.

Syndromes with genetic Hearing loss (table 1)

Fifty percent cases of infant hearing loss are genetic in origin. Of them, 75–80% is autosomal recessive, 15–20% is autosomal

dominant, and 1–2% is X-linked. Few children have mitochon- drial inheritance (Table 1).

HIgH-rISk rEgIStry

Failure to manage hearing loss in infants and early childhood can affect acquisition of speech, language, cognitive and socioemotional development. Two percent to 2–5% neonates with following risk factors have moderate to profound hearing loss (Fig. 1).

„ _{Family history of hereditary childhood SNHL} „ _{Prenatal infections TORCH}

„ _{Craniofacial abnormalities} „ _{Ototoxic drugs}

„ _{Birth weight less than 1,500 gm}

„ _{Stigmata or other findings associated with hearing loss}

(conductive or sensorineural) syndrome, such as deformed pinna, cleft palate and craniofacial deformities

„ _{Neonatal jaundice: Bilirubin level more than 20 mg %}

requiring an exchange transfusion

„ _{Bacterial meningitis: Especially Haemophilus influenzae} „ _{Neonatal asphyxia with seizures or coma: No spontaneous}

respiration in first 10 minutes; hypotonia persisting for 2 hours. Mechanical ventilation lasting for 5 days or more

„ _{Apgar score}1_{: 0–4 at 1 minute or 0–6 at 5 minutes}

About 50% of children with moderate to profound congen- ital hearing loss have no risk factors. Therefore, the universal newborn hearing screening (UNHS) has evolved.

unIVErSal nEwborn HEarIng ScrEEnIng (unHS)

The UNHS is done within first 3 months of life. It detects the permanent hearing loss at an average age of 3 months. But in the absence of UNHS, average age of diagnosis was found to be 31.25 months. Reliance on physician and parent’s observa- tions were not found successful. Behavioral methods of testing

1 _{Evaluation of a newborn’s physical status by assigning numerical values (0–2) to each of five criterias: 1) heart rate, 2) respiratory effort, 3)}

muscle tone, 4) response stimulation, and 5) skin color; a score of 8–10 indicates best possible condition.

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Electrocochleography measures auditory sensitivity to within 20 dB. It is an invasive procedure and avoided. The future development of frequency-specific auditory brain- stem responses [(ABR, BERA)] or auditory steady state responses (ASSR) will probably replace current two-tiered screening protocol (OAE, ABR/ASSR).

limitations

No test is perfect. Regular monitoring of hearing, speech and language milestones is important even in infants who pass TEAOE, DPOAE or ABR.

„ _{Brainstem evoked response audiometry: Click-evoked audi-}

tory nerve and brainstem evoked potentials (ABEP) often misses hearing losses when hearing is normal at some frequencies.

„ _{Otoacoustic emissions screening is difficult in noisy envi-}

ronment, presence of vernix or debris in external auditory canal (EAC) and collapsing EAC in first 24 hours after birth.

 _{Otoacoustic emissions may miss inner hair cell and}

auditory nerve hearing losses.

brainstem Evoked response audiometry

Synonyms: Auditory Brainstem Responses

For hearing screening, responses are elicited by air- conducted clicks (having broadband frequency spectrum) at a level that produces response in normal hearing ears. They produce no response in ears with hearing loss of 30–35 dB HL. This evoked potential, which is present in neonates as early as 25 weeks gestational age, is unaffected by sleep, attention and sedation (Chapter Hearing Evaluation).

Auditory brainstem responses is affected in disorders of external, middle and internal ears and auditory nerve and brainstem. The current automated ABR detection algorithms replace the subjective impression of the examiner as to the presence or absence of ABR.

Evoked otoacoustic Emission

Evoked otoacoustic emissions are acoustic signals generated by cochlear outer hair cells in response to auditory stimulation. Evoked otoacoustic emissions, which measures only cochlear status, is independent of neural activity and CNS status. Evoked otoacoustic emissions takes lesser time and uses broader frequency range than click-evoked ABR (Chapter Hearing Evaluation).

„ _{Transient evoked otoacoustic emission (TEOAE) provides infor-}

mation over a broad frequency range (500–6,000 Hz) that occurs after a brief stimulus. Transient evoked otoacoustic emission are observed in neonatal ears in the absence of external and middle ear disorders.

threshold frequency-specific ABR and OAE and visual reinforce- ment audiometry (VRA). Newborn hearing screening does not identify progressive hearing loss, which does occur in preschool children and constitute 15–20% of SNHL young children.

The ancillary testing includes laboratory and genetic testing, screening for maternally transmitted infection and temporal bone imaging.

History

„ _{Family history for congenital hearing loss, eye and cardiac}

abnormalities

„ _{Prenatal maternal history of infection (TORCH and syphilis),}

diabetes, hypothyroidism, alcohol, smoking and drugs

„ _{Perinatal risk factors}

Physical Examination

A complete physical examination is mandatory though majority of infants do no have any positive findings. See for the features mentioned in Table 1 showing hearing loss syndromes.

External and middle ear disorders are the most common source of failed initial hearing screening. A thorough evaluation should include following elements:

„ _{Neurologic and developmental milestones} „ _{Nystagmus: Spontaneous and head shaking} „ _{EAC: Clean it and see for stenosis and atresia}

„ _{Tympanic membrane for thickness, appearance and motion}

and middle ear effusion (MEF)

„ _{Pneumatic otoscopy in older children: In 0–6 months of age,}

both tympanometry and pneumatic otoscopy can miss MEF The incidence of MEF in the Ist year of life is quite high (61%). Tympanostomy tube insertion is done for persistent MEF. In infants of acute otitis media, antibiotic therapy is given with close follow-up for the effusion resolution.

Hearing tests

„ _{Frequency-specific ABR thresholds: Both air and bone conduc-}

tions are evaluated using tone-pip ABR. Significant air-bone gap indicates external and middle ear disorders.

„ _{Evoked otoacoustic emission: See other sections and Chapter}

Hearing Evaluation.

„ _{Tympanometry using a probe-tone frequency of 1,000 Hz or}

more: Provide status of middle ear. The traditional tympa-

nometry (using 226 Hz probe tone) is invalid in 0–6 months of age.

„ _{Visual reinforcement audiometry: Visual reinforcement audi-}

ometry is a form of conditioning technique. Infants turn their heads in the direction of sound source. If this response is rewarded by activation of a lighted, animated toy, the infant usually continue to respond and an audiogram is obtained.

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Visual reinforcement audiometry testing can be done either under earphones or sound field testing. Older infants, who yield fewer false positive responses than 6 months infant, tend to reject earphones.

 _{Visual reinforcement audiometry thresholds for 6}

months infant are within 10 dB of adult thresholds.

 _{Visual reinforcement audiometry detects even slight}

threshold elevations seen in MEF. otHEr HEarIng tEStS

The auditory function tests in neonates, infants and young children can be classified into various groups (Box 1). Though currently the gold standards are ABR and OAE, the following tests were done traditionally.

„ _{Screening procedures: These are based on infant’s behavioral}

response to the sound signal.

 Arousal test: A high-frequency narrow band noise

presented for 2 seconds to the light sleeping infant normally awakes the infant twice when three such stimuli are presented.

 Auditory response cradle: The baby is placed in a cradle.

The transducers monitor the infant’s behavior (trunk and limb movement, head jerk and respiration) in response to auditory stimulation.

„ _{Behavior observation audiometry: Auditory signal produces}

a change in infant’s behavior, such as alerting, cessation of an activity, widening of eyes and facial grimacing.

 Moro’s reflex: It consists of sudden movement of limbs

and extension of head in response to sound of 80–90 dB.

 Cochleopalpebral reflex: A child blinks in response to

a loud sound.

 Cessation reflex: In response to a sound of 90 dB, an

infant stops activity or starts crying.

„ _{Distraction techniques: The children of 6–7 months age turn}

their heads to locate the source of sound.

 Method: The child is seated in mother’s lap. One person

distracts the child’s attention while the other produces a sound from behind or from one side. Note whether the child tries to locate the sound by turning head.

 Sounds: They are high-frequency rattle (8 kHz), low-

frequency hum, whispered sound as “S, S, S”, xylophone, warbled tones or narrow band noise (500–4,000 Hz).

„ _{Conditioning techniques (play Aaudiometry): The child is}

conditioned to perform any act on hearing a sound. The acts may be placing a marble in a box, a wooden or plastic block in the bucket, or a ring on a post. The test can be done either in the free-field or by using headphones. A frequency- specific audiogram is possible in a child of 2–4 years of age.

„ _{Speech audiometry: The spondee words are presented to the}

child along with the pictures. The child is asked to point the appropriate picture or repeat the word. The intensity level of the spondee words is gradually lowered. The speech reception threshold is determined. To examine the expres- sive ability, the child is asked to name the toys and objects.

ancillary laboratory testing

They are ordered either to rule out or confirm specific etiologies suspected by hearing tests result, child’s age, history, physical examination, routine blood chemistry and complete blood count. For example, in cases of family history of episodes of syncope, ECG is taken to look for the evidence of Jervell and Lange-Nielsen syndrome.

Screening for maternally transmitted Infection (torcH and Syphilis)

„ _{Infant’ blood for specific IgM for TORCH and syphilis.} „ _{Cultures for CMV in blood, urine or saliva: Detection in first}

3 months of life and early treatment may lessen severity of neurologic sequelae.

„ _{FTA-ABS test for congenital syphilis.}

clinical Features

„ _{Congenital toxoplasmosis: Usually associated with chorio-}

retinitis, intracerebral calcification and microcephaly. Early treatment may reduce progress of hearing loss.

„ _{Herpes simplex type 1 (transplacental transmission) and type}

2 (vaginal transmission).

„ _{Congenital rubella: Fifty percent of the patients present with}

hearing loss alone.

genetic testing

„ _{Chromosomal karyotyping is indicated when SNHL infant}

has:

 _{Unrecognizable constellation of anomalies}  Neurologic or cardiac defects

 _{Mother gives history of multiple miscarriages}  Suspected Pendred’s syndrome

„ _{Screening for connexin 26 mutation: GJB2 gene encodes for}

connexin 26 and is said to be responsible for about 50% of all autosomal recessive congenital hearing loss.

 35delG deletion: It involves a single base pair and is

responsible for 70% of all connexin 26 mutations. The screening tests for 35delG deletion are available.

 DFNB1 (prefix DFNB, signifies autosomal recessive

hearing loss): It stands for autosomal recessive nonsyn- dromic hearing loss mutations in connexin 26 and is associated with prelingual nonprogressive bilateral SNHL (mild to profound) without temporal bone CT abnormality.

temporal bone Imaging

„ _{Noncontrast Temporal Bone CT:}

 _{In all children with SNHL especially in progressive SNHL}

and craniofacial anomalies.

 _{The dilated vestibular aqueduct is associated with}

Pendred’s syndrome.

box 1: Methods of hearing assessment in infants and young

children

• Neonatal screening procedures: Arousal test, auditory response cradle, electric response audiometry

• Behavior observation audiometry: Moro’s reflex, cochleopalpebral reflex, cessation reflex

• Distraction techniques

• Conditioning techniques: visual reorientation audiometry, play audiometry

• Objective tests: Evoked response audiometry, impedance audiometry, otoacoustic emissions, heart rate audiometry

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„ _{Otitis media: In infants of acute otitis media, antibiotic therapy}

is given with close follow-up for the effusion resolution.

 The incidence of MEF in the Ist year of life is quite high

(61%). Tympanostomy tube insertion is done for persis- tent MEF.

„ _{Meningitis: Immediate broad spectrum antibiotic and then}

modified as per the report of culture and sensitivity of CSF.

 Corticosteroids at the earliest for 2 days reduces

incidence of hearing losses, which once occur is permanent.

„ _{Auditory rehabilitation: After identifying the type and extent}

of hearing loss, appropriate rehabilitative measures should be initiated at the earliest, which include amplification and cochlear implantation. Hearing aids help in developing lip reading.

Hearing aids

„ _{Hearing aid should be fit at the earliest. Regular follow-up}

appointments with audiologists is important (Chapter “Hearing Aid and Cochlear Implant”).

„ _{Indication: Permanent bilateral hearing loss (conductive}

or sensorineural) more than 20 dB HL between 1,000 and 4,000 Hz.

„ _{Bone conduction hearing aids: They are indicated in cases of}

atresia, stenotic ear canals and recurrent otorrhea.

„ _{Children less than 7 years: They need behind-the-ear (BTE)}

or bone conduction hearing aids.

„ _{Infants with 55 dB or higher hearing losses: Personal wireless}

FM systems improve the speech-to-noise ratio.

cochlear Implants

Each child should be evaluated carefully for the cochlear implant candidacy (chapter “Hearing Aid and Cochlear Implant”).

„ _{Younger the child better are the results of cochlear implan-}

tation. Infants younger than 1 year of age are also receiving cochlear implants.

„ _{Post meningitis deafness needs early implantation to avoid}

later difficulties of implantation due to cochlear ossification.

„ _{Cochlear ossification (usually post meningitis) and auditory}

nerve aplasia preclude this intervention. rEHabIlItatIVE mEaSurES

Playgroups and parent groups facilitate parents to learn how to accommodate their baby’s communication needs. Services of expert professionals who deal with childhood hearing loss

Parental guidance

Hearing loss happens not just to a child but the whole family. The parents should be sympathetically told of child’s disability and how to care for it. Parents should know regarding the following requirements:

„ _{Care and periodic replacement of hearing aid} „ _{Change of ear moulds as the child grows} „ _{Follow up visits for reevaluation}

„ _{Education at home} „ _{Selection of vocation}

development of Speech and language

Reception of information occurs through visual, auditory or tactile faculties while expression is through the oral/written speech or manual sign language. The proper communication needs either the improvement in hearing through amplification or the development of visual or tactile means of communication.

„ _{Auditory-oral communication: This method of normal people}

communication can be used for the children of postlin- gual deafness. Hearing aids augment auditory reception. Training is imparted in speech reading, which encourages attention towards the movements of lips, face and natural gestures of hand and body. Expressive skill should be encouraged through verbal speech.

„ _{Manual communication: It uses the sign language and}

finger-spelling method. The abstract ideas are difficult to express because general public does not understand it.

total communication

This form of communication, which is good for children with prelingual severe to profound deafness, employs all the sensory inputs such as auditory, visual, tactile and kinesthetic. These children are taught to develop oral speech, lip-reading and sign language.

„ _{Vibrotactile aids: These are useful in children who are both}

deaf, as well as blind. The aids are fitted to the child’s hand or sternum. The vibrations of speech are perceived by the child through tactile sensation (Have you seen film “Black” of Amitabh and Rani Mukherji?).

Education and Vocation of deaf

„ _{The residential and day schools for the deaf children are}

available.

„ _{The children with moderate hearing loss can be integrated}

into normal schools with preferential seating arrangement in the class.

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„ _{In radio hearing aids, the microphone and transmitter are}

with the teacher and the receiver and amplifier are worn by the child. The child can hear the teacher’s voice better avoiding the environmental noises.

„ _{Given the opportunity, commensurate with their ability,}

the deaf people, who are sincere and good workers, can be usefully employed in several vocations.

1. antenatal causes: Inner ear malformation in fetus can occur when pregnant mother is exposed to radiation, German

measles, cytomegalovirus and thalidomide.

2. michel aplasia: It is the total lack of inner ear development. MRI, which shows membranous labyrinth, differentiates

Michel aplasia from the labyrinthine ossification.

3. mondini’s malformation: Cochlea is normal in size but lacks bony partitions between the coils. Cochlea looks empty on

CT scan. vestibule and vestibular aqueduct are dilated. External and middle ears are normal.

4. waardenburg’s syndrome (wS): The features include heterochromia iridis, dystopia canthorum, Hirschsprung’s disease,

hypopigmented areas of skin and sensorineural hearing loss. (SNHL)

5. Pendred’s syndrome: This congenital profound sensorineural hearing loss is associated with abnormality of thyroxin

In document Tatiana Inĩguez Berrozpe (página 66-82)