A 13-month-old boy presents because his parents are concerned that he does not speak recognizable words, has never made babbling sounds such as “baba” or “dada,” does not follow verbal commands, and does not respond to his name. He is appropriately affectionate and makes good eye contact with both of his parents. The child was a full-term baby without hospitalizations or frequent illnesses. He sat without support at 6 months and began walking at 11 months. He is active in the examination room, but he does not respond to his name or to verbal cues from his mother. He is a well-developed, well-nourished normal child otherwise.
What is the most likely diagnosis?
What is the next step?
ANSWERS TO CASE 56: Severe Hearing Loss
Summary: A 13-month-old healthy boy has severe language delay but normal motor development.
• Most likely diagnosis: Hearing loss.
• Next step: Audiologic evaluation.
ANALYSIS
Objectives
1. Understand the major types of hearing loss.
2. Be aware of common causes of hearing loss.
Considerations
This 13-month-old boy has never made babbling sounds such as “baba” and “dada,” which are the normal precursors to language development and usually are seen by 9 months of age. His history and physical examination do not lead to a specific reason for this speech delay (eg, global developmental delay, syndromic features, or history of prematurity with associated morbidity). The next step is an audiologic evaluation.
APPROACH TO:
Hearing Loss
DEFINITIONS
CONDUCTIVE HEARING LOSS: Hearing loss caused by disorders of the outer ear (external auditory canal atresia and otitis externa) or middle ear (otitis media and cholesteatoma).
RETROCOCHLEAR (CENTRAL) HEARING LOSS: Hearing loss caused by deficits in the auditory nerve or central auditory nervous system.
SENSORINEURAL HEARING LOSS (SNHL): Hearing loss caused by cochlea disorders (damage from infection, noise, ototoxic agents, or genetic defects).
CLINICAL APPROACH
Hearing can be divided into several categories ranging from normal hearing (threshold 0-15 decibels [dB]) to profound hearing loss (>70 dB). With mild hearing loss (25-30 dB), inability to hear some speech sounds is noted; with moderate hearing loss (30-50 dB), most normal speech is indiscernible. One to two newborns per 1000 live births have moderate to profound bilateral SNHL.
Sensorineural hearing loss can be congenital or acquired. Approximately half of SNHL cases result from genetic factors. The hearing loss may be isolated (70%) or occur with other syndromic anomalies. The most common autosomal dominant syndromes associated are Waardenburg syndrome types I and II (partial albinism [often a white forelock], deafness, lateral displacement of the inner canthi, heterochromic irises, eyebrow confluence, and a broad nasal bridge) and branchio-oto-renal syndrome (hearing impairment, preauricular pits, branchial fistulas, renal impairment, and external ear abnormalities). Other entities include Alport syndrome (nephritis, progressive renal failure, SNHL, ocular abnormalities), Down syndrome, neurofibromatosis, Jervell and Lange-Nielsen (prolonged QT) syndrome, and Hunter-Hurler syndrome. Ophthalmic or craniofacial abnormalities, external ear malformations, and metabolic, neurologic, or musculoskeletal disorders may be associated with SNHL.
Prenatal cytomegalovirus (CMV) infection is the most common infectious cause of congenital SNHL; it can cause hearing loss later in infancy and childhood. Toxoplasmosis, rubella, and syphilis can lead to congenital SNHL; ongoing hearing evaluations are important. Postnatal infections associated with acquired SNHL include group B streptococcal sepsis and Streptococcus pneumoniae meningitis. Haemophilus influenzae meningitis, mumps, measles, and rubella were common causes prior to current vaccination practices.
Conditions in the prenatal period that are associated with SNHL include prematurity, low birthweight (<1500 g), low Apgar score (0-4 at 1 minute or 0-6 at 5 minutes), mechanical ventilation greater than 5 days, hyperbilirubinemia, bacterial meningitis, ototoxic drug exposure, and craniofacial anomalies. Pharmacologic and chemical exposures can cause SNHL. Aminoglycosides, loop diuretics, chemo-therapeutic agents (cisplatin), isotretinoin, lead, arsenic, and quinine may cause SNHL with in utero or postnatal exposure. Other causes include temporal bone fractures, head trauma, extracorporeal membrane oxygenation (ECMO), radiation, and prolonged exposure to loud noise.
Early diagnosis of hearing impairment can impact development of communication skills. Hearing adequacy is evaluated at medical visits by asking parents about their baby’s response to sounds and their baby’s early language development. Universal newborn hearing screening through otoacoustic emissions (OAE) or auditory brain-stem–evoked responses (ABRs) is now recommended and is required by most states; the goal is hearing loss diagnosis prior to the age of 3 months and intervention before the age of 6 months. Early intervention is believed to enhance communication skills and academic performance.
Various hearing screening methods are used, depending on the child’s developmental level and degree of hearing loss. Auditory brainstem–evoked response testing, often used as the diagnostic test of choice for the mandatory screening in newborns, measures electrophysiologic response and does not require cooperation. Otoacoustic emissions are absent if the hearing threshold is above 30 to 40 dB. Infants through young preschool children can be assessed via visual reinforcement audiometry, behavioral audiometry, or play audiometry; these methods reveal information specific to each ear. In cooperative children, air conduction audiometry can be performed, using headphones and pure tones between 250 and 8000 Hz. The same sounds are presented through oscillator, usually on the mastoid, thus evaluating bone conduction.
Children with SNHL are evaluated by an otolaryngologist, an audiologist, and a speech pathologist. Children with SNHL have a small increased risk for otogentic meningitis and need careful attention to vaccination against Streptococcus pneumonia. Patients with mild to moderate hearing loss can benefit from hearing aids, which can be fitted in infants as young as 2 months. With severe and profound hearing loss, a combination of hearing aids, sign language, lip reading, and attention to appropriate educational surroundings is used. Cochlear implantation is a treatment option for selected children.
COMPREHENSION QUESTIONS
56.1 A 26-month-old boy presents because of maternal concern about his hearing. Over the past few weeks, his mother has had to speak more loudly in order for him to respond. He has a greater than 50-word vocabulary and can put together 2- to 3-word sentences. Three weeks prior he had an upper respiratory infection (URI). Which of the following is the best next step in treatment?
A. Order ABR testing.
B. Perform otoscopy with insufflation.
C. Send him for a complete audiologic evaluation.
D. Perform hearing screening in the clinic.
E. Explain to the mother that 2-year-old children often do not respond to their parents.
56.2 A 4-month-old boy has a white forelock, a broad mandible, and lateral displacement of his inner canthi. His mother also has a white forelock. Which of the following statements is true?
A. A urinalysis will demonstrate increased protein levels.
B. He is not at risk for hearing loss if his mother has normal hearing.
C. He is at risk for SNHL; order an audiologic evaluation.
D. The inheritance pattern of this disorder is X-linked recessive.
E. He should have ongoing clinic hearing screening with referral for formal hearing if abnormalities are detected.
56.3 Which of the following groups of children is at especially high risk for hearing loss?
A. A full-term, large-for-gestational-age male born to a mother with gestational diabetes
B. An appropriate-for-gestational-age (AGA) infant, the product of a 34-week pregnancy, who had Apgar scores of 7 and 8 at 1 and 5 minutes, respectively
C. A term, 3300-g infant born by cesarean section who had a peak total bilirubin level of 15 mg/dL at 72 hours of life
D. A term AGA baby who received cefotaxime and ampicillin for 48 hours for suspected sepsis
E. A term AGA infant born by cesarean section for placental abruption with Apgar scores of 3 and 5 at 1 and 5 minutes, respectively
56.4 Which of the following would be the expected language development of a normal 24-month-old child?
A. Speech that is 90% understandable
B. A 10-word vocabulary but no combination of words
C. A 50-word vocabulary and 2-word combinations to make a sentence
D. Appropriate use of pronouns
E. A 200-word vocabulary and 4- to 5-word combinations to make a sentence
ANSWERS
56.1 B. This child has normal speech development and was recently noted to have a possible hearing deficit. With the recent URI, he is at risk for otitis media with effusion and conductive hearing loss. Otoscopy with insufflation (gently blowing air into the ear canal to determine tympanic membrane movement) is helpful for qualitative evaluation of middle ear effusion. Tympanometry is a reliable, quantitative tool for assessing middle ear effusion. If he has conductive hearing loss, further evaluation is indicated.
56.2 C. This child has features of Waardenburg syndrome (partial albinism, often a white forelock, SNHL, lateral inner canthi displacement, eyebrow confluence, and a broad nasal bridge and mandible); inheritance is autosomal dominant. Children with syndromic features strongly associated with hearing loss require hearing evaluation.
56.3 E. Infants born with Apgar scores of 4 or less at 1 minute and 6 or less at 5 minutes require audiologic evaluation. Other infants who should undergo testing include those with a family history of childhood SNHL; cytomegalo-virus, rubella, syphilis, herpes, or toxoplasmosis infection; craniofacial anomalies; birth weight less than 1500 g; hyperbilirubinemia at a level requiring exchange transfusion; bacterial meningitis; mechanical ventilation for more than 5 days; and stigmata of syndromes associated with hearing loss, especially those with renal abnormalities.
56.4 C. At 24 months of age, the average child has a vocabulary of approximately 50 words and forms 2-word sentences. A 12-month-old child has a vocabulary of 2 to 4 words in addition to appropriately saying “mama” and “dada.” By 36 months, a child should have a vocabulary of 250 words, produce at least 3-word sentences, and use pronouns.
CLINICAL PEARLS
Cytomegalovirus infection is the most common infectious cause of congenital sensorineural hearing loss.
Aminoglycosides and loop diuretics may cause sensorineural hearing loss.
Syndromes associated with renal abnormalities have a higher incidence of hearing loss.
Universal hearing screening at birth is recommended.
REFERENCES
American Academy of Pediatrics. Newborn and infant hearing loss: detection and intervention. Pediatrics. 1999; 103:527-530.
Greinwald JH, Kenna MA, Papsin BC, Kerschner JK. Disorders of the ear. In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA eds. Rudolph’s Pediatrics. 22nd ed. New York, NY: McGraw-Hill; 2011:1309-1311.
Haddad J. Hearing loss. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: WB Saunders; 2011:2188-2196.
Joint Committee on Infant Hearing, American Academy of Audiology, American Academy of Pediatrics, American Speech-Language-Hearing Association, and Directors of Speech and Hearing Programs in State Health and Welfare Agencies. Year 2000 position statement: principles and guidelines for early hearing detection and intervention programs. Pediatrics. 2000; 106:798-817.
Kasthan CE. Hereditary glomerulopathies. In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA eds. Rudolph’s Pediatrics. 22nd ed. New York, NY: McGraw-Hill; 2011:1729-1730.
Tlougan BE, Paller AS. Disorders of pigmentation. In: Rudolph CD, Rudolph AM, Lister GE, First LR, Gershon AA eds. Rudolph’s Pediatrics. 22nd ed. New York, NY: McGraw-Hill; 2011:1266-1267.