Chapter 64- Hearing/Balance Flashcards
How is hearing conducted?
Hearing is conducted over two pathways: air and bone. Sounds transmitted by air conduction travel over the air-filled external and middle ear through vibration of the tympanic membrane and ossicles. Sounds transmitted by bone conduction travel directly through bone to the inner ear, bypassing the tympanic membrane and ossicles. Normally, air conduction is the more efficient pathway.
What are the two main functions of the ear?
Hearing and balance.
How is balance and equilibrium maintained?
Body balance is maintained by the cooperation of the muscles and joints of the body (proprioceptive system), the eyes (visual system), and the labyrinth (vestibular system).
What does an ear assessment include?
Assessment of hearing and balance involves inspection of the external, middle, and inner ear. Evaluation of gross hearing acuity also is included in every physical examination.
What does examination of the external ear involve?
Inspection of the external ear is a simple procedure, but it is often overlooked. The external ear is examined by inspection and direct palpation; the auricle and surrounding tissues should be inspected for deformities, lesions, and discharge, as well as size, symmetry, and angle of attachment to the head.
What is an otoscopic examination?
The tympanic membrane is inspected with an otoscope and indirect palpation with a pneumatic otoscope. The healthy tympanic membrane is pearly gray and is positioned obliquely at the base of the canal. The following landmarks are identified, if visible (see Fig. 64-2): the pars tensa, the umbo, the manubrium of the malleus, and its short process.
What are some hearing tests?
A general estimate of hearing can be made by assessing the patient’s ability to hear a whispered phrase, testing one ear at a time. The Weber and Rinne tests may be used to distinguish conductive loss from sensorineural loss when hearing is impaired.
What diagnostic tests are done for the ear?
What genetic syndromes are associated with hearing loss?
Waardenburg syndrome, Usher syndrome, Pendred syndrome, and Jervell and Lange-Nielsen syndrome.
What causes conductive hearing loss?
An external ear disorder, such as impacted cerumen, or a middle ear disorder, such as otitis media or otosclerosis.
What is mixed hearing loss?
Patients with mixed hearing loss have conductive loss and sensorineural loss, resulting from dysfunction of air and bone conduction.
What is deafness?
The partial or complete loss of the ability to hear.
How do loud noises cause hearing loss?
Loud, persistent noise has been found to cause constriction of peripheral blood vessels, increased blood pressure and heart rate (because of increased secretion of adrenalin), and increased gastrointestinal activity. Although research is needed to address the overall effects of noise on the human body, a quiet environment is more conducive to peace of mind. A person who is ill feels more at ease when noise is kept to a minimum.
What are risks for hearing loss?
- Family history of sensorineural impairment
- Congenital malformations of the cranial structure (ear)
- Low birth weight (<1,500 g)
- Use of ototoxic medications (e.g., gentamycin, loop diuretics)
- Recurrent ear infections
- Bacterial meningitis
- Chronic exposure to loud noises
- Perforation of the tympanic membrane
What is presbycusis?
Progressive, age-related hearing loss.
What are other age-related causes of hearing loss?
In addition to age-related changes, other factors can affect hearing in the older adult population, such as lifelong exposure to loud noises. Certain medications, such as aminoglycosides, aspirin, loop diuretics and platinum-based antineoplastic medications have ototoxic effects when kidney changes result in delayed medication excretion and increased levels of the medications in the blood.
What is cerumen impaction and how is it managed?
Accumulation of cerumen as a cause of hearing loss is especially significant in older adult patients. Cerumen can be removed by irrigation, suction, or instrumentation.
How are foreign bodies removed from the external auditory canal?
Removing a foreign body from the external auditory canal can be quite challenging. The three standard methods for removing foreign bodies are the same as those for removing cerumen: irrigation, suction, and instrumentation.
What is External Otitis?
Inflammation of the external auditory canal.
What causes External Otitis?
Causes include water in the ear canal (swimmer’s ear); trauma to the skin of the ear canal, permitting entrance of organisms into the tissues; and systemic conditions, such as vitamin deficiency and endocrine disorders. Bacterial or fungal infections are most frequently encountered. The most common bacterial pathogens associated with external otitis are Staphylococcus aureus and Pseudomonas species. The most common fungus isolated in both normal and infected ears is Aspergillus.
What are the symptoms of External Otitis?
Patients usually report pain; discharge from the external auditory canal; aural tenderness (usually not present in middle ear infections); and occasionally fever, cellulitis, and lymphadenopathy. Other symptoms may include pruritus and hearing loss or a feeling of fullness.
How is External Otitis managed?
The principles of therapy are aimed at relieving the discomfort, reducing the swelling of the ear canal, and eradicating the infection. Patients may require analgesic medications for the first 48 to 92 hours. Treatment most often includes antimicrobial or antifungal otic medications administered by dropper at room temperature. In bacterial infection, a combination antibiotic and corticosteroid agent may be used to soothe the inflamed tissues (Porth & Matfin, 2009).
What is malignant external otitis?
This is a progressive, debilitating, and occasionally fatal infection of the external auditory canal, the surrounding tissue, and the base of the skull. Pseudomonas aeruginosa is usually the infecting organism in patients with low resistance to infection (e.g., patients with acquired immunodeficiency virus).
What are exostoses and how are they managed?
Exostoses are small, hard, bony protrusions found in the lower posterior bony portion of the ear canal; they usually occur bilaterally. The skin covering the exostosis is normal. It is believed that exostoses are caused by an exposure to cold water, as in scuba diving or surfing. The usual treatment, if any, is surgical excision.
What happens if malignant tumors of the external ear are left untreated?
Malignant tumors also may occur in the external ear. Most common are basal cell carcinomas on the pinna and squamous cell carcinomas in the ear canal. If untreated, squamous cell carcinoma may spread through the temporal bone, causing facial nerve paralysis and hearing loss. Carcinomas must be treated surgically.
What causes tympanic membrane rupture?
Perforation of the tympanic membrane is usually caused by infection or trauma. Sources of trauma include skull fracture, explosive injury, or a severe blow to the ear. Less frequently, perforation is caused by foreign objects (e.g., cotton-tipped applicators, hairpins, keys) that have been pushed too far into the external auditory canal.
How are tympanic membrane perforations managed?
Although most tympanic membrane perforations heal spontaneously within weeks after rupture, some may take several months to heal.
Perforations that do not heal on their own may require surgery. The decision to perform a tympanoplasty (surgical repair of the tympanic membrane) is usually based on the need to prevent potential infection from water entering the ear or the desire to improve the patient’s hearing.
What is acute otitis media?
Inflammation in the middle ear lasting less than 6 weeks.
