Download Chapter 14 Sensory Function

Chapter 14
Sensory
Function
Sensory System
• General senses include pain, light touch,
pressure, temperature, and proprioception
• Special senses include taste, smell, sight,
hearing, and balance
Sensory Receptors
• Mechanoreceptors – activated by
mechanical stimuli such as touch or
pressure
• Chemoreceptors – activated by chemicals in
the blood, food, or air
• Thermoreceptors – activated by heat or cold
• Photoreceptors – activated by light
• Nociceptors – activated by painful stimuli
Pain
• Associated with many conditions
• Protective mechanism
• Most common reason that people seek medical
attention
• Can be used to aid diagnosis
• Subjective feeling
• Pain threshold – perception of pain
– Can be influenced by affective, behavior, cognitive,
sensory, and physiologic factors
• Unrelieved pain can delay healing, stimulate the
stress response and result in pain tolerance
Types of Pain
• Somatic pain
– Results from noxious stimuli to the skin, joints,
muscles, and tendons
– Generally easy to pinpoint
• Visceral pain
– Results from noxious stimuli to internal organs
– Usually vague and diffuse
– May be sensed on body surfaces at distant
locations from the originating organ, called
referred pain
Types of Pain
• Phantom pain
– Exists after the removal of a body part
– Severed neurons may result in spontaneous firing of spinal cord
neurons because normal sensory input has been lost
– Can be extremely distressing but usually resolves with time
• Intractable pain
– Chronically progressing pain that is unrelenting and severely
debilitating
– Does not usually respond well to typical pharmacologic pain
treatments
– Common with severe injuries, especially crushing injuries
• Neuropathic pain
– Results from damage to peripheral nerves by disease or injury
– Tends to be chronic and intractable
Eyes
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Perceive the environment
Sclera – white area
Cornea – lens on anterior surface
Choroid – middle layer of the eye, which contains
melanin to absorb stray light
• Ciliary body – anterior portion of the choroid, which
contains smooth muscle fibers that control the shape of
the lens to focus on incoming light
• Iris – colored portion
• Pupil – dark opening in the center of the iris
Eyes
• Retina – innermost layer of the eye
– Contains an outer, pigmented layer and an
inner layer consisting of photoreceptors
and nerve cells
– Weakly attached to the choroid, making it
vulnerable to damage
– Contains two types of photoreceptors
• Rods – sensitive to low light and function at night
• Cones – only operate in bright light and are
responsible for visual acuity and color vision
Eyes
• Optic nerve – form from the axons of the
ganglion cells at the back of the eye
– This area contains no photoreceptors and is
insensitive to light
• Visual images cast upside down onto the
retina, and impulses are transmitted to the
brain
Eyes
• Lens – transparent, flexible structure
behind the iris
• Anterior chamber - front of the lens
• Posterior chamber – behind the lens
• Aqueous humor - watery liquid in the
anterior chamber that provides nutrients to
the cornea and lens and carries away
cellular waste products
Eyes
• Vitreous humor – clear, gelatinous material that
fills the posterior chamber
• Conjunctiva – fragile membrane that covers the
inner surface of the eyelid and the exposed
surface of the eye
• Lacrimal glands keep surface moist
• Blinking cleans the eye by sweeping the fluid
• Tears drain on the inner side through two
lacrimal ducts
Ears
• Detect and process sound, detect body
position, and maintain balance
• Outer ear – auricle (or pinna), ear lobe, and
external ear canal
• Middle ear – tympanic membrane and the
ossicles
• Inner ear – cochlea, semicircular canals,
saccule, and utricle
Sound Transmission
• Enters through the auricle, an irregularly
shaped cartilage that channels sound into the
ear
• Sound travels through the external ear canal
until reaching the tympanic membrane, or
eardrum
• Sound hits the tympanic membrane, creating
vibrations
Sound Transmission
• The vibrations transmit from the membrane to the
ossicles—malleus (hammer), incus (anvil), and stapes
(stirrup)
• The malleus lies near the tympanic membrane, and
vibrations from the membranes cause the malleus to rock
back and forth
• This rocking causes the incus to vibrate, which, in turn,
causes the stapes to move in and out against the oval
window, an opening to the inner ear covered with a
membrane
Sound Transmission
• Vibrations created by the tympanic membrane amplify as
they are transmitted through the structures to the inner
ear
• Movement of the oval window causes fluid within the
cochlea to vibrate, creating waves
• The organ of Corti contains hearing receptors, the hair
cells, and vibrations at the organ of Corti stimulate hair
movement
• Dendrites wrap the bases of these hair cells
• Hair movement causes the dendrites to form nerve
impulses that travel to the brain via the vestibulocochlear
nerve, cranial nerve VIII
Position and Balance
• Vestibular apparatus – located in the inner
ear
• Two parts
– Semicircular canals – three ringlike, fluid-filled
structures that house receptors for body position and
movement; fluid movement stimulates dendrites to
send impulses to the brain to report this movement
– Vestibule – bony chamber positioned between the
cochlea and semicircular canals that houses receptors
that respond to body position and movement
Ears
• Eustachian tube – located in the middle
ear and opens into the pharynx
– Acts as a pressure valve
– Normally, the tube remains closed
– May become open with activities such as
yawning and swallowing
– Opening the eustachian tube allows air to flow
in and out of the middle ear, equalizing the
internal and external pressure on the
tympanic membrane
Understanding Sensory Conditions
• Alterations result Altered Sensory
Perception
• Alterations may also result in:
– Risk for Injury
Congenital Cataracts
• Clouding of the lens that is present at birth
• Results in hazy vision
• In most cases, no specific cause can be
identified
• Associated with several genetic and
chromosomal conditions (e.g., Down
syndrome, Patau syndrome, Lowe syndrome,
and galactosemia) as well as intrauterine
infection exposure (e.g., congenital rubella)
Congenital Cataracts
• Other manifestations: failure to demonstrate
visual awareness and presence of
nystagmus
• Diagnosis: history, physical examination
(including a thorough ophthalmology exam),
and additional tests may be necessary to
determine other associated conditions
• Treatment: may not be required, surgical
removal, artificial intraocular lens, patching,
manage any underlying disorder
Congenital Ear Conditions
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Anotia – absence of the auricle
Microtia – underdeveloped, small auricle
Atresia – lack an external ear canal
These conditions are more common in males
Often associated with other congenital conditions
affecting the head (e.g., hemifacial microsomia,
Goldenhar syndrome, and Treacher-Collins syndrome)
• May be unilateral or bilateral
• Congenital hearing loss can occur because of damage
associated with maternal rubella and syphilis infection
during pregnancy
Sensory Conditions
Associated With Aging
• The senses become less acute and less
able to distinguish details
• Aging increases the threshold needed to
perceive sensory input, so the amount of
sensory input needed to be aware of the
sensation becomes greater
• Physical changes account for most of the
other sensation changes
Sensory Conditions
Associated With Aging
•
Age-related eye changes may begin as early as 30
•
Eye changes include
– Less tear production
– Structural deteriorations
– Corneas becomes less sensitive
– Pupil size decrease and react more slowly
– Lens becomes yellowed, less flexible, and slightly cloudy
– Fat pads supporting eye decrease and eyes sinks back into the skull
– Eye muscles weaken, decreasing the ability to rotate the eye fully and
limiting the visual field
– Visual acuity may gradually decline
– Presbyopia – difficulty focusing the eyes
•
Treatment: glasses or contact lenses, use red lighting, and lower lighting
Sensory Conditions
Associated With Aging
• All the ear structures thicken with aging affecting balance
and hearing
• Hearing may decline slightly, especially with high-frequency
sounds
• Hearing loss accelerates in people who were exposed to
excessive noise or smoking when they were younger
• Presbycusis – age-related hearing loss
• Hearing acuity may decline slightly beginning about 50
years of age, possibly caused by changes in the auditory
nerve
• The brain may have a slight decreased ability to process or
translate sounds into meaningful information
Sensory Conditions
Associated With Aging
• Impacted cerumen is another cause of impaired
hearing and is more common with increasing age
• Sensorineural hearing loss involves damage to the
inner ear, auditory nerve, or the brain
• Conductive hearing loss occurs when sound has
problems transmitting through the outer and middle
ear to the inner ear
• Tinnitus is common
• Treatment: surgery or a hearing aid may be helpful
for conductive type of hearing loss, depending on the
specific cause
Conjunctivitis
• Infection or inflammation of the conjunctiva
• Caused by viruses (most common), bacteria
(e.g., Staphylococcus, Chlamydia, and
gonorrhea), allergens (e.g., pollen and dust),
chemical irritants, and trauma
• Can generate blurry vision and photophobia
• Viral infections normally produce a watery or
mucuslike exudate
Conjunctivitis
• Bacterial infections usually produce a yellow-green exudate
• Allergens and irritants typically produce redness, itching, and
excessive tearing
• Risk factors: wearing contact lenses and using contaminated
makeup or ophthalmic medications
• Bacterial and viral is highly contagious through direct contact
• Treatment: many resolve without treatment, vary depending
on the underlying agents, treat infants with ophthalmic
antibiotics shortly after birth, and warm moist compresses
Keratitis
• Inflammation of the cornea that can be
triggered by an infection or trauma
• The HSV type 1 can be self transmitted from
the mouth and cause an ulcerated form
• Manifestations: severe pain, photophobia,
and visual disturbances
• Treatment: varies depending on the
underlying etiology, but includes ophthalmic
or oral antibiotics and corticosteroid agents
Otitis Media
• Infection or inflammation of the middle ear
• Common condition in young children because the
eustachian tubes of young children are narrower,
straighter, and shorter than those of adults and older
children and an immature immune system
• Additional cause: fluid accumulation in the middle ear due
to adenoid enlargement, usually due to inflammation
• Typically begins as a viral upper respiratory infection
• More common in the winter months
• Fluid collection from the viral infection provides a prime
medium for secondary bacterial growth, usually
Streptococcus pneumoniae and Haemophilus influenzae
Otitis Media
• Additional risk factors: child care in group settings,
feeding infants in the supine position, environmental
smoke exposure, and a history of allergic rhinitis
• Complications: rupture of the tympanic membrane, scar
tissue formation, conductive hearing loss, mastoiditis,
cholesteatoma, meningitis, and osteomylitis
• Manifestations: ear pain, crying or irritability, rubbing or
pulling at the ear, mild hearing deficits, sleep
disturbances, red and bulging tympanic membrane,
indications of infection, purulent or clear exudate from
the external ear canal (if the tympanic membrane
ruptures), nausea, vomiting, and headache
Otitis Media
• Diagnosis
– History and a physical examination
– Otologic examination including visualization of the
tympanic membrane, tympanometry, and acoustic
reflectometry
• Treatment
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Oral or otologic antibiotics and analgesics
Oral decongestant and antihistamine agents
Antipyretics
Tympanostomy tubes
Removal of the adenoids
Otitis Externa
• Infection or inflammation of external ear canal or
auricle
• Usually bacterial in origin (often Pseudomonas
aeruginosa) but may also be fungal
• Generally arises from moisture in the ear that
creates an environment for bacterial or fungal
growth or introduction of the organisms from
external sources
Otitis Externa
• Risk factors: swimming in contaminated water,
scratching outside or inside of ear, and insertion
of foreign objects
• Complications: hearing loss, cellulitis, necrosis,
osteomylitis, and meningitis
• Manifestations: ear pain that worsens with
auricle movement, purulent exudate, itching, a
sensation of fullness in the ear, and hearing
deficits
Otitis Externa
• Diagnosis: history, physical examination (including
an otologic examination), and exudate analysis
• Treatment
– Otologic antibiotics, antifungals, corticosteroids, and
analgesics
– Clean the external canal
• Prevention: drying the ears after swimming or
bathing with an alcohol-based product, avoiding
insertion foreign objects into the ear, and treating
pools properly
Eye Trauma
• Causes: direct physical trauma or chemical
burns
• May vary in severity from mild (e.g., black
eye) to sight threatening (e.g., corneal
abrasions and closed-angle glaucoma)
• Vision deficits often result
Eye Trauma
• Manifestations: eye pain, edema, blurry
vision, diplopia, dry eyes, photophobia,
floaters, pupil dilatation, and pupils that are
unresponsive to light
• Early diagnosis and treatment can prevent
or limit the severity of visual deficits
• Diagnosis: history and physical examination
(including an ophthalmic examination often
by an ophthalmologist)
Eye Trauma
• Treatment
– Flushing irritant out of the eye with sterile saline
– Avoiding rubbing the eye
– Leaving an embedded object in the eye
– Covering the eye with a sterile dressing or cloth
– Applying eye patches to protect the eye during
the healing process
– Repairing any damage surgically
Ear Trauma
• Causes: direct physical trauma (e.g.,
foreign objects and insects) and excessively
loud noises (e.g., explosions and gunshots)
• Can result in permanent hearing deficits
• Manifestations: bloody or clear exudate,
tinnitis, dizziness, ear pain, hearing deficits,
nausea, vomiting, edema, and a sensation
that an object is in the ear
Ear Trauma
• Treatment
– Removing the object if it is visible and easily
removed
– Performing surgery to remove objects or repair
the damage
– Limiting exposure to loud sounds as structures
heal
Glaucoma
• Group of eye conditions that lead to damage to the
optic nerve
• Causes: increased intraocular pressure and
decreased blood flow to the optic nerve
• Pressures inside the eye can climb because of
blocked outflow of aqueous humor or increased
production of aqueous humor
• These increased pressures cause ischemia and
degeneration of the optic nerve
• Second leading cause of blindness (diabetic
retinopathy is number one)
Open-Angle Glaucoma
• Most common type
• Intraocular pressure increases gradually
over an extended period
• Risk factors: family history and African
American decent
• Manifestations: painless, insidious,
bilateral changes in vision (e.g., tunnel
vision, blurred vision, halos around lights,
and decreased color discrimination)
Closed-Angle Glaucoma
• Medical emergency
• Result of a sudden blockage of aqueous humor
outflow
• Causes: trauma, sudden pupil dilatation (e.g.,
exposure to bright light after prolonged
exposure to darkness), prolonged pupil
dilatation (e.g., medications for eye
examinations), and emotional stress
Closed-Angle Glaucoma
• Typically unilateral, but it may affect both
eyes
• Manifestations: sudden and severe eye
pain, headache, nausea, vomiting, a
nonreactive pupil, redness, haziness of
the cornea, and vision changes (e.g.,
halos around lights)
Glaucoma
• Congenital glaucoma
– Present at birth
– Result of abnormal development of outflow
channels (trabecular meshwork) of the eye
– X-linked, recessive hereditary pattern
– May go unnoticed for a few months
– Manifestations: excessive lacrimation,
photophobia, corneal edema, gray-white
appearance to the cornea, enlarged eye globe,
and vision deficits
Glaucoma
• Secondary glaucoma
– Result of certain medications (e.g.,
corticosteriods), eye diseases (e.g., uveitis
and nearsightedness), and systemic
diseases (e.g., arteriosclerosis and diabetes
mellitus)
Glaucoma
• Diagnosis
– History and physical examination
– Ophthalmic examination including
gonioscopy, tonometry, optic nerve
imaging, pupillary reflex response,
retinal examination, slit lamp
examination, visual acuity testing, and
visual field measurement
Glaucoma Treatment
• Strategies for open-angle glaucoma
– Ophthalmic medications
• Beta blockers
• Alpha agonists
• Carbonic anhydrase inhibitors
• Prostaglandin-like compounds
• Miotic or cholinergic agents
• Epinephrine compounds
• Alpha-2 adrenergic agonists
Glaucoma Treatment
– Oral medications (not generally effective
when used alone), including carbonic
anhydrase inhibitors
– N-methyl d-aspartate receptor antagonist
– Laser surgery to open aqueous humor
outflow
– Filtering surgery
– Drainage implants
Glaucoma Treatment
• The main strategy for treating closed-angle
glaucoma is iridotomy
• The main strategies for treating congenital
glaucoma is surgery to open the aqueous humor
outflow channels (e.g., laser, filtering, and
drainage implants)
• Strategies to treat secondary glaucoma include:
– Chronic disease management
– Treating or eliminating underlying causes
– Previously discussed glaucoma pharmacologic and
surgical treatments
Cataracts
• Opacity or clouding of the lens
• Can occur as a congenital condition or develop later
in life
• Risk factors for adult-onset cataracts: family history,
advancing age, smoking, ultraviolet (UV) light
exposure (natural or artificial), metabolic conditions
(e.g., diabetes mellitus), certain medications (e.g.,
corticosteroids), and eye injury (e.g., trauma and
infection)
• May affect one or both eyes and do not necessarily
affect eyes symmetrically
Cataracts
• Other manifestations
– Cloudy, fuzzy, foggy, or filmy vision
– Color intensity loss
– Diplopia
– Impaired night vision gradually progressing to
impaired day vision
– Halos around lights
– Photosensitivity
– Frequent changes in eyeglass or contact
prescription
Cataracts
• Diagnosis
– History and physical examination
– Ophthalmic examination includes visual
acuity testing, retinal examination, and
slit lamp examination
• Treatment: surgery and managing or
eliminating contributing factors
Macular Degeneration
• Deterioration of the macular area of the
retina
• Caused by impaired blood supply to the
macula that results in the cellular waste
accumulation and ischemia
• The most significant risk factor for this
condition is advancing age
• Risk factors: family history, being female,
Caucasian decent, smoking, high-fat diet,
and obesity
Macular Degeneration
• Dry macular degeneration
– Occurs when the blood vessels under the
macula become thin and brittle
– Small yellow deposits (drusen) form under the
macula
– Deposits increase in size and number,
blurring vision and creating a dim spot in the
central vision
– Almost all people with macular degeneration
start with the dry form
– Progresses gradually (over years)
Macular Degeneration
• Wet macular degeneration
– Occurs in only about 10% of people with macular
degeneration
– Brittle vessels break down, and new, abnormal, fragile
blood vessels grow under the macula
– Vessels leak blood and fluid, leading to macula
damage
– Not as common, but causes most of the vision loss
associated with the condition
– Progresses suddenly with rapid vision loss (over
weeks or months)
Macular Degeneration
• Diagnosis
– History and physical examination
– Ophthalmic examination includes visual
acuity using the Amsler grid, retinal
examination, fluorescein angiogram,
and optical coherence tomography
Macular Degeneration Treatment
• No treatment exists for dry macular
degeneration
• Age-Related Eye Disease Study formula can
slow progression, but smokers should not use
this treatment
– 500 milligrams of vitamin C
– 400 international units of beta-carotene
– 80 milligrams of zinc
– 2 milligrams of copper
Macular Degeneration Treatment
• No cure for wet macular degeneration
• Strategies may include:
– Laser surgery
– Photodynamic therapy
– Antiangiogenesis or anti-vascular endothelial
growth factor therapy
– Low-vision aids
– Occupational therapy
Otosclerosis
• Abnormal bone growth in the middle ear, usually
involving an imbalance in bone formation and
resorption
• Cause is unknown, but appears to be hereditary
• Abnormal spongelike bone grows in the middle ear,
preventing the ear structures from vibrating in response
to sound waves
• Conductive hearing loss progressively worsens
• Nerve loss can also occur
• Most common in young adults, women and Caucasians
• Pregnancy may also trigger
• Typically affects both ears
• Tinnitus may also be present
Otosclerosis
• Diagnosis: history, physical examination
(including a hearing test), and temporal-bone
computed tomography
• Treatment
– Medications such as oral fluoride, calcium, or
vitamin D may help to control the hearing loss,
but the efficacy remains in question
– Hearing aids to treat the hearing loss
– Surgery to remove the stapes and replace it with
a prosthesis
– Laser surgery to create an opening in the stapes
with or without the placement of the prosthetic
device
Meniere’s Disease
• Disorder of the inner ear that results from
endolymph swelling
• This swelling stretches the membranes and
interferes with the hair receptors in the cochlea
and vestibule
• The exact cause is unknown, but may be
associated with head injuries, otitis media, and
syphilis
• Additional risk factors: allergic rhinitis, alcohol
consumption, stress, fatigue, certain medications
(e.g., aspirin), and respiratory infections
Meniere’s Disease
• Manifestations
– Typically occur in waves of acute episodes that
last several months followed by brief periods of
relief
– Attacks triggered by changes in barometric
pressure or any of the risk factors
– Include: intermittent episodes of vertigo,
tinnitus, unilateral hearing loss, and a
sensation of fullness
• Complications: permanent hearing loss
Meniere’s Disease
• Diagnosis: history, physical examination
(including a neurologic assessment),
hearing test, balance test,
electrocholeography,
electronystagmography, caloric stimulation,
head computed tomography, and head
magnetic resonance imaging
Meniere’s Disease
• Treatment
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No cure
Antihistamine agents
Benzodiazepines
Anticholinergic agents
Diuretics
Antiemetic agents
Limitation of dietary sodium intake (to promote fluid retention)
Avoiding triggers (e.g., alcohol and stress)
Middle ear injections of gentamicin (an ototoxic antibiotic that can reduce
balance structures) or corticosteroids
Partial or complete surgical removal of the endolymph or inner ear
Vestibular nerve resection
Hearing aids
Physical therapy to improve balance
Eye Cancer
• Uncommon
• Affecting genders and ethnic groups relatively
evenly
• Can affect any part of the eye
• Most common intraocular cancers in adults are
melanoma and lymphoma
• Most frequent eye cancer in children is
retinoblastoma
Eye Cancer
• May metastasize to the eye from other parts of
the body
• Manifestations: some sort of visual disturbance
(e.g., losing part of the visual field and seeing
flashing lights)
• Diagnosis: history, ophthalmic examination,
ultrasound, fluorescein angiography (imaging of
blood vessels in the eye using contrast dye),
biopsy, and other tests to detect and evaluate
metastasis
• Treatment: surgery, radiation, and prosthetic eye
Strabismus
• Gaze deviation of one eye
• The eyes do not coordinate to focus on the
same object together, resulting in diplopia
• Most often appears at birth or shortly after
• In children, the brain will begin to ignore input
from one eye
• If the brain continues to ignore one eye, the eye
will never function properly, and permanent
visual deficits may result (e.g., amblyopia)
Strabismus
• Causes: a weak or hypertonic eye muscle, a short
muscle, or a neurologic deficit
• Often associated with chromosomal defects (e.g., Down
syndrome), intrauterine infection exposure (e.g.,
congenital rubella), eye cancers (e.g., retinoblastoma),
and traumatic brain injuries
• Diagnosis: history and physical examination (including an
ophthalmic examination and a neurologic examination)
• Treatment: glasses (e.g., prism glasses), eye muscle
exercises, eye patching, and surgery
Amblyopia
• Loss of one eye’s ability to see details
• Most common cause of vision problems in children
• Occurs when the brain and eyes do not work together
properly; the brain favors one eye
• The preferred eye has normal vision, but because the
brain ignores the other eye, vision does not develop
normally
• Normal eye attempts to compensate for affected eye,
creating a viscous cycle where normal eye becomes
stronger and affected eye becomes weaker
Amblyopia
• The brain stops growing between 5 and 10 years of age,
at which time the condition becomes permanent
• Causes: strabismus, family history, bilateral astigmatism,
congenital cataracts, farsightedness, and
nearsightedness
• Diagnosis: history and physical examination (including an
ophthalmic examination)
• Treatment: wearing glasses (e.g., prism glasses), eye
muscle exercises, eye patching, ophthalmic medication
(atropine may be used to dilate the pupil of the normal
eye to “chemically patch” it), and surgery
Retinal Detachment
• Acute condition that occurs when the retina
separates from its supporting structures
• Causes: spontaneously, severe
nearsightedness, trauma, diabetes mellitus,
inflammation, degenerative aging changes, and
scar tissue
• Occurs when vitreous humor leaks through a
retinal tear and accumulates underneath the
retina
Retinal Detachment
• Leakage can also occur through tiny holes where
the retina has thinned due to aging or other retinal
disorders
• Less commonly, fluid can leak directly underneath
the retina, without a tear or break
• As vitreous humor collects underneath it, the
retina peels away from the underlying choroid
• These detached areas may expand over time
• The retina becomes ischemic and stops
functioning, causing vision loss
Retinal Detachment
• Manifestations: typically painless, flashes of light
in the peripheral visual field, blurred vision,
floaters, and darkening vision (like a curtain
drawing across a visual field)
• Diagnosis
– History and physical examination
– Ophthalmic examination including an
electroretinogram, fluorescein angiography, intraocular
pressure measurements, ophthalmoscopy, a refraction
test, retinal photography, color discrimination, visual
acuity testing, slit lamp examination, and eye
ultrasound
Retinal Detachment
• Medical emergency
• Treatment: surgery including a cryopexy (intense
cold application to the area with an ice probe to
form scar tissue, which holds the retina to the
underlying layer), laser surgery (to seal the tears or
holes in the retina), pneumatic retinopexy (placing
a gas bubble in the eye to help the retina float back
into place), scleral buckle (indents the eye wall),
and vitrectomy (removes gel or scar tissue pulling
on the retina)
Tinnitus
• Hearing abnormal noises in the ear
• May be described as a ringing, buzzing,
humming, whistling, roaring, or blowing
• May be associated with presbycusis, exposure
to excessive noise, cerumen impaction,
otosclerosis, Meniere’s disease, stress, head
injury, acoustic neuroma, atherosclerosis,
hypertension, carotid stenosis, arteriovenous
malformation, caffeine, and ototoxic medications
(e.g., many antibiotics, aspirin, chemotherapies,
and diuretics)
Tinnitus
• Diagnosis: history, physical examination (including a
complete hearing test and otoscopic examination), and
tests to identify underlying cause
• Treatment:
– Treating the underlying cause (e.g., removing
cerumen and controlling blood pressure)
– Tricyclic antidepressants
– Alprazolam (Niravam, Xanax), a benzodiazepine
– Acamprosate (Campral), a drug used to treat
alcoholism
– White noise machines and hearing aids
– Avoiding things that can worsen tinnitus (e.g.,
caffeine, smoking, and ototoxic medications)
Vertigo
• Illusion of motion
• Not the same as dizziness
• Peripheral vertigo occurs when there is a problem with
vestibular labyrinth, semicircular canals, or vestibular
nerve
– Causes: certain medications (e.g., aminoglycoside antibiotics),
head injuries, Meniere’s disease, nerve compression, infections,
and inflammation
• Central vertigo occurs when there is a problem in the
brain, particularly in the brain stem or cerebellum
– Causes: arteriosclerosis, certain medications (e.g., antiseizure
agents and aspirin), alcohol, migraines, multiple sclerosis, and
seizures
– Additional manifestations: nausea and vomiting
Vertigo
• Diagnosis: history, physical examination, and
other tests to determine the underlying
etiology
• Treatment: anticholinergic agents,
antihistamines (especially meclizine
[Antivert]), benzodiazepines, antiemetics,
and safety precautions