Special Senses Conditions

What types of disorders can affect the special senses?

Disorders of the special senses can either be acquired or genetic.

How are visual acuity and colored vision tested?

Visual acuity is the sharpness of vision and is tested with a Snellen eye chart where a patient reads letters of various sizes from a distance of 20 feet. Colored vision is tested with multicolored charts to assess the patient’s ability to recognize different colors.

What does tonometry measure?

Interocular pressure.

What are tuning fork tests used for?

They are used in the office to test for hearing loss and can help distinguish between perceptive hearing loss and conductive hearing loss.

How is the Rinne test performed?

A tuning fork is struck and held on the mastoid process until the patient is unable to hear sound. The tuning fork is then held outside the ear.

What is expected during a Rinne test in a patient with healthy hearing?

The patient will be able to hear a sound again because air conduction of sound is faster than bone conduction of sound.

What are the two main types of hearing loss?

Conductive and sensorineural.

What is conductive hearing loss?

It occurs when there is external or middle ear dysfunction and sound cannot travel to the inner ear.

What can cause conductive hearing loss?

Obstruction by cerumen or a mass, fluid in the middle ear, otosclerosis (stiffness of the ossicles), or separation of the ossicles in the middle ear.

What is sensorineural hearing loss?

It occurs when there is deterioration of the cochlea.

What can cause sensorineural hearing loss?

It is most common in older adults as a result of aging, called presbycusis, but can also occur with persistent exposure to loud noise, head trauma, or other systemic diseases.

What should happen when a patient has indications of hearing loss?

The patient should be referred to an audiologist for formal hearing testing and assessment.

How can hearing loss that cannot be corrected medically be treated?

With hearing amplification tools such as hearing aids or a cochlear implant.

What are cochlear implants?

Small electronic devices that are surgically implanted to stimulate the cochlea with sounds detected on a receiver.

What do cochlear implants do?

They do not restore hearing; however, they enhance transmission of environmental sounds and speech to improve a patient’s understanding of their environment.

What is acute otitis media?

A bacterial infection of the middle ear.

What is the role of the eustachian tube in acute otitis media?

The middle ear is connected to the throat via the eustachian tube. When this tube is obstructed, most commonly during a viral upper respiratory infection, fluid and mucus can build up in the middle ear and then become infected with bacteria.

What are the symptoms of acute otitis media?

Otalgia, increased pressure in the ear, decreased hearing, and fever.

What findings are seen during examination of acute otitis media?

Upon physical examination with an otoscope, the tympanic membrane will appear erythematous and will have decreased mobility.

What can happen if acute otitis media is left untreated?

The tympanic membrane can rupture, and chronic otitis media may develop.

What is the first-line therapy for acute otitis media?

Oral antibiotics and nasal decongestants.

What is tympanocentesis used for?

It may be necessary for persistent infections to obtain a sample of fluid in the ear for a bacterial culture and to relieve pressure behind the tympanic membrane.

When may a myringotomy be used for otitis media?

Severe and/or persistent cases may require surgical drainage of the fluid in the middle ear via a myringotomy.

What is vertigo?

A sensation of movement when there is no motion or an exaggerated sense of movement in response to motion. Patients report feeling like they are spinning or that the world around them is spinning.

What commonly causes vertigo?

A disturbance in the inner ear from injury, infection, inflammation, or positioning.

What is Ménière’s syndrome?

A condition where patients experience episodic vertigo, hearing loss, tinnitus, and pressure in one ear.

What is labyrinthitis?

Inflammation of the inner ear that can cause vertigo.

What is benign paroxysmal positioning vertigo (BPPV)?

A condition of vertigo associated with changes in the position of the head.

What are cataracts?

Opacities of the lens of the eye. They are the leading cause of blindness in the world and develop as patients age.

What else can cause cataracts, and what symptoms do they cause?

Cataracts can be genetic or a result of a systemic disease such as diabetes mellitus. They are painless but cause progressive blurry vision.

How are cataracts treated surgically?

With surgical removal of the lens and placement of an intraocular lens implant.

What are phacolysis and phacoemulsification?

Treatments where the cataract is dissolved with ultrasound and then removed, and a lens implant put in place.

What is conjunctivitis?

Inflammation of the conjunctiva, also known as pinkeye.

What causes conjunctivitis?

It is most commonly caused by a bacterial or viral infection but can also be caused by allergens, chemical irritants, and/or trauma.

What are the symptoms of conjunctivitis?

Redness of the eye, increased tearing, thick discharge from the eye that crusts while sleeping, and itchy and burning eyes. Patients may also have blurry vision or an increased sensitivity to light.

How does discharge differ between viral and bacterial conjunctivitis?

Discharge from a viral infection tends to be watery, while bacterial infections cause purulent drainage.

How do viral and bacterial conjunctivitis differ in treatment and course?

Viral conjunctivitis is self-limiting and will resolve within 14 days. Bacterial conjunctivitis requires antibiotic eyedrops and also resolves within 10-14 days.

What is glaucoma?

A condition where there is increased intraocular pressure secondary to a backup of fluid in the eye.

What damage can increased intraocular pressure from glaucoma cause?

It can damage the optic nerve and cells of the retina, resulting in decreased vision or blindness.

What is aqueous humor and how does it flow through the eye?

Aqueous humor is fluid that fills the anterior chamber of the eye. It is produced in the posterior chamber, passes through the pupil into the anterior chamber, and leaves through the trabecular meshwork and Canal of Schlemn into the vascular system.

What happens when the flow of aqueous humor is slowed or blocked?

The intraocular pressure increases.

What are the two common types of glaucoma?

Acute angle-closure glaucoma and chronic glaucoma.

What is acute angle-closure glaucoma?

It occurs when the acute angle of the anterior chamber is blocked completely and aqueous humor cannot flow out of the eye. It is a medical emergency, and patients complain of severe eye pain and blurry vision.

What is chronic glaucoma?

It occurs when the flow of aqueous humor in the eye is slowed through the trabecular meshwork. It is typically discovered on a routine eye examination as elevated intraocular pressure.

What is the goal of treatment for both types of glaucoma?

To reduce the intraocular pressure.

How is acute angle-closure glaucoma treated?

With IV and topical medications that reduce the pressure in the eye. This can be followed by a surgical or laser iridectomy to prevent another closure of this space in the eye.

How is chronic glaucoma treated?

With topical medication to decrease the pressure in the eye and a laser procedure called a trabeculoplasty.