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Disorders of the Special Senses

• Disorders associated with the eye

• Disorders associated with the ear and vestibular function

Objectives:

Part 1: Eye Disorders

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Disorders of Eyelids:

Inflammatory Conditions:

• Blepharitis: inflammation due to infected eye glands at base of eyelid (meibomian glands)

• Hordeolum (stye): inflammation and infection of the sebacious glands of eyelids.

• Chalazion: chronic inflammation that leads to a granuloma that can occur after an internal hordeolum

Stye (hordeolum)

chalazion

blepharitis

Disorders of Conjunctiva:

Infectious Conjunctivitis:

• Etiologies: bacteria, viruses

Manifestations associated with acute bacterial conjunctivitis:

• Burning, tearing and mucopurulent or purulent discharge (sticky eyelids)

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Disorders of Cornea:

• Corneal abrasions: characterized by intense pain, small lesions of the epithelium heal without scar tissue forming, but if stroma is damaged, healing can be delayed and lead to scar tissue and reduced visual acuity.

• Keratitis: inflammation of the cornea due to infection, hypersensitivies, trauma, ischemia, lack of innervation.

Disorders of Uveal Tract: middle vascular

layer of eye (choroid, ciliary body and iris), supports

lens and neural components of the eye

• Uveitis: inflammation of the uveal tract due to infections (viral, bacterial, fungi, parasites) or autoimmunity, tumors.

Glaucoma: a disease that results in increased

intraocular pressure in the anterior chamber of the eye

• Etiologies: age, family history, hypertension, type 2 diabetes, hyperthyroidism, migraine headaches, sleep apnea, corticosteroid drug use.

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Glaucoma: a disease that results in increased

intraocular pressure in the anterior chamber of the eye

• Primary: occurs without any pre-existing ocular or systemic disease

• Secondary: occurs due to inflammation, tumors or trauma.

• Open-Angle Glaucoma: abnormal increase in intraoccular pressure associated with abnormalities of the canal of Schlemm or with trauma

• Angle-Closure Glaucoma: occlusion of the anterior chamber by the iris due to shallow chambers (inherited anatomical defects)

Glaucoma:

Treatment:• B-adrenergic antagonists, prostaglandin analogs,

adrenergic agonists, carbonic anhydrase inhibitors and cholinergic agonists (applied topically to facilitate better drainage of aqueous humor and lower intraocular pressure)

• Laser or surgical trabeculoplasty• Ultrasound to destroy ciliary epithelium in order to

reduce aqueous humor production

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Disorders of the Lens:

Cataracts: lesions of the lens that result in clouding of the lens so that it can no longer act as a transparent window for incoming light.• Risk factors: age, genetics, drugs, injury, diabetes,

smoking• Manifestations: increasingly blurred vision and visual

distortion, visual acuity for far and near objects decreases

• Treatment: vision correction devices, surgery (lens extraction and intraocular lens implantation)

Disorders of the Retina:

Retinal Detachment: the separation of the retinal layers (neuronal from pigmented epithelial layer). With this separation, the neurosensory layer cannot receive adequate blood supply so this can result in cell death and subsequent blindness.

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Disorders of the Retina:

Retinal Detachment: the separation of the retinal layers (neuronal from pigmented epithelial layer). With this separation, the neurosensory layer cannot receive adequate blood supply so this can result in cell death and subsequent blindness.

Disorders of the Retina: Retinal Detachment:• Exudative retinal detachment: occurs from the accumulation of

fluid in the subretinal space which can result from hypertension, inflammation or tumor leakage.

• Rhegmatogenous retinal detachment: occurs when the gelatinous matrix associated with the vitreous humor starts to liqeufy and doesn’t support the retina properly, liquid then enters into a retinal tear in the subretinal space as can occur with aging.

• Traction retinal detachment: due to pressure or force exerted on the peripheral retina that eventually leads to detachment (scar tissue from surgeries, diabetic retinopathy, injury, inflammation)

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Disorders of the Retina: Macular Degeneration: degeneration of the macula region of the retina leading the loss of central vision• Dry age-related macular degeneration: retinal atrophy,

drusen (whitish yellow epithelial deposits) that develop between the pigmented epithelium and the choroid capillaries. These begin to enlarge, merge and increase in number destabilizing the layers.

• Wet age-related macular degeneration: the formation of a new blood-rich choroidal membrane that separates the neurosensory layer from the pigmented epithelial membrane. These are weak blood vessels which tend to leak and are associated with the development of scar tissue and eventual loss of central vision.

Disorders of the Retina: Macular Degeneration:

Treatment:

• Anti-angiogenesis drugs

• Laser therapy, photodynamic laser therapy

• Vitamins C, E, beta-carotene, zinc and copper

• Surgery

• Vision-aid devices

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Neoplasms associated with the eye:Retinoblastoma: malignant neoplasm of the retina that occurs in young children.

Disorders of Eye Movement: Strabismus: improper alignment of the eyes due to abnormalities in eye coordination (results in diplopia).

Treatment is done with corrective surgery as well as eye glasses and eye exercises.

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Part 2 : Ear and Vestibular Function Disorders

Disorders of the middle ear and eustachian tube: Otitis Media: inflammation and infection of the middle ear

• Bacterial or viral

• More often occurs with children due to decreased length and shape of eustachian tube and in infants the infection can spread more easily

• Manifestations: fever, pain, irritability, hear pulling, hearing loss, middle ear effusion

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Disorders of the inner ear:

Tinnitus: inappropriate ear/head noises that are not produced externally

• Ringing, hissing, roaring, buzzing and humming sounds are heard

• Etiologies: impacted cerumen, medications, noise-induced hearing loss, hearing loss that occurs with aging, hypertension, atherosclerosis, head injury, infection/inflammation of the cochlea

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Hearing Loss: Conductive Hearing Loss:• Irreversible or reversible hearing loss due to

structural ear issues of the external or middle ear• Impacted cerumen, foreign bodies, infections of the

external/middle ear, trauma, otosclerosis, tumors.Sensorineural Hearing Loss:• Usually irreversible hearing loss due to disease or

disorders that affect the inner ear, the auditory nerve or the auditory pathways to the brain.

• Trauma, CNS infections, atherosclerosis, ototoxic drugs, tumors, Meniere Disease

Disorders of the vestibular system: inner ear, proprioceptors and vision

Vertigo: false sense of motion (spinning or rocking), can result from middle ear infections, trauma, vestibular system disorders, migraines, postural hypotension, peripheral neuropathy.

Meniere Disease: a progressive disease that involves abnormalities of the endolymph and distention of the endolymphatic compartment. Is characterized by hearing loss, vertigo and tinnitus.

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