Lesser Known Disorders
Each issue of this series contains at least three lesser known disorders. Some of these disorders may contain subtypes which will also be presented. You will also notice that each disorder has a code. These codes represent the coding system for all disabilities and disorders listed in the Educator’s Diagnostic Manual(EDM) Wiley Publications.
VI 1.06 Pterygium
Disability Category: Visual Impairment
Definition
A pterygium is a pinkish, triangular-shaped tissue growth on the cornea. Some pterygia grow slowly throughout a person’s life, while others stop growing after a certain point. A pterygium rarely grows so large that it begins to cover the pupil of the eye (National Eye Institute, 2005h).
Explanation
Pterygia are more common in sunny climates and in the 20–40 age group. Scientists do not know what causes pterygia to develop. However, since people who have pterygia usually have spent a significant time outdoors, many doctors believe ultraviolet (UV) light from the sun may be a factor. In areas where sunlight is strong, wearing protective eyeglasses, sunglasses, and/or hats with brims are suggested. While some studies report a higher prevalence of pterygia in men than in women, this may reflect different rates of exposure to UV light.
Because a pterygium is visible, many people want to have it removed for cosmetic reasons. It is usually not too noticeable unless it becomes red and swollen from dust or air pollutants. Surgery to remove a pterygium is not recommended unless it affects vision. If a pterygium is surgically removed, it may grow back, particularly if the patient is less than 40 years of age. Lubricants can reduce the redness and provide relief from the chronic irritation (National Eye Institute, 2005h).
HI 2.03-Otosclerosis
Disability Category-Hearing Impairment
Definition
Otosclerosis is a condition of the middle ear which causes hearing loss that gets worse over time. Unlike hearing loss resulting from damage to the inner ear, the hearing loss from otosclerosis is often reversible. The name otosclerosis comes from the Greek words for “hard” (scler-o) “ear” (oto). This is because otosclerosis is a disorder which causes a hardening of the bones of the middle ear (Harris, 2000)
Explanation
Otosclerosis can cause different types of hearing loss, depending on which structure within the ear is affected. Otosclerosis usually affects the last bone in the chain, the stapes, which rests in the entrance to the inner ear (the oval window). The abnormal bone fixates the stapes in the oval window and interferes with sound passing waves to the inner ear.
Hearing loss is the most frequent symptom of otosclerosis. The loss may appear very gradually. Many people with otosclerosis first notice that they cannot hear low-pitched sounds or that they can no longer hear a whisper. In addition to hearing loss, some people with otosclerosis may experience dizziness, balance problems, or tinnitus(National Institute on Deafness and Other Communication Disorders, 1999).
HI 2.03a-Classic Otosclerosis
A type of Otosclerosis in which the stapes is immobilized by a spongiotic growth along the footplate. Classic otosclerosis has traditionally been addressed through surgical management(Bukowski, J., 2004).
HI 2.03b-Cochlea Otosclerosis
A type of Otosclerosis that spreads to the inner ear a sensori-neural hearing impairment may result due to interference with the nerve function (New York Eye and Ear Infirmary, 2005).
HI 2.03c Stapedial Otosclerosis
A type of Otosclerosis that spreads to the stapes or stirrup bone, the final link in the middle ear transformer chain. The stapes rests in a small groove, the oval window, in intimate contact with the inner car fluids. Anything that interferes with its motion results in a conductive hearing impairment(New York Eye and Ear Infirmary, 2005).
VI 1.07 Stevens-Johnson Syndrome
Disability Category: Visual Impairment
Definition
Stevens-Johnson Syndrome (SJS), also called erythema multiform major, is a disorder of the skin that can also affect the eyes (National Eye Institute, 2005h).
Explanation
SJS is characterized by painful, blistery lesions on the skin and the mucous membranes (the thin, moist tissues that line body cavities) of the mouth, throat, genital region, and eyelids. SJS can cause serious eye problems, such as severe conjunctivitis; iritis, an inflammation inside the eye; corneal blisters and erosions; and corneal holes. In some cases, the ocular complications from SJS can be disabling and lead to severe vision loss.
Scientists are not certain why SJS develops. The most commonly cited cause of SJS is an adverse allergic drug reaction. Almost any drug—but most particularly sulfa drugs—can cause SJS. The allergic reaction to the drug may not occur until 7–14 days after first using it. SJS can also be preceded by a viral infection, such as herpes or the mumps, and its accompanying fever, sore throat, and sluggishness. Treatment for the eye may include artificial tears, antibiotics, or corticosteroids. About one-third of all patients diagnosed with SJS have recurrences of the disease.
SJS occurs twice as often in men as women, and most cases appear in children and young adults under 30, although it can develop in people at any age (National Eye Institute, 2005h).
Download this Issue
To Download a PDF file version of this Issue of the NASET’sLesser Known Disorders in Special Education Series – CLICK HERE
