Optho part dos Flashcards
Acute angle closure glaucoma
a painful condition in which elevation of intraocular pressure occurs as a result of obstruction of aqueous outflow by partial or complete closure of the angle by the peripheral iris. It leads to congestion of the conjunctival vessels and is often associated with a cloudy cornea. Nausea is also a hallmark. Definitive treatment is a laser peripheral iridotomy, however osmotic diuretics are often used as a temporary measure (acetazolamide, mannitol). REQUIRES IMMEDIATE REFERRAL TO AN OPHTHALMOLOGIST.
Iritis or iridocyclitis
inflammation of the iris or iris and ciliary body (also known as anterior uveitis). Key symptoms are photophobia, pain, redness (characteristically worse adjacent to the cornea and known as “ciliary flush”), decreased vision and lacrimation. Keratic precipitates are cellular deposits on the inner aspect of the cornea. Severe cases may have hypopyon. Iritis may be idiopathic, or associated with systemic inflammatory disease. It is most often treated with topical steroids, but severe cases may require systemic anti-inflammatory therapy.
Herpes Simplex Keratitis
a distinct viral infection of the cornea. Herpes simplex virus (HSV) is a DNA virus with humans as the only host. About 90% of the population is seropositive for HSV antibodies, but most infections are sub-clinical. HSV-1 is the most common cause of herpetic keratitis, however HSV-2 is occasionally responsible. The hallmark sign is a dendritic ulcer of the cornea, a linear ulcer with “branches” (thus the name dendrite – derived from the Greek word for tree). Herpes simplex keratitis can be treated with both topical and systemic anti-viral medications. Rarely, a corneal abrasion may heal in a pattern similar to a dendrite and is referred to as a pseudodendrite.
Bacterial Keratitis
bacterial infection of the cornea that nearly always results in a corneal ulcer. Very few bacteria can penetrate an intact corneal epithelium, so there is almost always a predisposing factor (such as contact lens wear or corneal injury). The most common pathogens are Staph aureus and Strep pneumonia and they tend to produce oval, yellow-white, densely opaque stromal lesion surrounded by relatively clear cornea. Bacterial corneal ulcer is a sight threatening condition demanding urgent identification and treatment. Generally a corneal culture is performed and initial empiric treatment is started with fortified topical antibiotics (tobramycin 1.5%, cefuroxime 5%)
Conjunctivitis
inflammation of the conjunctiva from any cause. It is nearly always associated with conjunctival injection, and is frequently associated with discharge, itching, pain and edema. In order to properly treat conjunctivitis it is necessary to properly identify the cause.
Conjunctivitis: Bacterial
simple bacterial conjunctivitis is a common and usually self-limiting condition. The most common causative organisms are Staph eidermidis. And Staph aureus but other gram positive cocci, including Strep pneumonia, are also frequent pathogens as are gram negative H. influenza and Moraxella lacunata. Presentation is with an acute onset of redness, grittiness, burning and discharge. On waking, the eyelids are frequently stuck together and difficult to open as a result of the accumulation of exudate during the night. Both eyes are usually involved, althought one may become affected before the other by a day or so. Even without treatment, simple conjunctivitis usually resolves within 10-14 days and laboratory tests are not routinely performed. Before initiating treatment it is important to bathe all discharge away. Initial treatment is broad-spectrum antibiotic drops during the day and ointment at night until the discharge has ceased.
Conjunctivitis: Viral
most often adenoviral conjunctivitis. The spectrum varies from mild and almost inapparent to full-blown infection with significant morbidity. Transmission of this highly contagious virus is via respiratory or ocular secretions, and dissemination by contaminated towels or pillow cases is common. The incubation period is 4-10 days. Following the onset of conjunctivitis the virus is shed for about 12 days. Thorough hand washing is important to avoid transmission. Treatment is largely symptomatic and supportive and spontaneous resolution occurs within 2 weeks.
Conjunctivitis: Allergic
allergic rhinoconjunctivitis is the most common form of eye allergy. It is a hypersensitivity reaction to specific airborne antigens. Patients frequently experience associated nasal symptoms. It may be either seasonal or perennial. Presentation is with acute, transient attacks of red, itchy, watery eyes which may be associated with sneezing and a watery nasal discharge. The eyelids may show mild to moderate edema. The conjunctiva has a milky pinkish appearance. Treatment is with a topical antihistamine (ketotifen, olopatadine, epinastine, bepotastine, many more)
Conjunctivitis: Neonatal
Chlamydial infection is the most likely cause of neonatal conjunctivitis. Presentation is usually between 5 and 19 days after birth, and it may be associated with otitis, rhinitis and pneumonitis. The infection is transmitted from the mother during birth, so the parents may require treatment as well. The signs include papillary conjunctivitis with a mucopurulent discharge. Treatment is with topical tetracycline and oral erythromycin.
Conjunctivitis: Neonatal gonococcal
This is a rare cause of neonatal conjunctivitis which is transmitted from the mother during delivery. It is caused by a Gram-negative diplococcus Neisseria gonorrhoeae. Presentation is usually between one and three days after birth. There is a hyperacute, purulent conjunctivitis and if left untreated there is a risk of secondary corneal involvement. The treatment is with topical and systemic penicillin.
Conjunctivitis: Episcleritis
a common, benign, self-limiting and frequently recurrent disorder which typically affects young adults. It is generally not associated with systemic disorders and never progresses to scleritis. It usually presents with unilater discomfort, localized redness, tenderness to touch and watering. It often responds spontaneously within 1-2 weeks. Treatment is generally with mild topical steroids (loteprednol), or topical NSAIDs (ketorolac, bromfenac, etc.). Severe, unresponsive cases may require systemic NSAIDs (ibuprofen 800mg tid).
Conjunctivitis: Scleritis
a granulomatous inflammation of the sclera. It is less common than episcleritis and covers a wide range of severity. It can be a self- limiting episode of inflammation that only results in mild annoyance, or it may be a necrotizing process that can lead to permanent loss of vision. About half of patients with scleritis have an associated systemic disease. Rheumatoid arthritis is the most common (about 0.5% of all RA patients develop scleritis), with other connective tissue disorders such as lupus, Wegener’s granulomatosis and polyarteritis nodosa also being in the differential. Treatment is generally oral and not topical. NSAIDs, steroids or a combination of both are generally effective. Severe necrotizing scleritis may require immunosuppressive agents such as cyclosporine, and is generally managed by both an Ophthalmologist and rheumatologist.
Adnexal Disease
primarily inflammatory diseases of the adjacent structures of the eye such as the lacrimal apparatus, the extraocular muscles and the eyelids, eyelashes and eyebrows.
Adnexal Disease: Blepharitis
– a common condition of chronic inflammation of the eyelid margin. It is generally bilateral and symmetrical. The etiology is unclear, but both staphylococcal infection and rosacea are contributing factors. Symptoms include burning, gritiiness, mild photophobia, and crusting and redness of the lid margins. Patients often complain of “crusting” of the lids upon awakening in the mornings. Treatment is often very involved and on -going. Lid hygiene is an important step that involves scrubbing the lid margins daily with commercially available lid scrubs or a cotton ball dipped in a mixture of warm water and a small amount of baby shampoo. Erythromycin ointment may be applied the lid margins initially, but is not generally useful long term. Periodic treatment with a combination antibiotic and steroid drop (neomycin and dexamethasone, tobramycin and dexamethasone, tobramycin and loteprednol) may be useful for acute exacerbations. Systemic treatment with tetracyclines is a useful ongoing treatment for chronic cases and fish oil is emerging as a common treatment option in this situation. Daily warm compresses can help to melt solidified sebum and may reduce the amount of irritating lipids within the glands.
Adnexal Disease: Thyroid Eye Disease
10 to 25% of the time there is no clinical evidence of thyroid dysfunction. When there is systemic involvement it usually does not correlate with the severity of the ocular disease. Thyroid eye disease appears to be an organ specific autoimmune disorder in which IgG is responsible for several changes. Hypertophy of the extraocular muscles is caused by an increase in glycosaminoglycans, and may cause the muscles to be enlarged up to eight times their normal size. This can compress the optic nerve and cause severe vision loss. Also, cellular infiltration of interstitial tissues with lymphocytes, plasma cells, macrophages and mast cells occurs in the congestive stage. Proliferation of orbital fat, connective tissue and lacrimal glands occurs with retention of fluid and accumulation of glycosaminoglycans. All of these factors lead to an increase in intraorbital contents and an elevation of intraorbital pressure. The result is a condition known as exophthalmos, where the eyes appear to “protrude” from the orbits.
