Systemic and Immunologic Conditions Affecting the Cornea
WILSON DISEASE (HEPATOLENTICULAR DEGENERATION)
Wilson disease is a rare condition that results in abnormal copper deposition throughout the body.
Etiology and Epidemiology
• Autosomal recessive (chromosome 13q14) condition caused by a deficiency of the enzyme ceruloplasmin
• Onset under 40 years
• Usually no ocular symptoms
• May experience cirrhosis, renal disease, neurologic dysfunction (typically motor disorders), or psychiatric disorders
• Kayser-Fleischer ring: green-brown band of copper deposition in the peripheral zone of Descemet membrane (Fig. 8-1; see also Fig. 6-8 in Chapter 6). This ring usually begins in the vertical meridians and may be seen earliest with gonioscopy. A Kayser-Fleischer ring may be the presenting sign of the disease.
• Cataract is found in less than 10% of cases. A disc-shaped, central, polychromatic opacity with peripheral radiations can be seen (sunflower cataract).
• Other causes of a Kayser-Fleischer ring: primary biliary cirrhosis, chronic active hepatitis, multiple myeloma
• Chalcosis: corneal copper deposition from an intraocular copper foreign body
• Slit-lamp or gonioscopic examination
• Serum copper and ceruloplasmin levels, urine copper level
• Treatment by an internist and/or a neurologist with copper chelating agents, such as d-penicillamine or tetrathiomolybdate
• Good with early recognition and treatment. The Kayser-Fleischer ring may resolve with treatment.
FIGURE 8-1. Wilson disease. A prominent Kayser-Fleischer ring can be seen. Brown copper pigment deposition is very apparent in the corneal periphery in this 18-year-old woman with Wilson disease. The deposits are at the level of Descemet membrane and deep stroma. In mild cases, the copper pigment is seen earliest using gonioscopy (see also Fig. 6-8 in Chapter 6).
VITAMIN A DEFICIENCY
Vitamin A deficiency is a rare, potentially blinding disorder that usually affects the malnourished and is common in areas where polished rice is the main source of food.
• Dietary deficiency of vitamin A, typically from chronic malnutrition
• Celiac diseases, biliary obstruction, cystic fibrosis, pancreatic or intestinal (e.g., gastric band or stapling) surgery, which impairs absorption of vitamin A
• Night blindness is the earliest symptom; dry eye, foreign body sensation, gradual loss of vision in severe cases
• Xerosis (severe drying) of cornea and conjunctiva
• Keratinization of conjunctiva (Bitot spot: superficial, triangular, silvery-gray, foamy, keratinized patch on the interpalpebral bulbar conjunctiva)
• Sterile corneal ulcers and melts (keratomalacia), which may lead to scarring or perforation (Fig. 8-2)
• Keratoconjunctivitis sicca
• Serum vitamin A level
• Consider impression cytology of the conjunctiva (demonstrates decreased goblet cell density) and electroretinogram.
• Systemic vitamin A orally or intramuscularly and repeated 1 month later
• Frequent preservative-free artificial tear drops or ointment to lubricate ocular surface
• Treat the malnutrition
• Corneal transplantation for scars or perforation. Consider a keratoprosthesis for bilateral severe scarring with good macular function.
• Very good if diagnosed and treated before significant corneal ulceration has occurred. Fair to poor if significant corneal damage is present.
Cystinosis is a rare disorder that results in accumulation of cystine in the body.
Etiology and Epidemiology
• Autosomal recessive disorder (chromosome 17p13), resulting in a defect in lysosomal cysteine transport protein leading to intracellular accumulation of the amino acid cystine
• Results in deposits of cystine in the conjunctiva, corneal stroma, iris, lens, and retina, depending on severity
• Three main forms are as follows:
▪ Infantile: associated with dwarfism and progressive kidney dysfunction. Poor prognosis without a renal transplant
▪ Adolescent (intermediate): Kidneys may be involved, but retinas are normal.
▪ Adult: minimal to no kidney disease, cystine deposits limited to anterior segment
• Irritation, foreign body sensation, pain, occasionally decreased vision
• Myriad tiny, glistening crystals in the corneal stroma, conjunctiva, iris, lens, and retina, depending on the severity of the disease (Fig. 8-3)
• May have superficial punctate keratopathy, filaments, and recurrent erosions
• Growth retardation, renal failure, hepatosplenomegaly, and hypothyroidism
• See Crystalline Keratopathy in Chapter 6.
• Lubrication for ocular surface disease
• Cysteamine eye drops have been reported to be useful.
• Rarely, a corneal transplant is required.
• Poor for the infantile form; good for the intermediate and adult forms.
MUCOPOLYSACCHARIDOSES AND LIPIDOSES
The mucopolysaccharidoses and lipidoses comprise a group of inherited systemic metabolic disorders, resulting in abnormal accumulation of material in the body.
Etiology and Epidemiology
• Mucopolysaccharidoses: lysosomal storage diseases, including Hurler, Scheie, Hunter, Sanfilippo, Morquio, Maroteaux-Lamy, and Sly syndromes. All are autosomal recessive except Hunter syndrome, which is X-linked recessive.
• Lipidoses: Numerous disorders of lipid metabolism, including Fabry disease. All lipidoses are autosomal recessive except Fabry disease, which is X-linked recessive.
• Mucopolysaccharidoses: All may have optic nerve, retinal, and central nervous system abnormalities. All have progressive corneal clouding except Hunter and Sanfilippo syndromes (Fig. 8-4, eFig. 8-4A1 and 2).
• Lipidoses: All may have macular cherry red spots and optic atrophy. Bilateral, symmetric, brownish corneal epithelial deposits arranged in a vortex manner from a point below the pupil and swirling outward but sparing the limbus (cornea verticillata) are seen in males with Fabry disease and female carriers. Conjunctival aneurysms, lens opacities, papilledema, optic atrophy, and macular and retinal edema are also seen in Fabry disease.
• Severe corneal opacity may require a corneal transplant. No ocular treatment is required for cornea verticillata.
• Follow up with a pediatrician or pediatric endocrinologist and a geneticist.
• Poor to good, depending on the specific metabolic disorder
COLLAGEN VASCULAR DISEASES
Collagen vascular diseases can cause a wide variety of ocular abnormalities, the most important of which are peripheral ulcerative keratitis and scleritis.
• Rheumatoid arthritis (most common)
• Granulomatosis with polyangiitis (Wegener granulomatosis) (often causes a necrotizing scleritis)
• Polyarteritis nodosa
• Relapsing polychondritis
• Systemic lupus erythematosus (SLE)
• Range from none to significant pain, redness, discharge, and decreased vision
• Corneal findings include severe ocular surface dryness, stromal keratitis, corneal stromal infiltrates, or ulceration, which is typically peripheral but may be central. The peripheral corneal ulceration may occur with or without symptomatic inflammation. The ulceration can be similar to Mooren ulcer in that it can extend circumferentially and centrally. However, unlike Mooren ulcer, the sclera is commonly involved. Corneal perforation may occur (Fig. 8-5A-C, eFig. 8-5A).
• Other findings include episcleritis, scleritis (necrotizing with or without inflammation), and sclerokeratitis (Fig. 8-5D and E). Healed episodes of scleritis can lead to scleral thinning and uveal show (Fig. 8-5F).
• The corneal changes in SLE are often unremarkable.
• Mooren ulcer: no underlying systemic disease
• Infectious infiltrate or ulcer: pain, iritis, more purulent discharge, cultures are positive
• Artificial tear drops, gels, and ointment, cyclosporine 0.05% to 2% drops, lifitegrast 5% drops, and punctal occlusion are used for dry eye disease. Topical corticosteroids are helpful in stromal keratitis but should generally be avoided in corneal and scleral ulcers.
• Oral nonsteroidal anti-inflammatory agents and/or corticosteroids are used for peripheral ulcerative keratitis and scleritis. Topical treatment is aimed at re epithelialization and prevention of secondary infection (e.g., artificial tear and antibiotic ointment q.i.d., punctal occlusion, lateral tarsorrhaphy).
• Stronger immunosuppressive agents (e.g., methotrexate, azathioprine, cyclosporine, or cyclophosphamide) or biologics (e.g., infliximab, adalimumab, rituximab, others) may be required, especially for scleritis or severe corneal stromal inflammation. • Resection of inflamed conjunctiva adjacent to a peripheral corneal ulcer may be helpful on rare occasions. Cyanoacrylate tissue glue can be used for small perforations (Fig. 8-5G and H). Larger perforations will require corneal patch grafts.
• Fair to good, depending on the severity and response of the underlying systemic disease
FIGURE 8-5. (continued) C. This eye has a large sterile corneal melt, leading to perforation in the midperiphery at the 4:30 position on the clock. The radiating stromal folds and peaked pupil suggest a perforation. Peripheral corneal neovascularization and scarring from the 3 to the 4 o’clock positions indicate no previous corneal inflammation in that area. Granulomatosis with polyangiitis (Wegener granulomatosis). D. This patient with a necrotizing scleritis and peripheral corneal melt had no known medical problems. Emergency systemic workup revealed granulomatosis with polyangiitis (Wegener granulomatosis). She was treated aggressively with systemic corticosteroids and cyclophosphamide, and her scleritis resolved. Appropriate diagnosis and treatment of granulomatosis with polyangiitis (Wegener granulomatosis) can be lifesaving.Premium Wordpress Themes by UFO Themes
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