Choroideremia

Introduction to choroidal disease Choroideremia is characterized by progressive onset of both eyes, from childhood blindness, diffuse full-thickness choroidal capillaries and RPE atrophy, and finally the choroid disappears completely. basic knowledge The proportion of illness: 0.0005% Susceptible people: no special people Mode of infection: non-infectious Complications: myopia, hyperopia, cataract, cataract

No choroidal disease

(1) Causes of the disease

Most patients are related to genetic factors.

(two) pathogenesis

Immune factor

From the histology and ultrastructure, macrophage phagocytic pigments and photoreceptor outer segments were found. In the phagocytic pigments, related proteins may cause allergic reactions, causing the choroidal interstitial collapse, Bruch membrane and blood vessels to disappear, and the choroid to undergo full-thickness atrophy.

genetic factors

The disease has been recognized as recessive inheritance of X chromosome, and its mechanism has not yet been elucidated. Males are morbid, and they are progressive, and women are genetic carriers.

Biochemical defect

Biochemical assays found a decrease in cyclic guanosine monophosphate (cGMP).

No choroidal disease prevention

The course of the disease can be delayed for several years, and acute attacks and remissions occur alternately, and most of them are relieved by themselves in adulthood. But a few still have a seizure. If arthritis has not healed for many years, it can cause severe joint deformity and movement disorders. This is more common in polyarthritis, older girls with onset and systemic type with polyarthritis. In the case of arthritis, chronic iridocyclitis occurs in girls who develop before the age of 4, causing blindness. Ankylosing spondylitis can be seen in older boys. In general, if treated promptly, 75% of patients will be relieved and their joint function is normal. Only a few have caused lifelong disability. Individual patients died of infection or amyloidosis.

No choroidal complications Complications, myopia, cataract, cataract

The refractive status of the disease (both male and female) often has moderate myopia, but sometimes face or farsightedness, patients may have cataract and iris atrophy, vitreous liquefaction and a little fibrous opacity, white cholesterol-like crystals and very small Pigment particles.

No choroidal symptoms common symptoms tight vision vision changes night blind pigmentation pigmentation loss green blind color vision abnormal fundus changes

1. Visual function change

It is early onset, may have been born at birth, vision loss or even decline to light perception, visual field centripetal narrowing, atrophy change begins in the middle and peripheral parts, expands toward the center with age, and finally remnants the central part, gradually forming a tubular view Usually, the visual acuity is moderately reduced at 10 to 30 years old, but the central vision is still maintained. After 40 to 50 years of age involving the macula, it is a tube or accompanied by a small island in the periphery. The final field of vision disappears completely, and remains in the central and the temporal side. After the disappearance of the island, the patient was completely blind, and the night was blind and early, showing a cone-shaped degeneration. The final threshold of dark-adapted rod cells showed a progressive increase. In the late stage, the dark adaptation curve was not detected, and the color vision disorder was red-green blind. Electrophysiological measurement, early clear vision ERG is normal, dark adaptation ERG is low wave, late extinction, EOG low wave or no wave, ERG changes in male patients with this disease are normal in the early stage of ERG modification, but dark adaptation part a Wave and b wave amplitude decreases, b wave latency increases, late ERG is extinguished, female patients' vision, visual field, dark adaptation, pigment, EOG, ERG are mostly normal, but occasionally abnormal, female carriers are in the fundus In the case of obvious plaque-like pigmentation disorder and accumulation, the ERG response is still normal, and the ERG amplitude can be reduced or increased. The change of EOG in this disease is more obvious than ERG. An abnormal feature of visual function test in patients without choroidal disease is EOG. The baseline potential was significantly decreased, the late EOG baseline potential was almost undetectable, the light peak completely disappeared, and the visual function of female patients was abnormally abnormal, but a few patients may have abnormalities.

2. Fundus changes

Fundus changes can occur in infants and young children, but also late, even after the age of 40, only the initial changes can be divided into three phases.

(1) In the early stage: there is mild atypical peripheral pigmentary retinopathy. Due to retinal pigment epithelial degeneration, the equator and peripheral part of the fundus are flashing yellow, there are pigment particles in the deep, and there is a depigmentation zone between the pigments. It is not osteocytes.

(2) Mid-term: The lesion gradually develops from the periphery to the posterior pole, and the inner layer of the retina is free of pigmentation. At this time, choroidal vessels and RPE atrophy appear, showing small areas of choroidal macrovascular exposure.

(3) Late stage: the choroid and RPE progressively atrophy to the posterior pole of the fundus, the pigment epithelium of the fundus is almost completely destroyed, the choroidal blood vessels disappear and atrophy, and sometimes only a small piece of choroid is left in the macula, and its boundary is clear, while the peripheral part A choroidal island can be left, but it disappears after 50 to 60 years old. Because the pigment epithelium and choroidal blood vessels disappear, the fundus exposes the white light of the sclera, and the remaining islands can be brownish red with a circle around the periphery. Shaped or irregular pigmented spots, but rarely seen all the fundus is white, no visible choroidal blood vessels, although the choroidal lesions are obvious, the retina and the visual god often remain normal, the late optic disc can be atrophy, the retinal blood vessels can be slightly thin.

Female patients are carriers. The typical fundus changes are similar to those of young male patients, but the fundus lesions are static, mild, and normal vision. The fundus can be characterized by pigmentation and hyperpigmentation. It is a salt-like atrophy, mostly located in the fundus. In the equator, the pigment particles vary in size, and they are arranged in a string and radiate strips around the periphery. The pigmentation is reduced in the peripheral part. In some cases, the pigmentation of the macula is fine, and the retina and optic disc are normal.

3. Fluorescence angiography

Early RPE defects present a wide range of strong fluorescence areas, followed by retinal pigment epithelial atrophy and choroidal capillaries disappearing, only fluorescently filled choroidal vessels, and extensive non-fluorescent areas in the late stage, with residual sparse choroidal vessels, female gene carriers Fluorescence angiography showed that RPE atrophied, showing fluorescence or extensive strong fluorescence.

No choroidal examination

The disease lacks specific laboratory tests. During the active period, there is often anemia, leukocytosis (more common between 20,000 and 40,000) and a marked increase in erythrocyte sedimentation rate. White blood cells can be up to 60,000 and have a nuclear left shift. Increased platelets can be as high as 1 million in severe systemic types. Plasma albumin is reduced, 2 and gamma globulin are increased. Most of the C-reactive proteins are positive. Most of the arthritis-type rheumatoid factor-negative patients were 25% antinuclear antibody positive, rheumatoid factor positive 75% positive, and in the arthritic type I, 60% antinuclear antibody positive. Lupus cells can sometimes be found. The rheumatoid factor is an antibody specific for IgG, which is a 19S IgM molecule capable of agglutinating sensitized sheep red blood cells, and the agglutination titer is positive at 1:32 or more. In juvenile rheumatoid arthritis type, girls with a high onset age (about 8 years old or older) and those with severe joint symptoms are more likely to be positive. Serum IgG, IgM and IgA increased, and complement was normal or increased. Joint synovial exudate examination: appearance turbidity, white blood cells increased, up to 5,000 ~ 80,000 / mm3, mainly polymorphonuclear leukocytes, protein increased, normal or reduced sugar, increased IgG, IgM, complement reduction, Bacterial culture was negative.

Diagnosis of choroidal disease

The clinical features of male patients with this disease are night blindness, narrowing of visual field centripetality, abnormal blue vision, elevated dark adaptation threshold, and progressive total choroidal vascular and RPE atrophy. According to typical fundus changes, electrophysiological changes and family history, A correct diagnosis is made.

Differential diagnosis

However, the early stage of the disease is easily confused with atypical primary retinitis pigmentosa and choroidal choroidal atrophy. In the case of severe atrophy in the late stage, it should be differentiated from diffuse choroidal capillary atrophy, albinism and pathological myopia. Therefore, long-term observation is often required. Correct judgment.

1. Retinitis pigmentosa: There is a typical "osteocyte"-like pigment, the choroid does not show diffuse full-thickness choroidal atrophy, and no choroidal pigmentation abnormality is granular, so it is different from retinitis pigmentosa.

2. Convoluted choroidal atrophy: the degree of atrophy is uniform, the border is sharp, and it has a convoluted shape.

3. Diffuse choroidal capillary atrophy: limited to RPE and choroidal capillary layer, fluorescent angiography is clearly visible, its genetic characteristics are autosomal dominant inheritance.

4. Albino fundus: There is obvious manifestation of albinism, without night blindness and visual field changes.

5. Pathological myopia: not only have high myopia, but also have scleral staphyloma and other changes.

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