retinitis pigmentosa
Introduction
Introduction to retinitis pigmentosa Retinitis pigmentation (retinitispigmentosa, primary retinalpigmentarydegeneration) is a type of hereditary retinopathy with progressive impairment of visual function. The typical fundus changes to the optic papilla sallow, the small blood vessels become thinner and the bone cell-like pigmentation spots near the equator. Night blindness and narrowing of vision are the main complaints. This disease is more common with both eyes. It is a common ocular genetic disease. The offspring of close relatives are especially common. Patients and their families may be accompanied by high myopia, mental disorders, epilepsy, mental decline and hoarseness. basic knowledge The proportion of illness: 0.003% Susceptible people: no specific population Mode of infection: non-infectious Complications: glaucoma myopia
Cause
Cause of retinitis pigmentosa
Genetic factors (90%)
The disease is a hereditary disease, and its hereditary pattern is autosomal recessive, dominant and sexually linked recessive, with autosomal recessive inheritance most; dominant second; sexually linked recessive inheritance is the smallest, currently considered autosomal The dominant hereditary type has at least two gene loci, located on the short arm of the first chromosome and the long arm of the third chromosome, and the sex-linked genetic gene is located in the short-wall region and the second region of the X chromosome.
Pathogenesis
In the past 20 to 30 years, with some clues, according to electron microscopy, histochemistry, electrophysiology, fundus fluorescein angiography and other examination data, it is speculated that the occurrence of this disease is mainly due to the retinal pigment epithelial cells to the extracellular disk. Membrane phagocytosis, digestive function decline, resulting in disc film disintegration, the procedure forms a layer of obstacles, hindering the rotation of nutrients from the choroid to the retina, causing progressive malnutrition and progressive degeneration and disappearance of the visual cells. It has been confirmed in a retina of RCS mice with primary retinal pigmentation. As for the cause of phagocytic digestive failure of pigment epithelial cells, it is still unclear, which may be related to genetic abnormalities, lack of certain enzymes or certain enzymes. In immunology, recent studies have found that patients with this disease have abnormal humoral immunity and cellular immunity. There are activated T cells in the vitreous, B cells and macrophages, and retinal pigment epithelial cells express HLA-DR antigen. Normal people have no such manifestations. It is also found that patients with this disease have autoimmune phenomena, but whether this disease is There is no sufficient basis for autoimmune diseases. In terms of biochemistry, it is also found that patients with this disease have autoimmune phenomena, but there is still no sufficient basis for whether the disease has autoimmune diseases. In biochemistry, it is found that patients with this disease have abnormal lipid metabolism. There are lipid-brown granules accumulated in the retina; zinc, copper, selenium and other trace elements and enzyme metabolism are also abnormal. In summary, the disease may have a variety of different pathogenesis.
Prevention
Retinitis pigmentosa prevention
The patients with recessive inheritance of this disease have early onset, serious illness, rapid development, and extremely poor prognosis. The visual function has been highly unhealed at the age of 30 years old, and nearly blind to the age of 50. The dominant genetic patients are vice versa, and occasionally they have developed to some extent. After the degree tends to be static, the prognosis is relatively better than the recessive hereditary type, so it can wait until the opportunity of normal schooling and employment. The occult inheritance of this disease has a history of close relatives and smoke, prohibiting close relatives. The incidence of this disease is reduced by about 22%. In addition, patients with recessive inheritance should try to avoid marriage with family members of this disease, and can not marry those who also suffer from this disease. Patients with dominant inheritance have a risk of developing this disease for their children. 50%.
Complication
Retinitis pigmentosa complications Complications glaucoma myopia
Post-polar cataract is a common complication of this disease. It usually occurs in the late stage. The crystal opacity is star-shaped and is located in the posterior capsule. The progress is slow, and finally the whole crystal is turbid. About 1% to 3% of cases are complicated with glaucoma. Mostly wide angle, angle closure is rare, some people from a statistical point of view, that glaucoma is associated with the disease rather than complications, about 50% of cases with myopia, myopia is more common in autosomal recessive and sexual chain Patients with sexual recessive heredity can also be found in other members of the family. The incidence of deafness and disease is as high as 19.4%. The Corti organs in the retina and inner ear are derived from the neuroepithelial, so the progressive degeneration of the two may be from the same gene.
Pigmentation and deafness can occur not only in the same patient, but also in different members of the same family, but the two do not seem to originate from different genes, may be caused by the multi-directionality of the same gene, the disease may be associated with other inheritance Sexually transmitted diseases, the common ones are Laurence-Moon-Bardt-Biedl syndrome, which is caused by the pituitary region and the retina at the same time. Typical cases have retinitis pigmentosa, genital dysplasia, obesity, multi-finger (toe) and intelligent defects. The component, which occurs in the early stages of development, has significant clinical manifestations around 10 years of age (or earlier), five components are not possessed, and are called incomplete, in addition, there is still a blink of an eye or other Concurrent or concomitant diseases of the organs are rare.
Symptom
Retinitis pigmentosa symptoms common symptoms visual acuity often foggy blurred visual impairment night blindness
There is night blindness, dark adaptation is reduced, central vision can be maintained for a long time, but the visual field is gradually reduced, and the vision in the late center is diminished, the field of vision is tubular, the patient has difficulty in action, and work and life are inconvenient.
The retinal trocar is involved, resulting in night blindness and a symptom that appeared in early childhood. The mid-circumferential dark spots (found through visual field examination) gradually expanded, resulting in a final reduction in central vision.
The most prominent findings under ophthalmoscopy are melanin-like appearance of osteoblast-like shape in the equator of the retina, retinal artery stenosis, yellow papillary color in the nipple, and other clinical manifestations of degenerative vitreous opacity, cataract and myopia, the disease can still be combined Congenital hearing loss.
Diagnosis may be by special examination (eg dark adaptation, electroretinogram), other retinopathy similar to retinitis pigmentosa (eg those with syphilis, rubella, chloroquine poisoning) must be excluded, and the patient's family should also be examined to determine Hereditary mode.
Examine
Examination of retinitis pigmentosa
Under the fundus examination, although the disease has been blinded at night, the fundus can be completely normal, and the fundus changes gradually appear after the disease progresses. The typical changes are
1. Retinal pigmentation: Beginning in the equator, the pigment has a small point of protrusion, which then increases and becomes larger. It is osteoblast-like, sometimes irregularly line-shaped, and is arranged in a circular shape around the equator. It is located in the vicinity of the retinal blood vessels, especially in the front of the vein. It can cover part of the blood vessels, or distribute along the blood vessels. It is denser at the branches of the blood vessels. Later, the pigmentation gradually spreads from the equator to the posterior pole and the periphery, and finally spreads the whole. At the same time, at the same time, the pigmentation of the retinal pigment epithelial layer is exposed to the choroidal blood vessels and is a leopard-like fundus. The advanced choroidal vessels are also hardened, with yellow-white stripes. The vitreous is generally clear, sometimes occasionally a few spots or linear opacity. .
2, retinal vascular changes: vascular consistency is narrow, with the progress of the disease is aggravated, especially the arteries are prominent, in the late, the arteries into a thin line, after leaving the optic disc for a distance, it is difficult to identify and disappear, but unchanged from white The line is also covered with no white sheath.
3, fluorescent fluoroscopy fundus angiography : background fluorescent large piece no fluorescence area, suggesting that the choroidal capillary layer is atrophy, retinal blood vessels can be occluded, and sometimes visible posterior or peripheral mottled fluorescent spots.
Diagnosis
Diagnosis and differentiation of retinitis pigmentosa
Identification of secondary retinitis pigmentosa after some congenital or acquired chorioretinal inflammation.
Congenital syphilis and fetal fundus lesions caused by pregnant women in the third month of pregnancy, the fundus findings after birth are almost identical to the disease, ERG, visual field and other visual function test results are also difficult to distinguish, only in the determination of children Parents with a negative serum syphilis reaction and a history of no rubella in the early pregnancy of the mother can be diagnosed as primary pigmentary degeneration. If necessary, a longer follow-up is needed. Congenital secondary pigmentary degeneration is already present at birth and the condition is still.
Acquired syphilis and certain acute infectious diseases (such as smallpox, measles, scarlet fever, mumps, etc.), can occur in chorioretinitis, the fundus changes after inflammation subsides, sometimes similar to primary pigmentary degeneration, when from the medical history Serological examination and fundus pigmentation are large and deep, forming irregular (non-osteocyte-like), with choroidal retinal atrophy, optic disc atrophy gray-white (not waxy yellow), and the degree of night blindness is relatively light.
