The appearance of conjunctival sand grains

Introduction The appearance of sputum conjunctival sand is one of the symptoms of trachoma. Trachoma is a chronic contagious conjunctival keratitis caused by Chlamydia and is one of the blinding diseases. Because it forms a rough and uneven appearance on the surface of the palpebral conjunctiva, it is shaped like sand, hence the name trachoma. In the early stage of the disease, the conjunctiva is infiltrated such as nipple and follicular hyperplasia, and corneal vasospasm occurs at the same time. In the late stage, the scar of the conjunctiva is affected, resulting in varus deformity and aggravation of corneal damage, which may seriously affect vision and even cause blindness.

Cause

(1) Causes of the disease

The research on trachoma pathogens has a long history. In 1907, Halbestaedter and Prowazek used optical microscopy and Giemsa staining to find inclusion bodies in the conjunctival epithelial cells of the trachoma, that is, red-blue protoplasts and dark blue precursor particles in the epithelial cells. The inclusion body has a matrix, which is surrounded by a coat and is mistakenly called "chlamydozoa". Since then, there have been many studies. However, the pathogen of trachoma was not isolated for the first time in 1955 by the method of chicken embryo culture in China, such as Tang Feifan and Zhang Xiaolou. Since this pathogen can pass through a bacterial filter, parasitizes into cells, and forms inclusion bodies, it was considered a virus at that time. Because it is different in size and shape from the general virus, it is called atypical or large virus, similar to the large virus of parrot fever and lymphogranuloma. Since then, scholars from various countries have further studied its molecular biology and metabolic functions, and proved that it has RNA, DNA and certain enzymes, which are multi-divided, have cell membranes and walls, and are sensitive to bacteria. These are not compatible with viruses. The nature, and there are many similarities with Gram-negative bacteria. Therefore, the "Bergey Bacterial Identification Manual" published in 1974 has set a new name for this type of microorganism, called chlamydia. Chlamydia trachomatis is one of them.

(two) pathogenesis

Chlamydia trachomatis easily invades columnar epithelial cells such as urethra, endocervix, endometrium, fallopian tube epithelium, eye, nasopharyngeal and rectal mucosa and causes lesions, does not invade the vaginal squamous epithelium, so it only parasitizes the vagina after infection but does not cause Vaginitis. In general, the body's reaction is mild and often asymptomatic and there is no acute phase in the clinic. In addition to the lesions caused by chlamydia itself, the body's immune response is also involved in the pathogenesis. LPS on the chlamydial membrane can induce the body's immune response, and its metabolites can also cause the body's allergic reaction, but the pathogen can parasitize into the cells to escape immune defense. Pathogens continue to infect and multiply in cells, and continue to infect new cells, causing repeated infections in the human body. In acute infection, the local is mainly a neutral multinucleated cell reaction, and chronic or reinfection causes a monocyte reaction. Long-term repeated inflammatory lesions, combined with the body's immune response, can lead to scar formation.

an examination

Related inspection

Chlamydia trachomatis challenge test

The incubation period is 5 to 14 days, and the eyes are sick, mostly in children or in a small period. Light trachoma can be completely free of symptoms or only slight itching, foreign body sensation and small amount of secretions. The severe cases involve the cornea due to sequelae and complications, and there are irritating symptoms such as light, tearing, pain, and conscious vision loss.

Chlamydia trachomatis mainly invades the palpebral conjunctiva and ends up with scar formation. The characteristics of the inspection are as follows:

1, blood and blood vessel blurred: due to vasodilatation, diffuse lymphocytes and plasma cells under the conjunctival epithelium infiltrated with chronic inflammatory cells, making the transparent conjunctiva become turbid and hypertrophic, the blood vessels are unclear, showing a fuzzy congestion.

2, nipple hypertrophy: , , , ,

3, filter hyperplasia: is the conjunctival subepithelial tissue on the basis of diffuse infiltration, formed by confined lymphocytes. At the initial onset, the upper conjunctiva appears scattered in the fine yellow-white dots, not prominent on the surface of the conjunctiva, and is intermingled between the hypertrophic nipples, which is one of the early diagnosis of trachoma.

4, corneal vasospasm: in the conjunctival lesions, at the same time, the upper half of the corneal gray area of the corneal vascular network is congested, new blood vessels occur, extending into the transparent corneal epithelium and the front elastic layer, accompanied by new blood vessels Gray-white spotted infiltration, is a tissue reaction of the corneal epithelium on Chlamydia trachomatis, called corneal vasospasm. It is one of the basis for early diagnosis of trachoma. As the disease progresses, the vasospasm hangs down to the pupil area, which resembles a drape. When the upper vasospasm passes down the pupil area, the other parts of the cornea also grow out of the vasospasm to the center, spreading the entire cornea. When the cells are infiltrated severely, hypertrophic meaty vasospasm can form. (pannus crassus), seriously affecting vision.

5, scar formation: When trachoma for several years or even decades, all inflammatory lesions such as follicles, nipples, will occur ulceration or necrosis, and gradually replaced by connective tissue, forming scars, which indicates that the lesion has entered the regression period. The course of trachoma varies depending on the severity of the infection and whether it is repeated infection. Light or no recurrent infection, the number of months can be more, the conjunctiva remains thin or no obvious scars. Repeated infections can last for years to decades.

Differential diagnosis

The sputum conjunctiva appears as an off-white membrane: the appearance of an off-white film on the palpebral conjunctiva can be seen in various types of conjunctivitis, usually caused by infectious factors. Due to leakage and bleeding of the new blood vessels, scars are formed eventually, forming a permanent mechanical film.

The hard and flat nipple of the conjunctiva: due to the clinical manifestations of catarrhal conjunctivitis in the spring, the conjunctival hyperemia is very dramatic at the beginning, and then many hard and flat nipples occur in the upper conjunctiva, varying in size. It is covered with pebbles on the conjunctiva. The crack between the nipples is light blue, and the surface of the nipple presents a milky turbidity. There are not many secretions, it is very sticky, and it is drawn into a filament. For smear examination, it can be seen that eosinophils increase. If there is a lesion in the conjunctiva of the lower jaw, the nipple is small and small, and it is not as prominent as the conjunctiva. Spring vernal conjunctivitis is an allergic disease with a strong seasonality and often invades both eyes. Whenever the spring blossoms, the symptoms disappear and the symptoms disappear when the cold is late in the autumn. Recurrence every year, mild cases will not be issued after 3 to 4 years, severe cases can continue to relapse for more than 10 years. The disease is characterized by itchy eyes, large and flat nipples and conjunctival hyperplasia near the limbus, and a large number of eosinophils in the secretion.

The huge nipple of the palpebral conjunctiva: The nipple hyperplasia of the palpebral conjunctiva caused by diseases such as keratoconjunctivitis in spring, which is the giant nipple of the conjunctiva, is one of the clinical manifestations of spring conjunctivitis.

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