Greek: trachôma, trachus - "rough"
Conjunctivitis (granulosa) trachomatosa, trachomatous inclusion conjunctivitis, Egyptian granulomatosis, Egyptian ophthalmia, conjunctival conjunctivitis
Trachoma is a chronic conjunctivitis caused by the bacterium Chlamydia trachomatis, which often leads to blindness.
Trachoma is very rare in Europe and is notifiable here. However, it is still one of the most common causes of blindness in India, Africa and southern Mediterranean developing countries, affecting about 4% of the population and the most common infectious cause of blindness in the world. Alone in Egypt, China and India, there are about 500 million sufferers.
After the initial infection with C. trachomatis, which primarily affects infants in endemic areas, nonspecific, weeping (serous) conjunctivitis with a foreign body sensation develops within 5-7 days. Soon thereafter, large granular accumulations of inflammatory cells ( follicles ) form on the conjunctiva (conjunctiva) of the upper lid, which look gelatinous, enlarge massively and finally burst open. In this way, the infectious fluid (secretion) trapped in the follicles expands to the outside. After the bursting of the follicles, scars develop, which leads to a shrinkage of the conjunctiva of the upper lid, causing the upper row of eyelashes to be drawn inwards (entropion). By the mentioned follicles, the surface of the conjunctiva of the upper lid appears rough, whence comes the name Trachoma.
The inflammation affects the conjunctiva and the transitional fold, but not the conjunctiva above the eyeball ( bulbar conjunctiva ). The nodular elevation ( carunculus ) and the conjunctival fold in the nasenseitigen corner of the eye ( plica semilunaris ) are often clearly swollen. From the upper edge of the cornea a gelatinous, follicular haze over the cornea ( cornea ) grows. This opacity is called "pannus from above" or pannus on the eye.
The entropion rubs the eyelashes on the cornea ( trichiasis ) and produces a corneal ulcer ( corneal ulcer ).
The terminal stage of a severe trachoma is a porcelain-like corneal scar consisting of degenerated (metaplasied) conjunctival and corneal cells with few blood vessels. It is caused by dehydration of the eyeball surface and recurring (recurrent) erosions. The advanced stages as well as the final stage of the disease develop over several years.
The World Health Organization ( WHO ) suggests the classification of the trachoma into 5 clinical stages based on the severity of the symptoms:
In addition, it can always come to a superinfection by bacteria such as Haemophilus, Moraxella, pneumococci and streptococci, which can aggravate the disease in the trachoma, both primary and chronic at any time.
The diagnosis of the trachoma is made on the basis of the symptoms, ie the clinical picture.
In addition, a microbiological diagnosis can be carried out: Direct microscopic detection is possible by immunofluorescence. The Chlamydia are stained with fluorescence-labeled antibodies and made visible. More costly and more expensive, but safer, is the DNA detection by DNA amplification by polymerase chain reaction ( PCR ). The test material consists of conjunctival cells, the recovery of which is very painful for the patient.
Systemic or local intracellular antibiotics are used to treat the trachoma. The WHO recommends local therapy with tetracyclines. Also possible is therapy with azithromycin, which is more expensive.
Scarring surgery should be performed to remove entropion and trichiasis. An operative restoration of the cornea (keratoplasty) has little chance of success in the end stage of a severe trachoma.
In most cases, the therapeutic options of trachoma are very limited due to the socioeconomic standard in the countries concerned.
The causative agent of trachoma is the gram-negative bacterium Chlamydia trachomatis, which belongs to the family Chlamydia. It comes in two different forms:
Outside a host cell, it exists as a very resilient elementary body ( EK ) with a diameter of 0.25-0.3 μm. In this form, the bacterium infects the host cell. Upon ingestion by the cell, the elementary bodies are trapped in vacuoles that protect them from cell degeneration. In these inclusions, the elementary bodies transform into reticulate bodies ( RK ), which have their own metabolism, and begin to multiply by division. After 2-3 days, the host cell disappears, the chlamydia, which meanwhile have ripened back to elementary bodies, become free and can then attack other cells.
The transmission of Chlamydia trachomatis occurs mainly by smear infection, a direct transmission of pathogens by contact, within close communities, for example, when sharing towels. They can also be transmitted by flies and insects that settle in the inner angle of the eyelids and cause inflammation in malnourished, weakened children and adults. Lack of hygiene plays a crucial role. In the population groups of tropical countries, which live by a sufficient water supply under good hygienic conditions, the trachoma practically does not occur anymore.
In the scar stage, the disease is hardly contagious. A permanent immunity does not arise.
Chlamydia trachomatis (trachoma) is the causative agent of two forms of conjunctivitis:
In countries with good hygienic conditions, such as Central Europe, serotypes D-K cause adult chlamydial conjunctivitis ("inclusion body conjunctivitis"), in countries with poor hygienic conditions serotypes A-C cause trachoma, often beginning in childhood.
The transmission by smear infection (trachoma) can be achieved by appropriate hygiene measures, eg. As hygienic hand disinfection with 70% alcohol, are largely prevented. Contact lens wearers must be informed about the possible dangers of contact lenses ( corneal injuries with superinfection ) and trained in proper cleaning and storage.
Lack of hygiene in underdeveloped countries favor the occurrence of the trachoma. Only by improving the infrastructure, adequate water supply and improved hygienic conditions (eg washing the face once a day) can the frequency of the trachoma be reduced.
The prognosis of the trachoma depends on the stage of the disease. The prognosis is good if treatment is started at an early stage. A blindness occurs only when the disease is not treated for years and it often comes to re-infection.
The term chlamydia is derived from chlamys ( gr. The mantle ).
A description of a trachoma-like disease (trachoma) of the human eye is already found in ancient traditions. 1907 was the first description of Chlamydia trachomatis by Ludwig Halberstadter ( born 1876 in Beuthen, Upper Silesia, † 1949 in New York City ) and Stanislaus of Prowazek ( * 1875 Czech Republic, † 1915 in Cottbus ). They were able to show that the clinical picture of trachoma is experimentally transferable from humans to apes: They identified vacuoles in cells from smears of the conjunctiva ( conjunctiva ) by means of a specific staining technique, the Giemsa stain, which they interpreted as the cause of the trachoma. In subsequent years, similar inclusion bodies were found in conjunctival necrosis of the neonates with conjunctivitis, in cervical smears of their mothers, and in urethral swab of males. Due to their lack of culturing on artificial nutrient media, their small size and their purely intracellular multiplication, the pathogens were mistakenly classified as viruses. Thanks to cell culture techniques and electro-microscopy, it became clear in the mid-1960s that chlamydia is not bacteria but bacteria. Thus they were recognized 1966 as Chlamydiales own order of the bacteria.