Pathology of trachoma

2021-02-02 12:00 AM

Trachoma is a chronic inflammation of the conjunctiva and cornea. The causative agent is Chlamydia Trachomatis, but there are many other microbial agents involved in the disease.

General situation of trachoma

In the world

Trachoma dates back to BC and once existed in almost every region of the world:

China, Egypt, Greece, Rome in the 27th, 19th, 5th, and 1st centuries BC.

Islamic countries (the Middle East) in the Middle Ages.

England and France in the Napoleonic period.

Trachoma is currently a major public health problem in at least 46 developing countries (rates between 10-40% in Africa and 3-15% in some parts of Asia).

According to the World Health Organization, there are about 500 million people suffering from trachoma, about 146 million people are suffering from trachoma and about 6 million people are blind due to trachoma (1995).

Countries with active trachoma also account for a high proportion (from over 20-50%) and still have many complications: some countries in North Africa, China, and Southeast A.

Trachoma in Vietnam

Since the beginning of the 20th century, trachoma has been seriously prevalent throughout Vietnam, with many complications, mainly eyesight and fur. The rate of trachoma in 1947-1951 was 85.6%. After 1954, the rate of trachoma was 81% (30% with complications, 0.22% with binocular blindness). In 1986, the rate of active trachoma was 20% (binocular blind rate was 0.17% in the population).

In recent years, Vietnam Ophthalmology has had many achievements in the prevention of trachoma: reducing the trachoma rate and its complications. Although no longer a top priority in the prevention of blindness, trachoma remains an important issue. Trachoma is also of a social nature and is also a cause of blindness.

According to the results of the epidemiological investigation of blindness in 8 provinces in 2000-2002, corneal scarring caused by the ocular eye is the fourth cause of blindness in Vietnam (accounting for 2.7% of the total causes of binocular blindness).. According to domestic experts, currently, the active trachoma in Vietnam has been much reduced (Nam Dinh 1.2%, Ninh Binh less than 7%). Trachoma still exists in some places with the scale of commune or village level in the Northern Delta and Midlands (Muong Lo Yen Bai 14%, Vinh Phuc 14%). In many other places, there are still many remains due to the old trachoma in people over 50 years old. Therefore, the Ophthalmology Department and the Ministry of Health have set a goal to eliminate trachoma causing blindness in Vietnam by 2010.

Define

Trachoma has been known since ancient times, the word Trachoma is derived from the Greek word meaning roughness and swelling in the upper cartilage conjunctiva.

Since 1981 the World Health Organization defines trachoma as follows:

Trachoma is a chronic inflammation of the conjunctiva and cornea.

The causative agent is Chlamydia Trachomatis, but there are many other microbial agents involved in the disease. In the infectious and inflammatory stage, the disease is characterized by the presence of special particles (granules), accompanied by a strong diffuse infiltration, papillae enlargement in the conjunctiva and the development of blood vessels on the cornea. cornea.

The disease usually appears at a young age. The disease lasts if left untreated or superinfection.

The basic lesions of trachoma

Trachoma causes damage to the conjunctiva and cornea.

The basic lesions of trachoma on the conjunctiva

Infiltration: Penetration of inflammatory cells, mainly lymphoid cells, into the follicular organization of the conjunctiva. Infiltration causes the conjunctiva to become red and thick, obscuring blood vessels.

Seed: seed usually appears in the upper eyelid cartilage conjunctiva, can be found in the lower eyelid conjunctiva and in the same map, irregular size, from 0.5 - 1mm.

The seed progresses through the following stages: the young seed - the developed seed - the fragile ripe seed forms a scar (Figure 1). There is no trachoma in infants during the first 3 months.

Scarring: Scarring on the conjunctiva is small white fibrous fragments, scar bands, reticular star. Scarring causes stretching of clothes - eyelashes in.

Papillary: Polygonal block has clear boundaries, between the papillae mass has a bunch of capillaries. The papillae appear during a period of prolonged inflammation or with constant irritation in the conjunctiva. Papillae are not a specific factor in trachoma.

Figure: Granules on the conjunctiva.

 

The basic lesions of trachoma on the cornea

Infiltration: Penetration of inflammatory cells into the superficial, superficial layer of the cornea. The post-infiltration stage makes the cornea grey.

Seed: Usually at the upper extremity, from 2 to 5 seeds. The seed on cornea regression, causing scarring to form granular concave (Herbert's concave).

The seeds on the cornea have near absolute diagnostic value, appearing only in the prosperous forms of trachoma in the full-blown stage:

New vessels: From the peripheral vascular system penetrates the cornea often appears at the upper pole, in some cases, the entire corneal circumference.

 Membrane: A specific lesion of trachoma on the cornea, the membrane is usually localized in the shallow layer, in the upper part of the cornea (Figure 2). The membrane is caused by corneal infiltrates, trachoma (or granular sequelae: concave) and neovascularization.

The blood membrane has a very rich clinical manifestation with many morphs. The blood membrane always leaves sequelae. The blood membrane can cause vision loss.

Picture: Trachoma blood membrane

Stages of trachoma: 4 stages

Onset of the disease

Common in children aged 2 - 5 years old.

Lesions: usually young seed, developed seed.

Phase I usually lasts from 3 months to 2 years.

Full-play period 1-3 years

Many seeds grow, ripen, infiltrate, causing thick red conjunctiva.

On the cornea can see granules, blood membranes.

Regression period.

Little or no seed left.

Pervasive or localized infiltration. Scarring a lot. This stage lasts many years, causing complications.

 Only scars on the conjunctiva, cured.

Classify

Purpose

Trachoma is a chronic disease, progressing in stages, and the clinical form is also different.

Evaluate the situation, develop a plan to prevent trachoma.

Evaluate treatment results.

Classification table

There are two classification tables: a complete classification table for the provincial level (see ophthalmology book) and a simple one for the commune level.

I: Ia: On the dominant seed conjunctiva.

Ib: The dominant seed.

II: On the conjunctiva:

Seed development prevails. Ripe seeds can be re-cast.

On the cornea has granules, blood membrane.

III: IIIa: granular, diffuse infiltration, scarring.

IIIb: seedless, localized infiltrates, multiple scarring.

IV: Out of seed, all infiltrates, many scars.

A new classification of the World Health Organization (WHO).

Evaluate lesions in the upper cartilage conjunctiva according to 5 signs:

TF (Trachomatous inflammation Follicular): Trachomatous inflammation. There are at least 5 seeds in the central area, the size of which is larger than 0.5mm.

TI (Trachomatous inflammation - Intense): Strong trachoma. Thick red conjunctiva, more than half of conjunctival blood vessels are obscured by inflammatory cell infiltrates (TF cover).

TS (Trachomatous Scarring): Scarring of the trachoma due to trachoma. Scarring on the conjunctiva are white fibrous segments, scar bands, star shapes, networks.

TT (Trachomatous Trichiasis): Feather. Have 1 or more sagging hairs brushed on the eyeballs, or the patient has just pulled the hair out.

CO (Corneal Opacity): Corneal scars that obscure or obscure pupils.

Evaluate:

The WHO classification of trachoma does not divide trachoma into periods, but divides trachoma into two categories:   

Active trachoma consists of TF and TI. TF is mild and moderate trachoma. TI is serious trachoma.

If the TF ratio is over 20%, TI over 5% in children under 10 years old, it is necessary to actively treat:

Trachoma with complications or sequelae:

TS: Trachoma has caused scarring.

TT: Complicated trachoma

CO: Trachoma can cause blindness.

Progression of trachoma

Trachoma on its own: Meet in the trachoma mild, burning stage. Tr Ia trachoma, hygiene to prevent disease, coordinate anti-inflammatory.

Superinfection trachoma: Severe disease, deep infiltration, many complications. May progress according to rules, or with clinical fluctuations.

Complications of trachoma

Combined conjunctivitis, blepharitis: Conjunctivitis, hormonal (red, lumpy), thick red eyelashes, cracked eyes (big eyes).

Ruffled feathers.

Lashes: There are a few lashes that brush against the eyeballs.

Feather: Thick cartilage, roll-shaped trough, a lot of hair, free edge of eyelashes is worn out.

Corneal ulcers: dizziness, photophobia, watery eyes. Edge convergence. Ulcers on the cornea.

Corneal scarring: impaired vision.

Vaginal obstructive inflammation, purulent inflammation: Watering eyes, pressing the inner corner with pus discharge.

Photo: Feather

Dry eyes: Completely reduced or absent tears. The conjunctiva loses the ball, frills. The cornea loses its shade, becomes cloudy.

Clinical diagnostic criteria for trachoma

The seed on the upper cartilage conjunctiva: only granular in the central region, not the granule in the two hippocampus and supernatant margins. It is necessary to distinguish the seeds from the limestone, the small capsule and the joinery.

Typical scarring on the upper eyelid cartilage conjunctiva. It should be differentiated from scarring caused by burns or scarring in pseudomembranous conjunctivitis.

Seed in the extreme upper margin or seed sequelae (seed concave).

Membrane blood on the cornea.

Need 2 out of 4 criteria for the definitive diagnosis of trachoma. In the high ratio trachoma areas, only 1 in 4 criteria is needed.

Subclinical trachoma

Cytology: Granular injection or slight curettage of the upper cartilage conjunctiva for cytological examination, can see: 

Inclusion in epithelial cytoplasm (CPH (+))

Young, missed old lymphocytes.

Lebar macrophages.

Degeneration of epithelial cells.

Differential diagnosis

Trachoma: Seeds of equal age, unbroken.

Spring conjunctivitis: Is allergic conjunctivitis. Lesions are large, flattened, polymorphic papillae (like paving stones) in the upper eyelid cartilage conjunctiva.

In commune health facilities, trachoma classification according to 5 signs of the World Health Organization is used to diagnose and classify trachoma.

Causes and epidemiology of trachoma

Trachoma agent

In 1907, two authors, Von Prowareck and Halberstaedler, found in the epithelial cells of people with trachoma to have assemblies of many small dots called the PH body. When Giemsa stained it was found that the PH bodies were close to the nucleus, in the protoplasm of the cell. The PH body is a collection of many microelements (CI: from 0.5 to 1 micron) in the centre of the PH body with smaller dots (CE from 0.23 to 0.5 micron).

The PH (CPH) form is common in the early stages of trachoma. According to Stepanova (1927), equitization (+) in TrI period: 76.21%, TrII: 65%. TrIII: 19%.

From 1907 to 1930 when Prowareck and Halberstaedler discovered the inclusions in the epithelial cells of the trachoma, the trachoma was assumed to be a large-sized virus.

From 1953 to 1960, the authors considered the trachoma to lie within the boundary between viruses and bacteria. The trachoma begins to be named Chlamydia. Trachoma chlamydia has bacteria and virus-like properties.

Virus-like characteristics:

The formation of inclusions in the protoplasm of epithelial cells.

The parasite is required to enter the cell (in the form of inclusion of CPH), to rely on the metabolism of the developing cell.

Can penetrate cell membranes.

Bacterial-like characteristics:

Reproduction according to the double mechanism.

There are 2 acids that multiply DNA and RNA.

Formation of cell membranes containing muramic acid.

Under the influence of some antibiotics and sulfamides.

Currently, Chlamydia trachomatis is a typical agent causing trachoma and urinary tract inflammatory diseases, a genitourinary tract in humans, belonging to the family Chlamydiaceae. Trachoma bacteria belong to the group of Gram-negative bacteria.

Epidemiology of trachoma

Ways of transmission of trachoma:

Patients with trachoma are caused by repeated infections with Chlamydia. Trachoma spreads easily, especially in children.

Age of disease:

In the most severe trachoma communities, most children get the disease at 1 to 2 years old (some 6 months old have the disease). Because children make up the majority of the population in areas with severe trachoma, children with active trachoma are the main carriers of transmission in the community.

Mode of transmission and risk factors for trachoma:

Trachoma can cause blindness or not completely blind depending on the interaction of three main factors: the host (human), environmental factors and pathogenicity of the agent Chlamydia trachomatis. In areas with good sanitation conditions, trachoma is mild, less contagious. The disease can be cured without causing blindness.

In areas where the sanitation and personal hygiene are poor, trachoma progresses and spreads strongly, causing serious complications causing blindness. These areas are called trachoma and trachoma is the trachoma that causes blindness.

Trachoma can be passed from person to person through the following ways:

Flies: Flies carry pathogens that are present in the eyes of infected people and enter the eyes of healthy people and transmit the disease (spread in the community).

Dirty towels, cloths: Towels that can catch the eyes of the sick person, if used together, will bring the bacteria into the healthy eye (spread at home).

Dirty fingers: Patients rubbing their hands on their eyes, using eyes with pathogenic bacteria will cling to them and accidentally move them to the other eye or wipe their hands-on other eyes, causing trachoma (self-transmission) on the other eye.

Family members: Trachoma transmission mainly occurs in families, especially children under 10 years old and women who are frequently exposed to the source of the disease.

Risk factors for trachoma:

For the living environment of the community:

Lack of clean water leads to dirty face, eyes that are abundant, hands are dirty, and clothes are dirty.

Dust causes the eyes to be stimulated to produce more energy.

Dirty: The environment has a lot of animal manure, human excrement, garbage will create conditions for flies to grow more.

For the home environment:

Exudates: Eye drops, runny nose and possibly genital secretions contain many pathogens that are easy to transmit the disease to others.

A large number of people living in the family: The more people living in a cramped house, the higher the likelihood of contact and infection between sick and healthy people.

Treat trachoma with medicine

Tetracycline ointment eye ointment 1%

Treatment continuously: eye application 2 times a day for 6 consecutive weeks.

Intermittent treatment: eye application 1 time in the evening before going to bed for 10 consecutive days for 1-month x 6 consecutive months. Or check 2 times / day x5 days for 1-month x 6 months.

Tetracycline 1% ointment eye ointment has the advantage of being easy to buy, inexpensive, can be applied to children under 1-year-old and pregnant women, but the downside is that the eye exam is prolonged, so it is difficult for the patient to do it properly.

Systemic antibiotic drugs:

Indicated in cases of severe trachoma.

Erythromycin 250 mg orally 4 capsules daily for 3 weeks.

Zithromax (Azithromycin) for active trachoma. Azithromycin is an antibiotic similar to erythromycin but better due to its strong penetration into the tissues, high concentration of the drug and prolonged with a single dose exactly once a year.

Trachoma treatment programs are mainly based on the maintenance of a mass ophthalmic antibiotic. Intensive and extensive initiation of drug therapy is likely to reduce the source of Chlamydia transmission in the eye among the population. Then continue to apply drugs intermittently in each family to control further the spread of Chlamydia from eyes to eyes.

Treatment of complications

Conjunctivitis, blepharitis.

Corneal ulcers.

Purulent cholecystitis: customary surgery of the nose.

Dry eyes: Apply medicine, artificial tears.

Morphology: This is a necessary and urgent treatment to prevent blindness caused by trachoma. If there are more than 5 hairs, the level of poking in the eye is not much, they do not have conditions to go to surgery immediately, they must regularly pluck the feathers and apply 1% tetracycline ointment daily and then go to surgery later. If there are 5 or more feathers, it is necessary to go to surgery immediately.

Ways and methods to prevent trachoma in public health

Subjects of trachoma in public health

Trachoma (trachoma causes blindness): chronic and lasting damage among people in a locality. Chlamydia Trachomatis spreads the disease and infects infected people. The difficult cycle ends. Complicated blind.

Simple trachoma: occurs sporadically. Progresses normally until the end of the pathological cycle, causes mild scarring, does not cause complications and is naturally cured.

Detecting trachoma disease

It is necessary to assess the prevalence and severity of trachoma through surveying the entire population, in coordination with local health workers.

Planning for treatment and prevention

OMS treatment regimen

Rate of children 1 - 10 years old with trachoma

Basic treatment

Additional treatment

TF ³ 20% and TI ³ 5%

Treatment of the whole

Systemic antibiotic treatment for severe cases

TF 5% ® 20%

Treatment: Collective or individual, family.

Treat as above

TF < 5%

Individual treatment

No need

 Collective treatment: All people, all families in the community are applied 1% Tetracycline ointment continuously 2 times / day for 6 weeks or interrupted 2 times / day x 5 days / 1 month / 6 months

Family treatment: when someone in the family has TF or TI. Tetracycline 1% ointment continuously or interrupted as collective treatment.

Since 2000, the Ophthalmology branch has implemented a SAFE trachoma prevention strategy.

S (Surgical correction for trichiasis):

A (Antibiotic): Antibiotic treatment of active trachoma cases.

F (Wash face): Wash face daily with clean water.

E (Environment): Improve sanitation and water supply.

Using the antibiotic Zithromax (Azithromycin) to treat active trachoma:

 Children from 1 to 5 years old: Drink Zithromax suspension.

 Children from 6 to 15 years old: Take Zithromax tablets (the oral dose is calculated according to the child's height).

 People over 16 years: Take a single dose (4 tablets of Zithromax).

Attention:

Do not give medicine to pregnant women and children under 1 year old.

Caution should be exercised in children weighing less than 8 kg.

Caution should be exercised in patients with severe renal and hepatic impairment.

Propaganda and education on prevention of trachoma in the community

Improve environmental sanitation to limit disease transmission and reinfection in families and communities, including the following:

Creating clean water supplies: Digging wells, making river water filter tanks ... to limit the spread of disease through using eyes, dirty hands, dirty cloth.

Build hygienic latrines, step up measures to kill flies.

Build a stable away from home (at least 10 meters).

Keep streets and villages clean, bury and incinerate waste.

Personal hygiene awareness education: Wash your face with clean water, do not share towels ...

In a family, there is a person with trachoma that needs treatment. If there is a rodent, it is necessary to have a grazing operation to avoid complications causing blindness.