| Trachoma | |
|---|---|
| Classification and external resources | |
Entropion and trichiasis secondary to trachoma |
|
| ICD-10 | A71 |
| ICD-9 | 076 |
| DiseasesDB | 29100 |
| MedlinePlus | 001486 |
| eMedicine | oph/118 |
| MeSH | D014141 |
Trachoma (Greek: τράχωμα, ‘roughness’) is an infectious disease causing a characteristic roughening of the inner surface of the eyelids. Also called granular conjunctivitis and Egyptian ophthalmia, it is the leading cause of infectious blindness in the world.[1] Globally, 41 million people suffer from active infection and nearly 8 million people are visually impaired as a result of this disease.
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Trachoma is caused by Chlamydia trachomatis and it is spread by direct contact with eye, nose, and throat secretions from affected individuals, or contact with fomites (inanimate objects that carry infectious agents, such as blankets and pillowcases), such as towels and/or washcloths, that have had similar contact with these secretions. Flies can also be a route of mechanical transmission. Untreated, repeated trachoma infections result in entropion—a painful form of permanent blindness when the eyelids turn inward, causing the eyelashes to scratch the cornea. Children are the most susceptible to infection due to their tendency to easily get dirty, but the blinding effects or more severe symptoms are often not felt until adulthood.
Blinding endemic trachoma occurs in areas with poor personal and family hygiene. Many factors are indirectly linked to the presence of trachoma including lack of water, absence of latrines or toilets, poverty in general, flies, close proximity to cattle, crowding and so forth.[2][3] However, the final common pathway seems to be the presence of dirty faces in children that facilitates the frequent exchange of infected ocular discharge from one child’s face to another. Most transmission of trachoma occurs within the family.[2]
The bacterium has an incubation period of 5 to 12 days, after which the affected individual experiences symptoms of conjunctivitis, or irritation similar to "pink eye." Blinding endemic trachoma results from multiple episodes of reinfection that maintains the intense inflammation in the conjunctiva. Without reinfection, the inflammation will gradually subside.[2]
The conjunctival inflammation is called “active trachoma” and usually is seen in children, especially pre-school children. It is characterized by white lumps in the undersurface of the upper eyelid (conjunctival follicles or lymphoid germinal centres) and by non-specific inflammation and thickening often associated with papillae. Follicles may also appear at the junction of the cornea and the sclera (limbal follicles). Active trachoma will often be irritating and have a watery discharge. Bacterial secondary infection may occur and cause a purulent discharge.
The later structural changes of trachoma are referred to as “cicatricial trachoma”. These include scarring in the eyelid (tarsal conjunctiva) that leads to distortion of the eyelid with buckling of the lid (tarsus) so the lashes rub on the eye (trichiasis). These lashes will lead to corneal opacities and scarring and then to blindness. Linear scar present in the Sulcus subtarsalis is called Arlt's line(named after Carl Ferdinand von Arlt). In addition, blood vessels and scar tissue can invade the upper cornea (pannus). Resolved limbal follicles may leave small gaps in pannus (Herbert’s Pits).
Most commonly children with active trachoma will not present with any symptoms as the low grade irritation and ocular discharge is just accepted as normal. However, further symptoms may include:
The major complication or the most important one is corneal ulcer occurring due to rubbing by concentrations, or trichiasis with superimposed bacterial infection.
1. McCallan's classification-McCallan in 1908 divided the clinical course of trachoma into 4 stages
| Stage 1 (Incipient trachoma) | Stage 2 (Established trachoma) | Stage 3 (Cicatrising trachoma) | Stage 4 (Healed trachoma) |
|---|---|---|---|
| Hyperaemia of palpebral conjunctiva | Appearance of mature follicle & papillae | Scarring of palpebral conjunctiva | Disease is cured or is not markable |
| Immature follicle | Progressive corneal pannus | Scars are easily visible as white bands | Sequelae to cicatrisation cause symptoms |
2. WHO classification-The World Health Organization recommends a simplified grading system for trachoma.[4] The Simplified WHO Grading System is summarized below:
• Trachomatous inflammation, follicular (TF) – Five or more follicles of >0.5 mm on the upper tarsal conjunctiva
• Trachomatous inflammation, intense (TI) – Papillary hypertrophy and inflammatory thickening of the upper tarsal conjunctiva obscuring more than half the deep tarsal vessels
• Trachomatous scarring (TS) - Presence of scarring in tarsal conjunctiva.
• Trachomatous trichiasis (TT) – At least one ingrown eyelash touching the globe, or evidence of epilation (eyelash removal)
• Corneal opacity (CO) – Corneal opacity blurring part of the pupil margin
Although trachoma was eliminated from much of the developed world in the last century, this disease persists in many parts of the developing world particularly in communities without adequate access to water and sanitation. In many of these communities, women are three times more likely than men to be blinded by the disease, due to their roles as caretakers in the family.[5]
Without intervention, trachoma keeps families shackled within a cycle of poverty, as the disease and its long-term effects are passed from one generation to the next.
National governments in collaboration with numerous non-profit organizations implement trachoma control programs using the WHO-recommended SAFE strategy, which includes:
Surgery: For individuals with trichiasis, a bilamellar tarsal rotation procedure is warranted to direct the lashes away from the globe.[6] Early intervention is beneficial as the rate of recurrence is higher in more advanced disease.[7]
Antibiotic therapy: WHO Guidelines recommend that a region should receive community-based, mass antibiotic treatment when the prevalence of active trachoma among one to nine year-old children is greater than 10 percent.[8] Subsequent annual treatment should be administered for three years, at which time the prevalence should be reassessed. Annual treatment should continue until the prevalence drops below five percent. At lower prevalences, antibiotic treatment should be family-based.
Antibiotic selection: Azithromycin (single oral dose of 20 mg/kg) or topical tetracycline (one percent eye ointment twice a day for six weeks). Azithromycin is preferred because it is used as a single oral dose. Although it is expensive, it is generally used as part of the international donation program organized by Pfizer through the International Trachoma Initiative.[9] Azithromycin can be used in children from the age of six months and in pregnancy.[2]
Facial cleanliness: Children with grossly visible nasal discharge, ocular discharge, or flies on their faces are at least twice as likely to have active trachoma as children with clean faces.[2] Intensive community-based health education programs to promote face-washing can significantly reduce the prevalence of active trachoma, especially intense trachoma (TI). If somebody is already infected washing one’s face is strongly encouraged, especially a child, in order to prevent re-infection.[10]
Environmental improvement: Modifications in water use, fly control, latrine use, health education and proximity to domesticated animals have all been proposed to reduce transmission of C. trachomatis. These changes pose numerous challenges for implementation. It seems likely that these environmental changes ultimately impact on the transmission of ocular infection by means of lack of facial cleanliness.[2] Particular attention is required for environmental factors that limit clean faces.
According to an online news article posted on Wednesday, December 21, 2011, by Leland Kim of the University of California at San Francisco (UCSF) News Center,: "A UCSF study shows a popular treatment for a potentially blinding eye infection is just as effective if given every six months versus annually. This randomized study on trachoma, the leading cause of infection-caused blindness in the world, could potentially treat twice the number of patients using the same amount of medication. “The idea is we can do more with less,” said Bruce Gaynor, MD, assistant professor of ophthalmology at the Francis I. Proctor Foundation for Research in Ophthalmology. “We are trying to get as much out of the medicine as we can because of the cost and the repercussions of mass treatments.” In a paper published this month in The Lancet, researchers conducted a cluster-randomized trial, using an antibiotic called azithromycin to treat trachoma in Ethiopia, which has among the highest prevalence in the world. They picked 24 communities and randomized the two treatment options: 12 villages were given azithromycin every six months and the other 12 were treated every 12 months. “What we found was the prevalence of trachoma is very high at baseline. Forty to 50 percent of the children in these communities have this condition,” Gaynor said. “They are the most susceptible and it can quickly spread from person to person by direct or even indirect contact.” Researchers tracked both groups and found the prevalence of infection decreased dramatically. “We found that from as high as 40 percent, the prevalence of trachoma went way down, even eliminated in some villages regardless of whether it was treated in an annual way or a biannual way,” Gaynor said. “You can genuinely get same with less.” Their finding is significant because of how easily the disease spreads (through various modes of easy transmission). ..."[11]
If not treated properly with oral antibiotics, the symptoms may escalate and cause blindness, which is the result of ulceration and consequent scarring of the cornea. Surgery may also be necessary to fix eyelid deformities.
The disease is one of the earliest known eye afflictions, having been identified in Egypt as early as 15 B.C.[2]
Its presence was also recorded in ancient China and Mesopotamia. Trachoma became a problem as people moved into crowded settlements or towns where hygiene was poor. It became a particular problem in Europe in the 19th Century. After the Egyptian Campaign (1798–1802) and the Napoleonic Wars (1798–1815), trachoma was rampant in the army barracks of Europe and spread to those living in towns as troops returned home. Stringent control measures were introduced and by the early 20th Century, trachoma was essentially controlled in Europe, although cases were reported up until the 1950s.[2] Today, most victims of trachoma live in underdeveloped and poverty-stricken countries in Africa, the Middle East, and Asia.
In the United States, the Centers for Disease Control says "No national or international surveillance [for trachoma] exists. Blindness due to trachoma has been eliminated from the United States. The last cases were found among Native American populations and in Appalachia, and those in the boxing, wrestling, and sawmill industries (prolonged exposure to combinations of sweat and sawdust often lead to the disease). In the late 19th century and early 20th century, trachoma was the main reason for an immigrant coming through Ellis Island to be deported." [12][13]
In 1913, President Woodrow Wilson signed an act designating funds for the eradication of the disease.[14][15] Immigrants who attempted to enter the U.S. through Ellis Island, New York had to be checked for trachoma.[12] During this time treatment for the disease was by topical application of copper sulfate. By the late 1930s, a number of ophthalmologists reported success in treating trachoma with sulfonamide antibiotics.[16] In 1948, Vincent Tabone (who was later to become the President of Malta) was entrusted with the supervision of a campaign in Malta to treat trachoma using sulfonamide tablets and drops.[17]
Although by the 1950s, trachoma had virtually disappeared from the industrialized world, thanks to improved sanitation and overall living conditions, it continues to plague the developing world. Epidemiological studies were also conducted in 1956-63 by the Trachoma Control Pilot Project in India under the Indian Council for Medical Research.[18] This potentially blinding disease remains endemic in the poorest regions of Africa, Asia, and the Middle East and in some parts of Latin America and Australia. Currently, 8 million people are visually impaired as a result of trachoma, and 41 million suffer from active infection.
Of the 54 countries that WHO cited as still having blinding trachoma occurring, Australia is the only developed country. Australian Aboriginal people who live in remote communities with inadequate sanitation are still blinded by this infectious eye disease.[19]
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