TRACHOMA

Trachoma is a form of chronic keratoconjunctivitis that is one of the leading causes of infectious blindness worldwide though its prevalence is restricted to the Middle East. It is caused by Chlamydia trachomatis (Serogroup A,B, C)  which is an obligate intracellular parasite. It commonly occurs in children and women in areas with poor sanitary conditions making the spread through direct contact and fomites very easy.

PATHOPHYSIOLOGY:

Chlamydial infections characteristically occur in the upper part of the eyelid and the eyeball. It causes a typical follicular conjunctivitis as seen in other viral infections but the difference is that it has a higher chance of producing scarring because of reinfection.

Trachomatous follicles

Pannus formation

           The process behind the drastic sequel of blindness is the scarring or cicatrisation that occurs in the palpebral conjunctiva that eventually leads to contracture and buckling of the eyelids causing an entropion or rolling in of the eyelid in the margins along with trichiasis, the introversion of eyelashes. All these changes in the usually smooth conjunctiva is going to damage the conjunctiva in the form of abrasion, ulcers and eventually corneal opacities that is going to cause a permanent blindness.

Entropion

CHARACTERISTIC FINDINGS:

•      Trachomatous follicle: Greater than 0.5mm in size and distributed in the upper tarsal plate                      quite unlike the other follicles in viral conjunctivitis
•      Cictrazation of the follicles seen as stellate scars on the tarsal plate
•      Arlt line: A linear scar present in the jumction of upper one third and lower two thirds of the tarsal plate
•      Trachomatous pannus which is an area of vascularization and lymphatic infiltration into the cornea, seen as an area of cloudiness in the upper part of the cornea. It may occur in the form of a progressive or regressive pannus based on the extent of blood vessels
•      Heber pits: Follicles near the limbus.
•      Corneal ulcers or opacities in the later stages

STAGES:

WHO classifies trachoma into the following 4 stages abbreviated as ‘FISTO’

F (follicles) : 5 or more trachomatotous follicles in the upper tarsal plate

I (Intense): Intense inflammation with follicles and papillae such that more than 50% of the tasal   blood vessels are not visible

S (Scarring): Cicatrisation with formation of white fibrous bands seen

T (Trichiasis)

O (Opacity)

SIGNS AND SYMPTOMS:

•      Redness
•      Watery discharge
•      Irritation
•      Photophobia
•      Foreign body sensation
•      Trachomatous ptosis
•      Entropion
•      Trichiasis
•      Pannus formation
•      Visual impairment

TREATMENT:

Tetracycline or Azithromycin ointment should be administered before the onset of scarring. Prophylactic use of these drugs valuable in endemic areas.